MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Radiological Physics and Technology' source. Sun, 21 Mar 2010 17:14:56 +0100 http://www.medworm.com/index.php?rid=3377871&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F8150r84660632067%2F Abstract  An energy-discrimination K-edge X-ray computed tomography (CT) system is useful for increasing the contrast resolution of a target region by utilizing contrast media. The CT system has a cadmium telluride (CdTe) detector, and a projection curve is obtained by linear scanning with use of the CdTe detector in conjunction with an X-stage. An object is rotated by a rotation step angle with use of a turntable between the linear scans. Thus, CT is carried out by repetition of the linear scanning and the rotation of an object. Penetrating X-ray photons from the object are detected by the CdTe detector, and event signals of X-ray photons are produced with use of charge-sensitive and shaping amplifiers. Both the photon energy and the energy width are selected by use of a m... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3377871 Tue, 16 Mar 2010 14:53:00 +0100 3377871 http://www.medworm.com/index.php?rid=3315968&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F83167154338117r3%2F Abstract  The influence of age and physique on dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) was investigated in young, middle-aged, and older women. The validity of the bilateral calcaneal QUS values was investigated regarding the bone mineral density (BMD) values on DXA of the lumbar spine, left femoral neck, and left femur as the optimal standards. The subjects were 55 young women (19.6 ± 1.0 years), and 152 middle-aged and older women (62.9 ± 7.2 years). The BMD on DXA was significantly correlated with the bone strength on QUS in both young and middle-aged or older women, but the positive likelihood ratios of the standard QUS values recommended by the manufacturer to the optimum standards on DXA were low, suggest... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3315968 Fri, 26 Feb 2010 16:44:27 +0100 3315968 http://www.medworm.com/index.php?rid=3315969&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fyg723wv17h65pk10%2F This study shows that different sequences and different T I and T S values can have an effect on the correlation between the SI and concentration. Regardless of the values of T I, T S, and the different IR and SR sequences chosen, the linear relationship between the SI and concentration was about twice that previously reported (i.e., 0.8 mmol/L, R 2 = 0.95). Content Type Journal ArticleDOI 10.1007/s12194-010-0087-9Authors Mahmood Nazarpoor, Tabriz University of Medical Sciences Department of Radiology, Faculty of Paramedicine Tabriz Iran Journal Radiological Physics and TechnologyOnline ISSN 1865-0341Print ISSN 1865-0333 (Source: Radiological Physics and Technology) Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3315969 Fri, 26 Feb 2010 16:44:25 +0100 3315969 http://www.medworm.com/index.php?rid=3306288&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fw52653l5874k8445%2F Content Type Journal ArticleCategory ErratumDOI 10.1007/s12194-010-0085-yAuthors Tomoya Nakamura, Tokai University Hachioji Hospital Department of Radiology 1838 Ishikawa Hachioji 192-0032 JapanTosiaki Miyati, Kanazawa University Division of Health Sciences, Graduate School of Medical Science 5-11-80 Kodatsuno Kanazawa 920-0942 JapanHarumasa Kasai, Nagoya City University Hospital Department of Radiology 1 Kawasumi, Mizuho, Mizuho-ku Nagoya 467-8602 JapanNaoki Ohno, Kanazawa University Division of Health Sciences, Graduate School of Medical Science 5-11-80 Kodatsuno Kanazawa 920-0942 JapanMasato Yamada, Nagoya City University Hospital Department of Radiology 1 Kawasumi, Mizuho, Mizuho-ku Nagoya 467-8602 JapanMitsuhito Mase, Nagoya City University Graduate School of Medical Sciences Depa... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3306288 Tue, 23 Feb 2010 08:08:50 +0100 3306288 http://www.medworm.com/index.php?rid=3306287&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fe7vv2242231qh716%2F Abstract  The aim of the study was to evaluate the perturbation correction factors at a reference depth for cylindrical ionization chambers in high-energy electron beams by means of the EGSnrc Monte Carlo user code cavity. The cylindrical chambers used in this study were the Farmer-type of PTW30010, PTW30011, PTW30012, and PTW30013 models. We calculated the wall correction factor, P wall, the cavity or electron fluence correction factor, P cav, the stem correction factor, P stem, the central electrode correction factor, P cel, and the overall perturbation correction factor, P Q, for each chamber. The calculated P cav values were higher by from 2 to 1% than those recommended by the IAEA-TRS-398 code of practice, in an energy range of 6–18 MeV. The P wall values al... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3306287 Tue, 23 Feb 2010 08:08:50 +0100 3306287 http://www.medworm.com/index.php?rid=3243257&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fh174x37274162061%2F Abstract  In order to evaluate the usefulness of a metal oxide-silicon field-effect transistor (MOSFET) detector as a in vivo dosimeter, we performed in vivo dosimetry using the MOSFET detector with an anthropomorphic phantom. We used the RANDO phantom as an anthropomorphic phantom, and dose measurements were carried out in the abdominal, thoracic, and head and neck regions for simple square field sizes of 10 × 10, 5 × 5, and 3 × 3 cm2 with a 6-MV photon beam. The dose measured by the MOSFET detector was verified by the dose calculations of the superposition (SP) algorithm in the XiO radiotherapy treatment-planning system. In most cases, the measured doses agreed with the results of the SP algorithm within ±3%. Our results demonstrated ... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3243257 Wed, 03 Feb 2010 06:56:13 +0100 3243257 http://www.medworm.com/index.php?rid=3207943&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fp3724g1n419x7551%2F Abstract  A nationwide survey was conducted on electron accelerators for radiation therapy in Japan for obtaining fundamental data on the actual operational situation of these accelerators. The research subjects were all medical institutions equipped with electron accelerators for radiation therapy (874 accelerators) in Japan. Postcards explaining the purpose and procedure of the survey were sent to each institution. Each institution was requested to download a questionnaire from the website and return it by e-mail. We obtained the following results. Energy: about 90% of the accelerators did not exceed 10 MeV as the permitted maximum energy. Beam intensity: a total of 94% of the accelerators did not exceed 4 Gy/min as the mean exposure dose rate. Beam time: a tota... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3207943 Fri, 22 Jan 2010 02:11:23 +0100 3207943 http://www.medworm.com/index.php?rid=3128794&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F937l4g48914l58u0%2F In this study, we investigated the processes of energy deposition by considering interactions including the nuclear reactions between protons and water molecules by a Monte Carlo simulation for proton therapy. We estimated the number of particles produced by a variety of nuclear reactions, and we focused on the interaction in the low-energy region (below 1 MeV). Furthermore, we considered the charge-changing processes in the low-energy region (less than a few hundred keV). Finally, we evaluated the total dose and the contribution of primary protons and secondary particles through nuclear reactions to the absorbed dose. The results showed that the protons generate numerous neutrons via nuclear reactions. Particularly, neutrons with relatively low energies produce recoil protons b... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3128794 Mon, 28 Dec 2009 07:12:47 +0100 3128794 http://www.medworm.com/index.php?rid=3123329&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fn06673j012353967%2F Abstract  Our purpose in this study was to evaluate the preliminary clinical efficacy of soft-copy reading of digital mammography, for a 15-mega-sub-pixel (MsP) and a 9-MsP super-high-resolution liquid-crystal display (SHR-LCD) by use of an independent sub-pixel driving technology. We performed three kinds of phantom observation studies by six radiological technologists. Detectability of a contrast-detail phantom and simulated small objects (SSOs) resembling microcalcifications (MCLs), and shape discrimination ability of SSOs with round and square shapes, were examined and compared with a 5-MP conventional LCD (5-MP LCD). In each study, four types of display magnification ratio were used. The detectability and the shape discrimination ability of the 15-MsP SHR-LCD were high... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3123329 Fri, 25 Dec 2009 00:23:22 +0100 3123329 http://www.medworm.com/index.php?rid=3106635&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fbm49552371712584%2F Abstract  We evaluated patients with atrial fibrillation (Af) to define the optimal phase for ECG-gated image reconstruction for multi-slice CT (MSCT) of the left atrial appendage (LAA). We performed MSCT scans in 37 patients with Af, and we reconstructed multi-planar reformation images of the LAA, defined by the absolute delay (ms) immediately after the T wave, and by the relative delay (%). For visual analysis of the image quality for each image, a four-grade scoring system (poor to excellent) was used by two blinded, independent reviewers. Images obtained by absolute delay and by relative delay were classified as being of poor, fair, good, or excellent quality in 2, 2, 8, and 25 cases, and in 18, 11, 8, and 0 cases, respectively. This phase-definition strategy in Af pati... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3106635 Fri, 18 Dec 2009 07:17:36 +0100 3106635 http://www.medworm.com/index.php?rid=3088833&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F86n2421260182504%2F Abstract  The quality control of liquid-crystal display (LCD) monitors has become one of the important topics for maintaining reliable soft-copy readings in the interpretation of diagnostic images. In this paper, the effects of correction in the luminance measurement of an LCD monitor by use of a telescopic-type luminance meter were investigated. The luminance of the LCD monitor in different ambient-lighting conditions was measured and compared to the results obtained with no ambient lighting (0 lux). The reproducibility of luminance measurements and luminance ratios without a baffled tube was lower than those measured with the baffled tube due to the effect of ambient light. These tendencies were obvious at a relatively low luminance. The correction method by subtract... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3088833 Thu, 10 Dec 2009 15:29:41 +0100 3088833 http://www.medworm.com/index.php?rid=3088834&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F0515440214462q27%2F Abstract  To design a range-compensating bolus for heavy-charged-particle radiotherapy of lung cancer, we propose an image-processing method that uses CT projection data for treatment planning. We studied six lung cancer patients in 4DCT mode. Three types of range-compensating bolus were designed with use of (1) each bolus for 4DCT images, (2) image-based maximum-intensity projection data (4DIM), and (3) CT images reconstructed by the use of maximum-attenuation projection data (4DPM) along the time axis around exhale (=respiratory-gated treatment). Carbon-ion dose distributions were calculated by the use of these designed range-compensating boluses and were compared. The dose distribution with 4DIM caused overdosing beyond the target. However, the dose distribution with 4DP... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3088834 Thu, 10 Dec 2009 15:29:40 +0100 3088834 http://www.medworm.com/index.php?rid=3066577&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Ft52018731937v316%2F In this study, the nuclear medicine staff wore one finger dosimeter placed at the base of the index finger of the working hand. When a physician injected radioisotope drugs, the finger dose was 22.4 µSv, that for radiological technologists handling 99mTc was 29.6 µSv/day (consultation period 20 days), that for a physician injecting 18F-FDG-PET drugs was 51.3 µSv (right finger 53.9 µSv, left finger 47.2 µSv), that for pharmacists’ assay of FDG was 31.5 µSv, and that for radiological technologists positioning patients was 1.9 µSv. The largest value (94.1 µSv) was observed in physicians in the case of aspiration of a delivered drug. The finger dosimeter provides an effective solution for radiation protection procedures and follow-up.... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3066577 Thu, 03 Dec 2009 12:54:08 +0100 3066577 http://www.medworm.com/index.php?rid=3016908&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fl27t42q10u274106%2F Abstract  In our conventional visual inspection for setup verification, we have routinely used a console monitor of a CR system and a monitor of a treatment-planning system (i.e., the separate-monitor method) in order to avoid the need for CR portal-film generation. However, the separate-monitor method provided insufficient precision in detecting setup errors. We devised a setup verification procedure that uses a high-resolution liquid-crystal display monitor (i.e., the single-monitor method). Our objective in the present study was to evaluate the precision of the single-monitor method. These two methods were compared in terms of the precision of visual inspection. The single-monitor method was significantly superior to the separate-monitor method in sensitivity and in the ... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=3016908 Thu, 19 Nov 2009 20:02:56 +0100 3016908 http://www.medworm.com/index.php?rid=2971829&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fn418188v26560175%2F Abstract  Pulmonary blood flow is reflected in dynamic chest radiographs as changes in X-ray translucency, i.e., pixel values. Thus, decreased blood flow should be observed as a reduction of the variation of X-ray translucency. We performed the present study to investigate the feasibility of pulmonary blood flow evaluation with a dynamic flat-panel detector (FPD). Sequential chest radiographs of 14 subjects were obtained with a dynamic FPD system. The changes in pixel value in each local area were measured and mapped on the original image by use of a gray scale in which small and large changes were shown in white and black, respectively. The resulting images were compared to the findings in perfusion scans. The cross-correlation coefficients of the changes in pixel value an... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2971829 Fri, 06 Nov 2009 09:53:28 +0100 2971829 http://www.medworm.com/index.php?rid=2962800&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fp3h1662328608728%2F In this study, the organ doses were measured using a human- body phantom simulating a medical staff member, and we considered an effective method for decreasing exposure to staff in positron emission tomography examinations. A fluorescence glass dosimeter was arranged for measurements in various organs. Regarding exposure, the average ratio of the dose at 100 cm from the source to the dose at 30 cm was 0.35. The ratio of the dose at 100 cm with a 3 cm lead shield to the dose at 100 cm with no shielding device was 0.01. To reduce the radiation exposure effectively, medical staff members should inform the patient of the details of the examination in advance, reduce the contact time with the patient during the examination, and maximize their distance from the pa... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2962800 Tue, 03 Nov 2009 07:03:49 +0100 2962800 http://www.medworm.com/index.php?rid=2898348&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fy5814p81168861k3%2F Abstract  We have developed new design algorithms for compensating boli to facilitate the implementation of four-dimensional charged-particle lung therapy in clinical applications. Four-dimensional CT (4DCT) data for eight lung cancer patients were acquired with a 16-slice CT under free breathing. Six compensating boli were developed that may be categorized into three classes: (1) boli-based on contoured gross tumor volumes (GTV) from a 4DCT data set during each respiratory phase, subsequently combined into one (GTV-4DCT bolus); (2) boli-based on contoured internal target volume (ITV) from image-processed 3DCT data only [temporal-maximum-intensity-projection (TMIP)/temporal-average-intensity-projection (TAIP)] with calculated boli (ITV-TMIP and ITV-TAIP boli); and (3) boli-b... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2898348 Tue, 13 Oct 2009 10:54:37 +0100 2898348 http://www.medworm.com/index.php?rid=2812221&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fr24n217392120631%2F Abstract  The results of Monte Carlo calculated dose distributions of proton treatment of ocular melanoma are presented. An efficient spot scanning method utilizing active energy modulation, which also minimizes the number of target spots was developed. We simulated various parameter values for the particle energy spread and the pencil beam diameter in order to determine values suitable for medical treatment. We found that a 2.5-mm-diameter proton beam with a 5% Gaussian energy spread was suitable for treatment of ocular melanoma while preserving vision for the typical case that we simulated. The energy spectra and the required proton current were also calculated and are reported. The results are intended to serve as a guideline for a new class of low-cost, compact accelera... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2812221 Fri, 18 Sep 2009 16:24:05 +0100 2812221 http://www.medworm.com/index.php?rid=2768432&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fv7486775383483x3%2F Abstract  Our purpose in this study was to examine the detectability of a lung nodule at different maximum luminance settings of a liquid-crystal display (LCD) monitor by utilizing receiver operating characteristic (ROC) analysis. The LCD monitor used in this study was calibrated to the grayscale standard display function with different maximum luminance settings (670, 450, and 170 cd/m2). The average area under the ROC curve (AUC) and the standard deviation for all observers at 670, 450, and 170 cd/m2 were 0.837 ± 0.076, 0.832 ± 0.051, and 0.830 ± 0.078, respectively. There was no statistically significant difference in AUC as a function of the maximum luminance setting of the LCD monitor. Considering the results, setting the maximum... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2768432 Thu, 03 Sep 2009 06:11:47 +0100 2768432 http://www.medworm.com/index.php?rid=2653373&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fq6545x1071533075%2F Abstract  Physics-related subjects are important in the educational fields of radiological physics and technology. However, conventional teaching tools, for example texts, equations, and two-dimensional figures, are not very effective in attracting the interest of students. Therefore, we have created several multimedia educational materials covering radiological physics and technology. Each educational presentation includes several segments of high-quality computer-graphic animations designed to attract students’ interest. We used personal computers (PCs) and commercial software to create and compile these. Undergraduate and graduate students and teachers and related professionals contributed to the design and creation of the educational materials as part of student resea... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2653373 Mon, 27 Jul 2009 22:38:26 +0100 2653373 http://www.medworm.com/index.php?rid=2610565&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F818646w13340739g%2F Content Type Journal ArticleDOI 10.1007/s12194-009-0064-3 Journal Radiological Physics and TechnologyOnline ISSN 1865-0341Print ISSN 1865-0333 (Source: Radiological Physics and Technology) Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2610565 Wed, 15 Jul 2009 13:49:34 +0100 2610565 http://www.medworm.com/index.php?rid=2597832&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F5312476843772628%2F Abstract  Titanium-encapsulated 125I brachytherapy sources are in use for treatment of the eye, brain, and head and neck region, and for early stage prostate cancer. The photoelectric interaction of 125I photons with titanium encapsulation generates Ti K X-rays (~5 keV). According to the National Institute of Standards and Technology (NIST) 1999 air-kerma strength, S k, standard, these X-rays should be excluded from S k. We used the EGSnrc Monte Carlo code system to calculate the S k (including the contribution of ~5-keV X-rays), dose rate constant, and radial dose function for five different 125I source models. Depending upon the source model, the contribution of 5-keV Ti X-rays to S k varies between 17.1 and 18.7%. Including these X-rays as part of S k would result in un... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2597832 Sat, 11 Jul 2009 06:53:21 +0100 2597832 http://www.medworm.com/index.php?rid=2579922&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F984330120415351t%2F Abstract  Electron applicators and cut-outs have been used for some time in the delivery of electron beam therapy. A dual electron multileaf collimator (eMLC) consisting of upper and lower eMLCs was designed, and dose distributions of electron beams delivered by it were evaluated by Monte Carlo simulations by use of the EGSnrc Monte Carlo code. The percentage depth dose (PDD), dose profiles, dose gradient falloff (G), depth of maximum dose (R 100), surface dose, bremsstrahlung background, beam flatness, and penumbra of the dual eMLC were evaluated and compared with those simulated and measured with the standard applicators inserted into the treatment head of the medical linear accelerator (linac). The results showed good agreement in most cases. Specifically, the flatness a... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2579922 Mon, 06 Jul 2009 16:53:49 +0100 2579922 http://www.medworm.com/index.php?rid=2569586&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Ft6k32228q2620k62%2F Abstract  To assess the relationship between intra-abdominal fat and sigmoid colon cancer, we investigated the intra-abdominal fat distribution in 172 examples of sigmoid colon cancer and 767 examples of various other pathologies by using data from multidetector-row computed tomography. One significant finding was that the intra-abdominal fat area in sigmoid colon cancer presents a small secondary peak in the pelvis on the profile of the intra-abdominal fat, which we called the pelvic sub-peak. The presence or absence of the pelvic sub-peak was determined based on the sub-peak ratio, which was calculated by dividing the maximum peak by the sub-peak value on the profile of the intra-abdominal fat area. The pelvic sub-peak was defined as having a sub-peak ratio ≥0.1. The pe... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2569586 Wed, 01 Jul 2009 06:24:56 +0100 2569586 http://www.medworm.com/index.php?rid=2569587&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F34206j0n5271w8q1%2F In this study, we demonstrate the feasibility of 3D NIR fluorescence tomography imaging by employing DOI-PET detectors in computer simulations. In the simulations, we used a 40 mm × 40 mm × 40 mm cubic phantom, a square detector geometry, and an optical diffusion equation to approximate the light propagation. We then evaluated imaging systems for 3D fluorescence tomography with different detector resolutions and excitation light arrangements using singular-value analysis and imaging simulation. We confirmed that the reconstructed images from low-resolution detectors (8 × 8 pixels for an area of 40 mm × 40 mm) are the same as those from high-resolution detectors (16 × 16 pixels for the same area). Conten... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2569587 Tue, 30 Jun 2009 15:43:58 +0100 2569587 http://www.medworm.com/index.php?rid=2462819&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F216418483483726r%2F Abstract  Our purpose in this study was to investigate the optimal position for the quantification of hepatic perfusion by using a dual-input, single-compartment model and dynamic contrast-enhanced computed tomography (DCE-CT) in rats. The DCE-CT studies were performed with the animals in the supine and prone position, with an interval of 1 day, on six male Sprague–Dawley rats. The distance between the inferior vena cava (IVC) and portal vein was calculated. The arterial hepatic blood flow (AHBF) and portal hepatic blood flow (PHBF) were also estimated by use of time–density curves (TDCs) in the aorta, portal vein, and liver. The distance between the IVC and portal vein in the supine position (3.68 ± 0.22 mm) was significantly greater than that in th... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2462819 Fri, 05 Jun 2009 08:56:17 +0100 2462819 http://www.medworm.com/index.php?rid=2423106&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F9100347704k5q657%2F Abstract  A medical compact cyclotron produces about 1015 neutrons per day along with 100 GBq of 18F. Therefore, it is important to establish radiation safety guidelines on residual radioactivity for routine operation, maintenance work, and decommissioning. Thus, we developed a simple method for measuring the thermal neutrons in a cyclotron room. In order to verify the feasibility of our proposed method, we measured the thermal neutron distribution around a cyclotron by using the activation of 23Na in salt. We installed 78 salt dosimeters in the cyclotron room with a 50 cm mesh. The photopeak of 24Na was measured, and the neutron flux distribution was estimated. Monitoring the neutron flux distribution in a cyclotron room appears to be useful for not only obtaining ... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2423106 Sat, 16 May 2009 05:57:51 +0100 2423106 http://www.medworm.com/index.php?rid=2423107&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fr0w8562663280428%2F Abstract  The differentiation of focal liver lesions in magnetic resonance (MR) imaging is primarily based on the intensity and homogeneity of lesions with different imaging sequences. However, these imaging findings are falsely interpreted in some patients because of the complexities involved. Our aim is to establish a computer-aided diagnosis system named LiverANN for classifying the pathologies of focal liver lesions into five categories using the artificial neural network (ANN) technique. On each MR image, a region of interest (ROI) in the focal liver lesion was delineated by a radiologist. The intensity and homogeneity within the ROI were calculated automatically, producing numerical data that were analyzed by feeding them into the LiverANN as inputs. Outputs were the ... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2423107 Thu, 14 May 2009 06:47:22 +0100 2423107 http://www.medworm.com/index.php?rid=2423108&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fh77m022765756042%2F Abstract  It is known that the performance of liquid-crystal display (LCD) monitors, such as the luminance and contrast ratio, is dependent on the viewing angle. Our purpose in this study was to compare the angular performance and the effect on observer performance of different types of LCD monitors. The luminance performance and contrast ratio as a function of viewing angle (−60° to 60°) in each direction for two types of LCD monitors, namely, a general-purpose LCD monitor and one especially designed for medical use, were measured in this study. Furthermore, the observer performance at various viewing angles in the horizontal direction for a medical-grade LCD monitor was investigated by eight observers based on a contrast-detail diagram. The two types of LCD monitors s... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2423108 Thu, 14 May 2009 06:47:21 +0100 2423108 http://www.medworm.com/index.php?rid=2387456&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Ff7j570462x9n2562%2F Abstract  Recent linear accelerators can perform cone-beam computed tomography to correct setup errors immediately before dose delivery. We calculated the dose distribution with setup errors acquired from cone-beam computed tomography to determine a more realistic and individual effect of setup errors. The differences in dose distribution were analyzed. The setup errors of three patients who were irradiated in the neck, esophagus, and pelvic area were obtained retrospectively. We found that the maximum dose variances for the three cases were 19.9–35.9%. The maximum dose variance points were relatively far from the isocenter. The volume of the 10% dose difference had widths of 1.3–1.85 cm around the beam edges. The V95 and mean doses at the clinical target volume we... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2387456 Fri, 01 May 2009 06:31:58 +0100 2387456 http://www.medworm.com/index.php?rid=2367181&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fv10p881414751186%2F Abstract  We evaluated dynamic changes in water diffusion in the brain during the cardiac cycle by using cine diffusion MRI. On a 1.5-T MRI, ECG-triggered single-shot diffusion echo planar imaging was used with sensitivity encoding, halfscan, and rectangular field of view techniques for minimizing bulk motion effects such as brain pulsation, with a data-sampling window of 3 ms. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in the white matter zone were determined in ten healthy volunteers and then compared with the intracranial volume change (ICVC) revealed by phase-contrast cine MRI during the cardiac cycle. In addition, a frequency analysis of these waveforms was performed. ADC and FA values changed significantly during the cardiac cycle, de... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2367181 Thu, 23 Apr 2009 07:54:06 +0100 2367181 http://www.medworm.com/index.php?rid=2363965&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Ft41k31l7544145h5%2F Abstract  We propose a new method for diagnostic assistance in oncology, [fluorine-18]-2-fluoro-2-deoxy-d-glucose (FDG)-positron emission tomography (PET). Early and delayed scans were performed on 10 patients with lung cancer by use of an ECAT EXACT 47 PET scanner, and standardized-uptake-value (SUV) images were created. Three segmentation (S1, S2, and S3) maps were created from the early and delayed SUV images according to various thresholds (SUVthreshold = 2.0, 2.5, and 3.0) based on the early image and the percentage change defined as (SUVdelayed − SUVearly) × 100/SUVearly. Voxels that had larger voxel values in their early images than the SUVthreshold were clustered into three classes: S1 if the percentage change was larger than 10, S2 if t... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2363965 Tue, 21 Apr 2009 11:19:36 +0100 2363965 http://www.medworm.com/index.php?rid=2340921&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fp83107v838747k73%2F Content Type Journal ArticleDOI 10.1007/s12194-009-0055-4Authors Kunio Doi, The University of Chicago Department of Radiology Chicago IL USA Journal Radiological Physics and TechnologyOnline ISSN 1865-0341Print ISSN 1865-0333 (Source: Radiological Physics and Technology) Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2340921 Tue, 14 Apr 2009 05:51:46 +0100 2340921 http://www.medworm.com/index.php?rid=2328712&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fx7255723j5053553%2F Abstract  It is essential to make accurate estimates of the scatter of radiation from the human body when calculating the leakage dose in medical X-ray imaging facilities. The scatter fraction varies with the size and shape of the radiation field in a way that is not exactly proportional to the area of the field. Japanese law quotes values for the scatter fraction that are provided by the National Council on Radiation Protection and Measurements, but these data were obtained 30 years ago, using equipment that differed considerably from that employed nowadays. To date, no attempt has been made to confirm whether these data accurately describe current Japanese equipment. In the present study, we used an ion chamber dosimeter to measure scattered radiation fractions, and ... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2328712 Wed, 08 Apr 2009 08:26:44 +0100 2328712 http://www.medworm.com/index.php?rid=2297368&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fc32v150675488356%2F Abstract  The management of induced radioactivity of the cyclotron itself and structures is an important issue in decommissioning of medical compact cyclotrons. To obtain basic data on the actual operational conditions of cyclotrons, we performed nationwide survey. The actual beam current was about half of the maximum beam current indicated in the official permits for cyclotron operation. The actual operating time was about 10% of the maximum operating time indicated in the official permits. The average daily radioactive-nuclide (18F) production was only 10% of the allowed maximum quantity. From these results, it became clear that the induced radioactivity of a cyclotron and its concrete structures based on the maximum beam current and the maximum operating time may be overe... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2297368 Fri, 27 Mar 2009 06:49:55 +0100 2297368 http://www.medworm.com/index.php?rid=2284059&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Ff1603074quj47962%2F Abstract  Neurosurgeons sometimes find it difficult to locate tumors precisely during microsurgery, particularly tumors located in the brain parenchyma because of the absence of boundaries in this region. Image-guided neurosurgical techniques conducted with the help of neuronavigation systems have been developed and have gained importance recently. Accuracy is vital during image-guided neurosurgery. We used a phantom to evaluate the errors introduced during navigation. The three errors evaluated were skin-shift, marker-gap, and table-rotation errors. The skin-shift error occurs if the fiducial markers positioned on the scalp move when the head is fixed to a head holder with head pins. The marker-gap error occurs when the marker ball is positioned incorrectly in the marker s... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2284059 Tue, 17 Mar 2009 06:48:00 +0100 2284059 http://www.medworm.com/index.php?rid=2076205&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Ft1371666782l32m2%2F Abstract  We have developed a practical dose verification method for radiotherapy treatment planning systems by using only a Farmer ionization chamber in inhomogeneous phantoms. In particular, we compared experimental dose verifications of multi-layer phantom geometries and laterally inhomogeneous phantom geometries for homogeneous and inhomogenous dose calculations by using the fast-Fourier-transform convolution, fast-superposition, and superposition in the XiO radiotherapy treatment-planning system. We applied the dose verification method to three kernel-based algorithms in various phantom geometries with water-, lung- and bone-equivalent media of different field sizes. These calculations were then compared with experimental measurements by use of the Farmer ionization ch... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2076205 Tue, 30 Dec 2008 06:58:18 +0100 2076205 http://www.medworm.com/index.php?rid=2068130&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fk13471661415u652%2F Abstract  We evaluated the water-equivalent length (WEL) reproducibility due to variation in the external respiratory marker position when using a 4DCT scan in respiratory-gated charged-particle treatment. Two sets of pancreatic 4DCT data from two patients were acquired under free breathing conditions with 256-slice CT. The 4DCT data included two exhalation phases and the respiratory patterns in each patient differed, one being regular and the other irregular. The WEL calculation region is defined in the first respiratory cycle by two planes, one at the patient entrance surface and the other behind the target in the anterior–posterior (AP) and posterior–anterior (PA) directions. In the regular respiratory pattern, the WEL variation within the target region was less than... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2068130 Thu, 25 Dec 2008 06:55:20 +0100 2068130 http://www.medworm.com/index.php?rid=2054184&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fk874xv4p25282424%2F This study concentrated on measuring the dependence of the polarity effect at various energies, and for various field size, ionization chamber, and electrometer combinations. Of the seven chambers, CC01, PTW23323, and PTW31006 had the largest polarity effect for small field sizes. The materials of the central electrode of these three chambers were steel or air-equivalent plastic C-552. The magnitude of the polarity effect was shown to be strongly dependent on the material of the collecting electrode. This polarity effect dependence was observed for the ionization chambers and small field sizes studied. Content Type Journal ArticleDOI 10.1007/s12194-008-0050-1Authors Tetsunori Shimono, Hoshigaoka Koseinenkin Hospital Department of Radiology 4-8-1 Hoshigaoka Hirakata Osaka 573-0013 ... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2054184 Thu, 18 Dec 2008 09:34:25 +0100 2054184 http://www.medworm.com/index.php?rid=2054183&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F443u4g07v703541v%2F Abstract  Currently, it is difficult to carry out refraction-contrast radiography by using a conventional X-ray generator. Thus, we developed an embossed radiography system utilizing dual-energy subtraction for decreasing the absorption contrast in unnecessary regions, and the contrast resolution of a target region was increased by use of image-shifting subtraction and a linear-contrast system in a flat panel detector (FPD). The X-ray generator had a 100-μm-focus tube. Energy subtraction was performed at tube voltages of 45 and 65 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. A 1.0-mm-thick aluminum filter was used for absorbing low-photon-energy bremsstrahlung X-rays. Embossed radiography was achieved with cohesion imaging by use of th... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2054183 Thu, 18 Dec 2008 09:34:25 +0100 2054183 http://www.medworm.com/index.php?rid=2048514&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fkp418h625192100n%2F Abstract  Our purpose in this study was to examine the potential usefulness of liquid–crystal display (LCD) monitors having the capability of rendering higher than 8 bits in display-bit depth. An LCD monitor having the capability of rendering 8, 10, and 12 bits was used. It was calibrated to the grayscale standard display function with a maximum luminance of 450 cd/m2 and a minimum of 0.75 cd/m2. For examining the grayscale resolution reported by ten observers, various simple test patterns having two different combinations of luminance in 8, 10, and 12 bits were randomly displayed on the LCD monitor. These patterns were placed on different uniform background luminance levels, such as 0, 50, and 100%, for maximum luminance. All observers participating in this study... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2048514 Tue, 16 Dec 2008 07:57:52 +0100 2048514 http://www.medworm.com/index.php?rid=2041722&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fg6h6t724l32g0451%2F We present a review of the rationale, technology, and methodology of image guidance, as well as an overview of current work in IGRT at the Massachusetts General Hospital. The technology is rapidly evolving, and synergisms between the various acquisition approaches are converging to provide unparalleled information on target and normal tissue location and motion. With these new approaches to patient localization, we expect improved clinical results to be forthcoming. Content Type Journal ArticleDOI 10.1007/s12194-008-0045-yAuthors George T. Y. Chen, Massachusetts General Hospital Department of Radiation Oncology 100 Blossom Street Boston MA 02114 USAGregory C. Sharp, Massachusetts General Hospital Department of Radiation Oncology 100 Blossom Street Boston MA 02114 USAShinichiro Mori... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2041722 Mon, 15 Dec 2008 06:54:57 +0100 2041722 http://www.medworm.com/index.php?rid=2034390&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fp061327146w44227%2F Abstract  We have developed a new protocol of myocardial perfusion-gated single-photon emission computed tomography (SPECT), by use of technetium-99m sestamibi (MIBI), in which SPECT imaging at rest followed by SPECT imaging after adenosine with low level ergometer stress can be conducted by use of the Monzen position within a shortened total testing time of 1 h or less. The study group consisted of 137 patients who underwent this new imaging protocol. The diagnostic quality of the images was as good as that of images obtained with the conventional method (30–60 min after the injection of MIBI). The SPECT image quality for the 137 patients was evaluated, and the percentages of images rated as excellent, good, fair, and poor were 65.3, 27.4, 5.8, and 1.5% for the... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2034390 Thu, 11 Dec 2008 11:59:43 +0100 2034390 http://www.medworm.com/index.php?rid=2034391&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fp03269017585671m%2F Abstract  We have proposed a new “OpenPET” geometry consisting of two detector rings of axial length W each separated by a gap G. For obtaining an axially continuous field of view (FOV) of 2W + G, the maximum limit for G must be W. However, two valleys of sensitivity appear on both sides of the gap. Setting a more limited range for the gap as G < W, which is desirable for filling in the sensitivity valleys, results in not only a shortened gap, but also a shortened axial FOV. In this paper, we propose an alternative method for improving the uniformity of sensitivity by shifting two detector rings axially closer or further apart at the same velocity to each other. In addition, image reconstruction of the OpenPET is an incomplete problem, and low-freque... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=2034391 Wed, 10 Dec 2008 07:23:43 +0100 2034391 http://www.medworm.com/index.php?rid=1976695&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F8383mg1013212030%2F Abstract  Monte Carlo numerical simulations were conducted to evaluate the effectiveness of colloidal gold as a contrast agent. The simulations were conducted using a simple configuration, modeling a phantom to maintain the generality of the results, and the effects of the mass percentage of gold accumulated inside the tumor and the energy of the irradiating X-rays were evaluated, as well as other information, such as the energy spectrum of the photons reaching the detector and the change in the energy deposited inside the phantom. The contrast of the X-ray image due to the layer is calculated from the total energy of photons transmitted to the back surface of the phantom. The simulation revealed that colloidal gold with a mass percentage of 1.0% provided an image for which... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1976695 Tue, 18 Nov 2008 08:10:25 +0100 1976695 http://www.medworm.com/index.php?rid=1964790&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fj6238x20n3633382%2F Abstract  For reducing the risk of skin injury during interventional radiology (IR) procedures, it has been suggested that physicians track patients’ exposure doses. The metal-oxide semiconductor field effect transistor (MOSFET) dosimeter is designed to measure patient exposure dose during radiotherapy applications at megavoltage photon energies. Our purpose in this study was to evaluate the feasibility of using a MOSFET dosimeter (OneDose system) to measure patients’ skin dose during exposure to diagnostic X-ray energies used in IR. The response of the OneDose system was almost constant at diagnostic X-ray energies, although the sensitivity was higher than that at megavoltage photon energies. We found that the angular dependence was minimal at diagnostic X-ray energies... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1964790 Fri, 14 Nov 2008 08:41:54 +0100 1964790 http://www.medworm.com/index.php?rid=1953184&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F0332m73tj22w532n%2F In conclusion, the quantitative analysis of hepatic tumors was able to differentiate among these lesions by use of the T2-shine ratio. Content Type Journal ArticleDOI 10.1007/s12194-008-0043-0Authors Akio Ogura, Kyoto City Hospital Department of Radiology 1-2, Higashitakada-cho, Mibu, Nakagyo-ku Kyoto JapanKatsumi Hayakawa, Kyoto City Hospital Department of Radiology 1-2, Higashitakada-cho, Mibu, Nakagyo-ku Kyoto JapanTosiaki Miyati, Kanazawa University Graduate School of Medical Science Kanazawa JapanFumie Maeda, Kyoto City Hospital Department of Radiology 1-2, Higashitakada-cho, Mibu, Nakagyo-ku Kyoto JapanAkira Miyai, Kyoto City Hospital Department of Radiology 1-2, Higashitakada-cho, Mibu, Nakagyo-ku Kyoto JapanFumito Saeki, Kyoto City Hospital Department of Radiology 1-2, Higash... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1953184 Mon, 10 Nov 2008 08:15:58 +0100 1953184 http://www.medworm.com/index.php?rid=1953185&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fp4328p1456858j04%2F Abstract  X-ray fluorescence (XRF) analysis is useful for measuring density distributions of contrast media in vivo. An XRF camera was developed for carrying out mapping for iodine-based contrast media used in medical angiography. Objects are exposed by an X-ray beam from a cerium target. Cerium K-series X-rays are absorbed effectively by iodine media in objects, and iodine fluorescence is produced from the objects. Next, iodine Kα fluorescence is selected out by use of a 58-µm-thick stannum filter and is detected by a cadmium telluride (CdTe) detector. The Kα rays are discriminated out by a multichannel analyzer, and the number of photons is counted by a counter card. The objects are moved and scanned by an x–y stage in conjunction with a two-stage controller, and X-r... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1953185 Mon, 10 Nov 2008 08:15:57 +0100 1953185 http://www.medworm.com/index.php?rid=1945633&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fv57t4uj446138427%2F Abstract  To provide faster calculation of digitally reconstructed radiographs (DRRs) in patient-positioning verification, we developed and evaluated a graphic processing unit (GPU)-based DRR software application and compared it with a central processing unit (CPU)-based application. The evaluation metrics were calculation speed and image quality for various slice thicknesses. The results showed that the GPU-based DRR computation was an average of 50 times faster than the CPU-based methodology, whereas the image quality was very similar. This excellent performance may increase the accuracy of patient positioning and improve the patient treatment throughput time. Content Type Journal ArticleDOI 10.1007/s12194-008-0040-3Authors Shinichiro Mori, National Institute of Radio... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1945633 Fri, 07 Nov 2008 08:13:58 +0100 1945633 http://www.medworm.com/index.php?rid=1860283&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fd167134828358142%2F We describe a technique for rendering the ESF method robust to image noise. We smooth out the noisy ESF through multiple stages of filtering. Invariably, the line spread function (LSF) obtained from the smoothed ESF is blurred, and the MTF obtained from the LSF is incorrect. However, because the filtering that has been applied is known, much of the LSF blurring can be corrected. An estimate of the true LSF is obtainable from the blurred LSF, assuming that the true LSF is not very different from either a Gaussian or a composite of multiple Gaussians. For an image reconstructed with a kernel for soft-tissue imaging, the MTF obtained by our method is sufficiently consistent with the theoretical MTF, even when the CNR is as low as 2. Content Type Journal ArticleDOI 10.1007/s12194-008-... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1860283 Mon, 06 Oct 2008 06:30:51 +0100 1860283 http://www.medworm.com/index.php?rid=1848547&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F7p697886224232t4%2F This study evaluated the feasibility of imaging rat brains using a human whole-body 3-T magnetic resonance imaging (MRI) scanner with specially developed transmit-and-receive radiofrequency coils. The T1- and T2-weighted images obtained showed reasonable contrast. Acquired contrast-free time-of-flight magnetic resonance angiography images clearly showed the cortical middle cerebral artery (MCA) branches, and interhemispheric differences could be observed. Dynamic susceptibility contrast MRI at 1.17 mm3 voxel resolution, performed three times following administration of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA, 0.1 mmol/kg), demonstrated that the arterial input function (AIF) can be obtained from the MCA region, yielding cerebral blood flow (CBF), cerebral bloo... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1848547 Wed, 01 Oct 2008 09:23:32 +0100 1848547 http://www.medworm.com/index.php?rid=1653346&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fh83kh46833672011%2F Content Type Journal ArticleDOI 10.1007/s12194-008-0037-y Journal Radiological Physics and TechnologyOnline ISSN 1865-0341Print ISSN 1865-0333 (Source: Radiological Physics and Technology) Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1653346 Tue, 22 Jul 2008 16:19:23 +0100 1653346 http://www.medworm.com/index.php?rid=1627176&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fbw67262j9863w231%2F In this study, the dosimetric characteristics of multileaf collimators (MLCs) with 120 leaves and 80 leaves were evaluated. The dose rate, percentage depth dose, surface dose, dose in the build-up region, beam profile, flatness, symmetry, and penumbra width were measured by three field-defining methods: (1) “Jaw only”, (2) “MLC only”, and (3) “MLC + Jaw”, for a 6-MV photon beam with the two MLC systems. Analysis of the dose rate showed that the dose rate for the “MLC only” field was higher than that for the other two fields. The surface dose was more pronounced for the “MLC only” fields. The dose in the build-up region was higher for the “MLC only” fields, and no significant difference was found in the percentage depth dose (PDD) beyond the dose maxi... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1627176 Mon, 14 Jul 2008 05:39:08 +0100 1627176 http://www.medworm.com/index.php?rid=1617009&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F551010047u135g28%2F Abstract  We conducted a study to determine optimal scan conditions for automatic exposure control (AEC) in computed tomography (CT) of low-dose chest screening in order to provide consistent image quality without increasing the collective dose. Using a chest CT phantom, we set CT-AEC scan conditions with a dose-reduction wedge (DR-Wedge) to the same radiation dose as those for low-tube current, fixed-scan conditions. Image quality was evaluated with the use of the standard deviation of the CT number, contrast-noise ratios (CNR), and receiver-operating characteristic (ROC) analysis. At the same radiation dose, in the scan conditions using CT-AEC with the DR-Wedge, the SD of the CT number of each slice position was stable. The CNR values were higher at the lung apex and lung... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1617009 Fri, 11 Jul 2008 07:24:15 +0100 1617009 http://www.medworm.com/index.php?rid=1594294&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fv377q57420004217%2F Abstract  We evaluated a newly developed digital image reader incorporating a columnar-crystal structured phosphor plate (CPP) to determine its effectiveness for chest and abdominal exposures by assessing contrast–detail (C–D) curves and image quality figure values obtained from a C–D phantom. With the help of five radiologic technologists with 5 years or more of experience in the interpretation of plain radiographs, we assessed chest and abdominal radiographic films that had undergone image processing. The exposure dose required for obtaining the same image quality under chest exposure conditions (110 kV) was 66% of that necessary for a conventionally used computed radiography system incorporating a powder phosphor plate, whereas the percentage under abdomin... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1594294 Sat, 05 Jul 2008 06:29:14 +0100 1594294 http://www.medworm.com/index.php?rid=1577912&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fa835381x71478634%2F Abstract  The CT number is theoretically independent of the number of incident photons and the thickness of a subject. However, when noise is added, the CT number becomes dependent on the number of incident photons because of the nonlinearity of the logarithm operation, and so the accuracy of the CT number is degraded, especially in a photon-starved state. The inconsistency of the CT number due to nonlinearity generates an intense streak artifact in a reconstructed image. We have theoretically clarified the statistical characteristics of both the nonlinearity of the logarithm transform and the non-zero/non-negative restriction in the logarithm operation. Moreover, we have formulated a correction method for such nonlinearity according to the statistical distribution of noise... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1577912 Thu, 03 Jul 2008 08:29:12 +0100 1577912 http://www.medworm.com/index.php?rid=1569571&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fh0131041316n3564%2F Abstract  We tested the ability of two separate nuclear reaction models, the binary cascade and JQMD (Jaeri version of Quantum Molecular Dynamics), to predict the dose distribution in carbon-ion radiotherapy. This was done by use of a realistic simulation of the experimental irradiation of a water target. Comparison with measurement shows that the binary cascade model does a good job reproducing the spread-out Bragg peak in depth-dose distributions in water irradiated with a 290 MeV/u (per nucleon) beam. However, it significantly overestimates the peak dose for a 400 MeV/u beam. JQMD underestimates the overall dose because of a tendency to break a nucleus into lower-Z fragments than does the binary cascade model. As far as shape of the dose distribution is concerne... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569571 Mon, 30 Jun 2008 05:54:41 +0100 1569571 http://www.medworm.com/index.php?rid=1569570&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fr4n77477715h0382%2F Abstract  Hepatic-vessel trees are the key structures in the liver. Knowledge of the hepatic-vessel tree is required because it provides information for liver lesion detection in the computer-aided diagnosis (CAD) system. However, hepatic vessels cannot easily be distinguished from other liver tissues in plain CT images. Automated segmentation of hepatic vessels in plain (non-contrast) CT images is a challenging issue. In this paper, an approach to automatic segmentation of hepatic vessels is proposed. The approach consists of two processing steps: enhancement of hepatic vessels and hepatic-vessel extractions. Enhancement of the vessels was performed with two techniques: (1) histogram transformation based on a Gaussian function; (2) multi-scale line filtering based on eigen... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569570 Mon, 30 Jun 2008 05:54:41 +0100 1569570 http://www.medworm.com/index.php?rid=1569572&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fq0u4323546475234%2F We present a simple method for evaluating the spatial resolution of multi-slice computed tomography (MSCT) multiplanar reconstruction images (MPRs). We scanned a bead phantom to obtain the three-dimensional point spread function (PSF), and bead-centric MPRs were generated. The modulation transfer function (MTF) was calculated from the MPRs via a two-dimensional Fourier transform (2DFFT) of the PSF. The results showed that, when MPRs were reconstructed using axial images less than or equal to a nominal 1.0-mm slice-width with a standard kernel for the abdomen, the MTF in the longitudinal direction (z-direction) was superior to that in the in-plane (x–y plane) direction. It was also found that the arbitrary-angle MTFs of MPRs were between the MTFs of the in-plane and longitudinal dire... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569572 Thu, 26 Jun 2008 06:20:22 +0100 1569572 http://www.medworm.com/index.php?rid=1569573&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Frv5x13474j301233%2F Abstract  Recently, a new method for acquiring SPECT data in deep inspiratory breath hold with a high-speed rotation (HSR-SPECT) technique was developed for pulmonary perfusion scintigraphy. Our purpose in this study was to apply this method to hepatic-function scintigraphy. A phantom study was performed for determining data acquisition times. The coefficient of variation (CV) value was used for evaluating nonuniformity of radioactivity in the liver area. Data acquisition times were determined based on the CV value. According to the results of the phantom study, this method needs at least ten projection data sets for acquiring sufficient counts for a proper diagnosis. Under clinical conditions, breath-holding HSR-SPECT can suppress the respiratory motion effects, better tha... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569573 Tue, 24 Jun 2008 07:49:23 +0100 1569573 http://www.medworm.com/index.php?rid=1569574&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fh31u77gv43687u0m%2F Abstract  The present study was performed for determining the optimal timing of MR sialography by use of the Japanese pickled plum (umeboshi) for promoting secretion by the salivary glands. MR sialography was performed in four healthy male volunteers. The four volunteers were examined before and 10 min after stimulation with umeboshi. On the next examination, three volunteers were examined before and after umeboshi stimulation every 1 min up to 5 min to allow assessment of the temporal changes in duct visualization. Dilatation of the salivary gland ducts and improvement of the visualization of the ducts were obtained after stimulation with umeboshi. The difference in the dilatation of the parotid duct was statistically significant. In the temporal study, the sali... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569574 Tue, 24 Jun 2008 07:49:22 +0100 1569574 http://www.medworm.com/index.php?rid=1569575&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F414642813174777n%2F Abstract  A real-time digital filter for noise reduction in X-ray images is proposed. The filter is based on averaging of only similar pixels (pixels that differ only little) rather than neighboring pixels, which are averaged in conventional linear low-pass filters. The effectiveness of the filter was evaluated by computer simulation, where original images that were acquired by X-ray exposure were processed in accordance with the filter algorithm. The resulting images were evaluated in terms of the pre-sampled modulation transfer function (MTF), the noise power spectrum (NPS), and the lag. Comparison of the filtered and original images revealed that the NPS was reduced for the full range of spatial frequencies in the filtered image, resulting in a reduction of total noise p... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569575 Fri, 20 Jun 2008 06:52:40 +0100 1569575 http://www.medworm.com/index.php?rid=1569576&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fw6w3x17465p8425t%2F Abstract  We investigated methods of analyzing the noise power spectrum (NPS) measurement for medical liquid crystal displays (LCDs). Uniform images displayed on the LCDs were imaged with a high-performance digital camera equipped with a close-up lens, and then the NPSs were calculated from the image data by means of several analysis methods. In a method using the 2D fast Fourier transform (FFT) with a 256 × 256 pixels data segment (basic method), we examined the efficacy of a background trend correction (BTC) and a Hanning windowing process used for reducing the spectral estimation errors in the Fourier analysis. To improve the frequency resolution of the basic method, we examined two 2D FFT methods by using 512 × 512 and 1024 × 1024&nb... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569576 Mon, 16 Jun 2008 06:07:35 +0100 1569576 http://www.medworm.com/index.php?rid=1569577&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fm4676457x566q1ht%2F Abstract  A voxel-based specific regional analysis system for Alzheimer’s disease (VSRAD) was used for quantitative analysis of parahippocampal atropy with 1.5-tesla (T) MRI in a voxel-wise manner. The analysis of images acquired under a different imaging condition provides an error factor that has a calculated value. Clinical application of 3T-MRI is necessary for establishing a normal data base (N-DB) specific for 3T-MRI data, which permits appropriate application of VSRAD. We established an N-DB specific for 3T-MRI for use in VSRAD. The “Z-score of the parahippocampal gyrus” was 0.79 ± 0.32, and the N-DB of each age group did not have a big deflection when we analyzed a group of physically unimpaired persons in an N-DB specific for 3T-MRI. Therefore, we w... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569577 Mon, 16 Jun 2008 06:07:34 +0100 1569577 http://www.medworm.com/index.php?rid=1569578&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fj11125hk63864t51%2F In this study, we examined the ability of an L-EPID to verify rectangular and irregular fields and to measure the transmitted exit doses. With respect to the beam profile of rectangular and irregular fields and the doses transmitted through an inhomogeneous phantom, the L-EPID dose obtained from the L-EPID measurement was compared with the conventional dose measured by use of a 0.12-cc ionization chamber and a 3D water phantom. In the comparison of the rectangular and irregular fields, the difference in the off-center ratio (OCR) between the L-EPID dose and the conventional dose was approximately 3% in the steep-dose-gradient region (penumbra regions, >30%/cm) and approximately ±0.5% in the gentle-dose-gradient region (5%/cm). On the other hand, the dose differences between the L... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569578 Fri, 06 Jun 2008 05:48:22 +0100 1569578 http://www.medworm.com/index.php?rid=1569579&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F917r8g8784r3403g%2F In this study, we analyzed the respiratory motion of the upper abdominal arteries preliminary to developing a method of respiratory motion correction for the roadmap technique used in vascular interventions. We retrospectively obtained six digital angiography sequences taken during respiration. The levels of the right and left hemidiaphragms and the positions of artery bifurcation points were measured manually through each sequence. Artery bifurcation points were classified as the hepatic artery group (HAG), splenic artery group (SAG), and celiac group (CG). Correlations between the motions of each hemidiaphragm and of the artery bifurcation points in each group were determined. We found that the vertical motion of the HAG and CG matched that of the right hemidiaphragm (r =&nbsp... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569579 Fri, 30 May 2008 06:00:55 +0100 1569579 http://www.medworm.com/index.php?rid=1569580&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F1382p8w857363062%2F In this study, we developed an automatic extraction scheme for the precise recognition of the contours of masses on digital mammograms in order to improve a computer-aided diagnosis (CAD) system. We propose a radial-searching contour extraction method based on a modified active contour model (ACM). In this technique, after determining the central point of a mass by searching for the direction of the density gradient, we arranged an initial contour at the central point, and the movement of a control point was limited to directions radiating from the central point. Moreover, it became possible to increase the extraction accuracy by sorting out the pixel used for processing and using two images—an edge-intensity image and a degree-of-separation image defined based on the pixel-value h... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569580 Thu, 08 May 2008 05:45:45 +0100 1569580 http://www.medworm.com/index.php?rid=1569581&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fx502p5q6w48382p1%2F In conclusion, sequential soft-tissue images were helpful for tracking of a target affected by respiratory motion. Dual-energy subtraction has the potential to improve the accuracy of IGRT without implanted markers. Content Type Journal ArticleDOI 10.1007/s12194-008-0021-6Authors Rie Tanaka, Graduate School of Medical Science, Kanazawa University Division of Health Sciences, Radiology 5-11-80 Kodatsuno Kanazawa 920-0942 JapanShigeru Sanada, Graduate School of Medical Science, Kanazawa University Division of Health Sciences, Radiology 5-11-80 Kodatsuno Kanazawa 920-0942 JapanTakeshi Matsui, Kanazawa University Hospital Department of Radiology 13-1 Takaramachi Kanazawa 920-8641 JapanNorio Hayashi, Kanazawa University Hospital Department of Radiology 13-1 Takaramachi Kanazawa 920-8641 J... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569581 Wed, 09 Apr 2008 06:26:53 +0100 1569581 http://www.medworm.com/index.php?rid=1569582&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fc7850675t0084151%2F Abstract  Dynamic FPD permits the acquisition of distortion-free radiographs with a large field of view and high image quality. In the present study, we investigated the feasibility of functional imaging for evaluating the pulmonary sequential blood distribution with an FPD, based on changes in pixel values during cardiac pumping. Dynamic chest radiographs of seven normal subjects were obtained in the expiratory phase by use of an FPD system. We measured the average pixel value in each region of interest that was located manually in the heart and lung areas. Subsequently, inter-frame differences and differences from a minimum-intensity projection image, which was created from one cardiac cycle, were calculated. These difference values were then superimposed on dynamic chest... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569582 Tue, 01 Apr 2008 07:06:31 +0100 1569582 http://www.medworm.com/index.php?rid=1569583&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fj793213l7604714j%2F In conclusion, our method will be promising for evaluating the treatment response in tumors visually. Content Type Journal ArticleDOI 10.1007/s12194-008-0019-0Authors Shohei Miyazaki, Osaka University Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine 1-7 Yamadaoka Suita Osaka 565-0871 JapanKenya Murase, Osaka University Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine 1-7 Yamadaoka Suita Osaka 565-0871 JapanYoshifumi Sugawara, Ehime University Department of Radiology, Graduate School of Medicine Tsushikawa Toon Ehime 791-0295 JapanMakoto Kajihara, Ehime University Department of Radiology, Gradu... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569583 Mon, 25 Feb 2008 15:18:53 +0100 1569583 http://www.medworm.com/index.php?rid=1569584&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fq5673854036g778h%2F In this study, in order to simulate the final version of the DOI detector of the project, which uses a larger number of crystal elements, we have developed a much faster and simpler simulator. In this paper the algorithm of the simplified simulator as well as the previously proposed Monte Carlo method is presented and the validation of the simplified simulator through comparisons with the full Monte Carlo simulation and with some experimental results is described. Content Type Journal ArticleDOI 10.1007/s12194-007-0017-7Authors Hideaki Haneishi, Chiba University Research Center for Frontier Medical Engineering 1-33, Yayoi-cho, Inage-ku Chiba 263-8522 JapanMasanobu Sato, Chiba University Research Center for Frontier Medical Engineering 1-33, Yayoi-cho, Inage-ku Chiba 263-8522 Japan... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569584 Mon, 17 Dec 2007 16:06:17 +0100 1569584 http://www.medworm.com/index.php?rid=1569585&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fb16300h837u02120%2F Abstract  To evaluate the clinical usefulness of gantry tilt scanning as an image reconstruction technique for avoiding artifacts caused by metallic dental fillings. Gantry tilt scanning was used with multidetector-row computed tomography for imaging in patients with dental fillings. Using a novel PC-based program, the oblique images obtained were reconstructed to transverse images using nearest neighbor and bilinear interpolation methodologies in order to avoid metallic streak artifacts. Coronal images were reformatted with the reconstructed transverse images, and the continuity of the reconstructed images was evaluated. Gantry tilt scanning was performed in 12 patients with metal artifacts, and the original and reconstructed images were classified into four grades and ass... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569585 Sat, 15 Dec 2007 19:43:17 +0100 1569585 http://www.medworm.com/index.php?rid=1569586&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Fm122827228542462%2F This study demonstrated that the LCS could be clearly visualized on longitudinal scanning in the LLD position. Therefore, this position may potentially be more useful for gastric US, even in view of the limitations of this approach. Content Type Journal ArticleDOI 10.1007/s12194-007-0018-6Authors Koichi Yabunaka, Katsuragi Hospital Department of Radiology 250-1 Makami Cho Kishiwada City Osaka 596-0842 JapanToshizo Katsuda, Himeji Dokkyo University Faculty of Health Care Sciences 7-2-1 Kamiono Himeji City Hyogo 670-0896 JapanShigeru Sanada, Kanazawa University Graduate School of Health Sciences 5-11-80 Kodatsuno Kanazawa City Ishikawa 920-0942 JapanHidetoshi Yatake, Okayama University Graduate School of Health Sciences 5-1 Shikata Cho, 2 Chome Okayama 700-8558 JapanKenyu Yamamoto, Oka... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569586 Wed, 12 Dec 2007 15:38:04 +0100 1569586 http://www.medworm.com/index.php?rid=1569587&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2Ff8636114732l774n%2F Abstract  Our purpose in this study was to compare the energy absorbed in a computed radiography (CR) plate with that absorbed by a film-screen system over the diagnostic X-ray tube voltage range. A Fuji ST-II and Fuji HGM/UR2 were selected as a CR plate and film-screen system, respectively. The X-ray energy absorbed by the phosphor layer (per mA per unit area) was calculated theoretically as an index of the radiographic sensitivity by use of the incident X-ray photon spectrum with the Birch-Marshall formula and the sensitivity spectrum for the range of 40–140 kV. The radiosensitive media were treated as layers involving mass loading. The relative radiographic sensitivity of the ST-II CR plate best approached that of the HGM/UR2 film-screen at 60 kV; it was cons... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569587 Mon, 10 Dec 2007 16:20:22 +0100 1569587 http://www.medworm.com/index.php?rid=1569588&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F714517k73507660u%2F Abstract  The jPET-D4 is a brain positron emission tomography (PET) scanner that we have developed to meet user demands for high sensitivity and high spatial resolution. For this scanner, we developed a four-layer depth-of-interaction (DOI) detector. The four-layer DOI detector is a key component for the jPET-D4, its performance has great influence on the overall system performance. Previously, we reported the original technique for encoding four-layer DOI. Here, we introduce the final design of the jPET-D4 detector and present the results of an investigation on uniformity in performance of the detector. The performance evaluation was done over the 120 DOI crystal blocks for the detectors, which are to be assembled into the jPET-D4 scanner. We also introduce the crystal ass... Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569588 Tue, 04 Dec 2007 20:56:32 +0100 1569588 http://www.medworm.com/index.php?rid=1569589&cid=s_37299_75_f&fid=37299&url=http%3A%2F%2Fspringerlink.com%2Fcontent%2F042436044gn1050m%2F Content Type Journal ArticleDOI 10.1007/s12194-007-0013-yAuthors Kunio Doi, The University of Chicago Department of Radiology Chicago IL USAFujio Araki, Kumamoto University Kumamoto JapanMasahiro Endo, National Institute of Radiological Sciences Chiba JapanShigehiko Katsuragawa, Kumamoto University Kumamoto JapanHideo Murayama, National Institute of Radiological Sciences Chiba JapanShigeru Sanada, Kanazawa University Kanazawa Japan Journal Radiological Physics and TechnologyOnline ISSN 1865-0341Print ISSN 1865-0333 Journal Volume Volume 1 Journal Issue Volume 1, Number 1 / January, 2008 (Source: Radiological Physics and Technology) Radiological Physics and Technology journals http://www.medworm.com/rss/comments.php?id=1569589 Fri, 30 Nov 2007 15:19:20 +0100 1569589