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Evaluation of overexposure risk when there is a space between the subject and the couch in computed tomography: a phantom study
AbstractThe purpose of this study was to investigate the risk of overexposure associated with automatic tube current modulation (ATCM) and automatic couch height positioning compensation mechanism (AHC) in computed tomography (CT) systems, particularly in scenarios involving a gap between the subject and the couch. Results revealed that when AHC was enabled, CT dose index volume (CTDIvol) increased by approximately 10% at 2.5  cm, 20% at 5.0 cm, and 40% at 10.0 cm gaps compared to close contact conditions. While the AHC function ensures consistent exposure doses and image quality regardless of subject positioning relati...
Source: Radiological Physics and Technology - April 26, 2024 Category: Physics Source Type: research

Utility of a skin marker –less setup procedure using surface-guided imaging: a comparison with the traditional laser-based setup in extremity irradiation
This study aimed to assess the feasibility of a skin marker –less patient setup using a surface-guided radiotherapy (SGRT) system for extremity radiotherapy. Twenty-five patients who underwent radiotherapy to the extremities were included in this retrospective study. The first group consisted of 10 patients and underwent a traditional setup procedure using skin marks and lasers. The second group comprised 15 patients and had a skin marker–less setup procedure that used an SGRT system only. To compare the two setup procedures for setup accuracy, the mean 3D vector shift magnitude was 0.9 mm for the traditional setup pr...
Source: Radiological Physics and Technology - April 26, 2024 Category: Physics Source Type: research

Predicting oxygen needs in COVID-19 patients using chest radiography multi-region radiomics
The objective is to evaluate the performance of blood test results, radiomics, and a combination of the two data types on the prediction of the 24-h oxygenation support need for the Coronavirus disease 2019 (COVID-19) patients. In this retrospective cohort study, COVID-19 patients with confirmed real-time reverse transcription-polymerase chain reaction assay (RT-PCR) test results between February 2020 and August 2021 were investigated. Initial blood cell counts, chest radiograph, and the status of oxygenation support used within 24  h were collected (n = 290; mean age, 45 ± 19 years; 125 men). Radiomics features...
Source: Radiological Physics and Technology - April 26, 2024 Category: Physics Source Type: research

An audit of patient radiation doses during interventional cardiology procedures in Uttarakhand, India, and establishment of local diagnostic reference levels
The objective of this study was to investigate patient radiation doses by a dose audit of three common interventional cardiology (IC) procedures: coronary angiography (CA), percutaneous transluminal coronary angioplasty (PTCA) and CA –PTCA procedures performed in IC centres in the Uttarakhand state of India, for the establishment of local diagnostic reference levels (DRLs) and the estimation of average effective dose (Eav) for these procedures. For each procedure, the values of kerma-area product (PKA), reference air kerma (Ka,r), fluoroscopy time (FT) and the number of cine images were recorded from 1233 CA, 458 PTCA an...
Source: Radiological Physics and Technology - April 23, 2024 Category: Physics Source Type: research

Evaluation of hafnium oxide nanoparticles imaging characteristics as a contrast agent in X-ray computed tomography
AbstractThis research aimed to compare the quantitative imaging attributes of synthesized hafnium oxide nanoparticles (NPs) derived from UiO-66-NH2(Hf) and two gadolinium- and iodine-based clinical contrast agents (CAs) using cylindrical phantom. Aqueous solutions of the studied CAs, containing 2.5, 5, and 10  mg/mL of HfO2NPs, gadolinium, and iodine, were prepared. Constructed within a cylindrical phantom, 15  cc small tubes were filled with CAs. Maintaining constant mAs, the phantom underwent scanning at tube voltage variations from 80 to 140 kVp. The CT numbers were quantified in Hounsfield units (HU), and the contras...
Source: Radiological Physics and Technology - April 17, 2024 Category: Physics Source Type: research

Simulation of time –intensity curve based on k-space filling in breast dynamic contrast-enhanced three-dimensional magnetic resonance imaging
This study elucidated the effects of a three-dimensional k-space trajectory incorporating the partial Fourier (PF) technique on a time –intensity curve (TIC) in a dynamic contrast-enhanced magnetic resonance imaging of a typical malignant breast tumor using a digital phantom. Images were obtained from the Cancer Imaging Archive Open Data for Breast Cancer, and 1-min scans with high temporal resolution were analyzed. The order of the k-space trajectory was set as Linear (sequential), Low–High (centric), PF (62.5%; Z-, Y-, and both directions), and Low–High Radial. k0 (center of the k-space) timing and TIC shape were a...
Source: Radiological Physics and Technology - April 13, 2024 Category: Physics Source Type: research

Cameron ’s impact on space biomedical sciences—expanding insights to Ng and Doi’s article
(Source: Radiological Physics and Technology)
Source: Radiological Physics and Technology - April 12, 2024 Category: Physics Source Type: research

Patient radiation exposure dose reduction using stent-enhanced image processing in percutaneous coronary intervention
We examined the effects of dose reduction based on the image quality of stent enhancement processing using a purpose-built dynamic phantom. We evaluated the image contrast (IC) of the stent in stent-enhanced images (SVref), digital angiography (DA), and stent-enhanced images with a 20%, 40%, and 60% lower imaging doses (SV20, SV40, and SV60). We visually evaluated graininess and stent shape using the mean opinion score (MOS) and retrospectively evaluated the acquisition duration of stent enhancement in PCI cases; finally, we estimated the decrease in patient radiation exposure due to stent enhancement. The image contrast o...
Source: Radiological Physics and Technology - April 5, 2024 Category: Physics Source Type: research

Monte carlo simulation study on the dose and dose-averaged linear energy transfer distributions in carbon ion radiotherapy
In this study, we calculated the physical doses and their linear energy transfer (LET) distributions for patterns of typical CIRT beams using Monte Carlo (MC) simulation. The LETd was then deduced from the MC simulation and compared with that obtained from the conventional method. The two types of LETd agreed well with each other, except around the distal end of the spread-out Bragg peak. Furthermore, an MC simulation was conducted with the material composition of water and realistic materials. The profiles of physical dose and LETd were in good agreement for both techniques. These results indicate that the previous studie...
Source: Radiological Physics and Technology - April 3, 2024 Category: Physics Source Type: research

An image-based metal artifact reduction technique utilizing forward projection in computed tomography
AbstractThe projection data generated via the forward projection of a computed tomography (CT) image (FP-data) have useful potentials in cases where only image data are available. However, there is a question of whether the FP-data generated from an image severely corrupted by metal artifacts can be used for the metal artifact reduction (MAR). The aim of this study was to investigate the feasibility of a MAR technique using FP-data by comparing its performance with that of a conventional robust MAR using projection data normalization (NMARconv). The NMARconv was modified to make use of FP-data (FPNMAR). A graphics processi...
Source: Radiological Physics and Technology - March 28, 2024 Category: Physics Source Type: research

Native myocardial T1 mapping using inversion recovery T1-weighted turbo field echo sequence
This study proposes the use of the inversion recoveryT1-weighted turbo field echo (IR-T1TFE) sequence for myocardialT1 mapping and compares the results obtained with those of the modified Look-Locker inversion recovery (MOLLI) method for accuracy, precision, and reproducibility. A phantom containing seven vials with differentT1 values was imaged, thereby comparing theT1 measurements between the inversion recovery spin-echo (IR-SE) technique, MOLLI, and the IR-T1TFE. The accuracy, precision, and reproducibility of theT1-mapping sequences were analyzed in a phantom study. Fifteen healthy subjects were recruited for the in vi...
Source: Radiological Physics and Technology - March 26, 2024 Category: Physics Source Type: research