Radiological Physics and Technology This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Sensitivity of a bone-equivalent polymer gel dosimeter for measuring the dose to bone during radiation therapy
In this study, we developed a bone-equivalent polymer gel dosimeter (BPGD) that can measure the dose absorbed by the bone and investigated its sensitivity. The BPGDs were prepared by adding 3.0 mol of calcium hydrogen phosphate dihydrate as a component of bone to an improved dose-sensitive polyacrylamide gelatin and tetrakis hydroxymethyl phosphonium chloride (iPAGAT). One day after preparation, the BPGDs were irradiated with a field size of 15 × 15 cm2 using a 10 MV X-ray beam to evaluate the dose sensitivity, dose-rate dependence, and dose-integration dependence. One day after dose exposure, the BPGDs were scanned...
Source: Radiological Physics and Technology - March 22, 2023 Category: Physics Source Type: research

Virtual clinical trial based on outcome modeling with iteratively redistributed extrapolation data
In this study, we developedExMixup, a novel training technique based on machine learning, using iteratively redistributed extrapolated data. Information obtained from 100 patients with prostate cancer and 385 patients with oropharyngeal cancer was used to predict the recurrence after radiotherapy. Model performance was evaluated by developing outcome prediction models based on three types of training methods: training with original data (baseline), interpolation data (Mixup), and interpolation + extrapolation data (ExMixup). Two types of VCTs were conducted to predict the treatment response of patients with distinct c...
Source: Radiological Physics and Technology - March 22, 2023 Category: Physics Source Type: research

Optimum selection for multi-interaction events in Compton-PET hybrid reconstruction: a Monte Carlo study
In this study, we aimed to establish a method to maximize image quality by utilizing such redundant events. We conducted brain-scale Monte Carlo simulations of a C-shaped Compton-PET geometry and a whole gamma imaging (WGI) geometry. Images were reconstructed by a hybrid image reconstruction method combining both PET and Compton events. The result showed that the spatial resolution was improved when treated as PET events while keeping the noise level. The effect of improvement was more significant in WGI than in C-shaped Compton PET because the number of events recovered as PET events having more accurate spatial informati...
Source: Radiological Physics and Technology - March 21, 2023 Category: Physics Source Type: research

Validation of the DoseCalcs Monte Carlo code for estimating the 18F S-values for ICRP adult and 15-year-old male and female phantoms
In this study, we applied DoseCalcs, a new Geant4-based tool, to estimate theS values of\(^{18}\)F using nuclear data from ICRP Publication 107. Geometrical data from ICRP Publications 110 and 143 were used to select four models representing male and female phantoms for adults and 15 years old to study the variability in theS-values arising from variations in anatomy and initial energy validations, because we used the\(\beta\) mean energy instead of the full beta spectrum. The\(^{18}\)F-released photons and\(\beta\) from 26 source organs were tracked using the Geant4 Livermore package. Accordingly, theS-values were calcula...
Source: Radiological Physics and Technology - March 14, 2023 Category: Physics Source Type: research

Evaluation of motion artifacts reduction software that compensate for respiratory movements in the craniocaudal direction during abdominal cone-beam computed tomography
AbstractWe acquired cone-beam computed tomography (CBCT) images of a locally made contrast-enhanced hepatic artery phantom under various conditions, both with the phantom still, and while moving it from the cranial to the caudal position. All the motion CBCT images were processed with and without motion artifacts reduction software (MARS). We calculated some quantitative similarity indexes between the still CBCT images (no-motion) and the motion CBCT images both processed with MARS (MARS ON) and without MARS (MARS OFF). In addition, the vessel signal values under the same movement conditions of the MARS ON/OFF and no-motio...
Source: Radiological Physics and Technology - March 7, 2023 Category: Physics Source Type: research

Impact of bone-equivalent solution density in a thoracic spine phantom on bone single-photon emission computed tomography image quality and quantification
In conclusion, SPECT image quality and quantification depends on the presence and concentration of the bone-equivalent solution. The optimal bone-equivalent solution density should be used to evaluate the bone image phantoms. (Source: Radiological Physics and Technology)
Source: Radiological Physics and Technology - March 6, 2023 Category: Physics Source Type: research

Dose estimation for cone-beam computed tomography in image-guided radiation therapy for pelvic cancer using adult mesh-type reference computational phantoms
AbstractThe use of cone-beam computed tomography (CBCT) is expanding owing to its installation in linear accelerators for radiation therapy, and the imaging dose induced by this system has become the center of attention. Here, the dose to patients caused by the CBCT imager was investigated. Organ doses and effective doses for male and female mesh-type reference computational phantoms (MRCPs) and pelvis CBCT mode, routinely used for pelvic irradiation, were estimated using the Particle and Heavy Ion Transport Code System. The simulation results were confirmed based on the point-dose measurements. The estimated organ doses f...
Source: Radiological Physics and Technology - March 6, 2023 Category: Physics Source Type: research

Investigation of the nuclear radiation interaction parameters of selected polymers for radiation therapy and dosimetry
This study is expected to be useful for radiation therapy and dosimetry. (Source: Radiological Physics and Technology)
Source: Radiological Physics and Technology - February 23, 2023 Category: Physics Source Type: research

Neutron dose from a 6-MV X-ray beam in radiotherapy
This study aimed to theoretically deduce the neutron dose from a 6-MV beam using Monte Carlo simulations for the notification of safety and risk in radiotherapy. Nuclei from a nuclear database with neutron separation energies below 6 MeV were surveyed, suggesting that the certain content of2H in the human body may result in some contribution. Thus, Monte Carlo calculation considering2H in a phantom was performed. The calculation suggested that the distribution of the neutron dose from a 6-MV beam consisted of two components: one had neutrons from2H concentrated within an irradiation field, and the other had those due to ...
Source: Radiological Physics and Technology - February 13, 2023 Category: Physics Source Type: research