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.

Evaluation of 3D-printed bolus for radiotherapy using megavoltage X-ray beams
In this study, the dosimetric properties of two 3D-printed filament materials, polylactic acid (PLA) and thermoplastic polyether urethane (TPU), used as radiotherapy boluses, were investigated. The dosimetric properties of PLA and TPU were compared with those of several conventional bolus materials and RMI457 Solid Water. Percentage depth-dose (PDD) measurements in the build-up region were performed for all materials using 6 and 10 MV photon treatment beams on Varian linear accelerators. The results showed that the differences in the PDDs of the 3D-printed materials from the RMI457 Solid Water were within 3%, whereas those...
Source: Radiological Physics and Technology - June 9, 2023 Category: Physics Source Type: research

Accuracy of skull stripping in a single-contrast convolutional neural network model using eight-contrast magnetic resonance images
In conclusion, PD-WI, PSIR, and PD-STIR should be used instead of T1-WI for skull stripping in the CNN models. (Source: Radiological Physics and Technology)
Source: Radiological Physics and Technology - June 8, 2023 Category: Physics Source Type: research

Usefulness of copper filters in digital chest radiography based on the relationship between effective detective quantum efficiency and deep learning-based segmentation accuracy of the tumor area
This study aimed to determine the optimal radiographic conditions for detecting lesions on digital chest radiographs using an indirect conversion flat-panel detector with a copper (Cu) filter. First, we calculated the effective detective quantum efficiency (DQE) by considering clinical conditions to evaluate the image quality. We then measured the segmentation accuracy using a U-net convolutional network to verify the effectiveness of the Cu filter. We obtained images of simulated lung tumors using 10-mm acrylic spheres positioned at the right lung apex and left middle lung of an adult chest phantom. The Dice coefficient w...
Source: Radiological Physics and Technology - June 1, 2023 Category: Physics Source Type: research

Nationwide survey on the current situation of quality control of diagnostic displays in Japan
AbstractThe Japan Association of Radiological Technologists (JART) and the Japan Medical Imaging and Radiological Systems Industries Association jointly conducted a nationwide survey to reveal the current situation of diagnostic displays in Japan using a questionnaire on the performance and quality control (QC) of diagnostic displays for mammography and common use. The questionnaire for radiological technologists (RTs) was distributed via email to 4519 medical facilities throughout Japan, where RTs affiliated with JART were employed; 613 (13.6%) facilities responded. Diagnostic displays with suitable maximal luminance (500...
Source: Radiological Physics and Technology - June 1, 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 - June 1, 2023 Category: Physics Source Type: research

Helical tomotherapy and two types of volumetric modulated arc therapy: dosimetric and clinical comparison for several cancer sites
AbstractRadiotherapy accelerators have undergone continuous technological developments. We investigated the differences between Radixact ™ and VMAT treatment plans. Sixty patients were included in this study. Dosimetric comparison between the Radixact™ and VMAT plans was performed for six cancer sites: whole-brain, head and neck, lymphoma, lung, prostate, and rectum. The VMAT plans were generated with two Elekta linear accelerato rs (Synergy® and Versa HD™). The planning target volume (PTV) coverage, organs-at-risk dose constraints, and four dosimetric indexes were considered. The deliverability of the plans was as...
Source: Radiological Physics and Technology - June 1, 2023 Category: Physics Source Type: research

Comparison of dosimetric parameters and robustness for rotational errors in fractionated stereotactic irradiation using automated noncoplanar volumetric modulated arc therapy for patients with brain metastases: single- versus multi-isocentric technique
AbstractTo compare the dosimetric parameters of automated noncoplanar volumetric modulated arc therapy plans using single-isocentric (SIC) and multi-isocentric (MIC) techniques for patients with two brain metastases (BMs) in stereotactic irradiation and to evaluate the robustness of rotational errors. The SIC and MIC plans were retrospectively generated (35  Gy/five fractions) for 58 patients. Subsequently, a receiver operating characteristic curve analysis between the tumor surface distance (TSD) andV25Gy was performed to determine the thresholds for the brain tissue. The SIC and MIC plans were recalculated based on the ...
Source: Radiological Physics and Technology - June 1, 2023 Category: Physics Source Type: research

Long-term experience in quality assurance of on-rail computed tomography systems for image-guided radiotherapy using in-house multifunctional phantoms
This study reported the QA status of the system during the period 2014–2021. The absolute mean accuracy of couch rotation was 0.4 ± 0.28 mm, 0.44 ± 0.36 mm, and 0.37 ± 0.27 mm in th e SI, RL, and AP directions, respectively. Horizontal and remote movement accuracies of the treatment couch were also within 0.5 mm of the absolute mean value. A decrease in the accuracy of couch rotation was also observed due to aging deterioration of related parts caused by the frequent use of co uch rotation. The three-dimensional accuracy of on-rail CT systems derived mainly from treatment couches can be maintained with...
Source: Radiological Physics and Technology - June 1, 2023 Category: Physics Source Type: research

Creation, evolution, and future challenges of ion beam therapy from a medical physicist ’s viewpoint (Part 2). Chapter 2. Biophysical model, treatment planning system and image guided radiotherapy
AbstractWhen an ion beam penetrates deeply into the body, its kinetic energy decreases, and its biological effect increases due to the change of the beam quality. To give a uniform biological effect to the target, it is necessary to reduce the absorbed dose with the depth. A bio-physical model estimating the relationship between ion beam quality and biological effect is necessary to determine the relative biological effectiveness (RBE) of the ion beam that changes with depth. For this reason, Lawrence Berkeley Laboratory, National Institute of Radiological Sciences (NIRS) and GSI have each developed their own model at the ...
Source: Radiological Physics and Technology - June 1, 2023 Category: Physics Source Type: research

Dr. Kunio Doi is awarded the 23rd Gray Medal by the ICRU
(Source: Radiological Physics and Technology)
Source: Radiological Physics and Technology - June 1, 2023 Category: Physics Source Type: research

Number of computed tomography scanners and regional disparities based on population and medical resources in Japan
This study aimed to discover the associations between the number of computed tomography (CT) scanners and the population, as well as number of medical resources to identify regional disparities in Japan. The number of CT scanners was tabulated for each detector row of CT scanners for hospitals and clinics in each prefecture. The number of CT scanners, patients, medical doctors, radiological technologists, facilities, and beds per 100,000 population was compared. Additionally, the number of hospitals with  ≥ 200 beds and multidetector-row CT scanners with ≥ 64 rows were tabulated, and their ratios were calculate...
Source: Radiological Physics and Technology - May 18, 2023 Category: Physics Source Type: research

Dr. Kunio Doi is awarded the 23rd Gray Medal by the ICRU
(Source: Radiological Physics and Technology)
Source: Radiological Physics and Technology - May 5, 2023 Category: Physics Source Type: research

Creation, evolution, and future challenges of ion beam therapy from a medical physicist ’s viewpoint (Part 2). Chapter 2. Biophysical model, treatment planning system and image guided radiotherapy
AbstractWhen an ion beam penetrates deeply into the body, its kinetic energy decreases, and its biological effect increases due to the change of the beam quality. To give a uniform biological effect to the target, it is necessary to reduce the absorbed dose with the depth. A bio-physical model estimating the relationship between ion beam quality and biological effect is necessary to determine the relative biological effectiveness (RBE) of the ion beam that changes with depth. For this reason, Lawrence Berkeley Laboratory, National Institute of Radiological Sciences (NIRS) and GSI have each developed their own model at the ...
Source: Radiological Physics and Technology - May 2, 2023 Category: Physics Source Type: research