Effect on Heart and Lung Doses Reduction of Abdominal and Thoracic Deep Inspiratory Breath-hold Assuming Involved-field Radiation Therapy in Patients with Simulated Esophageal Cancer.

Purpose: The purpose of this study was to evaluate the lung and heart doses in volumetric-modulated arc therapy (VMAT) using involved-field irradiation in patients with middle-to-lower thoracic esophageal cancer during free breathing (FB), abdominal deep inspiratory breath-hold (A-DIBH), and thoracic DIBH (T-DIBH) images.

Methods: Computed tomography images of A-DIBH, T-DIBH, and FB from 25 patients with breast cancer were used to simulate patients with esophageal cancer. The irradiation field was set at an involved-field, and target and risk organs were outlined according to uniform criteria.

Interim Report of a Japanese Phase II Trial for Cardiac Stereotactic Body Radiotherapy in Refractory Ventricular Tachycardia - Focus on Target Determination.

Cardiac radiotherapy using stereotactic body radiation therapy (SBRT) has attracted attention as a minimally invasive treatment for refractory ventricular tachycardia. However, a standardized protocol and software program for determining the irradiation target have not been established. Here, we report the first preclinical stereotactic radioregulation antiarrhythmic therapy trial in Japan, focused on the target-setting process.

Heavy Ion Irradiation Reduces Vulnerability to Atrial Tachyarrhythmias - Gap Junction and Sympathetic Neural Remodeling.

Background: Low-invasive stereotactic body radiation therapy is a novel anti-arrhythmic strategy. The mechanisms underlying its effects against ventricular tachycardia/fibrillation (VT/VF) are gradually becoming clear, whereas those underlying atrial tachycardia/fibrillation (AT/AF) remain unknown. This study investigated the effects of carbon ion beam on gap junction expression and sympathetic innervation.

[Questionnaire Survey of Japanese Medical Physicists on Working Conditions in 2020].

The questionnaire survey was conducted in 2020 to investigate the working conditions of qualified medical physicists in Japan. We developed a web-based system for administering the questionnaire and surveyed 1,228 qualified medical physicists. The number of received responses was 405.

Comparing the toxicity and disease control rate of radiotherapy for prostate cancer between salvage settings after high-intensity focused ultrasound therapy and initial settings.

The purpose of this retrospective study was to compare the toxicity and disease control rate of radiotherapy for prostate cancer in salvage settings after high-intensity focused ultrasound (HIFU) therapy (HIFU cohort) with those in radical settings (non-HIFU cohort). From 2012 to 2020, 215 patients were identified for this study and 17 were treated in the salvage settings after HIFU. The median follow-up time was 34.

Dosimetric study of whole-brain irradiation with high-energy photon beams for dose reduction to the scalp.

Objective: To evaluate the efficiency of high-energy photons for mitigating alopecia due to whole-brain irradiation (WBRT).

Methods: Planning CT data from 10 patients who received WBRT were collected. We prepared 4 WBRT plans that used 6 or 15 MV photon beams, with or without use of a field-in-field (FiF) technique, and compared outcomes using a treatment planning system.

Basic evaluation of a novel 4D target and human body phantom.

Stereotactic body radiation therapy (SBRT) is usually verified with a dynamic phantom or solid phantom, but there is a demand for phantoms that can accurately simulate tumor dynamics within an individual that would allow customized validation in every patient. We developed a new 4D dynamic target phantom (multi-cell 4D phantom) that allows simulation of tumor movement in patients. The basic quality and dynamic reproducibility of this new phantom was verified in this investigation.

Electron-tracking Compton camera imaging of technetium-95m.

Imaging was conducted using an electron tracking-Compton camera (ETCC), which measures γ-rays with energies in the range of 200-900 keV from 95mTc. 95mTc was produced by the 95Mo(p, n)95mTc reaction on a 95Mo-enriched target. A method for recycling 95Mo-enriched molybdenum trioxide was employed, and the recycled yield of 95Mo was 70%-90%.

Improved proton CT imaging using a bismuth germanium oxide scintillator.

Range uncertainty is among the most formidable challenges associated with the treatment planning of proton therapy. Proton imaging, which includes proton radiography and proton computed tomography (pCT), is a useful verification tool. We have developed a pCT detection system that uses a thick bismuth germanium oxide (BGO) scintillator and a CCD camera.

Educational outcomes of a medical physicist program over the past 10 years in Japan.

The promotion plan for the Platform of Human Resource Development for Cancer (Ganpro) was initiated by the Ministry of Education, Culture, Sports, Science and Technology of Japan in 2007, establishing a curriculum for medical physicists. In this study, we surveyed the educational outcomes of the medical physicist program over the past 10 years since the initiation of Ganpro. The Japan Society of Medical Physics mailing list was used to announce this survey.

Development of proton CT imaging system using plastic scintillator and CCD camera.

A proton computed tomography (pCT) imaging system was constructed for evaluation of the error of an x-ray CT (xCT)-to-WEL (water-equivalent length) conversion in treatment planning for proton therapy. In this system, the scintillation light integrated along the beam direction is obtained by photography using the CCD camera, which enables fast and easy data acquisition. The light intensity is converted to the range of the proton beam using a light-to-range conversion table made beforehand, and a pCT image is reconstructed.

SU-E-I-63: Performance Study of An Electron-Tracking Compton Camera for Medical Imaging.

Purpose: Conventional gamma-ray detector, PET and SPECT, have the limitation of energy and field of view. These limitations are major problems of studying for a new medical imaging. Therefore, we have developed the new imaging detector which is an electron-tracking Compton camera (ETCC).

[New medical imaging based on electron tracking Compton camera (ETCC)].

We have developed an Electron-Tracking Compton Camera (ETCC) for medical imaging due to its wide energy dynamic range (200-1,500keV) and wide field of view (FOV, 3 str). This camera has a potential of developing the new reagents. We have carried out several imaging reagent studies as examples; (1) 18F-FDG and 131I-MIBG simultaneous imaging for double clinical tracer imaging, (2) imaging of some minerals (Mn-54, Zn-65, Fe-59) in mouse and plants.

The acceleration of cosmic-ray protons in the supernova remnant RX J1713.7-3946.

Protons with energies up to approximately 10(15) eV are the main component of cosmic rays, but evidence for the specific locations where they could have been accelerated to these energies has been lacking. Electrons are known to be accelerated to cosmic-ray energies in supernova remnants, and the shock waves associated with such remnants, when they hit the surrounding interstellar medium, could also provide the energy to accelerate protons. The signature of such a process would be the decay of pions (pi(0)), which are generated when the protons collide with atoms and molecules in an interstellar cloud: pion decay results in gamma-rays with a particular spectral-energy distribution.