We aimed to determine the optimal pressure of continuous positive airway pressure (CPAP) for radiotherapy (RT) through changes in the dosimetric parameters and lung volume according to pressure. Patients with locally advanced lung cancer, who underwent CPAP during computed tomography (CT) simulation, were included. The air pressure was raised in five steps of 4, 7, 10, 14, and 17 cmH2O and a CT scan was performed at the baseline and at each pressure step, accompanied by contouring and RT planning. Paired t- and Wilcoxon signed rank tests were used to compare the volumetric and dosimetric parameters according to pressure and interpressure. A total of 29 patients were selected, and 158 CT datasets were obtained. The lung volume increased significantly at all pressures (p < 0.01). The Dmean of the lung decreased significantly from 7 cmH2O (p < 0.01), the V5, V10, V15, and V20 of the lung decreased significantly from 7 cmH2O with increasing pressure, and the Dmean and V5 of the heart decreased significantly from 14 cmH2O with increasing pressure. The V50 showed no significant differences at any pressure. We recommend the use of at least 7 cmH2O with 14 cmH2O as the optimal pressure to achieve the effect of heart preservation.

The bladder is subject to filling variation, which poses a challenge to radiotherapy (RT) delivery. We aimed to assess feasibility and clinical outcomes in patients with bladder cancer treated with adaptive RT (ART) using individualized plan libraries. We retrospectively analyzed 19 patients who underwent RT for muscle-invasive bladder cancer (MIBC) in 2015–2021. Four planning computed tomography (CT) scans were acquired at 15-min intervals, and a library of three intensity-modulated RT plans were generated using internal target volumes (ITVs). A post-treatment cone-beam CT (CBCT) scan was acquired daily to assess intra-fraction filling and coverage. All patients completed the treatment, with 408 post-treatment CBCT scans. The bladder was out of the planning target volume (PTV) range in 12 scans. The volumes of the evaluated PTV plans were significantly smaller than those of conventional PTV. The 1-year and 2-year overall survival rates were 88.2% and 63.7%, respectively. Of eight cases that experienced recurrence, only two developed MIBC. There were no grade 3 or higher RT-related adverse events. ART using plan libraries and ITVs demonstrated good survival outcomes with a high local control rate. Irradiated normal tissue volume and treatment margins may be reduced through this approach, potentially resulting in lower toxicity rates.

The use of IT applications for patients undergoing radiotherapy is limited. This study aimed to develop an integrated system for communication between patients and radiation oncologists using IT technology and report the first test results for the system “Assisted Radiation Oncology Mobile Application” (AROMA). This system consisted of a manager program, a server running on a PC, and a mobile application on a smartphone. A prospective survey was conducted to evaluate the usefulness of this system from October 2020 to January 2021. The survey consisted of a specific questionnaire on basic information and application use by the patients. The management program was designed such that the user (doctor) edits the treatment schedule, member (patient and doctor) information, self-management, disease information, and side effect questionnaire. The mobile application for patients consisted of the current schedule, treatment schedule calendar, side effect questionnaire, side effect management method, and disease information entered by the doctor. A total of 41 patients were enrolled in this study. The mean adverse event response time was 4.4 days. In the survey, the mobile application received positive views (8.6/10 points). Most responses related to the side effect reporting function (94%) and communication using the application (91%) were positive. Satisfaction with the application design and each menu item was high, with an average of ≥8 and ≥8.5 points in most cases, respectively. The survey showed good satisfaction with the design, operability, and reporting system. Therefore, the system can facilitate communication between patients and radiation oncologists in the future.

The purpose of this study was to compare the clinical quality assurance results of portal dosimetry using an electronic portal imaging device, a method that is extensively used for patientspecific quality assurance, and the newly released Mobius3D for intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT).Methods: This retrospective study includes data from 122 patients who underwent IMRT and VMAT on the Novalis Tx and VitalBeam linear accelerators between April and June 2020. We used a paired t-test to compare portal dosimetry using an electronic portal imaging device and the average gamma passing rates of MobiusFX using log files regenerated after patient treatment. Results:The average gamma passing rates of portal dosimetry (3%/3 mm) and MobiusFX (5%/3 mm) were 99.43%±1.02% and 99.32%±1.87% in VitalBeam and 97.53%±3.34% and 96.45%±13.94% in Novalis Tx, respectively. Comparison of the gamma passing rate results of portal dosimetry (3%/3 mm) and MobiusFX (5%/3 mm as per the manufacturer's manual) does not show any statistically significant difference.Conclusions: Log file-based patient-specific quality assurance, including independent dose calculation, can be appropriately used in clinical practice as a second-check dosimetry, and it is considered comparable with primary quality assurance such as portal dosimetry.