Publications by authors named "Tomohiro Sagawa"
Article Synopsis
- The study investigates how self-expandable metallic stents (SEMSs) affect radiation doses compared to plastic stents (PSs) during biliary decompression, using a water-equivalent phantom for evaluation.
- Results show that SEMSs generally cause smaller dose differences in radiation delivery compared to PSs, particularly in proximal and distal locations, which is statistically significant.
- However, significant dose variations were noted at the surfaces of the radiopaque markers on SEMSs, suggesting that while SEMSs can be used safely in patients undergoing radiation therapy, careful monitoring of dose distribution is essential.
Purpose: The study aimed to investigate the optimal isodose line (IDL) in linear accelerator-based stereotactic radiotherapy for single brain metastasis, using HyperArc. We compared the dosimetric parameters for target and normal brain tissue among six plans with different IDLs.
Methods: This study included 30 patients with single brain metastasis.
Article Synopsis
- A portable respiratory training system called the Gyroscope Respiratory Training System (GRTS) was developed to assess the feasibility of respiratory training.
- The study involved comparing respiratory waveforms from patients using GRTS and another system, the Respiratory Gating for Scanners (RGSC), to evaluate the stability and reproducibility of these waveforms during expiratory breath-hold radiation therapy.
- Results showed that GRTS provided similar accuracy to RGSC and effectively reduced variability in respiratory waveforms among patients, indicating its potential as an affordable and functional tool for respiratory training in clinical settings.
Article Synopsis
- The study investigates how the distance between the CBCT isocenter and the brain center (DBI) affects image quality in stereotactic irradiation for brain metastasis.
- Using both a phantom study and a patient study, researchers found that greater distances resulted in poorer image quality, particularly in objective measures like contrast-to-noise ratio and artifact levels.
- The findings suggest that aligning the CBCT isocenter with the brain center can enhance image quality and improve patient treatment outcomes.
Article Synopsis
- The study assessed the effectiveness of an immobilization system using a shell and wooden baseplate (SW) for lung stereotactic body radiotherapy (SBRT) by comparing setup errors and dose absorption to those from a BodyFix system (BF).
- In 109 patients, setup errors were measured, showing that both SW and BF achieved high accuracy, with over 90% success in keeping errors within 3 mm for interfractional and intrafractional shifts.
- The results indicated that the wooden baseplate had lower dose attenuation and a lesser impact on dose distribution compared to the carbon baseplate, making it a viable option for effective SBRT.
Objective: Dosimetric potential of knowledge-based RapidPlan planning model trained with HyperArc plans (Model-HA) for brain metastases has not been reported. We developed a Model-HA and compared its performance with that of clinical volumetric modulated arc therapy (VMAT) plans.
Methods: From 67 clinical stereotactic radiosurgery (SRS) HyperArc plans for brain metastases, 47 plans were used to build and train a Model-HA.
Article Synopsis
- * Administering CX3CL1 to aged mice reversed cellular aging markers and boosted the activity of immune cells in the peritoneal cavity, leading to increased neural stem cells and the brain's growth factor (BDNF) in the hippocampus.
- * The treatment improved memory recognition in aged mice, indicating a significant link between peritoneal cells, the vagus nerve, and brain function in reversing age-related memory decline.
Background/aim: The aim of this retrospective study was to detect the frequency, reasons, and significant factors for not receiving immunotherapy after chemoradiotherapy in non-small cell lung cancer (NSCLC) patients.
Patients And Methods: Thirty-four patients with NSCLC received definitive chemoradiotherapy. The endpoint of this study was receiving durvalumab within 45 days after chemoradiotherapy for NSCLC.
Purpose: The aim of this study was to develop a deep learning (DL) method for generating virtual noncontrast (VNC) computed tomography (CT) images from contrast-enhanced (CE) CT images (VNC ) and to evaluate its performance in dose calculations for head and neck radiotherapy in comparison with VNC images derived from a dual-energy CT (DECT) scanner (VNC ).
Methods: This retrospective study included data for 61 patients who underwent head and neck radiotherapy. All planning CT images were obtained with a single-source DECT scanner (80 and 140 kVp) with rapid kVp switching.
Purpose: In stereotactic radiosurgery (SRS) with single-isocentric treatments for brain metastases, rotational setup errors may cause considerable dosimetric effects. We assessed the dosimetric effects on HyperArc plans for single and multiple metastases.
Methods: For 29 patients (1-8 brain metastases), HyperArc plans with a prescription dose of 20-24 Gy for a dose that covers 95% (D ) of the planning target volume (PTV) were retrospectively generated (Ref-plan).
We assessed the effect of collimator angle on the dosimetric parameters for targets and organs at risk (OARs) for collimator-optimized HA (CO-HA) and non-CO-HA (nCO-HA) plans. The nCO-HA and CO-HA plans were retrospectively generated for 26 patients (1 to 8 brain metastases). The dosimetric parameters for planning target volume (homogeneity index [HI]; conformity index [CI]; gradient index [GI]) and for OARs were compared.
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