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Purpose: To analyze the respiratory‐induced motion trajectories of each liver segment for hepatocellular carcinoma (HCC) to derive a more accurate internal margin and optimize treatment protocol selection. Materials and Methods: Ten‐phase‐gated four‐dimensional computed tomography (4DCT) scans of 14 patients with HCC were analyzed. For each patient, eight representative regions of interest (ROI) were delineated on each liver segment in all 10 phases. The coordinates of the center of gravity of each ROI were obtained for each phase, and then the respiratory motion in the left–right (LR), anteroposterior (AP), and craniocaudal (CC) directions was analyzed. Two sets of motion in each direction were also compared in terms of only two extreme phases and all 10 phases. Results: Motion of less than 5 mm was detected in 12 (86%) and 10 patients (71%) in the LR and AP directions, respectively, while none in the CC direction. Motion was largest in the CC direction with a maximal value of 19.5 mm, with significant differences between liver segment 7 (S7) and other segments: S1 (p < 0.036), S2 (p < 0.041), S3 (p < 0.016), S4 (p < 0.041), and S5 (p < 0.027). Of the 112 segments, hysteresis >1 mm was observed in 4 (4%), 2 (2%), and 15 (13%) in the LR, AP, and CC directions, respectively, with a maximal value of 5.0 mm in the CC direction. Conclusion: A significant amount of respiratory motion was detected in the CC direction, especially in S7, and S8. Despite the small effect of hysteresis, it can be observed specifically in the right lobe. Therefore, caution is required when using 4DCT to determine IM using only end‐inspiration and end‐expiration. Understanding the respiratory motion in individual liver segments can be helpful when selecting an appropriate treatment protocol. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the dosimetric effect of six degrees of freedom (6DoF) couch top with rotational corrections in proton therapy (PT). Methods: The water equivalent thickness (WET) was measured using a proton beam with a 6DoF couch top and patient immobilization base plate (PIBP) placed in front of a motorized water phantom. The accuracy verification was performed with the beam axis set perpendicular to the 6DoF couch top and tilted in 10° steps from 10° to 30°. Up to 3° rotational correction may be added during the actual treatment to correct the rotational setup error on our system. The measured and calculated values using the treatment planning system were compared. Additionally, the effect of the 3° difference was evaluated using actual measurements concerning each angle on the proton beam range. Results: The WET of the 6DoF couch top and PIBP were 8.5 ± 0.1 mm and 6.8 ± 0.1 mm, respectively. The calculation and the actual measurement at each angle agreed within 0.2 mm at the maximum. A maximum difference of approximately 0.6 mm was confirmed when tilted at 3° following 30° with the 6DoF couch top plus PIBP. Conclusions: The dosimetric effect of the 6DoF couch top with rotational corrections in PT differs depending on the incidence angle on the couch top, and it increased with the increased oblique angle of incidence. However, the effect on the range was as small as 0.6 mm at the maximum. The amount of rotational correction, the angle of incidence of the beam, and the effect of rotational corrections on the proton beam range may differ depending on the structure of the couch top. Therefore, sufficient prior confirmation, and subsequent periodical quality assurance management are important. [ABSTRACT FROM AUTHOR]

Background: We conducted a historical cohort study of patients with schizophrenia to identify more robust risk factors at discharge that contribute to readmission within a year. Methods and Findings: The subjects underwent brief psychoeducation during hospitalization. Multivariate analysis was conducted using factors selected in the univariate analysis. Using logistic regression analysis, the number of hospital admissions (P =.01) and Schedule for Assessment of Insight Japanese version score (P =.04) were identified as risk factors for readmission, with odds ratios of 0.70 and 1.18, respectively. Conclusions: These results suggest that improvement in insight and early intervention may lead to a more stable community life. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the dosimetric impact of changes in the large bowel content during proton therapy (PT) with simultaneous integrated boost (SIB) for locally advanced pancreatic cancer (LAPC). Materials and methods: Fifteen patients with LAPC were included in this study. The SIB method was performed using five fields according to our standard protocol. A total dose of 67.5 Gy(relative biological effectiveness [RBE]) was prescribed in 25 fractions using the SIB method. A dose of 45 Gy(RBE) was prescribed for the entire planning target volume (PTV) by using four main fields. The remaining 22.5 Gy(RBE) was prescribed to the PTV excluding for the gastrointestinal tract using one subfield. Five simulated doses were obtained by the forward dose calculations with the Hounsfield units (HU) override to the large bowel to 50, 0, −100, −500, and −1000, respectively. The dose‐volume indices in each plan were compared using the 50 HU plan as a reference. Results: At D98 of the clinical target volume (CTV) and spinal cord‐D2cc, when the density of the large bowel was close to that of gas, there were significant differences compared to the reference plan (p < 0.05). By contrast, no significant difference was observed in stomach‐D2cc duodenum‐D2cc, small bowel‐D2cc, kidneys‐V18, and liver‐Dmean under any of the conditions. There were no cases in which the dose constraint of organs at risk, specified by our institution, was exceeded. Conclusion: Density change in the large bowel was revealed to significantly affect the doses of the CTV and spinal cord during PT with SIB for LAPC. For beam arrangement, it is important to select a gantry angle that prevents the large bowel from passing as much as possible. If this is unavoidable, it is important to carefully observe the gas image on the beam path during daily image guidance and to provide adaptive re‐planning as needed. [ABSTRACT FROM AUTHOR]