Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Technical Innovations and Patient Support in Radiation Oncology  

Introduction: This study evaluated dosimetric values of cone beam computed tomography (CBCT)-guided online adaptive radiotherapy (oART) in patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma, accounting for interfractional and intrafractional motion. Methods: Four patients with stage I gastric MALT lymphoma received CBCT-guided oART. For each of the 60 treatment sessions, scheduled (SCH) and adapted (ADP) plans were generated. Dosimetric evaluation focused on clinical target volume (CTV) and organs at risk (OARs). Metrics included CTV D98 % and D95 %, mean dose to the liver and left and right kidneys, maximum dose to the spinal cord, and V5Gy for bilateral kidneys. Adaptive planning CBCT-based contours were propagated to synthetic CTs of SCH and ADP plans to assess interfractional motion. Post-treatment CBCT-based contours were propagated to synthetic CTs of the ADP plan to evaluate intrafractional motion. Results: ADP plans significantly improved CTV coverage: mean D98% increased from 94.7 % in the SCH plan to 98.6 %, and D95% from 97.3 % to 99.2 % (p < 0.001). Most OAR doses were reduced in the ADP plans, including bilateral kidney V5Gy (11.3 % vs. 8.3 %, p < 0.001) and spinal cord Dmax (9.8 Gy vs. 7.9 Gy, p < 0.001). Liver Dmean was slightly higher in the ADP plan (11.4 Gy vs. 11.1 Gy, p = 0.002). No significant differences were observed in CTV and OAR dosimetric parameters between adaptive planning and post-treatment CBCTs (e.g., CTV D98%: 98.6 % vs. 98.5 %, p = 0.629). Conclusion: CBCT-guided oART improved target coverage and maintained post-treatment dosimetric stability in gastric MALT lymphoma, supporting clinical feasibility.

DOI： 10.1016/j.tipsro.2025.100321

Web of Science

Scopus

PubMed

Language：English   Publisher：Practical Radiation Oncology  

Purpose: We hypothesized that online adaptive radiation therapy (oART) could eliminate errors associated with interfractional deformation in gastric mucosa-associated lymphoid tissue (MALT) lymphoma, but errors in intrafractional deformation remained in 6 directions (anterior, posterior, superior, inferior, left, and right). This study aimed to quantify the anisotropic deformation errors of the clinical target volume (CTV) for MALT lymphoma using oART to determine deformations in the planning target volume (PTV) margins. Methods and Materials: Thirty fractional scans from 4 consecutive patients (a total of 120 cone beam computed tomography scans) with gastric MALT lymphoma treated with oART were chosen for this retrospective study. The CTV contours were manually delineated on the pretreatment and posttreatment cone beam computed tomography images. The center-of-mass matching of the CTVs was performed following the bone anatomy matching. Systematic and random errors of intrafractional deformations of the CTV were quantified using displacement vectors between the pretreatment and posttreatment CTV surfaces for each fraction. The PTV margins for oART were anisotropically calculated using the van Herk formula: 2.5Σ + 0.7σ, accounting for intrafractional errors. Results: For intrafractional deformation, the means of standard deviations of systematic errors ranged from 1.2 mm to 2.2 mm, whereas those of random errors ranged from 2.9 mm to 3.6 mm. The PTV margins were up to 13.1 mm in the inferior direction, whereas in other directions, they ranged from 9.7 mm to 12.8 mm. The PTV margin in integer achieved posttreatment CTV coverage for 90% of the fractions, with undercoverage volumes remaining below 0.6 cm³ in all fractions. Conclusions: This study suggests that the impact of intrafractional CTV deformation can not be eliminated even with oART. This highlights the need to set the appropriate anisotropic PTV margins.

DOI： 10.1016/j.prro.2025.05.008

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Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Radiation Research  

The aim of this study was to investigate planning target volume (PTV) margin in online adaptive radiation therapy (oART) for gastric mucosa-associated lymphoid tissue (MALT) lymphomas. Four consecutive patients with gastric MALT lymphoma who received oART (30 Gy in 15 fractions) on the oART system were included in this study. One hundred and twenty cone-beam computed tomography (CBCT) scans acquired pre- and post-treatment of 60 fractions for all patients were used to evaluate intra- and interfractional motions. Patients were instructed on breath-holding at exhalation during image acquisition. To assess the intrafraction gastric motion, different PTVs were created by isotropically extending the CTV contoured on a pre-CBCT image (CTV<inf>pre</inf>) at1 mm intervals. Intrafraction motion was defined as the amount of expansion covering the contoured CTV on post-CBCT images (CTV<inf>post</inf>). Interfractional motion was defined as the amount of reference CTV expansion that could cover each CTV<inf>pre</inf>, as well as the evaluation of the intrafractional motion. PTV margins were estimated from the cumulative proportion of fraction covering the intra- and interfractional motions. The extent of expansion covering the CTVs in 90% of fractions was adopted as the PTV margin. The PTV margin for intrafractional gastric motion using the oART system with breath-holding was 14 mm. In contrast, the PTV margin for interfractional gastric organ motion without the oART system was 25 mm. These results indicated that the oART system can reduce the PTV margin by >10 mm. Our results could be valuable data for oART cases.

DOI： 10.1093/jrr/rrae052

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Scopus

PubMed

Language：English   Publisher：Springer  

The recommended post-operative radiotherapy dose of approximately 60 Gy may be reduced during treatment planning, and the optimal irradiation method and dose remain unclear. We aimed to clarify the usefulness and safety of post-operative radiotherapy for soft tissue sarcomas. Forty-five patients with soft-tissue sarcomas who underwent adjuvant radiotherapy at two institutions from June 2014 to August 2020 were included. Patients with a high risk of recurrence underwent post-operative irradiation, with doses of 60–70 Gy and 50 Gy used in patients with positive and negative resection margins, respectively. The median patient age was 72 (21–88) years. The most common histological types of sarcomas were myxofibrosarcoma (n = 12) and dedifferentiated liposarcoma (n = 11), followed by other sarcomas. Thirty patients were newly diagnosed, and 15 underwent surgery for localized recurrent disease. Thirty-two and 13 patients underwent wide and marginal resection, respectively. Surgical margins were negative in 12 patients and positive in 33 patients. Chemotherapy was administered before or after radiotherapy in 16 patients. The 2-year local control, progression-free survival, and overall survival rates after post-operative radiotherapy were 88%, 78%, and 93%, respectively. In patients with positive resection margins, doses of ≥ 60 Gy contributed to local control (p = 0.0002, log-rank test) and progression-free survival (p = 0.0033). Late grade 3 adverse events were observed in 7% of the patients. Post-operative radiotherapy for soft tissue sarcomas is safe and effective, with high doses (≥ 60 Gy) contributing to reduced recurrence among patients with positive resection margins.

DOI： 10.1007/s42399-024-01648-8

Scopus

CiNii Research

Event date： 2025.11

Publishing type：Research paper, summary (international conference)  

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper, summary (international conference)  

Web of Science

Authorship：Lead author,　Corresponding author   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：日本メディカルセンター  

DOI： 10.19020/cg.0000002324

CiNii Research