Treatment time and dosimetric advantage in CBCT-guided online adaptive radiotherapy considering interfractional and intrafractional changes in patients with gastric MALT lymphoma.

Radiotherapy is the standard treatment for localized gastric mucosa-associated lymphoid tissue (MALT) lymphoma. The ETHOS (Varian Medical System) has enabled us to perform cone-beam computed tomography (CBCT)-guided online adaptive radiotherapy (oART). This study presents a retrospective dosimetric analysis for interfractional and intrafractional change and treatment time in oART for gastric MALT lymphoma. We included three male patients with gastric MALT lymphoma who underwent exhalation breath-hold fasting oART using the SpiroDynr'X system. Treatment details and plans (3 reference [REF] plans, 51 scheduled [SCH] plans, and adapted [ADP] plans) were retrospectively analyzed. Doses to the clinical target volume in planning CT (CTV_REF), CTV1, CTV2 (representing the stomach in planning and preirradiation CBCT, respectively) and planning target volume (PTV) in the planning CBCT were estimated. D CBCT-guided oART was completed within the scheduled period, utilizing the ADP plans instead of the SCH plans on each treatment day in all cases. The average treatment time was approximately 45 min. CTV1 and CTV2 exhibited intrafractional and interfractional variations, fluctuating above and below CTV_REF. Some ADP plans resulted in incomplete PTV coverage of CTV2, but the unincluded volume was < 1% of CTV2. D CBCT-guided oART in patients with gastric MALT lymphoma demonstrated that ADP plans improved CTV1, CTV2, and PTV doses and reduced the mean bilateral kidney and liver doses, suggesting that it may offer enhanced treatment precision for gastric MALT lymphoma.

Copyright © 2024. Published by Elsevier Inc.