Breath‐holding treatments in tomotherapy with active breathing coordinator: A first case report

Purpose Respiratory motion poses a significant challenge in radiation therapy for thoracic and abdominal malignancies. For tomotherapy machines, it is even more challenging due to the 10‐s warm‐up time before initiating the treatment beams. A recent tomotherapy system upgrade has reduced this warm‐up time to 0.5 s for the TomoDirect delivery mode, enabling the feasibility of performing breath‐holding treatments. In this study, we investigated the feasibility of performing breath‐holding treatments on a tomotherapy machine with spirometry technique. Methods A patient with gastric mucosa‐assisted lymphoid tissue lymphoma was treated with deep inspiration breath holding (30 Gy in 20 fractions) on a tomotherapy machine with Active Breathing Coordinator™. An in‐house visual system, featuring a compact 7″ LCD monitor, was implemented to provide visual feedback, allowing the patient to self‐monitor their breathings and adhere to the prescribed pattern. Results The patient tolerated the breath‐hold well for the entire treatment. The number of breath‐holds for treatment was 9. The beam‐on time for each field ranged from 12.4 to 19.7 s, average 15.2 s. Conclusions We have shown that BH treatment is feasible using an upgraded tomotherapy machine (Radixact v3.5) with Active Breathing Coordinator. Our proposed workflow includes an in‐house visual system that allows patients to visualize their breathing patterns on‐screen. This technique provides a practical solution for patients with thoracic and abdominal malignancies, addressing respiratory motion while minimizing radiation exposure for certain diseases.