Tailored stereotactic radiotherapy technique using deep inspiration breath-hold to reduce stomach dose for cardiac radioablation

Purpose: To provide a new insight on a novel safe cardiac radioablation using deep inspiration breath-hold (DIBH) to reduce gastrointestinal dose. Materials and Methods: For treating incessant ventricular tachycardia (VT) originated from left ven-tricle inferior scar abutting the stomach, a target delineation and treatment planning for cardiac ra-dioablation was performed. With four different computed tomography (CT) scan protocols—DIBH, full expiration breath-hold, four-dimensional (4D) CT without and with abdominal compression, the dis-tances between the target and the stomach were compared. Results: Among the protocols, the CT scan with DIBH showed largest distance between the target and the stomach and selected for the treatment planning. The prescribed dose was 25 Gy in a single fraction, and satisfactory dosimetric parameters were achieved with the DIBH. The patient was suc-cessfully treated with the DIBH, and experienced no acute toxicity. Conclusion: To gain the best benefit from cardiac radioablation, understanding the possible toxicity in the adjacent organs is crucial. By moving the heart with thoraco-diaphragmatic movement by DIBH, the target could be physically separated from the stomach.