Total Body Irradiation (TBI) Combining Step-And-Shoot Intensity Modulation (SS-IMRT) with Conformal 3-Dimensions (3DCRT) Radiotherapy

Abstract

Background: Total Body Irradiation (TBI) is integral to conditioning regimens for hematological malignancies, traditionally requiring complex and costly setups. This study introduces a simplified approach utilizing Step-And-Shoot Intensity Modulation (SS-IMRT) combined with Conformal 3-Dimensional Radiotherapy (3DCRT), aiming to maintain dosimetric rigor while enhancing practicality. Methods: The study retrospectively analyzed 27 patients treated with a novel TBI technique combining SS-IMRT and 3DCRT at the International Medical Center from January 2019 to July 2024. We focused on patient setup, equipment utilization, and dose distribution. SS-IMRT involves delivering radiation in segments with precise control, while 3DCRT shapes the radiation beam to conform to the shape of the target. Both methods leverage standard radiation therapy equipment without the need for specialized facilities. Results: The technique demonstrated precise control over the dose delivery with a mean Planning Target Volume (PTV) dose of 10.11 Gy, closely matching therapeutic targets with minimal specialized equipment. Critical organ doses were kept within safe limits, and effective management of overlapping fields at the pelvic matching volume highlighted the method’s capability to mitigate over- or under-dosing risks. Conclusion: Combining SS-IMRT with 3DCRT simplifies the TBI process, reducing operational complexities and costs. This method offers a practical and effective alternative to traditional TBI techniques, enhancing accessibility and potentially improving patient outcomes across various clinical settings.