Reproducibility of the lung anatomy under active breathing coordinator control: Dosimetric consequences for scanned proton treatments

Abstract

When treating under ABC controlled breath-hold, robustly optimized IMPT plans show limited dosimetric consequences due to anatomical variations between repeated ABC breath-holds for most cases. Thus, the combination of robustly optimized IMPT plans and the delivery under ABC controlled breath-hold presents a safe approach for PBS lung treatments.

Current status of proton therapy techniques for lung cancer

“…The inter-fractional variations were measured using repeated CT scans [82,83], daily CBCT [84] for lung cancer patients, and repeated MRI imaging [85] for healthy volunteers. The inter-fractional variations were larger than intra-fractional variations [79,[84][85][86]. ABC devices assisted BH was more stable than self-controlled BHs.…”

“…The stability of DIBH assisted by ABC was assessed by quantifying intra-and inter-fractional variations of organ for NSCLC patients. Intra-fractional variation of tumor motion was assessed using fluoroscopy videos [82], repeated breath hold CTs [83,84] for NSCLC patients undergoing radiation therapy, and magnetic resonance imaging (MRI) for healthy volunteers [85,86]. The intra-fractional mean variation ranged from 0.6 (range, 0 to 3) to 0.3 (0 to 1) mm, 0.6 (0 to 2) to 1.7 (0.1 to 6.0) mm, and 1.7 (0.2 to 5.0) to 1.5 (0 to 5.2) mm [83] in the right-left (RL) superior-interior (SI), and anterior-posterior (AP) directions, respectively [82].…”

“…To deliver a plan robust to intra-and inter-fractional variation of ABC controlled BHs, a robust optimized IMPT plan https://doi.org/10.3857/roj.2019.00633 mitigating the uncertainty under ABC controlled delivery is considered a safe approach for PBS lung treatment [86].…”

Dosimetric influence of deformable image registration uncertainties on propagated structures for online daily adaptive proton therapy of lung cancer patients

“…Besides intra-fractional motion, the dose calculation in low-density lung tissue has large uncertainties and large inter-fractional changes are expected to occur [24,[51][52][53]. Each of these challenges are discussed separately in the following paragraphs.…”

Impact of internal target volume definition for pencil beam scanned proton treatment planning in the presence of respiratory motion variability for lung cancer: A proof of concept

“…Many mitigation approaches have been proposed and applied clinically [2,3], including breathhold [4][5][6][7], gating [8],tumour tracking [9,10] or 4D optimisation [11]. All these, to a greater or lesser extent, rely on some form of online motion monitoring, plan adaptation and patient cooperation.…”