Optimizing quality assurance CT schedules during adaptive proton therapy for enhanced patient care

TL;DR

This study finds optimal schedules for quality assurance CT scans during proton therapy to reduce imaging dose and improve efficiency without compromising treatment quality.

Contribution

The study proposes tailored QACT schedules for brain, head and neck, and prostate cancer treatments based on replanning patterns.

Findings

For brain cancer, a single QACT at the start of the second treatment week is sufficient.

Head and neck cancer benefits from an initial QACT in the first three fractions followed by scans every 10 fractions.

Prostate cancer may require one initial QACT and an optional second scan for complex cases.

Abstract

This study aims to optimize the frequency of routine quality assurance CT (QACT) scans in proton beam therapy (PBT) for brain, head and neck (HN), and prostate treatments. The goal is to enhance treatment efficiency without compromising treatment quality. By reducing the frequency of QACT scans, the study seeks to minimize imaging dose and better utilize patient and staff resources.

A retrospective, IRB‐approved review analyzed 878 QACTs from 263 patients across three anatomical sites treated with PBT at our center in 2020. The study examined QACT and replanning patterns to identify the most efficient QACT schedules. Observational and post‐implementation analysis utilized treatment data spanning from 2021 to 2022. The QACT and replanning patterns of each site were analyzed to identify the optimal frequency of QACTs.

Out of 205 QACTs for brain cancer patients, only five (2.5%) led to adaptive planning, indicating that a single QACT at the start of the second treatment week is optimal. In HN cases, 38 of 437 QACTs (8.7%) necessitated replanning, leading to the recommendation of an initial QACT during the first three fractions then followed by QACT for every 10 fractions. For prostate cancer, three out of 236 QACTs (1.3%) were used for adaptive planning, with the suggestion of one initial QACT during the first three fractions, and possibly an additional scan halfway through for patients with more complex treatment plans, such as involving seminal vesicles and lymph nodes and/or planned as a sequential boost.

The retrospective analysis proposes a significant reduction in QACT frequency, which could reduce the overall QACT burden while maintaining treatment quality and accuracy. This tailored approach to QACT scheduling represents an important step in optimizing proton therapy protocols, improving patient experience, and conserving medical resources.

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