# Automated quality assurance of imaging dose and protocol adherence in computed tomography radiotherapy planning using TotalSegmentator-based segmentation

## TL;DR

This study uses automated segmentation to evaluate CT scan quality and radiation dose in radiotherapy planning, aiming to reduce patient exposure.

## Contribution

The study introduces an automated method using TotalSegmentator to assess CT protocol adherence and optimize imaging workflows.

## Key findings

- Brain CT protocols had the highest radiation dose (CTDIvol of 73 ± 12 mGy).
- Lung 4D protocols showed higher effective doses compared to standard lung protocols.
- Anatomical scan length discrepancies were found in the upper abdomen and spine, suggesting workflow improvements.

## Abstract

Computed tomography (CT) scans are vital for radiotherapy planning, providing essential data for dose calculations. This study retrospectively evaluated imaging doses, scan lengths, and protocol adherence to support imaging optimization and reduce patient radiation exposure.

CT data from patients undergoing external beam radiotherapy and brachytherapy in the period 04/2021 to 12/2024 were retrieved from the institutional picture archiving and communication system (PACS). Imaging doses (volumetric CT dose index [CTDIvol] and dose length product [DLP]) were extracted from dose reports. Automated organ segmentation was used to assess standard operating procedures (SOPs) adherence by estimating anatomical scan length differences. Additional quality assurance checks assessed protocol and imaging consistency.

Brain protocols exhibited the highest CTDIvol (73 ± 12 mGy), while head and neck protocols had higher DLP values (3212 ± 757 mGy·cm). The lung 4D protocol showed a higher effective dose (23 ± 9 mSv) compared to the standard lung protocol. Notable anatomical scan length differences were observed at the lower boundary in the upper abdomen (120 ± 75 mm) and spine (155 ± 159 mm), indicating opportunities for workflow improvement.

Enhancing CT workflows for radiotherapy patients is important and feasible. Dose and scan length analyses suggest that revising institutional SOPs, optimizing X‑ray tube modulation, and refining scan length boundaries should be considered to achieve this goal.

The online version of this article (10.1007/s00066-025-02494-w) contains supplementary material, which is available to authorized users.