Androulakis Ioannis, Godart Jérémy, Luthart Lorne, Christianen Miranda E M C, Westerveld Henrike, Nout Remi A, Hoogeman Mischa, Kolkman-Deurloo Inger-Karine K
Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center, Rotterdam, Netherlands.
Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center, Rotterdam, Netherlands; Department of Medical Physics & Informatics, HollandPTC, Delft, Netherlands.
Brachytherapy. 2025 Jan-Feb;24(1):177-185. doi: 10.1016/j.brachy.2024.11.004. Epub 2024 Dec 1.
To investigate the occurrence of errors in transrectal ultrasound (TRUS)-based implant reconstructions for high-dose-rate brachytherapy (HDR-BT) in prostate cancer using an afterloader-integrated electromagnetic tracking (EMT) system.
Fourteen patients were treated with one TRUS-based treatment fraction in an intraoperative setting while under general anesthesia, as part of their prostate HDR-BT (2×13.5 Gy) treatment. EMT measurements were performed before the start of the treatment in all implanted needles at dwell positions (DPs) with an interval of 5 mm. The Euclidean distances (EDs) between clinically reconstructed and EMT-measured DPs after registration were calculated. Errors were evaluated per needle (minimum ED of 2mm) and stratified into 4 severity levels (minor, moderate, major and severe). Error causes were investigated through retrospective inspection of TRUS imaging.
The median (range) ED between EMT-measured and clinically reconstructed DPs was 1.0 (0.1-9.4) mm. Higher EDs were observed in the anterior and lateral regions of the prostate. From 265 evaluated needle reconstructions, 23% (61/265) had minor errors or higher, while 9% (24/265) had major or severe errors. Severe errors were mostly caused by incorrect needle or depth selection. Major, moderate and minor errors were mostly caused by artifact, shadowing, and user errors, respectively.
This study found that a quarter of needle reconstructions contained errors >2mm, and that high and severe errors were not uncommon. EMT can play an important role in detecting and preventing these reconstruction errors without disrupting the clinical workflow.
使用后装集成电磁跟踪（EMT）系统，研究基于经直肠超声（TRUS）的前列腺癌高剂量率近距离放疗（HDR - BT）植入重建中的误差发生情况。
14例患者在全身麻醉下的术中环境中接受了一次基于TRUS的治疗分次，作为其前列腺HDR - BT（2×13.5 Gy）治疗的一部分。在治疗开始前，对所有植入针在驻留位置（DPs）以5 mm的间隔进行EMT测量。计算配准后临床重建的DPs与EMT测量的DPs之间的欧几里得距离（EDs）。每根针评估误差（最小ED为2mm），并分为4个严重程度级别（轻微、中度、重度和极重度）。通过回顾性检查TRUS图像来调查误差原因。
EMT测量的DPs与临床重建的DPs之间的中位数（范围）ED为1.0（0.1 - 9.4）mm。在前列腺的前部和侧部区域观察到较高的EDs。在265次评估的针重建中，23%（61/265）有轻微或更严重的误差，而9%（24/265）有重度或极重度误差。极重度误差主要由针或深度选择错误引起。重度、中度和轻微误差分别主要由伪影、阴影和用户错误引起。
本研究发现四分之一的针重建包含大于2mm的误差，且高误差和极重度误差并不罕见。EMT在检测和预防这些重建误差方面可发挥重要作用，同时不干扰临床工作流程。
