Department of Radiation Oncology, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria.
Austrian Center for Medical Innovation and Technology, Wr. Neustadt, Austria.
Brachytherapy. 2022 Mar-Apr;21(2):186-192. doi: 10.1016/j.brachy.2021.10.005. Epub 2021 Dec 6.
To qualitatively and quantitatively analyze needle visibility in combined intracavitary and interstitial cervical cancer brachytherapy on 3D transrectal ultrasound (TRUS) in comparison to gold standard MRI.
Image acquisition was done with a customized TRUS stepper unit and software (Medcom, Germany; Elekta, Sweden; ACMIT, Austria) followed by an MRI on the same day with the applicator in place. Qualitative assessment was done with following scoring system: 0 = no visibility 1 (= poor), 2 (= fair), 3 (= excellent) discrimination, quantitative assessment was done by measuring the distance between each needle and the tandem two centimeters (cm) above the ring and comparing to the respective measurement on MRI.
Twenty-nine implants and a total of 188 needles (132 straight, 35 oblique, 21 free-hand) were available. Overall, 79% were visible (87% straight, 51% oblique, 76% free-hand). Mean visibility score was 1.4 ± 0.5 for all visible needles. Distance of the visible needles to tandem was mean ± standard deviation (SD) 21.3 millimeters (mm) ± 6.5 mm on MRI and 21.0 mm ± 6.4 mm on TRUS, respectively. Difference between MRI and TRUS was max 14 mm, mean ± SD -0.3 mm ± 2.6 mm. 11% differed more than 3 mm.
Straight needles were better detectable than oblique needles (87% vs. 51%). Detectability was impaired by insufficient rotation of the TRUS probe, poor image quality or anatomic variation. As needles show a rather indistinct signal on TRUS, online detection with a standardized imaging protocol in combination with tracking should be investigated, aiming at the development of real time image guidance and online treatment planning.
在 3D 经直肠超声（TRUS）上与金标准 MRI 相比，定性和定量分析腔内和间质宫颈癌近距离放疗中针的可视性。
使用定制的 TRUS 步进器单元和软件（德国 Medcom、瑞典 Elekta、奥地利 ACMIT）进行图像采集，然后在同一天在放置施源器的情况下进行 MRI。定性评估采用以下评分系统：0=无可见度 1（=差），2（=尚可），3（=优秀），定量评估通过测量每个针与环上两厘米（cm）的距离进行测量串联，并与 MRI 上的相应测量值进行比较。
共 29 个植入物和 188 根针（132 根直针、35 根斜针、21 根徒手针）可用。总体而言，79%的针可见（直针 87%，斜针 51%，徒手针 76%）。所有可见针的平均可视性评分均为 1.4±0.5。MRI 上可见针与串联之间的距离平均值±标准差（SD）为 21.3 毫米（mm）±6.5mm，TRUS 上为 21.0mm±6.4mm。MRI 和 TRUS 之间的差异最大为 14mm，平均值±SD 为-0.3mm±2.6mm。11%的差异大于 3mm。
直针比斜针更容易检测（87%对 51%）。TRUS 探头旋转不足、图像质量差或解剖变异会降低检测能力。由于针在 TRUS 上显示出相当不明显的信号，因此应研究使用标准化成像协议结合跟踪进行在线检测，旨在开发实时图像引导和在线治疗计划。
