Roussakis Yiannis, Antorkas Georgios, Georgiou Leonidas, Strouthos Iosif, Karagiannis Efstratios, Zamboglou Constantinos, Ferentinos Konstantinos, Zamboglou Nikolaos, Anagnostopoulos Georgios
Department of Medical Physics, German Oncology Center, University Hospital of the European University, Limassol, Cyprus.
Department of Radiation Oncology, German Oncology Center, University Hospital of the European University, Limassol, Cyprus.
J Contemp Brachytherapy. 2024 Jun;16(3):211-218. doi: 10.5114/jcb.2024.140893. Epub 2024 Jun 28.
The aim of this study was a retrospective dosimetric comparison of iridium-192 (Ir) high-dose-rate (HDR) interstitial brachytherapy plans using model-based dose calculation algorithm (MBDCA) following TG-186 recommendations and TG-43 dosimetry protocol for breast, head-and-neck, and lung patient cohorts, with various treatment concepts and prescriptions.
In this study, 59 interstitial Ir HDR brachytherapy cases treated in our center (22 breast, 22 head and neck, and 15 lung) were retrospectively selected and re-calculated with TG-43 dosimetry protocol as well as with Acuros BV dose calculation algorithm, with dose to medium option based on computed tomography images. Treatment planning dose volume parameter differences were determined and their significance was assessed.
For the breast planning target volume (PTV), TG-43 formalism calculated higher D, V, V, and V values than Acuros BV, ranging from 2.2% to 5.4% (mean differences), as it did for the head and neck cases, ranging from 2.5% to 4.7% and for the interstitial lung cases, ranging from 2.2% to 4.4%, showing statistical significance ( < 0.001). For the skin D, D, and D, the values were overestimated by TG-43, with a mean absolute differences of 1.4, 1.8, and 2.0 Gy, respectively for the breast, and 1.0 Gy for all DVH statistics for the head and neck cases compared with Acuros BV ( < 0.001). Ipsilateral lung V was also higher in TG-43-calculated plans, with a mean difference of 1.0% and 1.1% in the breast and lung implants, respectively. For the chest wall TG-43, the respective overestimation in D and D was 0.8 and 0.8 Gy for the breast, and 0.4 and 0.3 Gy for the interstitial lung cases, respectively.
The TG-43 algorithm significantly overestimates the dose to PTVs and surrounding organs at risk (OARs) for breast, head and neck, and lung interstitial implants. TG-43 overestimation is in accordance with previous findings for breast and head and neck. To our knowledge, this is also exhibited for Acuros BV for the first time in interstitial lung HDR brachytherapy.
本研究旨在对铱 - 192（Ir）高剂量率（HDR）组织间近距离治疗计划进行回顾性剂量学比较，该计划采用基于模型的剂量计算算法（MBDCA），遵循TG - 186建议以及TG - 43剂量学协议，用于乳腺癌、头颈部癌和肺癌患者队列，涵盖各种治疗理念和处方。
本研究回顾性选取了在我们中心接受治疗的59例Ir HDR组织间近距离治疗病例（22例乳腺癌、22例头颈部癌和15例肺癌），并根据TG - 43剂量学协议以及Acuros BV剂量计算算法进行重新计算，剂量计算基于计算机断层扫描图像的中等剂量选项。确定治疗计划剂量体积参数差异并评估其显著性。
对于乳腺癌计划靶体积（PTV），TG - 43形式计算的D、V、V和V值高于Acuros BV，差异范围为2.2%至5.4%（平均差异），头颈部病例差异范围为2.5%至4.7%，组织间肺癌病例差异范围为2.2%至4.4%，具有统计学显著性（<0.001）。对于皮肤的D、D和D，TG - 43高估了这些值，与Acuros BV相比，乳腺癌的平均绝对差异分别为1.4、1.8和2.0 Gy，头颈部病例所有剂量体积直方图（DVH）统计量的平均绝对差异为1.0 Gy（<0.001）。TG - 43计算的计划中，同侧肺V也更高，乳腺癌和肺癌植入物中的平均差异分别为1.0%和1.1%。对于胸壁的TG - 43，乳腺癌的D和D分别高估0.8和0.8 Gy，组织间肺癌病例分别高估0.4和0.3 Gy。
TG - 43算法显著高估了乳腺癌、头颈部癌和肺癌组织间植入物的计划靶体积（PTV）以及周围危险器官（OAR）的剂量。TG - 43的高估与先前关于乳腺癌和头颈部癌的研究结果一致。据我们所知，并首次在组织间肺癌HDR近距离治疗中展示了Acuros BV的这种情况。
