Department of Medical Physics, IRCCS Regina Elena National Cancer Institute - Rome, Italy.
Department of Medical Physics, Michele e Pietro Ferrero Hospital, Verduno, Italy.
J Appl Clin Med Phys. 2023 Aug;24(8):e13947. doi: 10.1002/acm2.13947. Epub 2023 Jul 5.
We validate the routine use of a two-dimensional (2D) diode matrix for patient specific pre-treatment verification for Cyberknife (CK) stereotactic radiosurgery and to compare it with film dosimetry.
A total of 46 patients were selected according to the most frequent diseases treated at our institution with the CK system, that is, brain metastases, meningiomas, spine metastases, and prostate tumors. All cases were evaluated with GAFChromic EBT-3 films and SRS MapCHECK for Fixed cone, IRIS, and MLC collimators of the CK.
The highest mean passing rate was observed for the SRS MapCHECK system compared to films. In order to assess if the two techniques provide statistically different results, a Wilcoxon Signed-Rank non-parametric test was performed (p < 0.05) and we found gamma values significantly lower for EBT-3 films with respect to the SRS MapCHECK. We noticed a moderately significant association between the two techniques using Spearman's rank correlation coefficient (rs > 0.4). We also performed the Bland-Altman statistical method: less than 5% of the differences resulted outside the range (mean ± 1.96 × SD), so the two methods can be considered interchangeable within the combined inaccuracy.
The use of SRS MapCHECK for CK patient specific quality assurance (QA) is feasible for a variety of clinical districts and could be reliably used as a replacement for radiochromic films.
验证二维（2D）二极管矩阵在 Cyberknife（CK）立体定向放射外科中用于患者特定的治疗前验证的常规应用，并将其与胶片剂量学进行比较。
根据我们机构最常治疗的疾病，即脑转移瘤、脑膜瘤、脊柱转移瘤和前列腺肿瘤，选择了总共 46 名患者。所有病例均使用 GAFChromic EBT-3 胶片和 SRS MapCHECK 进行评估，用于 CK 的固定锥形、IRIS 和 MLC 准直器。
SRS MapCHECK 系统的平均通过率最高。为了评估这两种技术是否提供统计学上不同的结果，我们进行了 Wilcoxon 符号秩检验（p<0.05），发现 EBT-3 胶片的伽马值明显低于 SRS MapCHECK。我们使用 Spearman 等级相关系数（rs>0.4）发现这两种技术之间存在中度显著相关性。我们还进行了 Bland-Altman 统计方法：不到 5%的差异超出范围（均值±1.96×SD），因此这两种方法在组合误差内可以互换使用。
SRS MapCHECK 可用于 CK 患者特定的质量保证（QA），适用于各种临床环境，可以可靠地替代放射色胶片。
