Gazsi Iozsef, Marcu Loredana G
Faculty of Physics, West University of Timisoara, 300223, Timisoara, Romania.
Emergency County Hospital, 410167, Oradea, Romania.
Radiat Environ Biophys. 2025 May;64(2):291-302. doi: 10.1007/s00411-025-01113-7. Epub 2025 Mar 1.
External radiotherapy combined with internal radiotherapy in cervical cancer can provide a boost to the target volume to increase tumour control. At the same time internal radiotherapy protects neighboring organs. The aim of the present study was to dosimetrically compare three external beam radiotherapy techniques each combined with internal radiotherapy to evaluate the combination that offers the best organ protection. Treatment plans of 20 cervical cancer patients were created for external (including three-dimensional conformal radiotherapy (3D-CRT), intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT)) as well as brachytherapy. The prescribed dose was 50 Gy in 25 fractions for external and 21 Gy in three fractions for internal radiotherapy. The following organs at risk (OARs) were evaluated: bladder, rectum, sigmoid and bowel bag. The study analyzed the results of different treatment combinations in terms of dosimetric values for various parameters. The D for the clinical target volume was around 120 Gy, with the highest value seen in 3D-CRT + BT (brachytherapy) combination at 120.59 Gy. For the bladder, the D remained below the recommended threshold of 90 Gy, with the lowest value obtained for the BT + IMRT combination at 79.2 Gy. For the rectum, both D and D remained below the recommended threshold of 75 Gy for both parameters. All techniques fell below the recommended dose of 75 Gy for the sigmoid. For the intestine, there were statistically significant differences between BT + IMRT and BT + 3D-CRT. The VMAT technique showed superiority over IMRT in tumour volume coverage and several organ-at-risk parameters. Generally, intensity-modulated techniques showed dosimetric advantage over the traditional 3D technique in cervical cancer. In addition to providing better compliance and homogeneity, they provided superior protection for organs at risk, especially for bowel bag. It is concluded that the BT + IMRT technique provided the best protection for organs at risk based on the lowest OAR dosimetric values, especially for the intestine.
宫颈癌的外照射放疗联合内照射放疗可提高靶区剂量以增强肿瘤控制。同时，内照射放疗可保护邻近器官。本研究的目的是通过剂量学比较三种外照射放疗技术（均联合内照射放疗），以评估哪种联合方式能提供最佳的器官保护。为20例宫颈癌患者制定了外照射（包括三维适形放疗（3D-CRT）、调强放疗（IMRT）和容积调强弧形放疗（VMAT））以及近距离放疗的治疗计划。外照射的处方剂量为25次分割共50 Gy，内照射放疗为3次分割共21 Gy。对以下危及器官（OARs）进行了评估：膀胱、直肠、乙状结肠和肠袋。该研究根据各种参数的剂量学值分析了不同治疗组合的结果。临床靶区的D值约为120 Gy，其中3D-CRT + 近距离放疗（BT）组合的值最高，为120.59 Gy。对于膀胱，D值保持在推荐阈值90 Gy以下，BT + IMRT组合的值最低，为79.2 Gy。对于直肠，两个参数的D值和D值均保持在推荐阈值75 Gy以下。所有技术的乙状结肠剂量均低于推荐剂量75 Gy。对于肠道，BT + IMRT与BT + 3D-CRT之间存在统计学显著差异。VMAT技术在肿瘤体积覆盖和几个危及器官参数方面显示出优于IMRT的优势。一般来说，调强技术在宫颈癌中比传统的3D技术具有剂量学优势。除了提供更好的适形性和均匀性外，它们还为危及器官提供了更好的保护，尤其是对肠袋。结论是，基于最低的OAR剂量学值，BT + IMRT技术为危及器官提供了最佳保护，尤其是对肠道。
