Jamadagni Sumukh, Ponni Tr Arul, P Revathy
Department of Radiation Oncology, Vijayanagar Institute of Medical Sciences, Bellary, India.
Department of Radiation Oncology, Ramaiah Medical College and Hospitals, Ramaiah University of Applied Sciences, Bengaluru, India.
J Contemp Brachytherapy. 2024 Feb;16(1):28-34. doi: 10.5114/jcb.2024.135629. Epub 2024 Feb 23.
The aim of the study was to dosimetrically compare intra-cavitary brachytherapy technique (ICBT) with free-hand (intra-cavitary + interstitial, IC + IS) technique.
Twenty seven locally advanced carcinoma cervix patients were included in the study. Patients with more than medial 1/3 parametrial residual disease without extending upto lateral pelvic wall were included, following external beam radiotherapy (EBRT), in which cobalt-60 high-dose-rate (Co HDR) brachytherapy source was used. Dose for both plans were 6.5 Gy × 4 fractions, 2 fractions per day, 6 hours apart, over 2 days. Free-hand brachytherapy technique, consisted of placement of central tandem and 2 ovoids along with needles without using template, was applied. Two plans were generated by activating and deactivating the needles, and compared by normalizing to V.
A total of 79 needles were applied. Using paired- test, dosimetric comparison of both the plans was done. Free-hand plan had a significant higher mean V (volume receiving 90% of the dose) of 94.2% compared with 87.22% in ICBT plan ( ≤ 0.0001). Free-hand and ICBT plans presented a mean V values of 89.06% and 81.51% ( ≤ 0.0001), respectively, favoring free-hand plan. The mean D (dose to 90% volume), D, and D of free-hand plan were 6.28 Gray (Gy), 4.91 Gy, and 3.62 Gy, respectively, but equivalent parameters in ICBT plan were 5.26 Gy, 3.72 Gy, and 2.61 Gy, with value ≤ 0.0001. In both the plans, D of the bladder, rectum, and sigmoid were 4.59 Gy, 3.98 Gy, 2.77 Gy, and 4.46 Gy, 3.90 Gy, 2.67 Gy, respectively, with no statistical significance.
Free-hand brachytherapy (IC + IS) achieves a statistically significant better dose distribution to high-risk clinical target volume (HR-CTV) comparing with ICBT technique with similar dose to organs at risk.
本研究旨在对腔内近距离放射治疗技术（ICBT）与徒手（腔内+组织间插植，IC+IS）技术进行剂量学比较。
本研究纳入了27例局部晚期宫颈癌患者。纳入在体外放射治疗（EBRT）后，宫旁残留病灶超过中1/3但未累及盆腔侧壁的患者，采用钴-60高剂量率（Co HDR）近距离放射治疗源。两种计划的剂量均为6.5 Gy×4次分割，每天2次分割，间隔6小时，共2天。采用徒手近距离放射治疗技术，即不使用模板放置中央施源器和2个卵圆形容器以及针。通过激活和停用针生成两个计划，并通过归一化到V进行比较。
共应用了79根针。采用配对检验对两种计划进行剂量学比较。徒手计划的平均V（接受90%剂量的体积）显著高于ICBT计划，分别为94.2%和87.22%（P≤0.0001）。徒手计划和ICBT计划的平均V值分别为89.06%和81.51%（P≤0.0001），徒手计划更具优势。徒手计划的平均D（90%体积的剂量）、D和D分别为6.28格雷（Gy）、4.91 Gy和3.62 Gy，但ICBT计划中的等效参数分别为5.26 Gy、3.72 Gy和2.61 Gy，P值≤0.0001。在两种计划中，膀胱、直肠和乙状结肠的D分别为4.59 Gy、3.98 Gy、2.77 Gy和4.46 Gy、3.90 Gy、2.67 Gy，无统计学意义。
与ICBT技术相比，徒手近距离放射治疗（IC+IS）在对高危临床靶区（HR-CTV）的剂量分布上具有统计学显著优势，同时对危及器官的剂量相似。
