Rao Vrushab, Zade Bhooshan, Singh Soumya, Narayanan V K Sathiya, Moundekar Pooja
Department of CyberKnife Radiosurgery and Radiation Oncology, Ruby Hall Clinic, Pune, India.
J Contemp Brachytherapy. 2024 Apr;16(2):128-131. doi: 10.5114/jcb.2024.138840. Epub 2024 Apr 13.
Approximately 20% of women worldwide have a retroverted uterus. A retroverted uterus is closer to the rectum and may cause toxicity during brachytherapy. Upon manipulation, a small percentage turn anteverted. Conventional brachytherapy applicators are designed for an anteverted uterus and can pose issues during insertion. Modified Fletcher suit and ring applicators have major differences in their geometry to achieve similar target coverage, and were analyzed in this study with respect to immediate adverse events and dosimetry.
Three hundred seventy-four consecutive applications performed over a 20-month period were studied retrospectively to identify intra-cavitary applications (ICAs) in retroverted uteri. Cases were divided into 2 groups: modified Fletcher suit applicator with hemi-ovoids (group A) and ring applicator (group B). D for bladder and rectum were noted, and acute adverse events were recorded.
Seventy-five applications were identified, out of which 47 cases used Fletcher suit applicator, and 28 cases used ring applicator. The median bladder D for group A and B were 5.98 Gy and 6.3 Gy, respectively, and the median rectum D was 5.27 Gy and 3.68 Gy, respectively; the median dose prescribed to point A was 6 Gy (range, 5.5-9.0 Gy). All patients had a point A coverage between 97% and 102%. Eighteen cases in both groups complained of pain requiring analgesics. Twenty-five cases (53.2%) and 20 cases (71.4%) in group A and B, respectively, required dose optimization, which was statistically insignificant ( > 0.11). A significant difference was identified ( < 0.00001) in rectal doses. A higher reported pain was noted in ring applicator group ( < 0.03). No patient experienced a profuse bleeding.
In most parameters, the two applicators demonstrated comparable results. The control of rectal dosage is superior in the ring applicator at the cost of higher pain incidence. Patient's comfort and rectal dose in EBRT should be taken into consideration, with preference given to the ring applicator.
全球约20%的女性子宫后倾。子宫后倾更靠近直肠，在近距离放疗期间可能导致毒性反应。在操作过程中，一小部分子宫后倾的女性子宫会转为前倾。传统的近距离放疗施源器是为前倾子宫设计的，在插入过程中可能会出现问题。改良的弗莱彻套装式施源器和环形施源器在几何形状上有很大差异，但能实现相似的靶区覆盖，本研究对它们的即时不良事件和剂量学进行了分析。
回顾性研究了在20个月期间连续进行的374次施源操作，以确定子宫后倾患者的腔内放射治疗（ICA）情况。病例分为两组：使用半椭圆形的改良弗莱彻套装式施源器的A组和使用环形施源器的B组。记录膀胱和直肠的剂量D，并记录急性不良事件。
共确定75次施源操作，其中47例使用弗莱彻套装式施源器，28例使用环形施源器。A组和B组膀胱剂量D的中位数分别为5.98 Gy和6.3 Gy，直肠剂量D的中位数分别为5.27 Gy和3.68 Gy；A点的处方剂量中位数为6 Gy（范围5.5 - 9.0 Gy）。所有患者A点的覆盖范围在97%至102%之间。两组中有18例患者主诉疼痛需要使用镇痛药。A组和B组分别有25例（53.2%）和20例（71.4%）需要进行剂量优化，差异无统计学意义（>0.11）。直肠剂量存在显著差异（<0.00001）。环形施源器组报告的疼痛更严重（<0.03）。没有患者出现大出血情况。
在大多数参数方面，两种施源器的结果相当。环形施源器在控制直肠剂量方面更具优势，但代价是疼痛发生率较高。在体外放射治疗（EBRT）中应考虑患者的舒适度和直肠剂量，优先选择环形施源器。
