Choi Euncheol, Kim Byungyong, Byun Sang Jun, Kim Jin Hee, Park Seung Gyu, Kim Myeongsoo
Department of Radiation Oncology, Keimyung University, Dongsan Hospital, Dalgubeol-daero, Daegu, South Korea.
Department of Radiation Oncology, Keimyung University School of Medicine, Dalgubeol-daero, Daegu, South Korea.
J Contemp Brachytherapy. 2024 Jun;16(3):184-192. doi: 10.5114/jcb.2024.140931. Epub 2024 Jun 28.
This retrospective study aimed to investigate the influence of bladder filling type (BFT) on the relationship between bladder volume (BV) and maximum absorbed dose (D) in intra-cavitary brachytherapy (ICBT) for cervical cancer.
The study enrolled 269 patients who underwent 3D-optimized ICBT guided by MRI scans between 2016 and 2022. Bladder shape (categorized as tilted, curved, or E) was determined based on specific applicators used. D values were recorded for critical organs, such as bladder, rectum, sigmoid colon, and small bowel.
The tilted group exhibited lower D values for the small bowel when BV was less than 400 cc, while still ensuring minimal doses to the rectum and sigmoid colon. In the curved group (BV ≤ 100 cc), significant variations in D for organs at risk were observed. However, in the E group, no substantial correlation between BV and D was identified ( = -0.035). Additionally, the mean mid-sagittal line differences in the tilted group were 8.47 mm (pre-ICBT) and 7.11 mm (during ICBT simulation), surpassing measurements in the other two groups.
This study underscores the substantial impact of bladder shape on both the optimal bladder filling volume and maximum absorbed dose in cervical cancer ICBT. The implementation of BFT based on pre-ICBT MRI scans is both practical and beneficial. It accentuates the necessity of accounting for bladder shape when determining appropriate bladder filling volume, thus facilitating effective management of bladder and small bowel doses. Further prospective studies are warranted to assess the effect of BFT on the incidence of cystitis and proctitis following ICBT, all while maintaining consistent bladder distension.
本回顾性研究旨在探讨宫颈癌腔内近距离放疗（ICBT）中膀胱充盈类型（BFT）对膀胱体积（BV）与最大吸收剂量（D）之间关系的影响。
本研究纳入了2016年至2022年间在MRI扫描引导下接受三维优化ICBT的269例患者。根据所使用的特定施源器确定膀胱形状（分为倾斜、弯曲或E型）。记录膀胱、直肠、乙状结肠和小肠等关键器官的D值。
当BV小于400 cc时，倾斜组小肠的D值较低，同时仍能确保直肠和乙状结肠的剂量最小。在弯曲组（BV≤100 cc）中，观察到危及器官的D值有显著变化。然而，在E组中，未发现BV与D之间存在显著相关性（r = -0.035）。此外，倾斜组矢状中线的平均差异在ICBT前为8.47 mm，在ICBT模拟期间为7.11 mm，超过了其他两组的测量值。
本研究强调了膀胱形状对宫颈癌ICBT中最佳膀胱充盈体积和最大吸收剂量的重大影响。基于ICBT前MRI扫描实施BFT既实用又有益。它突出了在确定合适的膀胱充盈体积时考虑膀胱形状的必要性，从而有助于有效管理膀胱和小肠剂量。有必要进行进一步的前瞻性研究，以评估BFT对ICBT后膀胱炎和直肠炎发生率的影响，同时保持膀胱扩张一致。
