Taylor Alexandra, Powell Melanie E B
Department of Radiotherapy, St. Bartholomew's Hospital, London, UK.
Radiother Oncol. 2008 Aug;88(2):250-7. doi: 10.1016/j.radonc.2008.04.016. Epub 2008 Jun 5.
To assess interfractional movement of the uterus and cervix in patients with gynaecological cancer to aid selection of the internal margin for radiotherapy target volumes.
Thirty-three patients with gynaecological cancer had an MRI scan performed on two consecutive days. The two sets of T2-weighted axial images were co-registered, and the uterus and cervix outlined on each scan. Points were identified on the anterior uterine body (Point U), posterior cervix (Point C) and upper vagina (Point V). The displacement of each point in the antero-posterior (AP), superior-inferior (SI) and lateral directions between the two scans was measured. The changes in point position and uterine body angle were correlated with bladder volume and rectal diameter.
The mean difference (+/-1 SD) in Point U position was 7 mm (+/-9.0) in the AP direction, 7.1 mm (+/-6.8) SI and 0.8 mm (+/-1.3) laterally. Mean Point C displacement was 4.1 mm (+/-4.4) SI, 2.7 mm (+/-2.8) AP, 0.3 (+/-0.8) laterally, and Point V was 2.6 mm (+/-3.0) AP and 0.3 mm (+/-1.0) laterally. There was correlation for uterine SI movement in relation to bladder filling, and for cervical and vaginal AP movement in relation to rectal filling.
Large movements of the uterus can occur, particularly in the superior-inferior and anterior-posterior directions, but cervical displacement is less marked. Rectal filling may affect cervical position, while bladder filling has more impact on uterine body position, highlighting the need for specific instructions on bladder and rectal filling for treatment. We propose an asymmetrical margin with CTV-PTV expansion of the uterus, cervix and upper vagina of 15 mm AP, 15 mm SI and 7 mm laterally and expansion of the nodal regions and parametria by 7 mm in all directions.
评估妇科癌症患者子宫和宫颈的分次间运动，以辅助放疗靶区内部边界的选择。
33例妇科癌症患者连续两天进行了MRI扫描。将两组T2加权轴向图像进行配准，并在每次扫描上勾勒出子宫和宫颈。在前位子宫体（点U）、后位宫颈（点C）和上阴道（点V）上确定点。测量两次扫描之间每个点在前后（AP）、上下（SI）和侧向方向上的位移。点位置和子宫体角度的变化与膀胱体积和直肠直径相关。
点U位置的平均差异（±1标准差）在AP方向为7mm（±9.0），SI方向为7.1mm（±6.8），侧向为0.8mm（±1.3）。点C的平均位移在SI方向为4.1mm（±4.4），AP方向为2.7mm（±2.8），侧向为0.3（±0.8），点V在AP方向为2.6mm（±3.0），侧向为0.3mm（±1.0）。子宫SI运动与膀胱充盈有关，宫颈和阴道AP运动与直肠充盈有关。
子宫可发生较大运动，尤其是在上下和前后方向，但宫颈位移不太明显。直肠充盈可能影响宫颈位置，而膀胱充盈对子宫体位置影响更大，这突出了治疗时对膀胱和直肠充盈进行具体指导的必要性。我们建议采用不对称边界，子宫、宫颈和上阴道的临床靶区-计划靶区扩展在AP方向为15mm，SI方向为15mm，侧向为7mm，淋巴结区域和宫旁组织在各个方向扩展7mm。
