Assenholt Marianne S, Vestergaard Anne, Kallehauge Jesper F, Mohamed Sandy, Nielsen Søren K, Petersen Jørgen B, Fokdal Lars, Lindegaard Jacob C, Tanderup Kari
Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark.
Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark.
Brachytherapy. 2014 Jul-Aug;13(4):361-8. doi: 10.1016/j.brachy.2014.02.003. Epub 2014 Mar 18.
To describe a new technique involving high-precision stereotactic intensity-modulated radiation therapy (IMRT) boost in combination with intracavitary-interstitial (IC-IS) brachytherapy (BT) in cervical tumors that cannot be sufficiently covered by IC-IS-BT due to extensive residual disease and/or difficult topography at the time of BT.
Three patients with stage IIIB-IVA cervical cancer had significant residual disease at the time of BT. MRI-guided IC-IS-BT (pulsed-dose rate) was combined with a stereotactic IMRT boost guided according to the BT applicator in situ, using cone beam CT. The planning aim dose (total external beam radiotherapy and BT) for the high-risk clinical target volume (HR-CTV) was D90 >70-85 Gy, whereas constraints for organs at risk were D2cm3 <70 Gy for rectum, sigmoid, and bowel and <90 Gy for bladder in terms of equivalent total dose in 2 Gy fractions. An IMRT boost adapted to the BT dose distribution was optimized to target the regions poorly covered by BT.
HR-CTV doses of D90 >81 Gy were obtained in the central HR-CTV and D90 >69 Gy in the distal regions of HR-CTV. Image-guided set up of the IMRT boost with the applicator in situ was feasible. The dose plans were robust to intra-fraction uncertainties of 3 mm. Local control with acceptable morbidity was obtained at a followup of 3, 2.5, and 1 year, respectively.
The combination of MRI-guided BT with an applicator-guided stereotactic IMRT boost is feasible. This technique seems to be useful in the few cases where HR-CTV coverage cannot be obtained even with IS-IC-BT.
描述一种新技术，该技术涉及高精度立体定向调强放射治疗（IMRT）增敏联合腔内-组织间（IC-IS）近距离放射治疗（BT），用于治疗因广泛残留病灶和/或BT时地形复杂而无法被IC-IS-BT充分覆盖的宫颈肿瘤。
3例IIIB-IVA期宫颈癌患者在BT时存在明显残留病灶。MRI引导的IC-IS-BT（脉冲剂量率）与根据原位BT施源器通过锥形束CT引导的立体定向IMRT增敏相结合。高危临床靶区（HR-CTV）的计划目标剂量（总外照射放疗和BT）为D90>70-85 Gy，而危及器官的限制条件为直肠、乙状结肠和肠的D2cm3<70 Gy，膀胱的等效总剂量（2 Gy分割）<90 Gy。优化适应BT剂量分布的IMRT增敏，以靶向BT覆盖不佳的区域。
中央HR-CTV的HR-CTV剂量D90>81 Gy，HR-CTV远端区域的D90>69 Gy。在施源器原位的情况下，图像引导设置IMRT增敏是可行的。剂量计划对3 mm的分次内不确定性具有鲁棒性。分别在3年、2.5年和1年的随访中获得了具有可接受发病率的局部控制。
MRI引导的BT与施源器引导的立体定向IMRT增敏相结合是可行的。在即使采用IS-IC-BT也无法获得HR-CTV覆盖的少数情况下，该技术似乎是有用的。
