Dosimetric factors of stereotactic body radiation therapy for isolated spinal metastatic diseases:impact of distance from tumor target to spinal cord on planning dosimetry and low dose spillage restriction
Background: This study evaluated the impact of the distance from planning target volume (PTV) to spinal cord on planning dosimetry of stereotactic body radiation therapy (SBRT) in patients with isolated spine metastasis and established planning criteria and parameters to restricting low dose spillage.Methods: Six modified PTVs from each of 10 patients with isolated spinal metastasis were created by artificial uniform extension from clinical target volume (CTV) to ensure a minimum PTV-to-cord distance of 0, 1, 2, 3, 4 and 5 mm;respectively.The prescription dose (PD) was 22 Gy in a single fraction.PTV dosimetric parameters including V100, Dmin, D98”D95”D1”conformity index (CI), R50% (ratio of the 50% prescription isodose volume to the PTV), D2 cm (maximum dose in percentage of PD at 2 cm from PTV in any direction), and cord dose were measured and compared.Results: PTV V100, Dmin, D98”, D95were enhanced markedly along with the increase of the PTV-to-cord distance, with a significant difference.PTV CI,R50%, D2cm, and cord dose were not statistically significant in different PTV-to-cord distances.A PTV-to-cord distance of 2 to 3 mm meet PTV Dmin, D98”, D95”.R50%, and D2cm could restrict low dose spillage in SRS panning.Conclusions:PTV V100, Dmin, D98”, D95 are directly correlated with PTV-to-cord distance for spine SBRT in single fraction.A distance of 2 to 3 mm from PTV to spinal cord meets planning dose requirements.R50% and D2cm can quantitatively restrict low dose spillage and improve plan quality.
Spine metastasis stereotactic body radiation therapy distance spinal cord dose fall off
Hao Yang Xiaohu Cong Boning Cai Xiaoshen Wang Wei Xu Jinyuan Wang Jun Yang Haixia Liu Shouping Xu Zhongjian Ju Lin Ma
Department of Radiation Oncology, Chinese PLA General Hospital, Beijing, China;Department of Radiati Department of Radiation Oncology, Chinese PLA General Hospital, Beijing, China Department of Radiation Oncology, Chinese PLA General Hospital, Beijing, China;Department of Radiati
国内会议
北京
英文
652-660
2016-10-01（万方平台首次上网日期，不代表论文的发表时间）