Dosimetric Comparison of Stereotactic Body Radiotherapy for Spinal Metastasis in Cyberknife and Helical Tomotherapy

作者：Kang Young nam^*; Kay Chul Seung; Son Seok Hyun; Choi Byung Ock; Jung Ji Young; Shin Hun Joo; Kay Chul Seung; Son Seok Hyun; Kim Myong Ho; Seo Jae Hyuk; Lee Gi Woong

来源：Journal of the Korean Physical Society, 2012, 61(12): 2049-2053.

DOI：10.3938/jkps.61.2049

• Tomotherapy
• Cyberknife
• Conformity index
• Homogeneity index

This study seeks to evaluate the stereotactic body radiation therapy (SBRT) dosimetric benefit of cyberknife (CK) and helical tomotherapy (HT) for spinal tumor patients in regards to successful plan acceptance and lower dosage to critical structures. This study used dose volume histogram (DVH) compared the two systems quantitatively, by using several indices for the dosimetric comparisons, including the conformity index (CI) and homogeneity index (HI) for the planned target volume (PTV). We planned L3 (n = 2), L5 (n = 1), T12 (n = 1), C3 (n = 1), and T5 (n = 1) spinal tumors case with planning target volumes ranging from 3.55 similar to 17.95 cc. Prescription doses were 1600 similar to 2000 cGy per single fraction. CK prescribed 80 similar to 85% in PTV and HT 90 similar to 95%, respectively. The dosimetric data were compared between the two treatment systems by calculating the CI, HI, and maximum doses to the OARs based on the treatment plans, generated for each site. Regarding the homogeneity of PTV, both plans gave satisfactory results, and no significant differences were observed. The partial volume tolerance dose (received dose of 10 Gy at a spinal cord volume 10%) to the spinal cord in 16 similar to 18 Gy single fraction was satisfactory. We found that both planning systems satisfied the required PTV prescription, but better dose conformity and better dose homogeneity with a poorer dose gradient were achieved with HT then with CK.

• 出版日期2012-12