TITLE:
Dosimetric Comparisons of Lung SBRT with Multiple Metastases by Two Advanced Planning Systems
AUTHORS:
Ye Zhang, Yie Chen, Jie Qiu, Jack Yang
KEYWORDS:
SBRT, DMPO, Tomotherapy, Lung IMRT
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.3 No.4,
November
11,
2014
ABSTRACT: Purpose: To evaluate planning quality of Stereotactic body Radiotherapy (SBRT) with multiple lungmetastases generated by the Pinnacle and Tomotherapy planning systems, respectively. Methods and Materials: Nine randomly selected patients diagnosed with non-small cell lung carcinoma with multiple lesions were planned with Philips Pinnacle (version 9.2, Fitchburg, WI) and Tomotherapy (version 4.2, Madison, WI), respectively. Both coplanar and non-coplanar IMRT plans were generated on Pinnacle system. A total dose of 60 Gy was prescribed to cover 95% of Planning Target Volume (PTV) in 3 fractions based on the RTOG0236 protocol prescription [1]. All plans with single isocenter setting were used for multiple lesions planning. A set of nine static beams were used for Pinnacle plansusing Direct Machine Parameters Optimization (DMPO) algorithm of RTOT0236 dose constraints. Planning outcomes such as minimum and mean doses, V95, D95 (95% of target volume receivesprescription dose), D5, and D1 to PTV, maximum dose to heart, esophagus, cord, trachea, brachial plexus, rib, chest wall, and liver, mean dose toliver, total lung, right and left lung, volume of chest wall receives 30 Gy, volume of lungs receives 5 Gy and 20 Gy (V5 and V20), conformity index (CI) and heterogeneity index (HI) were all reported for evaluation. Results: Mean volume of PTV was 37.77 ± 23.4 cm3. D95 of PTV with Tomotherapy, coplanar, non-coplanar plan was 60.2 ± 0.3 Gy, 58.6 ± 1.2 Gy, and 59.1 ± 0.7 Gy, respectively. Mean dose to PTV was lower for Tomotherapy (p 5 (p 1 (p = 0.001). CI was higher with Tomotherapyplans (p p 5 which needs more attention for toxicity analysis.