Room: AAPM ePoster Library
Purpose: There is lack of consistency among institutions with regards to what is considered an optimum treatment plan in terms of target coverage and doses to organs at risk. However, clinical trials usually overcome this challenge by providing specific criteria for plans acceptability. The goal of this study is to develop an optimum treatment plan criterion that can be used by treatment planners or dosimetrists to minimize variations in patient treatment plans acceptability and improve confidence in planners and workflow
Methods: We retrospectively reviewed the treatment plans of 352 lung cancer patients treated using the SBRT technique at our cancer centre. Out of the 352 patients, 199 were treated with a prescription of 48 Gy in 4 fractions, 92 were treated with 50 Gy in 5 fractions and 61 patients were treated with a prescription of 60 Gy in 8 fractions. Patients were treated with either a volumetric modulated arc therapy technique using 2-3 arcs or a 3D conformal non coplanar technique that involves 7 or 9 beams with 2 couch angles on Varian TrueBeam linear accelerators using 6 MV photon beams.
Results: Dose volume histograms for all the treatment volumes: GTV, ITV, and PTV and the organs at risk (OAR): heart, trachea + bronchus, spinal cord, esophagus, great vessels and ribs were evaluated and the mean DVH were derived. Statistical analysis including the mean, minimum and maximum doses to the treatment volume and OARs was also calculated.
Conclusion: The results from this study could help in establishing the foundation for an institutional lung SBRT treatment plan criteria tailored to the individual patient’s needs and priorities with less variations. We hope that this endeavour will help in improving the planning process for patients and thus help in achieving optimal plans for radiation treatment of lung cancer patients.