MLC tracking for lung SABR reduces planning target volumes and dose to organs at risk. Issue 1 (July 2017)

• Record Type: Journal Article
• Authors: Caillet, Vincent; Keall, Paul J.; Colvill, Emma; Hardcastle, Nicholas; O'Brien, Ricky; Szymura, Kathryn; Booth, Jeremy T.
• Is Part Of: Radiotherapy and oncology. Volume 124:Issue 1(2017:Jul.)
• Page Start: 18
• Page End: 24
• Publication Date: 2017-07
• Subjects: Lung cancer -- Real time adaptive radiotherapy -- MLC tracking -- Radiation pneumonitis; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2017.06.016
• Languages: English
• ISSNs: 0167-8140

Abstract

Abstract: Purpose: Assess the dosimetric impact of multi-leaf collimator (MLC) tracking and mid-ventilation (midV) planning compared with the internal target volume (ITV)-based planning approach for lung Stereotactic Ablative Body Radiotherapy (SABR). Method: Ten lung SABR patients originally treated with an ITV-based plan were re-planned according to MLC tracking and midV planning schemes. All plans were delivered on a linac to a motion phantom in a simulated treatment with real lung motions. Delivered dose was reconstructed in patient planning scans. ITV-based, tracking and midV regimes were compared at the planning and delivered stages based on PTV volume and dose metrics for the GTV and OAR. Results: MLC tracking and midV schemes yielded favourable outcomes compared with ITV-based plans. Average reduction in PTV volume was (MLC tracking/MidV) 33.9%/22%. GTV dose coverage performed better with MLC tracking than the other regimes. Reduction in dose to OAR were for the lung (mean lung dose, 0.8 Gy/0.2 Gy), oesophagus (D3 cc, 1.9 Gy/1.4 Gy), great vessels (D10 cc, 3.2 Gy/1.3 Gy), trachea (D4 cc, 1.1 Gy/0.9 Gy), heart (D1 cc, 2.0 Gy/0.5 Gy) and spinal cord (D0.03 cc, 0.5 Gy/−0.1 Gy). Conclusion: MLC tracking showed reduction in PTV volume, superior GTV dose coverage and organ dose sparing than MidV and ITV-based strategies.