Selection of patient for gated treatment based on the information from 4DCT imaging in stereotactic body radiotherapy of non-small cell lung cancer

Abstract Purpose Stereotactic body radiotherapy (SBRT) is widely used for the treatment of stage-I non-small cell lung cancer (NSCLC). Patient-specific motion correlated with 4DCT could be essential for hypofractionated SBRT. All patients undergoing SBRT do not require motion management during the dose delivery. The objective of this study was to evaluate which patient may benefit from Gated SBRT. Materials and methods Treatment planning of 20 patients of stage-I NSCLC was analysed. Conventional and 4DCT scans were taken. Internal target volume as well as planning target volume (ITV and PTV) were determined in the CT data sets. PTV all phases created using 4DCT data sets and PTV 15mm created using conventional CT data were compared. Also, ITV all phases were compared with ITV created from maximum intensity projections (ITV MIP ). Suitability of patients for motion management-based treatment delivery was also evaluated. Results The average ITV MIP to ITV all phases ratio is 1·06 indicating good agreement between them. Based on the ratio of intensity projections, 9 out of 17 patients were found suitable for our existing gated treatment. Conclusion 4D CT is the main requirement in SBRT to identify the patients who can benefit from motion management during the dose delivery.