Katelyn M Atkins1, Yiyi Chen2, David A Elliott3, Tulsee S Doshi4, Sanja Ognjenovic5, Arjun S Vachhani3, Monica Kishore3, Steven L Primack6, Martin Fuss3, Mark E Deffebach7,8, Charlotte Dai Kubicky3, James A Tanyi3,9. 1. Department of Medicine, Providence St. Vincent Medical Center, 9205 SW Barnes Rd, Portland, OR 97225, USA. 2. Department of Public Health & Preventive Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA. 3. Department of Radiation Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA. 4. Stanford University, 450 Serra Mall, Stanford, CA 94305, USA. 5. Oregon State University, Corvallis, OR 97331, USA. 6. Department of Radiology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA. 7. Department of Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA. 8. Veterans Administration Medical Center, 3710 SW US Veteran Hospital Rd, Portland, OR 97239, USA. 9. Department of Nuclear Engineering & Radiation Health Physics, Oregon State University, Corvallis, OR 97331, USA.
Abstract
PURPOSE: Narrow PTV margins and steep dose gradients underscore the importance of evaluating breathing-associated tumor motion for lung SBRT. The specific aim of this study was to determine the impact of anatomic tumor location on inter-fraction tumor motion. METHODS AND MATERIALS: Forty-one patients underwent standard free-breathing 4DCT simulation and daily image-guidance 4DCTs during lung SBRT. Absolute tumor motion amplitude in the mediolateral (ML), anterior-posterior (AP), and superior-inferior (SI) directions was analyzed from 159 total 4DCT scans (simulation and daily pre-treatment). RESULTS: Overall, the inter-fraction tumor motion amplitude in the ML, AP, and SI directions was small (mean ≤2.5 mm). Similarly, while both upper lobe (UL) and lower lobe (LL) tumors exhibited limited inter-fraction motion in both the ML and AP directions (mean ≤2.2 mm), tumors in the LL had increased inter-fraction motion in the SI direction compared to UL tumors (mean 4.3±4.0 mm vs. 1.7±1.7 mm, p=0.008). Moreover, 28.6% (n=4) of LL tumors exhibited mean inter-fraction motion along the SI direction >5 mm (all of which resided in the supra-diaphragmatic basal segments of the LL). CONCLUSIONS: Mean inter-fraction tumor motion amplitude along the SI direction exceeded our PTV margins (an isotropic 5 mm expansion of the ITV) in 28.6% of LL tumors (all of which resided in the basal segments). These results suggest that typical ITV-to-PTV margins may be insufficient for a subset of LL lesions and that increased PTV margins, daily breathing motion re-assessment and/or adaptive re-planning may benefit patients with supra-diaphragmatic tumors in the LL.
PURPOSE: Narrow PTV margins and steep dose gradients underscore the importance of evaluating breathing-associated tumor motion for lung SBRT. The specific aim of this study was to determine the impact of anatomic tumor location on inter-fraction tumor motion. METHODS AND MATERIALS: Forty-one patients underwent standard free-breathing 4DCT simulation and daily image-guidance 4DCTs during lung SBRT. Absolute tumor motion amplitude in the mediolateral (ML), anterior-posterior (AP), and superior-inferior (SI) directions was analyzed from 159 total 4DCT scans (simulation and daily pre-treatment). RESULTS: Overall, the inter-fraction tumor motion amplitude in the ML, AP, and SI directions was small (mean ≤2.5 mm). Similarly, while both upper lobe (UL) and lower lobe (LL) tumors exhibited limited inter-fraction motion in both the ML and AP directions (mean ≤2.2 mm), tumors in the LL had increased inter-fraction motion in the SI direction compared to UL tumors (mean 4.3±4.0 mm vs. 1.7±1.7 mm, p=0.008). Moreover, 28.6% (n=4) of LL tumors exhibited mean inter-fraction motion along the SI direction >5 mm (all of which resided in the supra-diaphragmatic basal segments of the LL). CONCLUSIONS: Mean inter-fraction tumor motion amplitude along the SI direction exceeded our PTV margins (an isotropic 5 mm expansion of the ITV) in 28.6% of LL tumors (all of which resided in the basal segments). These results suggest that typical ITV-to-PTV margins may be insufficient for a subset of LL lesions and that increased PTV margins, daily breathing motion re-assessment and/or adaptive re-planning may benefit patients with supra-diaphragmatic tumors in the LL.
Authors: Robert Timmerman; Rebecca Paulus; James Galvin; Jeffrey Michalski; William Straube; Jeffrey Bradley; Achilles Fakiris; Andrea Bezjak; Gregory Videtic; David Johnstone; Jack Fowler; Elizabeth Gore; Hak Choy Journal: JAMA Date: 2010-03-17 Impact factor: 56.272
Authors: Geert Bosmans; Angela van Baardwijk; André Dekker; Michel Ollers; Liesbeth Boersma; André Minken; Philippe Lambin; Dirk De Ruysscher Journal: Int J Radiat Oncol Biol Phys Date: 2006-11-01 Impact factor: 7.038
Authors: John R van Sörnsen de Koste; Frank J Lagerwaard; Margriet R J Nijssen-Visser; Wilfried J Graveland; Suresh Senan Journal: Int J Radiat Oncol Biol Phys Date: 2003-06-01 Impact factor: 7.038
Authors: Peter G Maxim; Billy W Loo; Haider Shirazi; Brian Thorndyke; Gary Luxton; Quynh-Thu Le Journal: Int J Radiat Oncol Biol Phys Date: 2007-09-14 Impact factor: 7.038
Authors: Ylanga G van der Geld; Frank J Lagerwaard; John R van Sörnsen de Koste; Johan P Cuijpers; Ben J Slotman; Suresh Senan Journal: Radiat Oncol Date: 2006-11-01 Impact factor: 3.481