PURPOSE: To describe regional lung tissue density changes in normal lung tissue of patients with primary and metastatic lung tumors who received stereotactic body radiation therapy (SBRT). METHODS AND MATERIALS: A total of 179 post-SBRT follow-up computed tomography (CT) scans of 62 patients who received SBRT between 2003 and 2009 were studied. Median prescription dose was 54 Gy (range, 30-60 Gy) in 3 to 5 fractions. SBRT-induced lung density changes on post-SBRT follow-up CT were evaluated at approximately 3, 6, 12, 18, 24, and 30 months after treatment. Dose-response curves (DRC) were generated for SBRT-induced lung damage by averaging CT number (HU) changes for regions of the lungs receiving the same dose at 5-Gy intervals. RESULTS: For all follow-up interval periods, CT numbers linearly increased with dose until 35 Gy and were constant thereafter. For 3, 18, 24, and 30 months, the rate of relative electron density increase with dose was approximately 0.24% per Gy. At 6 months, the rate was also similar below 20 Gy but then rose to 0.6% per Gy above this threshold. After 6 months, DRCs were mostly time-independent. When split between patients treated with 3 fractions of 12 to 20 Gy (median, 20 Gy; average tumor volume, 12±16 cm3) and with >3 fractions of 6 to 12.5 Gy (median, 9 Gy; average tumor volume, 30±40 cm3), DRCs differed significantly. In both cases, CT changes at 3, 18, 24, and 30 months were identical to those of the population DRC; however, patients who received >3 fractions showed 6-month CT changes that were more than twice those for the group that received 3 fractions. CONCLUSIONS: This analysis of SBRT-induced normal lung density changes indicates that lung normal tissue has more pronounced self-limited acute effects than late effects. Differences in acute CT changes following treatments in 3 fractions were considerably less than for treatments in >3 fractions.
PURPOSE: To describe regional lung tissue density changes in normal lung tissue of patients with primary and metastatic lung tumors who received stereotactic body radiation therapy (SBRT). METHODS AND MATERIALS: A total of 179 post-SBRT follow-up computed tomography (CT) scans of 62 patients who received SBRT between 2003 and 2009 were studied. Median prescription dose was 54 Gy (range, 30-60 Gy) in 3 to 5 fractions. SBRT-induced lung density changes on post-SBRT follow-up CT were evaluated at approximately 3, 6, 12, 18, 24, and 30 months after treatment. Dose-response curves (DRC) were generated for SBRT-induced lung damage by averaging CT number (HU) changes for regions of the lungs receiving the same dose at 5-Gy intervals. RESULTS: For all follow-up interval periods, CT numbers linearly increased with dose until 35 Gy and were constant thereafter. For 3, 18, 24, and 30 months, the rate of relative electron density increase with dose was approximately 0.24% per Gy. At 6 months, the rate was also similar below 20 Gy but then rose to 0.6% per Gy above this threshold. After 6 months, DRCs were mostly time-independent. When split between patients treated with 3 fractions of 12 to 20 Gy (median, 20 Gy; average tumor volume, 12±16 cm3) and with >3 fractions of 6 to 12.5 Gy (median, 9 Gy; average tumor volume, 30±40 cm3), DRCs differed significantly. In both cases, CT changes at 3, 18, 24, and 30 months were identical to those of the population DRC; however, patients who received >3 fractions showed 6-month CT changes that were more than twice those for the group that received 3 fractions. CONCLUSIONS: This analysis of SBRT-induced normal lung density changes indicates that lung normal tissue has more pronounced self-limited acute effects than late effects. Differences in acute CT changes following treatments in 3 fractions were considerably less than for treatments in >3 fractions.
Authors: Yevgeniy Vinogradskiy; Quentin Diot; Bernard Jones; Richard Castillo; Edward Castillo; Jennifer Kwak; Daniel Bowles; Inga Grills; Nicholas Myziuk; Thomas Guerrero; Craig Stevens; Tracey Schefter; Laurie E Gaspar; Brian Kavanagh; Moyed Miften; Chad Rusthoven Journal: Int J Radiat Oncol Biol Phys Date: 2020-01-23 Impact factor: 7.038
Authors: Ke Nie; Hania Al-Hallaq; X Allen Li; Stanley H Benedict; Jason W Sohn; Jean M Moran; Yong Fan; Mi Huang; Michael V Knopp; Jeff M Michalski; James Monroe; Ceferino Obcemea; Christina I Tsien; Timothy Solberg; Jackie Wu; Ping Xia; Ying Xiao; Issam El Naqa Journal: Int J Radiat Oncol Biol Phys Date: 2019-01-31 Impact factor: 7.038
Authors: Yanjing Li; Michael Dykstra; Till D Best; Jennifer Pursley; Nitish Chopra; Florence K Keane; Melin J Khandekar; Gregory C Sharp; Harald Paganetti; Henning Willers; Florian J Fintelmann; Clemens Grassberger Journal: Radiother Oncol Date: 2019-04-20 Impact factor: 6.280
Authors: Edward Chandy; Adam Szmul; Alkisti Stavropoulou; Joseph Jacob; Catarina Veiga; David Landau; James Wilson; Sarah Gulliford; John D Fenwick; Maria A Hawkins; Crispin Hiley; Jamie R McClelland Journal: Cancers (Basel) Date: 2022-02-14 Impact factor: 6.639