PURPOSE: To evaluate the dosimetric consequences for irradiated lung tissue for different respiration conditions for hypofractionated stereotactic body radiotherapy (SBRT). METHODS AND MATERIALS: Thirteen patients with lung lesion undergoing SBRT treatment in shallow breathing with abdominal compression (SB+AP) underwent additional multislice CT studies in free breathing (FB), deep inspiration and expiration breath hold (DIBH, DEBH). For each patient 6 different treatment plans were designed for the various respiration conditions applying standard (7/7/10 mm), reduced (5/5/5 mm) and individual margins. The FB plan with standard margins was used as a reference. The percentage of volume of the ipsilateral lung receiving total doses > or=12, 15> or= and > or=18 Gy, mean lung dose (D(mean)), NTCP corrected for fractionation effects and the total monitor units (MU) were evaluated. RESULTS: With DIBH it was possible to reduce all lung dose parameters by about 20%. Applying reduced margins in DIBH, this reduction was even increased to about 40%. The standard technique (SB+AP) with individual margins showed similar results as DIBH with standard margins. DEBH showed some improvement over FB only when reduced margins were applied. Only for 5/13 patients NTCP values >1% were obtained. For these patients a significant NTCP reduction was achieved with DIBH techniques. CONCLUSIONS: In SBRT shallow breathing with abdominal compression produces acceptable results concerning lung DVHs. DIBH, especially with reduced margins, showed the best lung sparing. For the clinical implementation of such a technique some form of gating is advisable. However, there are some practical limitations due to high fractional doses.
PURPOSE: To evaluate the dosimetric consequences for irradiated lung tissue for different respiration conditions for hypofractionated stereotactic body radiotherapy (SBRT). METHODS AND MATERIALS: Thirteen patients with lung lesion undergoing SBRT treatment in shallow breathing with abdominal compression (SB+AP) underwent additional multislice CT studies in free breathing (FB), deep inspiration and expiration breath hold (DIBH, DEBH). For each patient 6 different treatment plans were designed for the various respiration conditions applying standard (7/7/10 mm), reduced (5/5/5 mm) and individual margins. The FB plan with standard margins was used as a reference. The percentage of volume of the ipsilateral lung receiving total doses > or=12, 15> or= and > or=18 Gy, mean lung dose (D(mean)), NTCP corrected for fractionation effects and the total monitor units (MU) were evaluated. RESULTS: With DIBH it was possible to reduce all lung dose parameters by about 20%. Applying reduced margins in DIBH, this reduction was even increased to about 40%. The standard technique (SB+AP) with individual margins showed similar results as DIBH with standard margins. DEBH showed some improvement over FB only when reduced margins were applied. Only for 5/13 patientsNTCP values >1% were obtained. For these patients a significant NTCP reduction was achieved with DIBH techniques. CONCLUSIONS: In SBRT shallow breathing with abdominal compression produces acceptable results concerning lung DVHs. DIBH, especially with reduced margins, showed the best lung sparing. For the clinical implementation of such a technique some form of gating is advisable. However, there are some practical limitations due to high fractional doses.
Authors: Jonathan H Bryant; Joerg Rottmann; John H Lewis; Pankaj Mishra; Paul J Keall; Ross I Berbeco Journal: Med Phys Date: 2014-12 Impact factor: 4.071
Authors: Pankaj Mishra; Ruijiang Li; Raymond H Mak; Joerg Rottmann; Jonathan H Bryant; Christopher L Williams; Ross I Berbeco; John H Lewis Journal: Med Phys Date: 2014-08 Impact factor: 4.071
Authors: Vikren Sarkar; Long Huang; Yu-Huei Jessica Huang; Martin W Szegedi; Prema Rassiah-Szegedi; Hui Zhao; Ying J Hitchcock; Kristine E Kokeny; Brian Wang; Bill J Salter Journal: J Radiosurg SBRT Date: 2016