EP-1657: DVH analysis automation in Tomotherapy

M.E. Perez Alvarez, J.C. Zapata Jiménez, C.B. Carrascosa Fernandez, J. Torres Donaire, J. Arjona Gutierrez, A. Gil Agudo
2016 Radiotherapy and Oncology  
S774 ESTRO 35 2016 _____________________________________________________________________________________________________ was treated with an IMRS plan designed with the isocenter located at the target center (plan A). A second off-target isocenter plan (plan B) was generated for each case. In all plans the 100% of the prescription dose covered the 99% of the target volume. The plans A and B were compared for the target dosage (conformity and homogeneity indices) and organs at risk (OAR) dose
more » ... risk (OAR) dose sparing. Peripheral dose falloff was compared by using the metrics V12 (volume of normal brain receiving more than 12 Gy) and CI 50% (conformity index at the level of the 50% of the prescription dose). Results: The values found for each metric (plan B vs. plan A) were (mean ± SD): CI (1.28 ± 0.15 vs. 1.28 ± 0.15, p = 0.978), HI (1.29 ± 0.14 vs. 1.34 ± 0.17, p = 0.079), maximum dose to brainstem (2.95 ± 2.11 vs. 2.89 ± 1.88 Gy, p = 0.813); maximum dose to optical pathway (2.65 ± 4.18 vs. 2.44 ± 4.03 Gy, p = 0.195) and maximum dose to eye lens (0.33 ± 0.73 vs. 0.33 ± 0.53 Gy, p = 0.970). The values of the peripheral dose falloff were (plan B vs. plan A): V12 (5.98 ± 4.95 vs. 6.06 ± 4.92 cm3, p = 0.622), and CI 50% (6.08 ± 2.77 vs. 6.28 ± 3.01, p = 0.119). Conclusion: The off-target isocenter solution resulted in dosimetrically comparable plans as the center-target isocenter technique, by avoiding the risk of gantry-couch collision during the CBCT acquisition.
doi:10.1016/s0167-8140(16)32908-5 fatcat:pnmzmuxdp5gvhnzoojaogktmgy