title: Evaluations of secondary cancer risk in spine radiotherapy using 3DCRT, IMRT, and VMAT: A phantom study.
abstract: This study evaluated the secondary cancer risk from volumetric-modulated arc therapy (VMAT) for spine radiotherapy compared with intensity-modulated radiotherapy (IMRT) and 3-dimensional conformal radiotherapy (3DCRT). Computed tomography images of an Radiological Physics Center spine anthropomorphic phantom were exported to a treatment planning system (Pinnacle(3), version 9.4). Radiation treatment plans for spine were prepared using VMAT (dual-arc), 7-field IMRT (beam angles: 110°, 130°, 150°, 180°, 210°, 230°, and 250°), and 4-field 3DCRT technique. The mean and maximum doses, dose-volume histograms, and volumes receiving more than 2 and 4Gy to organs at risk (OARs) were calculated and compared. The lifetime risk for secondary cancers was estimated according to the National Cancer Registry Programme Report 116. VMAT delivered the lowest maximum dose to the esophagus (4.03Gy), bone (8.11Gy), heart (2.11Gy), spinal cord (6.45Gy), and whole lung (5.66Gy) as compared with other techniques (IMRT and 3DCRT). The volumes of OAR (esophagus) receiving more than 4Gy were 0% for VMAT, 27.06% for IMRT, and up to 32.35% for 3DCRT. The estimated risk for secondary cancer in the respective OAR is considerably lower in VMAT compared with other techniques. The results of maximum doses and volumes of OARs suggest that the risk of secondary cancer induction for the spine in VMAT is lower than IMRT and 3DCRT, whereas VMAT has the best target coverage compared with the other techniques.
authors.affiliation: Department of Physics, The Islamia University of Bahawalpur, Bahawalpur, Pakistan; Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, TX. Electronic address: jalil_khanphy@yahoo.com.
authors.forename: Jalil ur
authors.initials: Ju
authors.lastname: Rehman
authors.affiliation: Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, TX.
authors.forename: Ramesh C
authors.initials: RC
authors.lastname: Tailor
authors.affiliation: Department of Physics, The Islamia University of Bahawalpur, Bahawalpur, Pakistan; Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Isa
authors.affiliation: Department of Physics, The Islamia University of Bahawalpur, Bahawalpur, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Afzal
authors.affiliation: Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada.
authors.forename: James
authors.initials: J
authors.lastname: Chow
authors.affiliation: Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, TX.
authors.forename: Geoffrey S
authors.initials: GS
authors.lastname: Ibbott
mesh_terms: D000328:Adult; D000368:Aged; D015984:Causality; D006801:Humans; D015994:Incidence; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology* / Q000209:etiology; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data*; D018570:Risk Assessment; D013125:Spinal Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy*; D055815:Young Adult
keywords: Dose-volume histogram; Organs at risk; VMAT