title: DOSIMETRIC CONSEQUENCES OF USING CONTRAST-ENHANCED COMPUTED TOMOGRAPHIC IMAGES FOR INTENSITY-MODULATED STEREOTACTIC BODY RADIOTHERAPY PLANNING.
abstract: Potential benefits of planning radiation therapy on a contrast-enhanced computed tomography scan (ceCT) should be weighed against the possibility that this practice may be associated with an inadvertent risk of overdosing nearby normal tissues. This study investigated the influence of ceCT on intensity-modulated stereotactic body radiotherapy (IM-SBRT) planning. Dogs with head and neck, pelvic, or appendicular tumors were included in this retrospective cross-sectional study. All IM-SBRT plans were constructed on a pre- or ceCT. Contours for tumor and organs at risk (OAR) were manually constructed and copied onto both CT's; IM-SBRT plans were calculated on each CT in a manner that resulted in equal radiation fluence. The maximum and mean doses for OAR, and minimum, maximum, and mean doses for targets were compared. Data were collected from 40 dogs per anatomic site (head and neck, pelvis, and limbs). The average dose difference between minimum, maximum, and mean doses as calculated on pre- and ceCT plans for the gross tumor volume was less than 1% for all anatomic sites. Similarly, the differences between mean and maximum doses for OAR were less than 1%. The difference in dose distribution between plans made on CTs with and without contrast enhancement was tolerable at all treatment sites. Therefore, although caution would be recommended when planning IM-SBRT for tumors near "reservoirs" for contrast media (such as the heart and urinary bladder), findings supported the use of ceCT with this dose calculation algorithm for both target delineation and IM-SBRT treatment planning.
authors.affiliation: Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, CO, 80523.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Yoshikawa
authors.affiliation: Department of Radiation Oncology, Rex Cancer Center, Raleigh, NC, 27607.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Roback
authors.affiliation: Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, CO, 80523.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Larue
authors.affiliation: Department of Clinical Sciences, Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, NC, 27695.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Nolan
mesh_terms: D000818:Animals; D001921:Brain / Q000528:radiation effects; D003287:Contrast Media; D003430:Cross-Sectional Studies; D004283:Dog Diseases / Q000532:radiotherapy*; D004285:Dogs; D005121:Extremities / Q000528:radiation effects; D005123:Eye / Q000528:radiation effects; D006321:Heart / Q000528:radiation effects; D007472:Iohexol; D009061:Mouth Mucosa / Q000528:radiation effects; D009369:Neoplasms / Q000532:radiotherapy / Q000662:veterinary*; D009669:Nose Neoplasms / Q000532:radiotherapy / Q000662:veterinary; D058958:Organs at Risk; D021362:Palate, Hard / Q000528:radiation effects; D010386:Pelvic Neoplasms / Q000532:radiotherapy / Q000662:veterinary; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement; D011879:Radiotherapy Dosage / Q000662:veterinary; D011880:Radiotherapy Planning, Computer-Assisted / Q000662:veterinary; D050397:Radiotherapy, Intensity-Modulated / Q000662:veterinary*; D012189:Retrospective Studies; D013238:Stereotaxic Techniques / Q000662:veterinary; D014057:Tomography, X-Ray Computed / Q000662:veterinary*; D001743:Urinary Bladder / Q000528:radiation effects
chemical_list: D003287:Contrast Media; D007472:Iohexol
keywords: dogs; intensity-modulated radiation therapy; stereotactic radiation therapy; translational research; veterinary