Dosimetric Comparison of 6 MV and 15 MV Single Arc Rapidarc to Helical TomoTherapy for the Treatment of Pancreatic Cancer

Journal Article · Sat Oct 01 00:00:00 EDT 2011 · Medical Dosimetry

OSTI ID:21590489

Jinbo, Yue ^[1]; McLawhorn, Robert; Wensha, Yang; Wijesooriya, Krishni; Dunlap, Neal E; Ke, Sheng ^[2]; Fangfang, Yin ^[1]; Benedict, Stanley H ^[2]

---

1. Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States)
2. Department of Radiation Oncology, University of Virginia, Charlottesville, VA (United States)

We conducted a planning study to compare Varian's RapidArc (RA) and helical TomoTherapy (HT) for the treatment of pancreatic cancer. Three intensity-modulated radiotherapy (IMRT) plans were generated for 8 patients with pancreatic cancer: one using HT with 6-MV beam (Plan{sub HT6}), one using single-arc RA with 6-MV beam (Plan{sub RA6}), and one using single-arc RA with 15-MV beam (Plan{sub RA15}). Dosimetric indices including high/low conformality index (CI{sub 100%}/CI{sub 50%}), heterogeneity index (HI), monitor units (MUs), and doses to organs at risk (OARs) were compared. The mean CI{sub 100%} was statistically equivalent with respect to the 2 treatment techniques, as well as beam energy (0.99, 1.01, and 1.02 for Plan{sub HT6}, Plan{sub RA6}, and Plan{sub RA156,} respectively). The CI{sub 50%} and HI were improved in both RA plans over the HT plan. The RA plans significantly reduced MU (MU{sub RA6} = 697, MU{sub RA15} = 548) compared with HT (MU{sub HT6} = 6177, p = 0.008 in both cases). The mean maximum cord dose was decreased from 29.6 Gy in Plan{sub HT6} to 21.6 Gy (p = 0.05) in Plan{sub RA6} and 21.7 Gy (p = 0.04) in Plan{sub RA15}. The mean bowel dose decreased from 17.2 Gy in Plan{sub HT6} to 15.2 Gy (p = 0.03) in Plan{sub RA6} and 15.0 Gy (p = 0.03) Plan{sub RA15}. The mean liver dose decreased from 8.4 Gy in Plan{sub HT6} to 6.3 Gy (p = 0.04) in Plan{sub RA6} and 6.2 Gy in Plan{sub RA15}. Variations of the mean dose to the duodenum, kidneys, and stomach were statistically insignificant. RA and HT can both deliver conformal dose distributions to target volumes while limiting the dose to surrounding OARs in the treatment of pancreatic cancer. Dosimetric advantages might be gained by using RA over HT by reducing the dose to OARs and total MUs used for treatment.

• OSTI ID: 21590489
• Journal Information: Medical Dosimetry, Vol. 36, Issue 3; Other Information: DOI: 10.1016/j.meddos.2010.07.002; PII: S0958-3947(10)00114-7; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0958-3947
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
COMPARATIVE EVALUATIONS
COMPUTERIZED TOMOGRAPHY
CT-GUIDED RADIOTHERAPY
DOSIMETRY
HAZARDS
KIDNEYS
LIVER
NEOPLASMS
PANCREAS
PLANNING
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
SMALL INTESTINE
STOMACH
BODY
DIAGNOSTIC TECHNIQUES
DIGESTIVE SYSTEM
DISEASES
DOSES
ENDOCRINE GLANDS
EVALUATION
GASTROINTESTINAL TRACT
GLANDS
INTESTINES
MEDICINE
NUCLEAR MEDICINE
ORGANS
RADIOLOGY
RADIOTHERAPY
THERAPY
TOMOGRAPHY