Helical Tomotherapy Versus Single-Arc Intensity-Modulated Arc Therapy: A Collaborative Dosimetric Comparison Between Two Institutions
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD (United States)
- Department of Human Oncology and Medical Physics, University of Wisconsin-Madison, WI, Madison (United States)
Purpose: Both helical tomotherapy (HT) and single-arc intensity-modulated arc therapy (IMAT) deliver radiation using rotational beams with multileaf collimators. We report a dual-institution study comparing dosimetric aspects of these two modalities. Methods and Materials: Eight patients each were selected from the University of Maryland (UMM) and the University of Wisconsin Cancer Center Riverview (UWR), for a total of 16 cases. Four cancer sites including brain, head and neck (HN), lung, and prostate were selected. Single-arc IMAT plans were generated at UMM using Varian RapidArc (RA), and HT plans were generated at UWR using Hi-Art II TomoTherapy. All 16 cases were planned based on the identical anatomic contours, prescriptions, and planning objectives. All plans were swapped for analysis at the same time after final approval. Dose indices for targets and critical organs were compared based on dose-volume histograms, the beam-on time, monitor units, and estimated leakage dose. After the disclosure of comparison results, replanning was done for both techniques to minimize diversity in optimization focus from different operators. Results: For the 16 cases compared, the average beam-on time was 1.4 minutes for RA and 4.8 minutes for HT plans. HT provided better target dose homogeneity (7.6% for RA and 4.2% for HT) with a lower maximum dose (110% for RA and 105% for HT). Dose conformation numbers were comparable, with RA being superior to HT (0.67 vs. 0.60). The doses to normal tissues using these two techniques were comparable, with HT showing lower doses for more critical structures. After planning comparison results were exchanged, both techniques demonstrated improvements in dose distributions or treatment delivery times. Conclusions: Both techniques created highly conformal plans that met or exceeded the planning goals. The delivery time and total monitor units were lower in RA than in HT plans, whereas HT provided higher target dose uniformity.
- OSTI ID:
- 21587677
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 81, Issue 1; Other Information: DOI: 10.1016/j.ijrobp.2010.10.059; PII: S0360-3016(10)03560-1; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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COMPARATIVE EVALUATIONS
COMPUTERIZED TOMOGRAPHY
CRITICAL ORGANS
CT-GUIDED RADIOTHERAPY
HEAD
LUNGS
NECK
NEOPLASMS
PROSTATE
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
BODY
DIAGNOSTIC TECHNIQUES
DISEASES
DOSES
EVALUATION
GLANDS
MALE GENITALS
MEDICINE
NUCLEAR MEDICINE
ORGANS
RADIOLOGY
RADIOTHERAPY
RESPIRATORY SYSTEM
THERAPY
TOMOGRAPHY