Experimental Investigation of the Implementation of Fermi-Eyges-Hogstrom Electron Beam Model of the Pinnacle{sup 3} System at Extended SSDs

Journal Article · Mon Oct 01 04:00:00 EDT 2007 · Medical Dosimetry

DOI:https://doi.org/10.1016/j.meddos.2007.01.012· OSTI ID:21045974

Al-Ghazi, Muthana ^[1]; Sehgal, Varun ^[1]; Sanford, Robert ^[2]; Chung, Heeteak ^[3]

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1. Department of Radiation Oncology, University of California Irvine Medical Center, Orange, CA (United States)
2. Department of Radiation Oncology, Tulane University, New Orleans, LA (United States)
3. Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL (United States)

A commercially available ADAC Pinnacle{sup 3} radiation treatment planning system has been used to model electron beams from a Varian Clinac 2300C/D in the energy range of 6 to 22 MeV. Prior to clinical use, the dosimetric characteristics of the beams have to be modeled accurately. As a first step for beam modeling, a number of dose profile and depth dose measurements were taken at standard source-to-surface distance (SSD) of 100 cm. Dose profiles and depth dose measurements at extended SSDs up to 120 cm are important for ascertaining accuracy of the model, as well as their clinical usefulness in the treatment of some sites (e.g., head-and-neck tumors). Modeled and measured beam data were compared. Over 98% of comparison points (modeled vs. measured) at 100-cm SSD were within 2.5% or 2.5 mm. At 110 cm SSD, over 98% of compared points were within 4% or 4 mm, and at 120-cm SSD, over 98% of compared points were within 5% or 5 mm. Overall, more than 98% of compared points were within 4% or 4 mm. Better models were produced for lower energies (6 to 15 MeV) than higher energies (18 and 22 MeV). For 6, 9, 12, and 15 MeV, 89% of compared points were within 2% or 2 mm. For 18- and 22-MeV electron energies, 75% and 67%, respectively, were within 2% or 2 mm. These results are consistent with the recommendations of AAPM Task Group Report 53.

• OSTI ID: 21045974
• Journal Information: Medical Dosimetry, Journal Name: Medical Dosimetry Journal Issue: 3 Vol. 32; ISSN 0958-3947; ISSN MEDOEJ
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
ACCURACY
BEAM PROFILES
DEPTH DOSE DISTRIBUTIONS
DIFFERENTIAL THERMAL ANALYSIS
ELECTRON BEAMS
HEAD
NECK
NEOPLASMS
PLANNING
RADIATION DOSES
SIMULATION