Ambient dose equivalent versus effective dose for quantifying stray radiation exposures to a patient receiving proton therapy for prostate cancer

Jonas D. Fontenot, Phillip T. Taddei, Yuanshui Zheng, Dragan Mirkovic, Wayne D. Newhauser

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The purpose of this study was to evaluate the suitability of the quantity ambient dose equivalent H*(10) as a conservative estimate of effective dose E for estimating stray radiation exposures to patients receiving passively scattered proton radiotherapy for cancer of the prostate. H*(10), which is determined from fluence free-in-air, is potentially useful because it is simpler to measure or calculate because it avoids the complexities associated with phantoms or patient anatomy. However, the suitability of H*(10) as a surrogate for E has not been demonstrated for exposures to high-energy neutrons emanating from radiation treatments with proton beams. The suitability was tested by calculating H*(10) and E for a proton treatment using a Monte Carlo model of a double-scattering treatment machine and a computerized anthropomorphic phantom. The calculated E for the simulated treatment was 5.5 mSv/Gy, while the calculated H*(10) at the isocenter was 10 mSv/Gy. A sensitivity analysis revealed that H*(10) conservatively estimated E for the interval of treatment parameters common in proton therapy for prostate cancer. However, sensitivity analysis of a broader interval of parameters suggested that H*(10) may underestimate E for treatments of other sites, particularly those that require large field sizes. Simulations revealed that while E was predominated by neutrons generated in the nozzle, neutrons produced in the patient contributed up to 40% to dose equivalent in near-field organs.

Original languageEnglish (US)
Pages (from-to)173-177
Number of pages5
JournalNuclear Technology
Volume168
Issue number1
DOIs
StatePublished - Jan 1 2009

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radiation dosage
Dosimetry
therapy
Neutrons
Protons
cancer
Radiation
dosage
Sensitivity analysis
protons
Hydrogen
Proton beams
Radiotherapy
sensitivity analysis
neutrons
Nozzles
Scattering
intervals
anatomy
Air

Keywords

  • Proton therapy
  • Radiation protection
  • Stray radiation

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering
  • Condensed Matter Physics

Cite this

Ambient dose equivalent versus effective dose for quantifying stray radiation exposures to a patient receiving proton therapy for prostate cancer. / Fontenot, Jonas D.; Taddei, Phillip T.; Zheng, Yuanshui; Mirkovic, Dragan; Newhauser, Wayne D.

In: Nuclear Technology, Vol. 168, No. 1, 01.01.2009, p. 173-177.

Research output: Contribution to journalArticle

Fontenot, Jonas D. ; Taddei, Phillip T. ; Zheng, Yuanshui ; Mirkovic, Dragan ; Newhauser, Wayne D. / Ambient dose equivalent versus effective dose for quantifying stray radiation exposures to a patient receiving proton therapy for prostate cancer. In: Nuclear Technology. 2009 ; Vol. 168, No. 1. pp. 173-177.
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