Verification of calculated skin doses in postmastectomy helical tomotherapy

Shima Ito, Brent C. Parker, Renee Levine, Mary Ella Sanders, Jonas Fontenot, John Gibbons, Kenneth Hogstrom

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

Purpose: To verify the accuracy of calculated skin doses in helical tomotherapy for postmastectomy radiation therapy (PMRT). Methods and Materials: In vivo thermoluminescent dosimeters (TLDs) were used to measure the skin dose at multiple points in each of 14 patients throughout the course of treatment on a TomoTherapy Hi·Art II system, for a total of 420 TLD measurements. Five patients were evaluated near the location of the mastectomy scar, whereas 9 patients were evaluated throughout the treatment volume. The measured dose at each location was compared with calculations from the treatment planning system. Results: The mean difference and standard error of the mean difference between measurement and calculation for the scar measurements was -1.8% ± 0.2% (standard deviation [SD], 4.3%; range, -11.1% to 10.6%). The mean difference and standard error of the mean difference between measurement and calculation for measurements throughout the treatment volume was -3.0% ± 0.4% (SD, 4.7%; range, -18.4% to 12.6%). The mean difference and standard error of the mean difference between measurement and calculation for all measurements was -2.1% ± 0.2% (standard deviation, 4.5%: range, -18.4% to 12.6%). The mean difference between measured and calculated TLD doses was statistically significant at two standard deviations of the mean, but was not clinically significant (i.e., was <5%). However, 23% of the measured TLD doses differed from the calculated TLD doses by more than 5%. Conclusions: The mean of the measured TLD doses agreed with TomoTherapy calculated TLD doses within our clinical criterion of 5%.

Original languageEnglish (US)
Pages (from-to)584-591
Number of pages8
JournalInternational Journal of Radiation Oncology Biology Physics
Volume81
Issue number2
DOIs
StatePublished - Oct 1 2011
Externally publishedYes

Keywords

  • Chest wall
  • Helical tomotherapy
  • PMRT
  • Skin dose
  • in vivo dosimetry

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

Fingerprint Dive into the research topics of 'Verification of calculated skin doses in postmastectomy helical tomotherapy'. Together they form a unique fingerprint.

  • Cite this