Verification of Calculated Skin Doses in Postmastectomy Helical Tomotherapy

Journal Article · Sat Oct 01 00:00:00 EDT 2011 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2010.11.041· OSTI ID:21587752

Ito, Shima ^[1]; Levine, Renee; Sanders, Mary Ella ^[2]; Fontenot, Jonas; Gibbons, John; Hogstrom, Kenneth ^[1]

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1. Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, Baton Rouge, LA (United States)
2. Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States)

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%.

• OSTI ID: 21587752
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 81, Issue 2; Other Information: DOI: 10.1016/j.ijrobp.2010.11.041; PII: S0360-3016(10)03662-X; 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

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CHEST
COMPUTERIZED TOMOGRAPHY
CT-GUIDED RADIOTHERAPY
DOSIMETRY
RADIATION DOSES
SKIN
THERMOLUMINESCENT DOSEMETERS
VERIFICATION
BODY
DIAGNOSTIC TECHNIQUES
DOSEMETERS
DOSES
LUMINESCENT DOSEMETERS
MEASURING INSTRUMENTS
MEDICINE
NUCLEAR MEDICINE
ORGANS
RADIOLOGY
RADIOTHERAPY
THERAPY
TOMOGRAPHY