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Title: SU-E-T-467: Definition of the Proper Tolerances for Beam-Position Accuracy and Beam Width for Quality Assurance in Active Proton Pencil Beam Scanning

Abstract

Purpose: To estimate the correlation between different dosimetric indices and the clinical outcome, which was recorded at different time points after the treatment, regarding the structure of salivary glands in head and neck cancer radiotherapy. Methods: 218 salivary glands from patients with head and neck tumours treated at IPOCFG from 2007 to 2013 were included in this study. The follow up of those patients consisted on weekly medical visits during the treatment that take about seven weeks. After that the patients had consults every three months. Treatment complications were graded using the RTOG/EORTC guidelines. The response of the salivary glands (both parotids, oral cavity and both submandibular glands) was analyzed for six time periods: 7th week, 3rd, 7th, 12th, 18th and 24th months after the start of the radiotherapy. The total dose distributions, converted to a fractionation scheme of 2Gy fractional doses, were used to calculate the DVHs and dose-response plots of salivary glands. Results: The small differences obtained between the mean DVHs showed that patients should be grouped into: with complications (G1+G2) and without complications (G0). The mean dose/2Gy was 22.2±13.2 Gy (G0) and 33.2±8.0 Gy (G1+G2) for the 7th week, 31.9±9.6 Gy (G0) and 34.6±6.8 Gy (G1+G2) formore » the 12th month and, 32.9±9.3 Gy (G0) and 37.2±8.5 Gy (G1+G2) for the 24th month. The dose-response plots for the 7th week and 24th month were similar to the dose-response curves published in the literature. Conclusion: In some cases, there were not major differences between the mean DVHs of the groups with and without complications in the salivary glands, when comparing them at different time periods. More radiobiological analysis should thus be made to estimate the clinical impact of those differences.« less

Authors:
 [1]
  1. Paul Scherrer Institute, Villigen - PSI (Switzerland)
Publication Date:
OSTI Identifier:
22369611
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 41; Journal Issue: 6; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 60 APPLIED LIFE SCIENCES; ACCURACY; BEAM POSITION; BEAM PROFILES; BEAMS; DIAGRAMS; DOSES; FRACTIONATION; HEAD; INDEXES; NECK; NEOPLASMS; ORAL CAVITY; PATIENTS; PROTONS; QUALITY ASSURANCE; RADIATION DOSE DISTRIBUTIONS; RADIOTHERAPY; RECOMMENDATIONS; SALIVARY GLANDS; TOLERANCE

Citation Formats

Safai, S. SU-E-T-467: Definition of the Proper Tolerances for Beam-Position Accuracy and Beam Width for Quality Assurance in Active Proton Pencil Beam Scanning. United States: N. p., 2014. Web. doi:10.1118/1.4888800.
Safai, S. SU-E-T-467: Definition of the Proper Tolerances for Beam-Position Accuracy and Beam Width for Quality Assurance in Active Proton Pencil Beam Scanning. United States. https://doi.org/10.1118/1.4888800
Safai, S. 2014. "SU-E-T-467: Definition of the Proper Tolerances for Beam-Position Accuracy and Beam Width for Quality Assurance in Active Proton Pencil Beam Scanning". United States. https://doi.org/10.1118/1.4888800.
@article{osti_22369611,
title = {SU-E-T-467: Definition of the Proper Tolerances for Beam-Position Accuracy and Beam Width for Quality Assurance in Active Proton Pencil Beam Scanning},
author = {Safai, S},
abstractNote = {Purpose: To estimate the correlation between different dosimetric indices and the clinical outcome, which was recorded at different time points after the treatment, regarding the structure of salivary glands in head and neck cancer radiotherapy. Methods: 218 salivary glands from patients with head and neck tumours treated at IPOCFG from 2007 to 2013 were included in this study. The follow up of those patients consisted on weekly medical visits during the treatment that take about seven weeks. After that the patients had consults every three months. Treatment complications were graded using the RTOG/EORTC guidelines. The response of the salivary glands (both parotids, oral cavity and both submandibular glands) was analyzed for six time periods: 7th week, 3rd, 7th, 12th, 18th and 24th months after the start of the radiotherapy. The total dose distributions, converted to a fractionation scheme of 2Gy fractional doses, were used to calculate the DVHs and dose-response plots of salivary glands. Results: The small differences obtained between the mean DVHs showed that patients should be grouped into: with complications (G1+G2) and without complications (G0). The mean dose/2Gy was 22.2±13.2 Gy (G0) and 33.2±8.0 Gy (G1+G2) for the 7th week, 31.9±9.6 Gy (G0) and 34.6±6.8 Gy (G1+G2) for the 12th month and, 32.9±9.3 Gy (G0) and 37.2±8.5 Gy (G1+G2) for the 24th month. The dose-response plots for the 7th week and 24th month were similar to the dose-response curves published in the literature. Conclusion: In some cases, there were not major differences between the mean DVHs of the groups with and without complications in the salivary glands, when comparing them at different time periods. More radiobiological analysis should thus be made to estimate the clinical impact of those differences.},
doi = {10.1118/1.4888800},
url = {https://www.osti.gov/biblio/22369611}, journal = {Medical Physics},
issn = {0094-2405},
number = 6,
volume = 41,
place = {United States},
year = {Sun Jun 01 00:00:00 EDT 2014},
month = {Sun Jun 01 00:00:00 EDT 2014}
}