Radiation Therapy of Large Intact Breasts Using a Beam Spoiler or Photons with Mixed Energies

Hunt, Margie A; Hong, Linda X; Amols, Howard I

doi:10.1016/j.meddos.2007.02.002

Title: Radiation Therapy of Large Intact Breasts Using a Beam Spoiler or Photons with Mixed Energies

Full Record
Other Related Research

Abstract

Radiation treatment of large intact breasts with separations of more than 24 cm is typically performed using x-rays with energies of 10 MV and higher, to eliminate high-dose regions in tissue. The disadvantage of the higher energy beams is the reduced dose to superficial tissue in the buildup region. We evaluated 2 methods of avoiding this underdosage: (1) a beam spoiler: 1.7-cm-thick Lucite plate positioned in the blocking tray 35 cm from the isocenter, with 15-MV x-rays; and (2) combining 6- and 15-MV x-rays through the same portal. For the beam with the spoiler, we measured the dose distribution for normal and oblique incidence using a film and ion chamber in polystyrene, as well as a scanning diode in a water tank. In the mixed-energy approach, we calculated the dose distributions in the buildup region for different proportions of 6- and 15-MV beams. The dose enhancement due to the beam spoiler exhibited significant dependence upon the source-to-skin distance (SSD), field size, and the angle of incidence. In the center of a 20 x 20-cm{sup 2} field at 90-cm SSD, the beam spoiler raises the dose at 5-mm depth from 77% to 87% of the prescription, while maintaining the skin dosemore »« less

Authors:

Hunt, Margie A ^[1]; Hong, Linda X ^[2]; Amols, Howard I ^[1]

Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)
Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States)

Publication Date:: Mon Jan 01 00:00:00 EST 2007

OSTI Identifier:: 21045979

Resource Type:: Journal Article

Journal Name:: Medical Dosimetry

Additional Journal Information:: Journal Volume: 32; Journal Issue: 4; Other Information: DOI: 10.1016/j.meddos.2007.02.002; PII: S0958-3947(07)00046-5; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0958-3947

Country of Publication:: United States

Language:: English

Subject:: 62 RADIOLOGY AND NUCLEAR MEDICINE; BEAMS; INCIDENCE ANGLE; IONIZATION CHAMBERS; LUCITE; MAMMARY GLANDS; NEOPLASMS; PLANNING; POLYSTYRENE; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; RADIOTHERAPY; SKIN; X RADIATION

Citation Formats


                    Lief, Eugene P., Hunt, Margie A, Hong, Linda X, and Amols, Howard I. Radiation Therapy of Large Intact Breasts Using a Beam Spoiler or Photons with Mixed Energies.  United States: N. p., 2007. 
        Web.  doi:10.1016/j.meddos.2007.02.002.

Copy to clipboard


                    Lief, Eugene P., Hunt, Margie A, Hong, Linda X, & Amols, Howard I. Radiation Therapy of Large Intact Breasts Using a Beam Spoiler or Photons with Mixed Energies.  United States.  https://doi.org/10.1016/j.meddos.2007.02.002

Copy to clipboard


                    Lief, Eugene P., Hunt, Margie A, Hong, Linda X, and Amols, Howard I. 2007.  
        "Radiation Therapy of Large Intact Breasts Using a Beam Spoiler or Photons with Mixed Energies".  United States.  https://doi.org/10.1016/j.meddos.2007.02.002.

Copy to clipboard


                    
@article{osti_21045979,

  title        = {Radiation Therapy of Large Intact Breasts Using a Beam Spoiler or Photons with Mixed Energies},

  author       = {Lief, Eugene P. and Hunt, Margie A and Hong, Linda X and Amols, Howard I},

  abstractNote = {Radiation treatment of large intact breasts with separations of more than 24 cm is typically performed using x-rays with energies of 10 MV and higher, to eliminate high-dose regions in tissue. The disadvantage of the higher energy beams is the reduced dose to superficial tissue in the buildup region. We evaluated 2 methods of avoiding this underdosage: (1) a beam spoiler: 1.7-cm-thick Lucite plate positioned in the blocking tray 35 cm from the isocenter, with 15-MV x-rays; and (2) combining 6- and 15-MV x-rays through the same portal. For the beam with the spoiler, we measured the dose distribution for normal and oblique incidence using a film and ion chamber in polystyrene, as well as a scanning diode in a water tank. In the mixed-energy approach, we calculated the dose distributions in the buildup region for different proportions of 6- and 15-MV beams. The dose enhancement due to the beam spoiler exhibited significant dependence upon the source-to-skin distance (SSD), field size, and the angle of incidence. In the center of a 20 x 20-cm{sup 2} field at 90-cm SSD, the beam spoiler raises the dose at 5-mm depth from 77% to 87% of the prescription, while maintaining the skin dose below 57%. Comparison of calculated dose with measurements suggested a practical way of treatment planning with the spoiler-usage of 2-mm 'beam' bolus-a special option offered by in-house treatment planning system. A second method of increasing buildup doses is to mix 6- and 15-MV beams. For example, in the case of a parallel-opposed irradiation of a 27-cm-thick phantom, dose to D{sub max} for each energy, with respect to midplane, is 114% for pure 6-, 107% for 15-MV beam with the spoiler, and 108% for a 3:1 mixture of 15- and 6-MV beams. Both methods are practical for radiation therapy of large intact breasts.},

  doi          = {10.1016/j.meddos.2007.02.002},

  url          = {https://www.osti.gov/biblio/21045979},
  journal      = {Medical Dosimetry},

  issn         = {0958-3947},

  number       = 4,

  volume       = 32,

  place        = {United States},

  year         = {Mon Jan 01 00:00:00 EST 2007},

  month        = {Mon Jan 01 00:00:00 EST 2007}

}

Copy to clipboard

Journal Article:

https://doi.org/10.1016/j.meddos.2007.02.002

Other availability

Find in Google Scholar

Search WorldCat to find libraries that may hold this journal

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

Accurate skin dose measurements using radiochromic film in clinical applications

Journal Article Devic, S; Seuntjens, J; Abdel-Rahman, W; ... - Medical Physics

Megavoltage x-ray beams exhibit the well-known phenomena of dose buildup within the first few millimeters of the incident phantom surface, or the skin. Results of the surface dose measurements, however, depend vastly on the measurement technique employed. Our goal in this study was to determine a correction procedure in order to obtain an accurate skin dose estimate at the clinically relevant depth based on radiochromic film measurements. To illustrate this correction, we have used as a reference point a depth of 70 {mu}. We used the new GAFCHROMIC[reg] dosimetry films (HS, XR-T, and EBT) that have effective points of measurementmore »« less
https://doi.org/10.1118/1.2179169
SU-E-T-219: Comprehensive Validation of the Electron Monte Carlo Dose Calculation Algorithm in RayStation Treatment Planning System for An Elekta Linear Accelerator with AgilityTM Treatment Head

Journal Article Wang, Yi; Park, Yang-Kyun; Doppke, Karen - Medical Physics

Purpose: This study evaluated the performance of the electron Monte Carlo dose calculation algorithm in RayStation v4.0 for an Elekta machine with Agility™ treatment head. Methods: The machine has five electron energies (6–8 MeV) and five applicators (6×6 to 25×25 cm {sup 2}). The dose (cGy/MU at d{sub max}), depth dose and profiles were measured in water using an electron diode at 100 cm SSD for nine square fields ≥2×2 cm{sup 2} and four complex fields at normal incidence, and a 14×14 cm{sup 2} field at 15° and 30° incidence. The dose was also measured for three square fields ≥4×4more »« less
https://doi.org/10.1118/1.4924580
Surface and superficial dose dosimetric verification for postmastectomy radiotherapy

Journal Article Shiau, An-Cheng; Chiu, Min-Chi; Chen, Tung-Ho; ... - Medical Dosimetry

In patients given postmastectomy radiotherapy (PMRT), the chest wall is a very thin layer of soft tissue with a low-density lung tissue behind. Chest wall treated in this situation with a high-energy photon beam presents a high dosimetric uncertainty region for both calculation and measurement. The purpose of this study was to measure and to evaluate the surface and superficial doses for patients requiring PMRT with different treatment techniques. An elliptic cylinder cork and superflab boluses were used to simulate the lung and the chest wall, respectively. Sets of computed tomography (CT) images with different chest wall thicknesses were acquiredmore »« less
https://doi.org/10.1016/J.MEDDOS.2012.03.005
Superficial dosimetry imaging based on Čerenkov emission for external beam radiotherapy with megavoltage x-ray beam

Journal Article Zhang, Rongxiao; Glaser, Adam; Gladstone, David; ... - Medical Physics

Purpose: Čerenkov radiation emission occurs in all tissue, when charged particles (either primary or secondary) travel at velocity above the threshold for the Čerenkov effect (about 220 KeV in tissue for electrons). This study presents the first examination of optical Čerenkov emission as a surrogate for the absorbed superficial dose for MV x-ray beams.Methods: In this study, Monte Carlo simulations of flat and curved surfaces were studied to analyze the energy spectra of charged particles produced in different regions near the surfaces when irradiated by MV x-ray beams. Čerenkov emission intensity and radiation dose were directly simulated in voxelized flatmore »« less
https://doi.org/10.1118/1.4821543
Three-dimensional photon dose distributions with and without lung corrections for tangential breast intact treatments

Journal Article Chin, L; Cheng, C; Siddon, R; ... - International Journal of Radiation Oncology, Biology and Physics; (USA)

The influence of lung volume and photon energy on the 3-dimensional dose distribution for patients treated by intact breast irradiation is not well established. To investigate this issue, we studied the 3-dimensional dose distributions calculated for an 'average' breast phantom for 60Co, 4 MV, 6 MV, and 8 MV photon beams. For the homogeneous breast, areas of high dose ('hot spots') lie along the periphery of the breast near the posterior plane and near the apex of the breast. The highest dose occurs at the inferior margin of the breast tissue, and this may exceed 125% of the target dosemore »« less
https://doi.org/10.1016/0360-3016(89)90545-2

Similar Records