Journal List > Prog Med Phys > v.26(4) > 1098487

Prog Med Phys. 2015 Dec;26(4):234-240. Korean.
Published online December 31, 2015.  https://doi.org/10.14316/pmp.2015.26.4.234
Copyright © 2015 Korean Society of Medical Physics
Comparison of Dosimetric Parameters of Patient with Large and Pendulous Breast Receiving Breast Radiotherapy in the Prone versus Supine Position
Sun Young Moon,* Myonggeun Yoon,* Weon Kuu Chung, Mijoo Chung, Dong Oh Shin, and Dong Wook Kim
*Department of Bio-convergence Engineering, Korea University, Korea.
Department of Radiation Oncology, Kyung Hee University Hospital at Gangdong, Korea.
Department of Radiation Oncology, Kyung Hee University Hospital, Seoul, Korea.

Co-correspondence: Dong Wook Kim. (Email: joocheck@gmail.com ), Tel: 82-2-440-7398, Fax: 82-2-440-7393
Received December 01, 2015; Revised December 18, 2015; Accepted December 19, 2015.

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Abstract

The purpose of this study is to analyze dosimetric parameters of patient with large and pendulous breast receiving breast radiotherapy in the prone versus supine position. The patient underwent computed tomography simulation in both prone and supine position. The homogeneity index (HI), conformity index (CI), coverage index (CVI) to the left breast as planning target volume (PTV) and the doses to the lung, heart, and right breast as organ at risk (OAR) were compared by using dose-volume histogram. The lifetime attributable risk (LAR) according to the prone and supine position was measured for the lung and right breast. The HI, CI of the PTV decreased 21.7%, 6.49%, respectively and the CVI increased 10.8% with the prone position. The mean and maximum dose to the left lung decreased 91.6%, 87.0%, respectively and the volume parameters also decreased over 99% with the prone position. The parameters to the right lung were same regardless of the position. The mean and maximum dose to the heart decreased 51.6%, 14.2% with the prone position. But the mean and maximum dose to the right breast increased unlike the other OARs. The LARs to the lung decreased 80.3% (left), 24.2% (right) but the LAR to the right breast doubled with the prone position. The prone position is a favorable alternative for irradiation of breast in patients with large and pendulous breasts.

Keywords: Large breast; Breast cancer; Prone position; Radiotherapy

Figures


Fig. 1
Dose-volume histogram of the patient; (a) Prone (b) Supine. PTV: red, right lung: blue, left lung: bluish green, right breast: green, heart: plum.
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Fig. 2
CT image of the patient; (a) Prone (b) Supine.
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Tables


Table 1
HI, CI, CVI of the left breast according to the patient's position.
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Table 2
Parameters of the OAR according to the patient's position.
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Table 3
LAR of the OAR according to the patient's position.
Click for larger image

Notes

This work was supported by the General Researcher Program (NRF-2015R1D1A1A09056828), the Nuclear Safety Research Program (Grant No. 1403019) of the Korea Radiation Safety Foundation.

References
1. Ferrari A, Ivaldi G, Leonardi MC, Rondi E, Orecchia R. Prone breast radiotherapy in a patient with early stage breast cancer and a large pendulous breast. Tumori 2009;95:394–397.
2. Kim SK, Shin SO, Kim MS. Radiotherapy Treatment Planning using Computed Tomography in Breast Cancer. Korean J Med Phys 1992;3(2):59–65.
3. Grann A, McCormick B, Chabner ES, et al. Prone breast radiotherapy in early-stage breast cancer: a preliminary analysis. Int J Radiat Oncol Biol Phys 2000;47:319–325.
4. Kim S, Choi Y. Dosimetric Advantages of the Field-in-field Plan Compared with the Tangential Wedged Beams Plan for Whole-breast Irradiation. Prog Med Phys 2014;25(4):199–204.
5. Feuvret L, Noël G, Mazeron JJ, Bey P. Conformity index: A review. Int J Radiat Oncol Biol Phys 2006;64:333–342.
6. Yoon M, Park SY, Shin D, et al. A Simple Scoring Method to Calculate the Homogeneity and Coverage Indices of Dose Volume Histogram. Korean J Med Phys 2006;17(1):6–16.
7. Kim DW, Chung WK, Ahn SH, Yoon M. Estimate of the Secondary Cancer Risk from Megavoltage CT in Tomotherapy. J Korean Phys Soc 2013;62:1199–1203.
8. Kim DW, Chung WK, Shin D, et al. Risk of second cancer from scattered radiation of intensitymodulated radiotherapies with lung cancer. Radiat Oncol 2013;8:47.
9. Schneider U, Walsh L. Cancer risk estimates from the combined Japanese A-bomb and Hodgkin cohorts for doses relevant to radiotherapy. Radiat Environ Biophys 2008;47:253–263.
10. Donovan EM, James H, Bonora M, Yarnold JR, Evans PM. Second cancer incidence risk estimates using BEIR VII models for standard and complex external beam radiotherapy for early breast cancer. Med Phys 2012;39:5814–5824.
11. Kirby AM, Evans PM, Helyer SJ, Donovan EM, Convery HM, Yarnold JR. A randomised trial of Supine versus Prone breast radiotherapy (SuPr study): Comparing set-up errors and respiratory motion. Radiother Oncol 2011;100:221–226.
12. Stegman LD, Beal KP, Hunt MA, Fornier MN, McCormick B. Long-term Clinical Outcomes of Whole-Breast Irradiation Delivered in the Prone Position. Int J Radiat Oncol Biol Phys 2007;68:73–81.