Dosimetric Study of Tissue Heterogeneity Correction for Breast Conformal Radiotherapy

Sinousy, Dina and Attalla, Ehab and Hanafy, Magda Sayed and Abouelenein, Hassan Shafik and Abdelmajeed, Mohamed and Osama, Mohamed (2019) Dosimetric Study of Tissue Heterogeneity Correction for Breast Conformal Radiotherapy. Iranian Journal of Medical Physics, 16 (2). pp. 179-188.

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Abstract

Introduction: Heterogeneity correction is an important parameter in dose calculation for cancer patients where it may be cause inaccuracy in dose calculation as a result of different densities of patients. This study studied the impact of dose calculation of breast cancer patients with and without heterogeneity correction. Material and Methods: Twenty breast cancer patients were treated with Three-Dimensional Conformal Radiotherapy(3DCRT). Dose calculations were performed using two modes: Fast Photon mode for homogeneity and Fast Photon Effective Path length for heterogeneity with two photon energies. Monitor Units(MU), Modulation Factor, Dose Volume Histograms(DVH) and quality indices were used to evaluate the effect of heterogeneity correction on dose calculation and investigate the mechanism of this effect in the low and high energies. Results: Heterogeneity correction compared to without it showed significant reduction in MU and modulation factor at 6MVand 10MV (p<0.05). Dosimetric parameters derived from DVH were significantly lower for Planning Target Volume (PTV) with homogeneity versus heterogeneity (p<0.05) as D95 (95.1vs93.7) and V95(95.3vs89) for 6MV while max Dose and D2 increased. Also the dose for organs at risk exhibited an increase with heterogeneity correction. Quality indices were be worst with heterogeneity correction with a significant difference (p <0.05). The differences between the dose with heterogeneity correction and without it in 6MV and 10MV were as follows: Î�D95 (4.4vs3.4;P=0.001) and Î�V95(4.76vs4.5;P=0.001). Conclusion: non-use of the heterogeneity correction can be cause to deliver under or overdose dose to the target volume. Tissue heterogeneity correction had an impact on dose calculation for breast cancer patients and this impact was more effective for the low energy.Â

Item Type: Article
Subjects: WN Radiology . Diagnostic Imaging
Divisions: Journals > Iranian J Medical Physics
Depositing User: ijmp ijmp
Date Deposited: 13 Apr 2019 04:52
Last Modified: 13 Apr 2019 04:52
URI: http://eprints.mums.ac.ir/id/eprint/11330

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