Comparing the Absorbed Dose of the Contralateral Breast between Physical Stationary and Motorized Wedged Fields Radiotherapy Techniques

Fatemeh  Ziyaei; Somaye  Malmir; Raheleh Tabari  Juybari; Masoumeh  Dorri Giv; Maryam  Yaftian

doi:10.18502/fbt.v12i2.18281

Fatemeh Ziyaei Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
Somaye Malmir Department of Physics, Payame Noor University, P. O. Box 19395-4697, Tehran, Iran
Raheleh Tabari Juybari Department of Radiology Technology, Behbahan Faculty of Medical Sciences, Behbahan, Iran
Masoumeh Dorri Giv Nuclear Medicine Research Center, Department of Nuclear Medicine, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
Maryam Yaftian Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

DOI: https://doi.org/10.18502/fbt.v12i2.18281

Keywords: Absorbed Dose; Contralateral Breast; Radiotherapy; Thermoluminescent Dosimeters

Abstract

Purpose: The breast is a radiosensitive organ and it is important to prevent the Contralateral Breast (CLB) from irradiation in radiotherapy. In this study, the received dose of CLB was calculated and compared between two breast radiotherapy techniques, including physical stationary and motorized wedged fields.

Materials and Methods: Forty female patients undergoing breast radiotherapy with supraclavicular involvement were randomly selected. Twenty were treated with the tangential fields using physical wedges and twenty patients were treated with the tangential fields using motorized wedges. Three thermo-luminescent dosimeters (TLD GR-200) were placed on the CLB skin to estimate the breast dose. Dosimetric parameters for target tissue and Organs At Risk (OARs) were obtained from the plans of the evaluated techniques and compared to find the differences. CLB doses were compared between the radiotherapy techniques using an independent T-test.

Results: There were no significant differences in the target tissue and OARs dosimetric parameters between the evaluated radiotherapy techniques. The results showed that the measured CLB skin doses in patients treated with the motorized wedges were significantly higher than the physical wedge radiotherapy technique, 201.5±20.4 mGy vs. 159.8 ±14.2 mGy (P<0.05).

Conclusion: The physical wedged fields technique had lower doses for CLB compared to the fields using motorized wedges. Therefore, it can be proposed to use tangential physical wedged fields for patients with high concern about the CLB. Furthermore, more research considering radiotherapy techniques without using wedges in medial tangent fields and other relevant parameters can be performed to obtain a better evaluation of the CLB dose.