Dosimetric Comparision of Coplanar versus Noncoplanar Volumetric Modulated Arc Therapy for Treatment of Bilateral Breast Cancers.

Autor: Bharati A; Department of Radiation Oncology, NCI-AIIMS, New Delhi, India., Rath S; Department of Radiation Oncology, Gujarat Cancer and Research Institute, Ahmedabad, India., Khurana R; Department of Radiation Oncology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India., Rastogi M; Department of Radiation Oncology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India., Mandal SR; Department of Radiation Oncology, AIIMS, New Delhi, India., Gandhi AK; Department of Radiation Oncology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India., Hadi R; Department of Radiation Oncology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India., Srivastava AK; Department of Radiation Oncology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India., Mishra SP; Department of Radiation Oncology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India.
Jazyk: angličtina
Zdroj: Journal of medical physics [J Med Phys] 2023 Jul-Sep; Vol. 48 (3), pp. 252-258. Date of Electronic Publication: 2023 Sep 18.
DOI: 10.4103/jmp.jmp_36_23
Abstrakt: Introduction: The purpose of this study was to compare the dosimetric parameters of volumetric modulated arc therapy (VMAT) treatment plans using coplanar and noncoplanar beams in patients with bilateral breast cancer/s (BBCs) in terms of organ at risk sparing and target volume coverage. The hypothesis was to test whether VMAT with noncoplanar beams can result in lesser dose delivery to critical organs such as heart and lung, which will result in lesser overall toxicity.
Materials and Methods: Data of nine BBC cases treated at our hospital were retrieved. Computed tomography simulation data of these cases was used to generate noncoplanar VMAT plans and the parameters were compared with standard VMAT coplanar plans. Contouring was done using radiation therapy oncology group guidelines. Forty-five Gray in 25 fractions was planned followed by 10 Gy in five fractions boost in breast conservation cases.
Results: No significant difference in planning target volume (PTV) coverage was found for the right breast/chestwall ( P = 0.940), left breast/chestwall ( P = 0.872), and in the total PTV ( P = 0.929). Noncoplanar beams resulted in better cardiac sparing in terms of D mean heart. The difference in mean dose was >1 Gy (8.80 ± 0.28 - 7.28 ± 0.33, P < 0.001). The D mean , V 20 and V 30 values for total lung slightly favor noncoplanar beams, although there was no statistically significant difference. The average monitor units (MUs) were similar for coplanar plans (1515 MU) and noncoplanar plans (1455 MU), but the overall treatment time was higher in noncoplanar plans due to more complex setup and beam arrangement. For noncoplanar VMAT plans, the mean conformity index was slightly better although the homogeneity indices were similar.
Conclusion: VMAT plans with noncoplanar beam arrangements had significant dosimetric advantages in terms of sparing of critical organs, that is D mean of heart doses with almost equivalent lung doses and equally good target coverage. Larger studies with clinical implications need to be considered to validate this data.
Competing Interests: There are no conflicts of interest.
(Copyright: © 2023 Journal of Medical Physics.)
Databáze: MEDLINE
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