DOSIMETRIC COMPARISON OF TANGENTIAL VOLUMETRIC ARC THERAPY AND HALF ARC VOLUMETRIC ARC THERAPY PLANNING TECHNIQUE FOR CARCINOMA OF THE BREAST

Document Type : Original Paper

Authors

1 Radiotherapy and Oncology Assistant Professor in Medical Physics School of Allied Health Sciences Kasturba Medical College Manipal Academy of Higher Education Manipal 576104

2 Department of Radiotherapy and Oncology, Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal, India

3 Radiotherapy and Oncology Senior Grade Lecturer Medical Physics Kasturba Medical College Manipal Academy of Higher Education Manipal India

4 ASSISTANT PROFESSOR, MEDICAL RADIATION PHYSICS PROGRAM, MANIPAL COLLEGE OF HEALTH PROFESSIONS(MCHP), MANIPAL ACADEMY OF HIGHER EDUCATION(MAHE), MANIPAL-576104, KARNATAKA, INDIA

10.22038/ijmp.2024.69049.2219

Abstract

Aim: This study aims to compare tangential volumetric modulated arc therapy with half-arc volumetric modulated arc therapy in treating cancer in the left and right breasts.



Methods and Materials: A total of 25 with ten left and ten right breast cancer were chosen and assessed. All the cases were designed by using both tVMAT and HALF-ARC VMAT techniques with a 6MV photon beam with a dose of 42. 56Gy in 16#. The main difference between tVMAT and VMAT was the area of avoidance sector within specific degrees of angle with no monitor unit (MU) delivery used in the arc planning. The dosimetries of the PTV, ipsilateral lung, heart and contralateral breast were compared. Dose calculations were done using the Monte Carlo algorithm in a MONACO version 5. 1. The dosimetric parameters were evaluated and compared with Repeated measures ANOVA with a significance level set to 5%.



Results:

tVMAT gives more target coverage than HALF-ARC VMAT. HALF-ARC VMAT in the left-sided breast reduces the dose in the ipsilateral lung, the contralateral breast dose is slightly higher in HALF-ARC VMAT. Heart doses are almost the same in both plans. For right-sided breasts, tVMAT planning gives high target coverage and homogeneity and decreases the dose in almost all the parameters. The present results support the hypothesis that the introduced tVMAT technique is feasible for treating both left and right breast cancer. With tVMAT, the dose to the ipsilateral lung and heart can be reduced, and the dose homogeneity can be improved without increasing the dose to the contralateral breast or lung.



Conclusion:

For advanced left breast cancer, TVMAT is a groundbreaking radiotherapy preparation technique. It overcomes the drawbacks of conventional VMAT in terms of less dose spreading and contralateral organ effects on treatment plan dosimetry while retaining target coverage and homogeneity.

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Iranian Journal of Medical Physics

Articles in Press, Accepted Manuscript
Available Online from 02 April 2024

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History

  • Receive Date: 29 November 2022
  • Revise Date: 11 March 2024
  • Accept Date: 02 April 2024

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