Dosimetric Comparison of Stereotactic Radiosurgery for Brain Metastases: Volumetric Modulated Arc Therapy vs. Dynamic Conformal Arc
10.14316/pmp.2024.35.4.155
- Author:
Youngkuk KIM
1
;
Sangwook LIM
;
Ji Hoon CHOI
;
Kyung Ran PARK
Author Information
1. Department of Radiation Oncology, Kosin University Gospel Hospital, Busan, Korea
- Publication Type:Original Article
- From:
Progress in Medical Physics
2024;35(4):155-162
- CountryRepublic of Korea
- Language:English
-
Abstract:
Purpose:This study aimed to compare the dose characteristics of the volumetric modulated arc therapy (VMAT) and dynamic conformal arc (DCA) techniques for metastatic brain tumor treatment using various indices to evaluate the quality of the plan and provide insights into the clinical implications of each approach.
Methods:Twelve patients with single metastatic brain tumors treated with VMAT were retrospectively analyzed. For comparison with DCA, identical geometric parameters (excluding multileaf collimators) were applied. Dose coverage, normal tissue sparing, and treatment efficiencywere evaluated using indices such as CILIM98 , CIICRU , CIRTOG , QCRTOG , CISALT , HTCISALT , and CIPADDIC .These indices were statistically assessed to evaluate the differences between VMAT and DCA.
Results:VMAT was superior to DCA in most indices for both small and large planning targetvolumes (PTVs). DCA plans for large PTVs showed a higher V12Gy , exceeding 10 mL and failing tomeet the recommended criteria (<10 mL). However, DCA required nearly half the monitor units(MUs) of VMAT, resulting in shorter treatment times. All indices, except for QCRTOG , demonstratedsignificant differences between VMAT and DCA.
Conclusions:Careful consideration is necessary for larger PTVs when deciding a plan becauseDCA can occasionally result in V12Gy of a brain minus PTV >10 mL. Conversely, DCA provides theadvantage of shorter treatment times because of its lower MU. This study highlights the importance of using a combination of indices to comprehensively assess treatment plan quality.
