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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2025-08-20 23:00 |
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Conference: Bucharest University Faculty of Physics 2025 Meeting
Section: Biophysics; Medical Physics
Title:
Stereotactic treatment plan quality metrics and clinical experience- a data review
Authors:
Tia POPESCU (1,2), Mihai Ștefan BÂRHALĂ (1,2), Ionuț DUMITRU (2)
*
Affiliation:
1) Faculty of Physics, University of Bucharest, Bucharest, Romania
2) Neolife, Bucharest, Romania
E-mail
tiap20@yahoo.com
Keywords:
radiotherapy, stereotactic treatments, quality, indexes
Abstract:
Brain tumor control plays an important role in the patient’s neurological integrity and quality of life. The principle underlying radiosurgery treatments is the delivery of large doses, up to 24 Gy/fraction [1], delivered to the tumor, sparing the healthy normal tissues. In order to obtain the best results a very precise delivery is necessary, which depends on several factors, such as immobilization devices, daily imaging, surface guidance, and a rigorous quality assurance program to maintain a sub-millimeter accuracy. The closer the prescription dose is matched to the treated target and the steeper the dose gradient around the target, the less normal tissue is irradiated.
This work aims to elaborate a compendium of our clinical data where we analyze industry standard and specific plan quality metrics according to target size and target proximity to various organs at risk in an effort to standardize our planning process and compare it with other peer reviewed data.
In this analysis, we look at individual "targets" defined as the Planning Target Volumes (PTV) within the patient's brain. As one treatment plan can contain multiple lesions/PTV's and one treatment session can contain multiple plans, we have decided to analyze individual targets on the summation of all irradiated plans in order to take into account the dose contribution plans have on each other and the influence on the plan quality metrics we asses.
The plan quality metrics that we asses are as follows: Conformity Index (CI), Homogeneity Index (HI), Quality of coverage, Gradient Index Paddick, Conformity Index Paddick [2], Conformity Index Lomax [3], Gradient Measure (GM), etc.
We also briefly discuss on the effectiveness of the various plan quality indexes as worthwhile evaluation tools for choosing the right approach when elaborating the treatment plans.
References:
[1] Adler J. R. et al., Stereotactic radiosurgical treatment of brain metastases, Journal of Neurosurgery 76, 3, 444-449, 1992
[2] Stanley, J., Breitman, K., Dunscombe, P., Spencer, D. P., & Lau, H. (2011). Evaluation of stereotactic radiosurgery conformity indices for 170 target volumes in patients with brain metastases. Journal of Applied Clinical Medical Physics, 12(2), 245–253
[3] Yaparpalvi, R., Garg, M. K., Shen, J., Bodner, W. R., Mynampati, D. K., Gafar, A., Tome, W. A. (2018). Evaluating which plan quality metrics are appropriate for use in lung SBRT. The British Journal of Radiology
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