Grams, Michael P; Mateus, Chrystian Quintero; Mashayekhi, Maryam; Mutter, Robert W; Djonov, Valentin; Fazzari, Jennifer M; Xiao, Huaping; Frechette, Kelsey M; Wentworth, Adam J; Morris, Jonathan M; Thull, Jack C; Guenzel, Rachael M; Wismayer, David J Schembri; Lucien, Fabrice; Park, Sean S; Lester, Scott C (2024). Minibeam Radiation Therapy Treatment (MBRT): Commissioning and First Clinical Implementation. (In Press). International journal of radiation oncology, biology, physics Elsevier 10.1016/j.ijrobp.2024.06.035
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BACKGROUND
Minibeam radiation therapy (MBRT) is characterized by the delivery of submillimeter wide regions of high "peak" and low "valley" doses throughout a tumor. Preclinical studies have long shown the promise of this technique, and we report here the first clinical implementation of MBRT.
METHODS
A clinical orthovoltage unit was commissioned for MBRT patient treatments using 3, 4, 5, 8, and 10 cm diameter cones. The 180 kVp output was spatially separated into minibeams using a tungsten collimator with 0.5 mm wide slits spaced 1.1 mm on center. Percentage depth dose (PDD) measurements were obtained using film dosimetry and plastic water for both peak and valley doses. PDDs were measured on central axis for offsets of 0, 0.5, and 1 cm. The peak-to-valley ratio (PVR) was calculated at each depth for all cones and offsets. To mitigate the effects of patient motion on delivered dose, patient-specific 3D printed collimator holders were created. These conformed to the unique anatomy of each patient and affixed the tungsten collimator directly to the body. Two patients were treated with MBRT, both received 2 fractions.
RESULTS
Peak PDDs decreased gradually with depth. Valley PDDs initially increased slightly with depth, then decreased gradually beyond 2 cm. PVRs were highest at the surface for smaller cone sizes and offsets. In vivo film dosimetry confirmed a distinct delineation of peak and valley doses on both patients treated with MBRT with no dose blurring. Both patients experienced prompt improvement in symptoms and tumor response.
CONCLUSIONS
We report commissioning results, treatment processes, and the first two patients treated with MBRT using a clinical orthovoltage unit. While demonstrating feasibility of this approach is a crucial first step toward wider translation, clinical trials are needed to further establish safety and efficacy.
Item Type: |
Journal Article (Original Article) |
|---|---|
Division/Institute: |
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy 04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy > Topographical and Clinical Anatomy |
UniBE Contributor: |
Djonov, Valentin Georgiev |
Subjects: |
500 Science > 570 Life sciences; biology 600 Technology > 610 Medicine & health |
ISSN: |
1879-355X |
Publisher: |
Elsevier |
Language: |
English |
Submitter: |
Pubmed Import |
Date Deposited: |
18 Jul 2024 10:49 |
Last Modified: |
18 Jul 2024 10:57 |
Publisher DOI: |
10.1016/j.ijrobp.2024.06.035 |
PubMed ID: |
39002850 |
BORIS DOI: |
10.48350/199001 |
URI: |
https://boris.unibe.ch/id/eprint/199001 |
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