TURKISH JOURNAL OF ONCOLOGY 2023 , Vol 38 , Num 2
The Use of EPID-based in vivo Dosimetry for Small Animal Radiation Research
Fatih BILTEKIN1,Gökhan ÖZYIĞIT1
1Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara-Türkiye DOI : 10.5505/tjo.2023.3855 OBJECTIVE
To validate the feasibility of electronic portal imaging device (EPID)- based in vivo dosimetry system for the verification of small animal radiation research

METHODS
The workflow can be divided into three steps. In the first part, external body of the rat phantom was modeled based on the computed tomography (CT) dataset of a real rat previously scanned for another radiobiological experiment and the structure set was exported to 3D Slicer program to convert DICOM file to. stl file format. Tissue-equivalent rat phantom was, then, printed using Makerbot Replicator Z18 3D-printer. In the second part, treatment plans were created for different anatomical sites including whole brain and total lung irradiation using Elekta Versa HD linear accelerator. In the last part, measurements were performed with EPID-based 3D in vivo dosimetry system. During the analysis, 3D ? analysis method was used and ? evaluation criteria were set to 3 mm distance-to-agreement and 3% dose differences for local dose.

RESULTS
According to our analysis, EPID measurement for each modality and anatomical site met the protocol value except for % γ ≤ 1 and γ mean values for total lung irradiation, but both of these parameters met the proposed minor variation criteria.

CONCLUSION
Implementation of EPID-based 3D in vivo dosimetry for preclinical radiation research with small animals seems to be feasible. Keywords : Electronic portal imaging device; in vivo dosimetry; preclinical radiotherapy