Effects of Focal Radiation on [18F]-Fluoro-D-Glucose Positron Emission Tomography in the Brains of Miniature Pigs: Preliminary Findings on Local Metabolism
Journal
Neuromodulation
Journal Volume
24
Journal Issue
5
Pages
863
Date Issued
2021-07-01
Author(s)
Liu, Chien Chu
Chen, Hung Yi
Chen, Yilin
Bodduluri, Mohan
Chong, Ngot Swan
Wu, Liang Hsiang
Adler, John R.
Schneider, Michael Bret
Abstract
Objectives: It would be a medically important advance if durable and focal neuromodulation of the brain could be delivered noninvasively and without ablation. This ongoing study seeks to elucidate the effects of precisely delivered ionizing radiation upon focal brain metabolism and the corresponding cellular integrity at that target. We hypothesize that focally delivered ionizing radiation to the brain can yield focal metabolic changes without lesioning the brain in the process. Materials and Methods: We used stereotactic radiosurgery to deliver doses from 10 Gy to 120 Gy to the left primary motor cortex (M1) of Lee Sung miniature pigs (n = 8). One additional animal served as a nonirradiated control. We used positron emission tomography-computed tomography (PET-CT) to quantify radiation dose-dependent effects by calculating the ratio of standard uptake values (SUV) of 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) between the radiated (left) and irradiated (right) hemispheres across nine months. Results: We found that the FDG-PET SUV ratio at the targeted M1 was significantly lowered from the pre-radiation baseline measurements for animals receiving 60 Gy or higher, with the effect persisting at nine months after radiosurgery. Only at 120 Gy was a lesion suggesting ablation visible at the M1 target. Animals treated at 60–100 Gy showed a reduced signal in the absence of an identifiable lesion, a result consistent with the occurrence of neuromodulation. Conclusion: Focal, noninvasive, and durable changes in brain activity can be induced without a magnetic resonance imaging (MRI)-visible lesion, a result that may be consistent with the occurrence of neuromodulation. This approach may provide new venues for the investigation of neuromodulatory treatments for disorders involving dysfunctional brain circuits. Postmortem pathological analysis is needed to elucidate whether there have been morphological changes not detected by MRI.
Subjects
FDG-PET | MRI | stereotactic radiosurgery
Publisher
WILEY
Type
journal article