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Gliomas, malignant brain tumors accounting for approximately 30% of primary brain tumors, are typically treated with gross total resection (GTR) followed by radiation therapy (RT) and chemotherapy. Nonetheless, certain conditions render GTR unfeasible, necessitating alternative therapies like MRI-guided laser interstitial thermal therapy (LITT). Although MRI-guided LITT can monitor the temperature distribution in the tissue by using an MRI thermometer and estimate the resulting necrosis prognosis based on a necrosis formation model, fixed model parameters are usually used for patients universally, resulting in necrosis estimation error. Hence, spectroscopic photoacoustic (sPA) imaging is considered for direct intraoperative necrosis monitoring. While sPA’s utility has been explored in organs like the heart and liver, it seems no studies have been conducted in the brain yet. In this study, we evaluate the feasibility of sPA in characterizing ablation-induced brain necrosis, using brain-specific spectra from ablated and non-ablated areas in the goat’s grey matter. With the aim to quantify the extent of necrosis, we implement the Necrotic Extent (NE) index defined as the photoacoustic intensity ratio between ablated and non-ablated tissue, and generate an NE map to visualize the result. Results showed statistically significant differences between the spectrum of the ablated and non-ablated regions, indicating that sPA can differentiate between them. In the NE map, the regions showing high NE values correspond to the ablated area, supporting the feasibility of the technique for the brain domain. The study concludes that sPA-based direct necrosis monitoring is feasible for the grey matter of the goat brain. As future work, it is necessary to conduct further investigations including data collection for white matter and bridging the gap between goat and human applications for actual clinical use.
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