Dosimetry considerations for Endovascular Photo-activated Ablation (EPA) aimed at downstaging locally advanced pancreatic cancers.

Targeting pancreatic tumours immediately adjacent to major blood vessels aims to render patients suitable for surgery to improve prognosis. We are developing endovascular photo-activated ablation (EPA) as an innovative form of photodynamic therapy (PDT), to achieve this goal. However, it requires careful light and drug dosimetry. Building on reported pancreatic tumour response following interstitial BPD-mediated PDT, the tissues’ responsivities were determined and applied to in silico dosimetry studies. Monte Carlo simulations were employed to determine the endovascular power delivery required to achieve necrotic radii of 5 to 15 mm beyond the arterial or venous wall as a function of the vessel lumen diameter. Pancreatic cancer necrosis up to 15mm deep is attainable adjacent to the blood vessel, albeit with limited selectivity to normal pancreatic tissues. Depending on the vessel’s location, simulations should include adjacent organs. Simulations can assist in EPA dose estimations to downgrade pancreatic cancer.