Feasibility of ablating normal renal parenchyma by interstitial photon radiation energy: Study in a canine model

Background and Purpose: A miniature photon radiosurgery system (PRS) has be en described as an alternative to surgical resection and external-beam radi ation for tumors and may now offer an alternative for ablation of renal les ions, We evaluated the feasibility of ablation by PRS in a normal parenchym a canine model. Materials and Methods: Twelve mongrel dogs were used in this survival study , In the left and right kidneys of each animal, a peripheral lesion and cen tral-hilar lesion, respectively, were induced with PRS, The probes were pla ced in the renal parenchyma, and local radiation of 15 Gy at a radius of 1. 3 cm was delivered over 10 minutes. Serum electrolytes were measured serial ly. Computed tomography scans were obtained, and the animals were sacrifice d for pathologic correlation. In a separate study, the liver received three additional treatments of 10 to 20 minutes of radiation. Results: Eleven dogs survived this B-month study and were sacrificed as sch eduled, One animal expired after 2 weeks from radiation-induced fulminant h epatic failure with normal renal function, No other complications were obse rved. The average lesion size was 2.5 cm in diameter, Histologic analysis c onfirmed coagulative necrosis with sharp demarcation from the surrounding p arenchyma, Conclusion: Preliminary studies demonstrate the feasibility of PRS ablation of the renal parenchyma. Further tumor model testing will be important to determine the ultimate efficacy of local photon radiation energy.