Computed tomography in the assessment of pancreatic tumor response after intraoperative radiation therapy

Computed tomography was used in 7 patients given intraoperative electron beam therapy for advanced carcinoma of the pancreas. The local tumor response was studied quantitatively by defining the tumor contour in consecutive CT scans and then estimating the tumor volume. The maximum diameters of the tumor in 3 planes (X, Y and Z) were also estimated. There was evidence of initial tumor regression in all patients during the first few months after the treatment. No specific behaviour of the diameters in the X, Y and Z planes could be detected. Later on, regrowth of the tumor could sometimes be observed, preferably in one of the 3 planes. On the whole, CT was found to be a useful tool for assessing tumor response to this form of therapy.