Image quality and radiopharmaceutical parameters of Indium-111 granulocytes in scintigraphy of inflammatory bowel disease

This study was undertaken to investigate the influence of various parameters of injected autologous 111In labelled granulocytes on scintigraphic image quality. Forty-two scintigrams of 37 patients with inflammatory bowel disease were evaluated. The images were divided into three groups according to quality: good, intermediate and poor. The relationships between image quality and such radiopharmaceutical parameters as injected dose of 111In, number of injected cells and specific activity were investigated. It appeared that in order to obtain interpretable images, a specific activity of at least 85 kBq 111In/million cells was necessary. The activity of the injected dose must exceed 7 MBq if poor quality images and very long acquisition times are to be avoided.