Scintigraphic visualisation of Walker carcinoma-256 in Sprague-Dawley rats by means of 99mTc-labelled monocytes.

Labelled macrophages accumulate in Walker carcinosarcoma-256 after 'in vivo' and 'in vitro' stimulation with a lectin and are therefore theoretically suitable for scintigraphic tumour detection. At present, routine application of the technique in man is precluded by: the use of PHA, and a labelling method for macrophages with considerable limitations to its application and which results in significant uptake of activity in liver and spleen. However, the purpose of the study was primarily to demonstrate the principle of a possible alternative to the use of labelled monoclonal antibodies for the scintigraphic detection of tumours.