The Distribution of Dyes and Fluorescent Substances by the Blood Stream within Tumours

Abstract

The most obvious, if not the only route, by which a chemical substance can be carried to a tumour, is, of course, by its vascular supply. Preliminary investigation using a timed intra-arterial injection method appeared to show good and uniform distribution of the dye, patent blue violet, throughout widely scattered malignant melanomata. This even penetration of dye stuff to cutaneous aspects of the tumour was at variance with the observation of erratic regression of disease which sometimes follows chemotherapy not only in patients with essentially similar tumours but even where adjacent tumour nodules in the same region respond in a markedly different manner. One explanation for this could be the varying degrees of access of the therapeutic agent to different parts of the tumour by reason of inequality of blood supply. Conventional arteriography cannot give an entirely accurate picture of tumour blood supply for technical reasons. In the first place, the contrast medium is usually injected rapidly and with considerable force—a state of affairs which does not apply physiologically, and secondly, the contrast medium is rather viscous and heavy. Only the vessels themselves can be shown by this method and even then, there is a limit to the smallest calibre which can be demonstrated. The distribution of the blood within the tumour is not visualised and it is here that dye and fluorescent studies give much fuller and more helpful information.