Observations on dermal blood flow as reflected by technetium-99m pertechnetate clearance.

Skin blood flow as reflected by the clearance rate of intradermal injections of Technetium-99m (99mTc) was studied in the skin of human volunteers and in a variety of clinical situations. In volunteers comparisons between the effect on clearance following intradermal injections of either lignocaine or lignocaine/adrenaline showed that the latter resulted in a dramatic reduction in the clearance rate of the technetium isotope and that such clearance curves exhibited no fast component. Clinical studies in grossly ischaemic skin revealed a similar absence of the fast component of isotope clearance and this was also the case for healed split thickness skin grafts. The dermal isotope clearance was also used in pedicle skin flaps both before and after clamping the axial pedicle in order to derive clearance ratios which would reflect the degree of neovascularisation to the flap. These preliminary observations suggest that the technique is safe, and easy to use in many clinical circumstances. We consider that it offers a valuable method by which changes in dermal blood flow may be quantified, when simultaneous control areas of isotope clearance are also studied. Suggestions are made for further avenues of study.