To the Editor.—
The technique of measurement and the method of data
analysis for fibrinogen I 125 scanning
of the lower limbs markedly influences the incidence of "positive"
scans (detection of thrombus). In a
detailed analysis of the technique,
Roberts1 has strongly crticized previous published reports on the basis of
a number of technical errors and the
differing end points taken as a "positive" scan. He has pleaded for standardization of technique and analysis,
and some recent studies have adopted
this procedure.2,3With respect to the article by Sautter et al in the Archives (139:148-153,
1979), the following points are of particular note:1. There is a need for more than one
precordial measurement during each
scan, to allow for positional errors in
the setting of the reference value
(these errors can be considerable).2. A correction factor must be
applied to all readings to allow for
daily variations in background radiation.3. Postoperative, rather than