Renal background correction and measurement of split renal function: The challenge

Excerpt

One of the sources of error in performing quantitative nuclear medicine studies is correction for the presence of background activity surrounding the area of interest. This problem is particularly difficult to resolve in evaluating the kidney because of its location deep within the body surrounded by other highly vascular organs including the liver and spleen. The difficulty in determining quantitative individual renal function measurements accurately and subtracting the correct background activity was noted in a consensus report from the International Society of Radionuclides and Nephrourology (ISCORN) [1]. They stated that “Background subtraction is particularly critical in some methods, since intra- and extravascular activity is rapidly changing (in opposite directions) during the time when individual function is usually calculated and the contribution of each type of activity varies within different regions of interest”. They also pointed out that renal depth may influence the amount of measured activity through attenuation. Taylor et al. [2] suggested improved formulas for correction of renal depth, but there remains an error from this source, which is fortunately small in most patients. …