The urinary tract image obtained during 99mTc bone scanning.

During the course of a technetium (99mTc) bone scan, it is usual to obtain an image of both kidneys and the bladder. A review of 96 bone scans performed over a two-year period was undertaken in an attempt to assess the accuracy of this image. Ten examinations showed abnormalities of the urinary image suitable for inclusion in the paper, and were subsequently further investigated. Three cases showed that relatively small lesions may be detected within a kidney if localised caliectasis produced a 'hot-spot'. However, greater diffuse concentration of the imaging agent within one renal image does not necessarily represent an abnormality. Space-occupying lesions can be detected as areas of diminished activity within the renal image, if the tumour is extensive. 'Defects' in the bladder image reflect extrinsic impression rather than intrinsic lesions. A further six cases are included to demonstrate how unusual accumulation of the imaging agent within the abdomen may mimic renal tract pathology.