Shoe Scan – Answer 

Although extraneous collections of radioactivity are not unusual when the entire body is imaged, it is very uncommon to see a shoe as clearly defined as it is on this image. There is a hint of the explanation included on the image. You might notice that the urinary bladder is relatively small indicating that the technologist asked the patient to empty the bladder immediately before the scan was started. There is an irregular collection of radioactivity between the patient’s thighs suggesting that a considerable amount of urine was actually leaked into the clothing. That would suggest that the patient has relatively poor control of the urine stream (because that is the excretory path). The urine is very radioactive, it is possible to image anything that is covered with urine. In this case, it is likely that the patient managed to urinate a considerable amount of radioactive urine directly onto his right shoe. The absorption was somewhat different in different materials of the shoe and that gave a very clear picture of the shoe recorded on the scintillation camera image.

Did you notice the lesion in the mid-left humeral shaft? Sometimes it is easy to be distracted by interesting findings on the film and actually miss the real abnormality. The abnormality of the left humerus was not related to metastatic involvement but was the site of a healed fracture which occurred approximately two years before the bone scan.