Kidney and bladder activity can cause interpretation problems in the abdomen and pelvis but those problems can be overcome. Perform the SPECT of the upper abdomen and liver as late in the imaging sequence as possible. The additional time will allow for extra clearance of activity from the kidneys and decrease blood pool activity in the liver.

Empty the Bladder
Artifacts from a full bladder will make it impossible to find disease in the presacral space and the area near the bladder. Therefore, patients with a history of cancer within the pelvis (especially rectal cancer) should have the urinary bladder catheterized.

Bladder catheterization should be strongly considered in men with benign prostatic hypertrophy (BPH) or any patient who cannot empty the bladder. If a Foley catheter is not medically indicated, in many cases a small diameter catheter, such as a pediatric feeding tube, can be used to improve bladder drainage during the imaging procedure.

If a patient can’t be catheterized, allow the patient sufficient time to empty the bladder thoroughly before acquiring the planar study. After the planar scan, allow the patient to get off the table and void again. Then immediately acquire the pelvic SPECT while the bladder is nearly empty.

Patients with colorectal cancer are referred for a CEA-Scan study for various reasons. These reasons include patients with a rising blood CEA level with no other evidence of disease, extensive scarring and fibrosis following surgery which "blinds" the CT to any possibility of recurrence, or to find metastases when the presence of tumor is already known. Because much disease is found in the pelvis, good quality imaging of the pelvis can be critical. By catheterizing the bladder, artifacts can be minimized. The improved images that result from catheterization can help resolve the dilemma caused by the soft tissue abnormalities (scarring/fibrosis versus tumor) often seen on the pelvic CT.