Protocols for PSS

The patients will fast for a 12-hour period and have an enema at least two hours before imaging. All animals will be sedated (anesthetized if necessary) for this procedure. Depending on the body weight, 1 - 3 mCi (37 - 111 MBq) of 99mTc-Pertechnate in 1.5 ml saline are prepared in a syringe. The dog/cat is positioned in right lateral recumbency and a soft rubber catheter fitted with a three-way stopcock will be inserted 15 to 20 cm into the descending colon. The radiopharmaceutical will be administered through the catheter and flushed with 12 ml room air. The radiopharmaceutical injected into the descending colon is absorbed quickly by the colonic mucosa. The radioactive marker is then transported through the portal circulation into the liver and heart. A dynamic series of 2-second images are acquired over a 3-minute period.

Interpretation
In a negative study, activity is identified successively in the liver and the heart. The radiopharmaceutical is later distributed to the lungs and to the entire body. In a positive study, activity is identified in the heart, before it is redistributed in the abdominal organs.

Length of stay
The animals will be housed for 4 days maximum. There should be no risk of radioactive contamination, as the animals will have no levels of radioactivity present in their system upon discharge.