Other CT Scan Protocols

 

I wrote this in 1999. This was how things were done, back then. I'm updating the styling of the page in 2014, but not the content of the page, because this is part of the history of how things were, when the dose-based protocols were developed. This page does not contain state-of-the-art information anymore, just history.

 

This listing is not a complete list of our own protocols,  and is certainly not a list of possible CT protocols.  Our CT scanning practice at the Cross Cancer Institute, is primarily for Oncology.   The diversity of our protocols is therefore smaller than a typical tertiary hospital.  For example, we don't need "trauma" protocols, and we rarely do non-contrast-enhanced scanning.  The few other protocols listed below, are not a complete description of our protocols.  The list simply notes some concepts about a few of them.

Neck - Same Dose and Rate as the Abdomen and Chest protocols. Delay used is "Chest - 9 seconds".  We reduce the Dose by 10-20ml, because the neck has no parenchymal organs.  Veins and arteries can be recognized with the lower dose,  and the enhancement pattern of pathologic lymph nodes is unreliable, no matter what dose is used.

Brain  - For post-contrast brain scanning (for metastases or primary CNS tumors), we inject contrast agent at the same weight-based Doses as the Abdomen and Chest  protocols.  Injection rate isn't important, and is usually hand-injected.   Scan delay is 4 minutes, to allow sufficient time for contrast to leak across the blood-brain barrier.

Pelvis  - For post-contrast pelvis scanning, we use the same weight-based Doses and Rates as the Abdomen protocol, but the Delays are "Abdomen + 14 seconds".

Pancreas - For post-contrast "late-arterial phase" (pancreatic-phase) pancreas scanning, we locate the pancreas with pre-contrast scans,  then inject contrast agent at the same Dose and Rate as the Abdomen protocol,  but the Delays are "Abdomen - 11 seconds".

Dual-Phase Liver - Used for hepatocellular carcinoma, and selected hypervascular metastases, such as carcinoid. Same Dose and Rate as the Abdomen protocol, but the arterial-phase images are acquired after a Delay of  "Abdomen - 29 seconds". The portal-venous-phase is after 60 seconds.   By the way, for typical metastatic screening, it might be more productive to do a single non-enhanced slice through the liver,  and if "fatty liver" is present,  add non-enhanced scans through the liver.

Extremities - Same as pelvis.

Head&Neck tumor  - Same as pelvis.  (This isn't used much, as MRI is usually used instead.)

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