A SAP scan is a type of

nuclear medicine Nuclear medicine or nucleology is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease. Nuclear imaging, in a sense, is "radiology done inside out" because it records radiation emit ...

imaging test which uses

iodine-123 Iodine-123 (123I) is a radioactive isotope of iodine used in nuclear medicine imaging, including single-photon emission computed tomography (SPECT) or SPECT/CT exams. The isotope's half-life is 13.2230 hours; the decay by electron capture to ...

(¹²³I) and

serum amyloid P component The serum amyloid P component (SAP) is the identical serum form of amyloid P component (AP), a 25kDa pentameric protein first identified as the pentagonal constituent of in vivo pathological deposits called "amyloid". APCS is its human gene. In ...

(SAP) to diagnose

amyloidosis Amyloidosis is a group of diseases in which abnormal proteins, known as amyloid fibrils, build up in tissue. There are several non-specific and vague signs and symptoms associated with amyloidosis. These include fatigue, peripheral edema, weig ...

. In patients with amyloidosis, large deposits of SAP coat the affected organs, in addition to the low levels normally found in the blood stream. The injected ¹²³I-SAP localises specifically to amyloid deposits, showing up as hot spots in the image.

Procedure

The

radiopharmaceutical Radiopharmaceuticals, or medicinal radiocompounds, are a group of pharmaceutical drugs containing radioactive isotopes. Radiopharmaceuticals can be used as diagnostic and therapeutic agents. Radiopharmaceuticals emit radiation themselves, which is ...

is injected into the patient, with imaging taking place on a gamma camera 6-24 hours later. An early blood-pool image provides a baseline for comparison with the organ SAP uptake after 24 hours.

Availability

Europe

¹²³I-SAP was granted orphan designation by the European Medicines Agency in 2003, however this was withdrawn in 2016. SAP scanning is only carried out at two European centres; in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

from the National Amyloidosis Centre, based at the

Royal Free Hospital The Royal Free Hospital (also known simply as the Royal Free) is a major teaching hospital in the Hampstead area of the London Borough of Camden. The hospital is part of the Royal Free London NHS Foundation Trust, which also runs services at B ...

, and in

the Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Nether ...

University Medical Center Groningen The University Medical Center Groningen (UMCG, nl, Universitair Medisch Centrum Groningen), formerly Groningen University Hospital, is the main hospital in Groningen, Netherlands. The medical centre is affiliated with the University of Groningen ...

North America

SAP scanning is not approved in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

due to its use of human blood products.

References

{{reflist Nuclear medicine procedures Amyloidosis

Procedure

Availability

Europe

North America

See also

References