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 emitting ...

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 tellu ...

(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, weight ...

. 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 An orphan drug is a pharmaceutical agent developed to treat medical conditions which, because they are so rare, would not be profitable to produce without government assistance. The conditions are referred to as orphan diseases. The assignment of ...

by the

European Medicines Agency The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of medicinal products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products or Euro ...

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 continental mainland. It comprises England, Scotland, Wales and North ...

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 Barn ...

, 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 Netherl ...

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 Groninge ...

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 states, a federal district, five major unincorporated territorie ...

due to its use of human blood products.

References

{{reflist Nuclear medicine procedures Amyloidosis

Procedure

Availability

Europe

North America

See also

References