SAP scan
File:SAP scan response to chemotherapy.jpg
{{For|the amyloid scan used in diagnosis of Alzheimer's disease|Positron emission tomography#Neuroimaging}}
A SAP scan is a type of nuclear medicine imaging test which uses iodine-123 (123I) and serum amyloid P component (SAP) to diagnose amyloidosis.{{cite journal |last1=Lass |first1=Piotr |title=Nuclear imaging of amyloidosis |journal=Polish Journal of Radiology |date=2014 |volume=79 |pages=222–227 |doi=10.12659/PJR.890147 |pmc=4111651}}{{cite journal |last1=Sachchithanantham |first1=S. |last2=Wechalekar |first2=A. D. |title=Imaging in systemic amyloidosis |journal=British Medical Bulletin |date=29 July 2013 |volume=107 |issue=1 |pages=41–56 |doi=10.1093/bmb/ldt021 |pmid=23896486 |doi-access=free}}
In patients with amyloidosis, large deposits of SAP coat the affected organs, in addition to the low levels normally found in the blood stream.{{cite web |title=The SAP scan (AL amyloidosis) |url=https://www.myeloma.org.uk/documents/the-sap-scan-infosheet/ |website=Myeloma UK |accessdate=28 July 2019 |language=en}} The injected 123I-SAP localises specifically to amyloid deposits, showing up as hot spots in the image.{{cite journal |last1=Sachchithanantham |first1=S. |last2=Wechalekar |first2=A. D. |title=Imaging in systemic amyloidosis |journal=British Medical Bulletin |date=29 July 2013 |volume=107 |issue=1 |pages=41–56 |doi=10.1093/bmb/ldt021 |pmid=23896486|doi-access=free}}
Procedure
The radiopharmaceutical 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123I-SAP was granted orphan designation by the European Medicines Agency in 2003, however this was withdrawn in 2016.{{cite web |title=EU/3/03/134 - Iodine (123I) Serum Amyloid P |url=https://www.ema.europa.eu/en/medicines/human/orphan-designations/eu303134 |website=European Medicines Agency |accessdate=28 June 2019 |language=en |date=17 September 2018}}
SAP scanning is only carried out at two European centres; in the United Kingdom from the National Amyloidosis Centre, based at the Royal Free Hospital,{{cite web |title=NHS STANDARD CONTRACT FOR DIAGNOSTIC SERVICE FOR AMYLOIDOSIS |url=https://www.england.nhs.uk/wp-content/uploads/2013/06/e13-diag-serv-amyloidosis.pdf |website=NHS England |accessdate=28 June 2019 |date=2013}} and in the Netherlands at University Medical Center Groningen.{{cite journal |last1=Noordzij |first1=Walter |last2=Glaudemans |first2=Andor W. J. M. |last3=Slart |first3=Riemer H. J. A. |last4=Dierckx |first4=Rudi A. |last5=Hazenberg |first5=Bouke P. C. |title=Clinical use of differential nuclear medicine modalities in patients with ATTR amyloidosis |journal=Amyloid |date=22 August 2012 |volume=19 |issue=4 |pages=208–211 |doi=10.3109/13506129.2012.717993 |pmid=17504868 |doi-access=}}
=North America=
SAP scanning is not approved in the United States due to its use of human blood products.