Single photon emission computed tomography (SPECT)

Last revised by Raymond Chieng ◉ on 14 Mar 2023

Citation, DOI, disclosures and article data

Citation:

Smith H, Chieng R, Mellam Y, et al. Single photon emission computed tomography (SPECT). Reference article, Radiopaedia.org (Accessed on 01 Oct 2023) https://doi.org/10.53347/rID-62599

DOI:

https://doi.org/10.53347/rID-62599

Permalink:

https://radiopaedia.org/articles/62599

rID:

62599

Article created:

24 Aug 2018, Hamish Smith

Disclosures:

At the time the article was created Hamish Smith had no recorded disclosures.

View Hamish Smith's current disclosures

Last revised:

14 Mar 2023, Raymond Chieng ◉

Disclosures:

At the time the article was last revised Raymond Chieng had no financial relationships to ineligible companies to disclose.

View Raymond Chieng's current disclosures

Revisions:

12 times, by 8 contributors - see full revision history and disclosures

Sections:

Imaging Technology

Synonyms:

SPECT
SPECT/CT
Single photon emission computed tomography
SPECTCT
CT/SPECT
SPECT-CT

Single photon emission computed tomography (SPECT) is a three-dimensional nuclear medicine imaging technique combining the information gained from scintigraphy with that of computed tomography. This allows the distribution of the radionuclide to be displayed in a three-dimensional manner offering better detail, contrast and spatial information than planar nuclear imaging alone.

SPECT machines combine an array of gamma cameras (ranging from one to four cameras) which rotate around the patient on a gantry. SPECT may be also combined with a separate CT machine in a form of hybrid imaging; single photon emission computed tomography-computerized tomography (SPECT-CT) mainly for the purposes of attenuation correction and anatomical localization ¹.

Principle

Gamma cameras rotate around the patient providing spatial information on the distribution of the radionuclide within tissues. The use of multiple gamma cameras increases detector efficiency and spatial resolution. The projection data obtained from the cameras are then reconstructed into three-dimensional images usually in axial slices ^1-3. When SPECT-CT is used, attenuation correction and higher resolution anatomical localization can be achieved ¹.

Uses

Tc-99m sestamibi myocardial perfusion study
brain imaging (perfusion and receptor-binding radiotracers)
Tc-99m sestamibi parathyroid scan
white cell scan
bone scan

Quality control

Upon installation of the SPECT system, tests should be performed to ensure the system functions properly in a proper and stable environment. The sets of tests that should be performed are as below ⁴:

physical and mechanical inspection of the system
determine the absolute size of a pixel
determine the tomographic uniformity
determine the tomographic resolution in air
determine the tomographic resolution with scatter
determine the offset for center of rotation and alignment of axes
determine slice thickness at the central slice
determine the variations of uniformity and sensitivity with rotation of the system