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what is a spect scanner?
what is a spect scanner?
Single-photon emission computed tomography (SPECT) uses radioactive tracers injected into the patients to perform imaging to evaluate the function of the organs such as brain, bones, liver, kidneys etc.
The radiopharmaceutical is detected by nuclear medicine gamma cameras. The camera or cameras rotate over a 360-degree arc around the patient, allowing for images to be reconstructed in three dimensions.
Combining the information from a nuclear medicine SPECT scan and a CT scan allows information about body ‘function’ from the nuclear medicine scan to be easily combined with the information about where and how the body structure ‘looks’ in the CT scan. (1)
WHY DO WE NEED TO KNOW THIS AS MITS?
Because the CT component of this scanner can operate without the use of the gamma camera to perform regular CT imaging. We therefore use this as our back-up CT scanner at RCH.
what are the main differnces compared to the force?
what are the main differnces compared to the force?
16 slice scanner
16 slice scanner
Longer scan times
Longer breath holds needed
Lower temporal resolution
different injector
different injector
Not linked to the scanner - so needs to be manually started
Harder to perform diluted contrast scans (70%)
no dose modulation
no dose modulation
User must manually modulate doses for every scan
scheduler not linked to our worklist
scheduler not linked to our worklist
Must create manual registration
reduced advanced scanning
reduced advanced scanning
No gating
No perfusion
manual dose modulation
manual dose modulation
As the scanner does not modulate the dose in SPECT, we must provide the scanner with the mA and kV value required for the scan.
The mA is controlled by the Qref and the kV can be changed directly in the scan tab (see below)
Quality reference mAs (Qref)
The QRef parameter determines the level of mA used in the scan.
Higher QRef: Higher level of image quality required so more mA will be given.
Lower QRef: Lower level of quality needed so less mA will be given.
How do we know what exposure factors are required?
We aim to keep the DLP of the scan at the 75th percentile of the CT Force/Flash doses and below the ARPANSA average dose limits. See two examples below of where you find this infromation in the SPECT protocol book
Refresh you knowledge on CT Dose Estimators such as DLP here
spect protocols
spect protocols
Found on teams and in the protocol book in SPECT
Link to Teams: SPECT CT scan protocols
Head down to SPECT and try complete the following tasks;
Turn scanner on/off
Perform check-up
Load new patients to CT examination card
Scan the following on the phantom;
Brain
Extremity
CAP
Head Angiogram
references
references
https://www.insideradiology.com.au/spect-ct-scan/
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