Physicist Considerations for PET-CT and SPECT-CT

The issues to address radiation dose reduction in SPECT-CT are much the same as those described above for PET-CT. Because of the limited gantry rotation speed when the X-ray source and detector are mounted on same gantry as the gamma cameras, these systems should only be used for low-quality CT attenuation correction scans. For systems with separate CT and SPECT gantries, where the CT scanner is a “diagnostic” quality system, the SPECT-CT system has the same flexibility as a PET-CT system in terms of types of CT acquisition. Many of the links provided above for radiation dose and dose reduction in PET-CT also apply to SPECT-CT.

Other resources include:

 

Vendors of PET-CT and SPECT-CT Systems

 

Several vendors offer PET-CT and SPECT-CT systems. These include:

GE Healthcare: http://www.gehealthcare.com

» PET-CT

» SPECT-CT

Siemens Healthcare: http://www.medical.siemens.com

» PET-CT

» SPECT-CT

Philips: http://www.healthcare.philips.com

» PET-CT

» SPECT-CT

 

Concluding Remarks

 

When setting up scanning protocols and recommendations, think of all aspects of the expected studies that will affect radiation dose, within the context of the diagnostic requirements of these studies. Recommendations can include minimizing injected activity, using scan parameters adapted to patient size and age, and eliminating extraneous scans when possible. When specifying and purchasing equipment, consider how system implementation and performance parameters such as sensitivity can affect radiation dose. All medical physicists should be familiar with the ALARA concept, As Low As Reasonably Achievable, for radiation protection. ALARA should be kept in mind when contemplating radiation dose and dose reduction from PET-CT and SPECT-CT.