AM Quick Scan: a simple but effective Daily QC test for PET/CT and SPECT/CT

Objectives Separate quality control (QC) tests are normally performed for each modality portion of a hybrid scanner(PET/CT or SPECT/CT) at the beginning of an operation day. This work will demonstrate a way to create a daily quick scan, a combined, simple and effective daily QC test to address certain issues for a hybrid scanner.

Methods For a PET/CT, a cylindrical volumetric Ge68 phantom source (half life=271days) is used for the daily quick scan. The activity is between 1-2 mCi. If the Ge68 source is difficulty to obtained, it can be replaced with a cylindrical phantom filled with solution containing 1-2 mCi F18. The scan would be performed each day before the start of scanning patients. The same scan parameters set for a typical PET/CT patient scan should be used to scan the phantom. A two bed scan should be performed on the phantom so that any image misregistration in axial direction would be detected. A similar set up can be used for a SPECT/CT. A cylindrical phantom filled with Tc99m(half life=6 hr) solution is used. The phantom would be scanned with a same setup for a typical SPECT/CT patient scan.

Results The scan itself is simple and fairly quick to perform. The resulting images can be viewed individually for uniformity for CT and PET or CT and SPECT. The registered emission and transmission images should be observed for any misregistration in the radial direction as well as in the transaxial direction. With the attenuation correction applied, an averaged SUV value can also be calculated for an emission transverse slice as well as for a coronal or sagittal slice.

Conclusions The proposed daily quick QC scan may not substitute for the individual QC tests normally performed for each modality of a hybrid scanner but can serve as a good supplement test to yield a quick check for certain parameters such as image misregistration and SUV, , thereby providing extra assurance that the scanner is operating properly.

Research Support None