Kevin W. Edwards BSRT (N),(R); CNMT (RS),(PET)

Introduction: LPHR vs MEGP Collimators for I123 Imaging Evaluation

Objectives: To evaluate image quality of Phantom SPECT studies on an LPHR (Low Penetration High Resolution) collimator vs a MEGP (Medium Energy General Purpose) collimator to determine if there is a substantially equivalent or better scan on either of the collimators.

Methods: Acquisition of the standard Jaszczak Phantom using 5.23 mCi of I123 was obtained on both the LPHR collimators and the MEGP collimators at an acquisition time of 16 minutes, 8 minutes, 4 minutes and 2 minutes. Acquisitions were performed immediately following one another to minimize decay of the radioactivity and any effects it may have on the imaging.

Results: Images were evaluated by a total of 7 nuclear medicine professionals (1 physician and 6 technologists, the technologists experience ranged from 3 years to 36 years. Images were evaluated in terms of best image quality for the varying acquisition times for both sets of reconstructed data (FBP or Filtered Back Projection and Flash3D) and for both sets of collimators LPHR (Low Penetration High Resolution) collimator and MEGP (Medium Energy General Purpose). Images were also reviewed for best display of uniformity, resolution and contrast for the same data points. The results showed that the 16 minute acquisition time was a clear preference in terms of producing a better image. The Flash3D reconstruction was preferred for uniformity evaluation for both sets of collimators. The filtered back projection was preferred for the cold rod and cold sphere reconstructions. Overall the LPHR acquisitions were preferred at a rate of 4 to 2 with one respondent abstaining. The tally’s that do not equal seven respondents were due to respondents leaving blank or determining neither was a clear preference. These preliminary results are promising but additional research is being obtained to include higher count imaging similar to actual patient acquisitions and phantom acquisitions to better replicate ACR standard phantom acquisitions.