Joe O’Brien & Bill Thomson, City Hospital, Birmingham A Survey of Current Acquisition & Analysis Techniques for Myocardial Perfusion Imaging Using Philips Gamma Cameras Joe O’Brien & Bill Thomson, City Hospital, Birmingham & Cariss Bird, Priory Hospital, Birmingham

Introduction Decided to provide a survey for Philips NMUG Meeting. Aware of some variation amongst Philips users in acquiring and analysing Myocardial Perfusion Imaging (MPI) studies. Decided to provide a survey for Philips NMUG Meeting. The survey would be beneficial: Forms a basis of discussion at UG Meeting. Allows users to compare their technique with others.

Marconi & Picker Systems Survey & Presentation ADAC Systems Cariss Bird Marconi & Picker Systems Joe O’Brien Due to work commitments and time constraints, just the Marconi & Picker users have been surveyed.

The Survey 30 customers on Philips NM customer list Contacted via telephone for anonymous survey 12 customers do not perform MPIs 1 customer did not participate So 17 customers surveyed Completed surveys available

The Survey Radio-pharmaceutical Gamma Camera Acquisition Basic Questions e.g. how many patients per year? Radio-pharmaceutical e.g. type of RP, activity per test, delay time? Gamma Camera e.g. which camera and collimator do you use? Acquisition e.g. matrix size & zoom (pixel size), orbit setup, gated or non-gated? Reconstruction e.g. FBP or iterative reconstruction, Pre-filter or 3D Post filter ?

Basic Questions

Radiopharmaceutical Most commonly used: MIBI (5) Tetrofosmin (12)

Radiopharmaceutical Protocol: 1 Day 1000MBq (2) 2 Day 400MBq (15)

Radiopharmaceutical Imaging Delay Time: MIBI Tetro

Cameras Included in Survey (11) (4) (2) (1) Dual headed AXIS most common Exclude others from presentation

Acquisition Settings Used By All AXIS Users Orbit settings: Non-Circular Head Orientation at 102° 102° of rotation per head 34 projections per head Acquisition based on TIME per step Factory set energy window

Variable Acquisition Settings Orbit setting Step & Shoot - 3 Continuous - 8 Gating Gated - 5 Non-Gated - 6 BEACON Used - 3 Not Used - 8

Variable Acquisition Settings Time per step

Variable Acquisition Settings Collimator LEGAP (6) LEHR (5)

Variable Acquisition Settings Matrix & Zoom (i.e Pixel Size)

Reconstruction Settings Used By All AXIS Users Routinely Check for Patient Motion No Pre-filtering of data All use 3D Post-filter

Variable Reconstruction Settings Reconstruction Method Iterative (3) Don’t Know (1) FBP (7)

Variable Reconstruction Settings Diameter Left as Default (8) Don’t Know (2) Varied between patients (1) Effectively zooms data and alters pixel size.

Variable Reconstruction Settings Filter All used ‘Low Pass’ but with variable settings:

Variable Reconstruction Settings Gated Analysis Programs QGS (4) Emory (1)

Conclusions Survey of Philips NM Users performing MPI. Majority using AXIS system. Users have some similar methods of acquisition and analysis. But overall there are significant differences e.g. 1/2 use LEHR, the other 1/2 use LEGAP Worthy of discussion at UGM!

Effect of Collimator Local standard protocol for MPI uses LEGAP collimator. We considered the effect on lesion detectability using a LEHR collimator instead. Scanned a torso phantom fitted with a cardiac insert Installed a large 100% and small 50% defect. Filled with 8MBq Tc-99m

Effect of Collimator HR GP Short Axis Images Qualitatively, there is no discernable difference in lesion detectability

Effect of Collimator HR GP HLA Images Qualitatively, no discernable difference in lesion detectability. But up to 40% more counts.