PT  - JOURNAL ARTICLE
AU  - Kalen, Joseph D.
AU  - Arthur, John H.
AU  - Jolles, Paul R.
TI  - Effect of Fanbeam Focus Misalignment on Multihead SPECT Imaging
DP  - 1996 Dec 01
TA  - Journal of Nuclear Medicine Technology
PG  - 314--315
VI  - 24
IP  - 4
4099  - http://tech.snmjournals.org/content/24/4/314.short
4100  - http://tech.snmjournals.org/content/24/4/314.full
SO  - J. Nucl. Med. Technol.1996 Dec 01; 24
AB  - Multihead camera inspection usually examines only head alignment with parallel-hole collimators, therefore, fanbeam collimators are not analyzed. We demonstrate that acceptance testing should include evaluating fanbeam collimator alignment. Methods: Two sets of low-energy ultra-high resolution (LEUHR) fanbeam collimators, Sets A (misaligned) and B (aligned), were examined. SPECT acquisitions were acquired for the three point sources aligned in the Z and Y directions, offset in the X direction and a three-dimensional Hoffman brain phantom. Results: Cinematic display of the raw data revealed artifactual motion in the Y direction for collimator Set A (misaligned), a SPECT spatial resolution (FWHM) increase of 4 mm in the Y direction and 1 mm in the X direction for Set A compared to Set B. Reconstructed images from the three-dimensional Hoffman brain phantom resulted in no clinical discernible differences. Conclusion: We recommend testing fanbeam collimators during acceptance testing, before patient data is assumed to be reliable.