PT  - JOURNAL ARTICLE
AU  - William C. Klingensmith III
AU  - Phillip J. Koo
AU  - Adam Summerlin
AU  - Bradley W. Fehrenbach
AU  - Ramesh Karki
AU  - Benjamin C. Shulman
AU  - Christopher D. Raeburn
AU  - Robert C. McIntyre, Jr.
TI  - Parathyroid Imaging: The Importance of Pinhole Collimation with Both Single- and Dual-Tracer Acquisition
AID  - 10.2967/jnmt.112.118208
DP  - 2013 Jun 01
TA  - Journal of Nuclear Medicine Technology
PG  - 99--104
VI  - 41
IP  - 2
4099  - http://tech.snmjournals.org/content/41/2/99.short
4100  - http://tech.snmjournals.org/content/41/2/99.full
SO  - J. Nucl. Med. Technol.2013 Jun 01; 41
AB  - Our objective was to rigorously compare pinhole and parallel-hole collimation in an intrapatient, intrastudy design in 2 parathyroid imaging protocols: the first was dual-phase 99mTc-sestamibi imaging, and the second was dual-phase 99mTc-sestamibi plus dual-tracer (99mTc-sestamibi and 123I) simultaneous-acquisition subtraction imaging. Methods: Thirty-three patients with 37 surgically proven nonectopic parathyroid adenomas were evaluated. Anterior pinhole and parallel-hole images of the neck were available for 99mTc-sestamibi at 15 min and 3 h, and for simultaneously acquired 99mTc-sestamibi and 123I subtraction at 15 min, all from a single study. The images were modified so that all had a square border and so that the thyroid filled approximately three quarters of the image. The images were evaluated by 2 experienced nuclear medicine physicians who did not know the surgical results or whether the images were acquired with pinhole or parallel-hole collimation. The observers indicated the location of any identified adenoma and graded the certainty of diagnosis on a 3-point scale. Results: The localization success rate for the 2 observers combined for the single-tracer dual-phase images was 66.2% with pinhole collimation and 43.2% with parallel-hole collimation (P < 0.0001). The localization success rate with the addition of the dual-tracer simultaneous-acquisition subtraction image was 83.8% with pinhole collimation and 62.2% with parallel-hole collimation (P = 0.0018). In addition, the degree of certainty of localization was greater with pinhole collimation with both imaging protocols (P < 0.001 in both cases). Conclusion: In the anterior projection, pinhole collimation is superior to parallel-hole collimation for parathyroid imaging with either dual-phase 99mTc-sestamibi or dual-phase 99mTc-sestamibi plus dual-tracer (99mTc-sestamibi and 123I) simultaneous-acquisition subtraction.