RT Journal Article SR Electronic T1 Parathyroid Imaging: The Importance of Pinhole Collimation with Both Single- and Dual-Tracer Acquisition JF Journal of Nuclear Medicine Technology JO J. Nucl. Med. Technol. FD Society of Nuclear Medicine SP 99 OP 104 DO 10.2967/jnmt.112.118208 VO 41 IS 2 A1 Klingensmith, William C. A1 Koo, Phillip J. A1 Summerlin, Adam A1 Fehrenbach, Bradley W. A1 Karki, Ramesh A1 Shulman, Benjamin C. A1 Raeburn, Christopher D. A1 McIntyre, Robert C. YR 2013 UL http://tech.snmjournals.org/content/41/2/99.abstract 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.