Electronic Off-Peak Status of One Head of a Dual-Head Gamma Camera Resulted in Bone Scintigraphy Artifacts and Faulty Findings on Gated Myocardial SPECT

(A) Dual-isotope dipyridamole ^99mTc-tetrofosmin (top images in each row) and rest ²⁰¹Tl (bottom images in each row) myocardial SPECT images from first myocardial SPECT examination. Uptake is virtually absent in apical, lateral, and inferior walls and is decreased in anterior wall on ^99mTc-tetrofosmin SPECT images; perfusion of these walls on ²⁰¹Tl SPECT images is normal. Absence of perfusion in lateral wall is indicated by arrow on short-axis image and by arrowhead on horizontal longitudinal-axis image. Accordingly, LVEF was calculated as 40%. (B) Dual-isotope dipyridamole (top images in each row) ^99mTc-tetrofosmin and rest ²⁰¹Tl (bottom images in each row) myocardial SPECT images of second myocardial SPECT examination. Again, uptake is virtually absent in apical, lateral, and inferior walls and is decreased in anterior wall on ^99mTc-tetrofosmin SPECT images. ²⁰¹Tl SPECT images show normal perfusion in apical, lateral, and anterior walls; defect remains in most-inferior wall. Top 2 rows = stress (^99mTc-tetrofosmin) and rest (²⁰¹Tl-chloride) short axes; middle 2 rows = stress (^99mTc-tetrofosmin) and rest (²⁰¹Tl-chloride) horizontal axes; bottom 2 rows = stress (^99mTc-tetrofosmin) and rest (²⁰¹Tl-chloride) vertical axes.

(A) ^99mTc-HMDP anterior (ANT) and posterior (POST) total-body bone images. Markedly decreased activity and loss of contrast in bone structures are noted in anterior image. Posterior image shows abnormally increased activity in right hemipelvis, especially in sacrum and lower portion of right sacroiliac joint; this patient was known to have Paget’s disease of bone and was followed up by bone scanning. (B) Anterior images of chest, abdomen, and pelvis obtained by head II show increased uptake in right pelvis.