Furosemide administration onehour before bone scintigraphy examination in horses does not improve the image quality or reduce the radiation dose rate

Radiation from the equine perineal region is low compared with the elbow and head 24 hours after bone scintigraphic examination

The timing of follow-up radiography and ultrasound in horses that undergo skeletal scintigraphy for lameness investigation varies internationally and between equine hospitals. The prospective, one-group, pretest, posttest study aimed to estimate radiation levels from horses three and 24 h after injection of hydroxydiphosphonate labeled with metastable technetium (99mTc-HDP) and investigate which anatomical locations of the horse had higher radiation levels. Included were 46 horses referred for lameness investigation between June and December 2021. Radiation levels from the horse surface were measured using an electronic device from six anatomical locations (head, elbow, dorsum, ventrum, stifle, and perineum) at two time points and adjusted to three and 24 h after injection of 99mTc-HDP using the radioactive decay law. The radiation measured was significantly different in the various locations of the horses for both time points. At 3 h after injection of 99mTc-HDP, the ventrum had the highest radiation dose. At 24 h, the radiation emitted from the perineal region was significantly lower (P < .0001) than from the elbow and head, which had the highest values. There was a negative correlation between age and the radiation detected at 24 h postinjection (P = .02). Radiation from the perineal region was low compared with other regions of the horse 24 h postscintigraphy. Additional care should be taken around the ventrum area during the scintigraphy examination and around the elbow and head at 24 h postscintigraphy to minimize radiation to personnel.

The impact of different bone tracers and acquisition times on image quality of equine bone scintigraphy

The impact of different acquisition times (AqT) and technetium-99 m-labeled (^99m Tc) diphosphonates on the image quality of bone scintigraphy is poorly documented in horses. The aim of this prospective experimental study was to evaluate the impact of varying ^99m Tc-disphosphonates and AqT on semiquantitative and qualitative image parameters of bone scintigraphy in horses. Twenty-four horses undergoing bone scintigraphy were divided equally and randomly into methylene- (MDP), hydroxymethylene- (HDP), and dicarboxypropane diphosphonate (DPD) groups. Lateral scintigraphic images of the antebrachium were obtained 3 h post ^99m TC-diphosphonate injection using three AqT (60, 90, 120 s). The images were analyzed semiquantitatively using the bone-soft tissue ratio (B:ST), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and image contrast. Furthermore, a blinded qualitative analysis was performed using a visual grading analysis. The results showed that DPD images had a significantly higher B:ST ratio than MDP images (P < .01) but not HDP images in all AqT (P > .08). However, DPD and HPD images acquired at 60 s had significantly higher CNR (P < .05) than those acquired at 90 and 120 s. The qualitative analysis revealed no significant differences between ^99m Tc-diphosphonates at AqT 60 and 90 s. However, MDP images acquired at 120 s had significantly lower image quality compared to DPD and HDP (P = .01 and .03, respectively). In conclusion, the bone tracers affected the semiquantitative image parameters but not the qualitative analysis findings. Increasing AqT did not necessarily improve the image quality. Therefore, decreasing the AqT enabled a reduction in personnel radiation exposure.