Purpose To evaluate the diagnostic accuracy of the quantitative parameter standardized uptake value (SUV) at single photon emission computed tomography (SPECT)/computed tomography (CT) for the evaluation of temporomandibular joint (TMJ) disorder (TMD). Materials and Methods This study was approved by the institutional review board, and the need for informed consent was waived. Forty-four TMJs in 22 patients with TMD (five men and 17 women; mean age ± standard deviation, 30.0 years ± 12.1) were evaluated. The patients underwent planar bone scintigraphy and SPECT/CT 3-4 hours after injection of technetium 99m hydroxymethylene diphosphonate. The planar scintigraphy parameter of relative ratio (RR) and SPECT/CT parameters mean SUV (SUVmean) and maximum SUV (SUVmax) were compared for the visual assessment of TMD on planar scintigraphy images and for the presence of TMJ arthralgia. Group comparisons, receiver operating characteristic analysis, and Pearson correlation analysis were conducted. Results SUVmax gradually increased from normal (2.82 ± 0.73) to mild or moderately abnormal (3.56 ± 0.76, P .05). On the other hand, SUVmax was significantly greater in arthralgic TMJs (4.15 ± 1.11) than in nonarthralgic TMJs (2.97 ± 0.75, P < .001), as was SUVmean (1.63 ± 0.42 vs 1.30 ± 0.31, respectively; P = .005). However, there was no significant difference in RR (3.61 ± 0.57 vs 3.76 ± 0.68, P = .45). In receiver operating characteristic curve analyses for arthralgic TMJ, SUVmax had the greatest area under the curve (area of 0.815). Conclusion SUVmax derived from bone SPECT/CT may be useful for the evaluation of TMD. (©) RSNA, 2016 Online supplemental material is available for this article.