Fig. 1

Representative image of the visual grading of radiopharmaceutical uptake. In the planar images, cases where no significant uptake was observed in the knee were classified as grade 0 (a), grade 1 when uptake was mild (b), and grade 2 when uptake was intense (c). In the SPECT images, similarly, grade 0 signified that no meaningful uptake was observed visually (d), grade 1 denoted mild uptake (e), and grade 2 was when intense uptake was observed (f)