Figure 1 54-year old female diagnosed with breast cancer presented with left foot pain of 3 months. A. 18F-NaF PET/CT was performed for staging. MIP images demonstrate increased radiotracer uptake in the anteromedial aspect of left mid foot region and right distal femur (bone infarct). B. 18F-NaF PET/CT images show increased radiotracer uptake in the anteromedial aspect of left mid foot. C. Axial CT images demonstrate a bilateral osseous density medial to the navicular bone which was suggestive of a Type II accessory navicular bone. D-F. Fused 18F-NaF PET/CT shows increased tracer uptake in the articulation with sclerosis between the medial border of the left navicular and an os naviculare. Scan appearances are suggestive of left painful accessory os syndrome.

Figure 2 64-year old female with breast cancer and right posterolateral knee pain underwent 18F-NaF PET/CT for staging. A. MIP images show increased tracer activity in both acromioclavicular joints, the facet joints of L5/S1, the right knee as well as in the bones of both feet. B, C. Axial CT images demonstrate bilateral osseous density posterolateral to the femoral condyle. D-F. Fused 18F-NaF PET/CT show increased tracer uptake in the right patellofemoral joint and articulation of right gastrocnemius muscle with fabella. The tracer uptake within the left fabella is relatively normal. The scan findings are suggestive of right painful fabella syndrome and patellofemoral joint arthritis.

Figure 3 66-year old female with left sided breast cancer complains of generalized bone pain. A. 18F-NaF PET/CT MIP images show increased tracer activity in the sternum, the left 1st and 2nd rib. Increased tracer uptake is also seen in both knees and the distal right leg. B. Transaxial NaF images show increased tracer uptake in the right ankle. C. CT shows a bifid appearance of the tip of the lateral malleolus of the right fibula, representing an accessory ossicle. D, E. Fused 18F-NaF PET/CT images show increased tracer uptake at the articulation site. Findings are consistent with a symptomatic os subfibulare.

Figure 4 44-year old female complained of right distal leg pain for 4 months. A. 18F-NaF MIP images shows increased tracer activity in distal right tibia. B. Transaxial PET images show increased tracer uptake at tip of medial malleolus. C. CT shows an unfused medial malleolus ossification center of the right tibia representing an accessory ossicle. D. Fused 18F-NaF PET/CT images show increased tracer uptake at the articulation site. These findings are consistent with a painful os subtibiale.

Figure 5 55-year old female has left breast cancer and liver metastases receiving 18F-NaF PET/CT because of right leg pain. A. MIP images show increased tracer activity in both acromioclavicular joints, the right sternoclavicular and knee joints. B. PET images show focally increased tracer uptake at the posterior aspect of the proximal tibia on the right. C. On CT there is a round bone density posterior of right proximal tibia, a finding compatible with an accessory sesamoid ossicle of the popliteus known as cyamella. D. Fused 18F-NaF-PET/CT images show increased tracer uptake at this site, consistent with painful cyamella syndrome.

Figure 6 42-year old female with right sided breast cancer and severe left shoulder pain. A. MIP images show increased tracer activity in the left acromioclavicular region, right knee and both mid foot regions. B. PET images show increased tracer activity at the left acromioclavicular joint. C. CT images shows unfused left anterior acromial ossification center (os acromiale) with sclerosis of on the articular surface. D. Fused 18F-NaF PET/CT axial, coronal and sagittal images show increased tracer uptake at the articulation site. These findings are consistent with painful os acromiale