Table 1.

Features of the original articles reviewed.

Radiotracer	Subjects	Procedure	Main Results	Ref.
[18F]FDG	Healthy volunteers (each group n = 5)	Scans were conducted following an injury-prevention exercise program.	The exercise group demonstrated higher [18F]FDG accumulation than that of the control group in the abdominal rectus, gluteus medius, and minimus muscles.	[26]
	Patients (n = 1164)	Whole-body [18F]FDG PET scans were performed.	Of 1164 patients, 146 exhibited excessively increased muscle uptake, corresponding to technologists’ observations of muscle activity during the uptake phase or prior to [18F]FDG injection.	[27]
	Skilled pitchers and healthy volunteers (each group n = 10)	Participants threw 40 baseballs before receiving an injection of [18F]FDG, followed by 40 pitches. PET-CT images were acquired 50 min after the injection of [18F]FDG.	Significant increases in glucose metabolism were observed in the muscle groups of the fingers and toes on the throwing and non-throwing sides. Symmetric increases in glucose metabolism were also noted in the thigh muscles.	[28]
	Healthy volunteers (n = 8)	[18F]FDG was injected during exercise, followed by a whole-body PET scan conducted after the exercise.	[18F]FDG uptake did not increase in the upper body; however, increased uptake was observed in the lower body muscles, including the knee flexors and extraterrestrial and abdominal muscles.	[29]
	Healthy volunteers (n = 20)	[18F]FDG was injected 10 min after the start of exercise or after 20 min of rest. Whole-body PET scan was conducted after the exercise or rest periods.	The exercise group exhibited significantly greater uptake than that of the control group in the iliacus muscle and muscles of the anterior part of the thigh.	[30]
	Hemiparetic patients (n = 8)	Whole-body [18F]FDG PET scans were conducted after walking.	The [18F]FDG uptake levels in the flounder, foreground, posterior tibia, and obtuse muscles were significantly reduced in the paralyzed muscles of hemiplegic patients compared to non-paralyzed muscles of healthy participants.	[31]
	Sprague-Dawley rats (each group n = 4)	Rats underwent 3 days of fasting followed by [18F]FDG PET imaging scans.	Rats induced with muscle atrophy exhibited significantly reduced [18F]FDG uptake compared to that of the control group.	[32]
[18F]FCH	Patient with a history of prostate neoplasm	Patients were scanned 5, 45, and 120 min after [18F]FCH injection; post-5 min-Pelvic image scans were conducted, while whole-body scans were performed at 45 and 120 min postinjection.	The scans revealed heterogeneous [18F]FCH uptake throughout the body, attributed to intense physical activity.	[33]
	Sprague-Dawley rats (each group n = 4)	Rats were starved for 48 h and then scanned for [18F]FCH PET imaging.	[18F]FCH uptake of hind leg muscle was significantly lower in the muscle atrophy-induced model than in the control group.	[13]
	Patients (n = 10)	Three groups with different [18F]FCH injection and absorption conditions were compared.  Group 1: Strict (bed) rest  Group 2: Allowed to walk  Group 3: Performed strenuous single-arm exercise	Strenuous exercise significantly increases muscle absorption. Strict bed rest did not show significantly lower muscle absorption compared to walking for a short distance.	[34]
[11C]Acetate	Patients undergoing hip arthroplasty (n = 2)	Investigated 3 and 12 weeks after hip arthroplasty with the muscle at rest and during exercise.	Increased [11C]acetate uptake of muscles indicated the degree of functional recovery after hip arthroplasty.	[35]
	Wistar rats (n = 8)	Both legs of the one-leg knee-extensor excise model were compared.	The rate at which the exercised leg absorbed the [11C]acetate was faster than that of the non-exercised leg.	[36]
[15O]H2O	Healthy volunteers (n = 20)	Quantitation of blood flow in the thigh muscles was measured using autoradiography and [15O]H2O PET (steady state flow).	Although blood flow could be obtained through [15O]H2O PET, it was less efficient than autoradiography.	[37]
	Control group (n = 5) and normoglycemic hyperinsulinemic (n = 7)	After injecting bradykinin into the femoral artery, blood flow in both femurs was measured using [15O]H2O.	Blood flow in the skeletal muscles could be measured.	[38]

PET, positron emission tomography; CT, computed tomography; [¹⁸F]FDG, [¹⁸F]fluoro-2-deoxy-D-glucose; [¹⁸F]FCH, [¹⁸F]fluorocholine; [¹⁵O]H₂O, [¹⁵O]water.