This study will enroll 20 rheumatoid arthritis patients meeting the 2010 ACR/EULAR classification criteria with moderate-to-high disease activity, with all participants undergoing both 99mTc-CTR-FAPI SPECT and 68Ga-FAPI PET/CT imaging for head-to-head comparison.The imaging results of both 99mTc-CTR-FAPI SPECT and 68Ga-FAPI PET/CT were independently interpreted by two nuclear medicine physicians with ≥10 years of diagnostic experience. A joint-by-joint comparison was performed between: (1) FAPI-positive joints identified by 99mTc-CTR-FAPI SPECT versus 68Ga-FAPI PET/CT, and (2) imaging-detected joints versus tender/swollen joints confirmed by physical examination.
