Introduction: Methotrexate (MTX) is being used for treatment of rheumatoid arthritis (RA) and a variety of other inflammatory joint diseases.
Methods: The aim of the present study was to use Tc99m labeled MTX as imaging agent in rheumatoid arthritis. Labeling efficiency was studied with paper chromatography (PC) and Instant thin layer chromatography (ITLC) and found it to be 99.8% ± 0.2. We then tested the radiopharmaceutical on five diagnosed patients of RA. Percentage of ID (%ID) uptake in the major joints was evaluated in all patients. For this we first developed normal %ID data for major joints in 14 volunteers who underwent conventional Tc99m-MDP bone scintigraphy. Then normal %ID data was calculated in five normal subjects for Tc99m-MTX as well for future comparison with patient data.
Results: Scintigraphic results showed excellent selective tracer uptake of Tc99m-MTX in all effected joints of patients which correlated well with the conventional bone scan data as well. High T/NT ratios were highest for Tc99m- MTX when compared with Tc99m-MDP.
Conclusions: Tc99m-MTX is a promising imaging agent for RA and it also predicts sensitivity of disease to Methotrexate. This agent can also be used for follow up of disease as it can pick active disease or residual disease even during the course of treatment.the patient who shall be sensitive to MTX treatment and further will help for response evaluation during therapy.