Background: 201Tl chloride scintigraphy allows malignant tumors of the locomotor apparatus to be diagnosed. The capacities of scintigraphy with 199Tl chloride, a 201Tl chloride analog, in addition to routine visualization of malignant tumors of the locomotor apparatus, have revealed its untypical variants.
Objective: to study the specific features of 199Tl chloride scintigraphic visualization of malignant tumor processes in the locomotor apparatus.
Subjects and methods: 199Tl chloride scintigraphy was performed in 85 patients having 107 foci of involvement presented with malignant (n = 57) and benign (n = 50) tumor processes.
Results: Malignant tumors were scintigraphically visualized in 98.1% of cases. Three types of their visualization were identified and studied; these included positive (82.4%) and rare: negative (7.8%), and mixed (9.8%) types associated with the specific features of the histological structure, metabolism, and blood supply of neoplasms and with the pharmacodynamic features of 199Tl chloride. The negative and mixed types, unlike metastatic neoplasms, were highly specific to primary or recurrent malignant tumors.
Conclusion: Consideration of the negative and mixed types of scintigraphic visualization in addition to routine positive one permitted the sensitivity of diagnosis of malignant locomotor tumors to be increased from 90.4 to 98.1%, without reducing the specificity of 199Tl chloride scintigraphy.