Thallium-201 imaging in evaluation of Hodgkin's disease

The role of Ga 67 in the evaluation of Hodgkin's disease has been widely established. Tl 201 has been used to evaluate a wide variety of malignant lesions. This prospective study was performed to evaluate the role of Tl 201 imaging in Hodgkin's disease at the time of initial presentation and in the assessment of response to therapy, relapse, and remission.

Fifty-one consecutive patients (23 female, 28 male) with known Hodgkin's disease underwent 111 Tl 201 and Ga 67 studies. The age range was 16-56 years (mean age, 34.7 years). The histopathologies included nodular sclerosis (in 31 cases), mixed cellularity (in 12), lymphocytic predominant (in five), lymphocytic depletion (in one), and unknown (in two). All patients underwent whole-body imaging after intravenous injection of 3 mCi of Tl 201 chloride and 10 mCi of Ga 67 citrate. Comparison with Ga 67 imaging, anatomical imaging (computed tomography and/or magnetic resonance imaging), and clinical correlation were performed.

The combined analysis of all various histologies demonstrated that a comparison of Tl 201 with Ga 67 scintigraphy revealed a sensitivity of 0.76 versus 0.89; a specificity of 0.96 versus 0.73, an accuracy of 0.86 versus 0.81, a positive predictive value of 0.95 versus 0.77, and a negative predictive value of 0.81 versus 0.87. Tl 201 imaging was similar in sensitivity, specificity, and accuracy among the nodular sclerosis and the mixed-cellularity Hodgkin's disease.

Tl 201 imaging offers more specificity with a higher positive predictive value in the diagnosis of Hodgkin's disease. The Ga 67 study is more sensitive than Tl 201 in the detection of disease. There is no significant difference in accuracy and negative predictive value between the two studies. Therefore, we recommend Tl 201 imaging in the initial evaluation and assessment of patients' response to radiation therapy and/or chemotherapy.