Radionuclide imaging of lymphoma with Gallium-67(67Ga) is a well establish procedure. However 67Ga scan has some limitations (is not readily available at Nuclear Medicine Labs, tumor imaging and interpretation should be delayed until 3-7 days postinyection, low spatial resolution and high cost). 99mTc labelled agents could be used as an alternative to 67Ga. Glucosamine (G) is a six-carbon amino sugar, enters the cells by a glucose transporter system and by phosphate and glycolitic pathways forms glucosamine-6-phosphate, is promising as an oncologic imaging agent. Reacting G with cysteine (C) has been labeled with 99mTc (99mTc-CG). This agent has been evaluated in patients with different types of cancer to show hypermetabolic lesions.
Objective: Comparison of 99mTc-CG and 67Ga in patients with Hodgkin’s disease(HD) in different stages of disease.
Materials and Methods: 27 consecutive patients (8 M, 19 F; age range 14 – 72 years) with histopathologic diagnosis of HD were studied with 99mTc-CG and 67Ga. All patients underwent whole body scan and SPECT(reconstructed with OSEM algorithm) on the field of view of the lesion, with 1) 99mTc-CG (patients fasted for 12 hrs, dose: 1088MBq, imaging 1 and 4 hrs after injection). To eliminate the intravascular and interstitial activity of SPECT images, patients were given 737 MBq of 99mTc human serum albumin(99mTc-HSA) and other SPECT was done. Both SPECT were normalize and subsequently the 99mTc-HSA image was subtracted from the 99mTc-CG imaging, 2) 67Ga (inyection of 220MBq and imaging done after 3-4 days). 26 patients had histology of nodular sclerosis and one mixed cellularity. Patients were classified as active HD (n=17) or in complete remission (n=10) according to the clinical stage of the disease(CSD) (defined by physical examination, laboratory values, lymph node biopsy, Chest X-Ray and Computerized Axial Tomography of the neck, chest,and abdomen).99mTc-CG and 67Ga scans were defined as positive in the presence of uptake unrelated to the normal biodistribucion of both isotopes.
Results: In patienst with active HD, images with 99mTc-CG were positive in all sites showing abnormal 67Ga uptake. All patients with HD in remission showed negative images with both 99mTc-CG and 67Ga. Considering CSD as the reference standard we found that the sensitivity and specificity of 99mTc-CG was 100%. No false positive images were visualized. Only two patients (11%) with active HD who completed chemotherapy were imaged again with both agents 3 weeks later. In both patients the images were negative.
Conclusion: Scintigraphy with 99mTc-CG is a good alternative to 67Ga for evaluating patients with active and in remission of HD. Compared with 67Ga, <99mTc-CG can be done in one day and also is less expensive. Image subtraction is helpful in highlight tumoral uptake.
