1Clinic and Institute for Nuclear Medicine, University Hospital, Basel, Switzerland
2School of Medical Science and Technology, Indian Institute of Technology, Kharagpur
Fusion technology is the buzzword in medical diagnostics. The power of SPECT-CT Fusion is emerging at a greater pace in the field of Molecular Imaging especially in Oncology. Fusion imaging also has an indispensable role in the monitoring of Receptor targeted radionuclide therapy. Materials and methods: We present our experience with Symbia T2? (Siemens Inc.), a SPECT-CT system with an in tegrated dual detector variable angle gamma camera and a dual slice, noncontrast CT scanner. Non-contrast CT imaging provides us the anatomical maps for attenuation correction of SPECT images. We present three unique clinical cases which highlight the power of Fusion Imaging.
A case of neuroendocrine tumour with Liver metastases treated with 200mCi of 111In-/90Y-DOTATOC. The SPECT-CT images after first and second course of Peptide Receptor adionuclide therapy in the interval of 10 weeks show a significant decrease in radionuclide uptake and size of liver lesions.
Fig. 1. Fusion, SPECT and CT Images after first 90Y-DOTATOC therapy (above) Note the change in uptake in the same lesions after the Second 90Y-DOTATOC therapy (below)
A case of Pheochromocytoma, after administration of tracer 99mTc-Meta-Iod-Benzyl guani din (MIBG) and SPECT-CT imaging (115 MBq, 28 hours p.i.) localized the tumour in the left suprarenal gland.
A case of postoperative calcaneus fixation showing uptake in the region of ankle in the planar scintigraphy
SPECT-CT (750 MBq, 4 hours p.i) with 99mTc DPD showed focal uptake in talonavicular joint depicting degenerative changes and no uptake in calcaneum.
SPECT-CT (785 MBq, 25 hours p.i) with 99mTc tagged antigranulocyte anti body (Antigran) showed focal uptake in the track of the drilling channel in calcaneum, thus confirming nidus of infection.
Discussion: From the above clinical cases, it is evident that fusion imaging provides us additional information, increasing the accuracy and influencing the therapeutic decisions. With the recent advancements in radiochemistry, SPECT-CT is gaining importance in the field of Molecular Oncology targeting various receptors. With CT providing the attenuation map for various radiopharmaceuticals, and the high specificity of the SPECT tracers means that more than one agent, each emitting a particular energy photons, can be injected to track the biological processes which is unlikely in PET Imaging.
SPECT-CT Fusion Imaging, Peptide Receptor Radionuclide therapy (PRRT), Molecular imaging, Molecular Medicine
