A preliminary feasibility study of simultaneous dual-isotope imaging with a solid-state dedicated cardiac camera for evaluating myocardial perfusion and fatty acid metabolism

Abstract

Simultaneous dual-isotope SPECT imaging with 201Tl and (123)I-β-methyl-p-iodophenylpentadecanoic acid (BMIPP) is used to study the perfusion-metabolism mismatch. It predicts post-ischemic functional recovery by detecting stunned myocardium. On the other hand, (99m)Tc-MIBI is another radioisotope widely used in myocardial perfusion imaging because of its better image quality and lower radiation exposure than 201Tl. However, since the photopeak energies of (99m)Tc and (123)I are very similar, crosstalk hampers the simultaneous use of these two radioisotopes. To overcome this problem, we conducted simultaneous dual-isotope imaging study using the D-SPECT scanner (Spectrum-Dynamics, Israel) which has a novel detector design and excellent energy resolution. We first conducted a basic experiment using cardiac phantom to simulate the condition of normal perfusion and impaired fatty acid metabolism. Subsequently, we prospectively recruited 30 consecutive patients who underwent successful percutaneous coronary intervention for acute myocardial infarction, and performed (99m)Tc-MIBI/(123)I-BMIPP dual-isotope imaging within 5 days after reperfusion. Images were interpreted by two experienced cardiovascular radiologists to identify the infarcted and stunned areas based on the coronary artery territories. As a result, cardiac phantom experiment revealed no significant crosstalk between (99m)Tc and (123)I. In the subsequent clinical study, (99m)Tc-MIBI/(123)I-BMIPP dual-isotope imaging in all participant yielded excellent image quality and detected infarcted and stunned areas correctly when compared with coronary angiographic findings. Furthermore, we were able to reduce radiation exposure to significantly approximately one-eighth. In conclusion, we successfully demonstrated the practical application of simultaneous assessment of myocardial perfusion and fatty acid metabolism by (99m)Tc-MIBI and (123)I-BMIPP using a D-SPECT cardiac scanner. Compared with conventional (201)TlCl/(123)I-BMIPP dual-isotope imaging, the use of (99m)Tc-MIBI instead of (201)TlCl improves image quality as well as lowers radiation exposure.

Novel SPECT Technologies and Approaches in Cardiac Imaging

“…The feasibility of simultaneous imaging of inflammation with 111 In-labeled white cells and myocardial perfusion with technetium (99mTc) sestamibi was demonstrated in the phantom and in 34 patients [42]. Simultaneous imaging of fatty metabolism with 123I-β-methyliodophenylpentadecanoic acid and perfusion with technetium (99mTc) sestamibi has been shown in 30 patients [43]. An 123I-metaio dobenzylguanidine/201Tl imaging protocol has been proposed for evaluation of trigger zones after revascularization [44].…”

Simultaneous Tc-99m and I-123 dual-radionuclide imaging with a solid-state detector-based brain-SPECT system and energy-based scatter correction

“…In simultaneous dual-radionuclide imaging, even if the energy resolution of the CdTe detectors is very good, down-scatter is unavoidable. Furthermore, scatter within the crystals, k-escape, and incomplete charge collection can cause a considerable fraction of the primary gamma rays to be measured as lower energy events [ 4 – 8 ]. An iterative deconvolution-based scatter and crosstalk correction method for simultaneous dual-radionuclide imaging and a solid-state detector SPECT system have been developed [ 4 ].…”

“…The method improves the contrast in simultaneous Tc-99m and Tl-201 imaging using CdZnTe-based SPECT. The feasibility of using this method for simultaneous Tc-99m and I-123 cardiac imaging has been investigated [ 8 ].…”

Semiconductor Detector-Based Scanners for Nuclear Medicine

“…The scanning of multi-radionuclide pharmaceuticals will enable various kinds of functional images to be obtained without position error or time difference. The recent development of several cardiac SPECT systems that use solid-state detectors with a fine energy resolution [3][4][5] has led to simultaneous multi-radionuclide imaging recapturing the spotlight. A number of simultaneous multiradionuclide imaging studies have been reported, especially for myocardial perfusion diagnosis [4,5].…”