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Market Research in the Healthcare Field with Expertise in Medical Imaging and Radioisotopes
Bio-Tech Systems, Inc. - 4167 West Pinecrest Circle - Las Vegas, Nevada 89121 phone: (702) 456-7608 - fax: (702) 456-2189
Can SPECT-CT Revitalize Nuclear Medicine?Feb. 23, 2008
These prospects have prompted scanner manufacturers to introduce two new hybrid SPECT CT systems. The Siemens system is known as “Symbia True Point” and the Philips systems is called “Precedence”. The Siemens system builds on its successful E-Cam platform and the Philips systems is designed around its high-end Skylight SPECT nuclear camera, which utilizes an overhead suspension for the camera heads. Although a hybrid SPECT-CT has been available from GE for a number of years (Infinia-Hawkeye), the CT images are not considered diagnostic quality, but do provide an anatomic reference for the SPECT image. An important factor in the success of PET-CT was that it introduced an image format familiar to radiologists, while adding important anatomic information regarding metabolically active tissue. The concept was originally sold to radiologists as CT imaging enhanced with PET as a contrast agent. One effect was that it brought radiologists and nuclear physicians closer together and also helped referring physicians understand the information conveyed by the images. This added confidence in the overall diagnostic workup. Differences Between PET and SPECT
SPECT imaging offers certain advantages over PET in that many SPECT agents have targeting capabilities that are more specific than FDG. A number of SPECT radiopharmaceuticals incorporate antibody and peptide formulations that can be targeted to specific tissue receptors, allowing one to discriminate healthy from diseased tissue with a high confidence level. However, the more specific the targeting agent is, the more difficult it is to interpret its position anatomically, since there are fewer landmarks. This may make it difficult for the average physician to interpret certain SPECT images. FDG, on the other hand, is a broad-spectrum agent that only images metabolic activity. FDG lights up healthy tissue as well as diseased tissue, but the diseased tissue has higher brightness because of higher metabolic activity. Whereas this can often be used to distinguish diseased from healthy tissue (as in malignant tumors), it is an indirect indication of disease.In the case of SPECT, the addition of CT may achieve some of the same advantages as it has with PET, allowing one to carefully analyze the extent and location of radiopharmaceutical uptake, improving diagnostic accuracy. This has already been demonstrated with targeted oncology radiopharmaceuticals such as Octreoscan and ProstaScint. It has also been possible to justify reimbursement for these procedures at a level similar to PET. This has encouraged manufacturers of these radiopharmaceuticals to increase their promotional efforts and expand training programs to include fusion imaging. Another aspect of SPECT is that it is based primarily on radiopharmaceuticals such as technetium that have a relatively slow decay rate compared with FDG. This simplifies the logistics of handling SPECT agents compared with PET. Potential Applications of SPECT-CT
Nuclear medicine procedures can be classified in three major groups: 1) nuclear cardiology 2) general nuclear medicine for functional imaging and 3) targeted oncology. There were 15.9 million SPECT procedures in 2007 comprised of 8.3 million nuclear cardiology procedures, 7.0 million general nuclear medicine procedures and about 25,000 targeted-cancer-imaging procedures. In comparison, there were about 1.6 million PET procedures performed in 2007. The most important application of PET is in oncology, where whole body imaging is used effectively to identify tumors at their source and scan for metastatic disease that might be remote from the source. SPECT, on the other hand, is more focused on organ function, such as the heart, lungs, kidneys, gall bladder, liver and thyroid. Although some SPECT procedures utilize whole body scanning, such as bone scans, these are not as specific as many of the organ studies. SPECT-CT in Cardiology
Whereas PET-CT has a natural fit in oncology, the opportunities for SPECT-CT have to be considered quite differently. SPECT imaging is strongly driven by cardiology, primarily nuclear perfusion studies. Growth in interventional cardiology and angioplasty procedures has required that patients be tracked with nuclear medicine for an extended period of time to assure that cardiac function has not been compromised by a recurrence of disease. From this standpoint, anything that can be done to improve the information yield from these procedures and reduce the number of inconclusive SPECT studies can be clinically and economically justified. SPECT CT may be able to accomplish this by adding certain vital information that will reduce the number of equivocal studies in difficult cases.Cardiologists have recognized the benefits of utilizing CT for detecting coronary calcification. Calcium scoring has become an accurate noninvasive test for early detection of coronary atherosclerosis and consequent stenosis. When coupled with SPECT perfusion imaging, it increases the accuracy in diagnosing and treating patients with these indications. Where perfusion abnormalities are revealed with SPECT, it would be clinically useful to augment this information with CT angiography, revealing the cause of the perfusion deficiency. Whereas myocardial perfusion imaging has a high success rate in indicating which patients are likely to benefit from revascularization or angioplasty, it doesn’t detect early atherosclerosis and has a tendency to underestimate the extent of coronary artery disease. In advanced disease, there may be multiple causes for perfusion defects, where the additional information from CT would allow more specific diagnosis and treatment. From this standpoint, SPECT-CT should incorporate multi-slice CT technology capable of functioning in a cardiology environment. This requires at least 16 slices and preferably 64 slices, which puts these CT systems at the high end of the price spectrum. However, it is likely that applications in cardiology will provide enough patient referrals to justify the investment. The slower systems, such as 6-slice CT’s will not fill the same need in cardiology and may be limited to other nuclear medicine areas where the procedure volume is much lower. SPECT-CT in General Nuclear Medicine
SPECT-CT should find applications in general nuclear medicine where anatomic localization is important, such as infection imaging. Current methods, using the patient’s white blood cells labeled in vitro, would benefit from CT's ability to provide accurate anatomic localization. This could help in diagnosing diffuse sites of infection and assist in analyzing fever of unknown origin. There were about 100,000 of these procedures performed in 2007.Lung imaging is another area where there may be a fit between SPECT and CT. There were 1.3 million lung scans performed in 2007. The nuclear V/Q scan has become standard for distinguishing ventilation defects from pulmonary embolism. This is accomplished by comparing the ventilation and perfusion scans for mismatches. If there is a mismatch between the two scans, pulmonary embolism is suspected. However, the image quality of these scans is sometimes equivocal, where the addition of CT could substantially increase diagnostic accuracy. SPECT-CT in Neurology
SPECT has had limited application in neurology. However, there are SPECT agents emerging for imaging Parkinson's disease and Alzheimer's that could be augmented with CT to improve diagnostic accuracy. This would allow nuclear physicians to read the SPECT images more clearly by being able to analyze the symmetry of the radiopharmaceutical uptake in the two halves of the brain and better distinguish the presence of disease. Neurologists have recognized the importance of distinguishing Parkinson's and Alzheimer's from diseases with similar outward symptoms. Therefore, a definitive diagnosis is critical in selecting the proper course of treatment.Oncology Applications
Although, there is a logical fit for SPECT-CT in oncology, the number of procedures with targeted agents, such as Octreoscan for imaging endocrine tumors and ProstaScint for prostate imaging has been limited. In addition, PET CT has preempted many oncology SPECT procedures because of the universal nature of FDG and the strong referral patterns established through radiology. Although there is an opening for SPECT-CT in oncology, it would not offer enough justification to make the investment without other prospects with higher procedure volume, such as cardiology and areas of general nuclear medicine referenced earlier. The Learning Curve
Equipment manufacturers often have to invest in new technology in anticipation of future demand, while clinicians must see the potentials and be willing to commit to the technology. To this extent, SPECT-CT has the potential to be utilized in a broad spectrum of nuclear procedures and improve diagnostic sensitivity in a cost-effective manner. To achieve this goal, SPECT-CT must be used early in the diagnostic workup as a primary imaging modality rather than as a confirmatory methodology for other imaging procedures. Ultimately, the CT portion of the exam must be reimbursable and this can only happen if it does not duplicate other imaging studies.For SPECT-CT to be applied widely, it must also offer users greater choice in terms of equipment configurations compatible with medium-size hospitals with smaller imaging budgets. At present, this is a challenge because the CT scanners have to be versatile enough in terms of multi-slice capability to operate in cardiology. As more experience is gained with SPECT-CT, procedure volume will increase. To the extent that nuclear physicians are able to work synergistically with other modalities to reduce overlap, it will help in the rate of adoption. Although equipment price may be an issue initially, the growing markets generated by expanded procedure volume should more than offset the high cost. In the final analysis, both manufacturers and patients will benefit from the broader availability of SPECT CT as it is integrated more effectively with other modalities. by Marvin Burns
Feb. 23, 2008 BIO-TECH SYSTEMS, INC., founded in 1980, provides clients with market research services in the healthcare field. This focuses on strategic planning, market research and development of new business opportunities. Bio Tech specializes in product and market evaluation where technical insight is important as well as the ability to communicate with many levels of management and end-users. One objective is to assess technological risk and target new products and services effectively in order to generate the best market response. Bio-Tech's expertise is in medical imaging and radioisotope products covering a broad range of diagnostic and therapeutic applications. For further details and information, please visit us at: Related Reading:
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