Clinical Applications Of Positron Emission Tomography Research Articles

Current and Future Use of Positron Emission Tomography (PET) in Breast Cancer

Positron emission tomography (PET) is a radiotracer imaging method that is increasingly used in both the clinical care of breast cancer patients and in translational breast cancer research. This review emphasizes current and future clinical applications of PET to breast cancer, and highlights some translational research using PET to elucidate the clinical biology of breast cancer. PET principles are reviewed, followed by a review of current applications of (18)F-fluorodeoxyglucose (FDG) to clinical breast cancer care. Finally we review work done with other radiopharmaceuticals beyond FDG designed to image a number of aspects of breast cancer biology, emphasizing those most likely to enter clinical trials in the near future.

Positron emission tomography in gynecological malignancies

Positron emission tomography (PET) is a functional diagnostic imaging technique. F-18 fluoro-2-deoxy-d-glucose (FDG) is a commonly used radiopharmaceutical that is an analog of glucose. PET with FDG is now the standard of care in initial staging, monitoring the response to the therapy and management of various cancers. There is not sufficient data to support the use of PET in the initial diagnosis of cervical cancer; however, FDG-PET has a role in initial staging in the detection of distant metastases in patients with cervical cancer. PET has limited value in lesion localization in early stages of ovarian cancer, but plays a significant role in identifying recurrent tumors in patients with rising tumor markers. In this article, the clinical application of PET in gynecological malignancies is reviewed.

Positron emission tomography application for myocardial blood flow and coronary flow reserve measurement in patients with cardiovascular pathology

This article summarizes data of the studies with positron emission tomography (PET) and devotes the clinical application of PET for myocardial blood flow and coronary flow reserve measurement in the patients with cardiovascular pathology. Measurement of myocardial blood flow and coronary flow reserve allows to assess the functional importance of coronary stenosis in patients with coronary heart disease. According the results of experimental and clinical studies the impairment of coronary vasomotor reactivity seems to be the main cause of coronary microcirculatory abnormalities in the patients with high risk of cardiovascular diseases. Noninvasive PET diagnostics of myocardial blood flow provides the valuable information for stratification of the risk of the severe cardiovascular complications. PET seems to be a good tool for assessment of the medical treatment efficiency of arterial hypertension, diabetes mellitus, hypercholesterolemia and hypoestrogenemia. Myocardial blood flow impairment is independent prognostic marker of future adverse cardiac events and sudden cardiac death in patients with hypertrophic cardiomyopathy and idiopathic dilated cardiomyopathy.

Mapping of the cardiac sympathetic nervous system by single photon emission tomography with technetium-99m-labelled fluorobenzylpiperidine derivative (99mTc-FBPBAT): result of a feasibility study in a porcine model and an initial dosimetric estimation in humans

Positron emission tomography (PET) and single photon emission tomography (SPET) offer the most promising tools for the in-vivo assessment of the cardiac autonomic nervous system in humans. However, the clinical application of PET and SPET on a routine basis is severely limited by the lack of widely available selective radiotracers. Technetium-99m-labelled 4-fluorobenzyl-4-(2-mercapto-2-methyl-4-aza-pentyl)-4-(2-mercapto-2-methyl-propylamino)-piperidine (99mTc-FBPBAT) is a recently developed radiotracer which exhibited marked adrenergic affinity in previous investigations in vascular smooth muscle cells and cardiac myocytes, and in rats. In this study, we have verified these findings in a porcine model, and evaluated the potential of SPET with 99mTc-FBPBAT to assess the adrenergic nervous system of the heart. Using a SPET camera, scintigraphic evaluations were carried out in pigs following intravenous injection of 99mTc-FBPBAT. The specificity of the cardiac uptake was determined by pharmacological intervention, using alpha- and beta-adrenoceptor antagonists and adrenergic re-uptake blocker. Whole-body kinetic and radiation absorbed doses were estimated from whole-body scintigraphies in two healthy volunteers. 99mTc-FBPBAT-SPET demonstrated a homogeneous distribution of radioactivity in myocardium of pigs and in humans. The cardiac uptake was specifically suppressed by previous treatment of the animals with metoprolol and prazosin, and was displaceable by norepinephrine. In contrast, the inhibition of radioactivity uptake into the heart was less pronounced after pretreatment with desipramine. The peak radioactivity in blood was determined after 1.5-2 min, followed by a plateau of nearly constant radioactivity from 25-30 min onwards. Within 6 h, more than 35% of the injected activity was excreted in the urine. The effective dose according to International Commission on Radiological Protection Publication 60 (ICRP 60) was 0.0064 mSv.MBq-1 for adults. In view of these findings, we conclude that the myocardial uptake of 99mTc-FBPBAT reflects the sympathetic adrenergic nervous system of the heart. The effective dose estimated indicates that the clinical use of 99mTc-FBPBAT results in an acceptable radiation dose in humans. Despite the relatively high radioactivity uptake into the lung and liver, 99mTc-FBPBAT appears to be the first promising Tc-based radiotracer for scintigraphic assessment of the cardiac adrenergic system. This result encourages further development of Tc-based agents for routine SPET studies in humans.

Positron emission tomography in molecular imaging

The development of high-resolution positron emission tomography (PET) devices is an area of increasing interest to engineers and physicists. Because this technology is eminently translatable to the clinic, PET is becoming established as an invaluable - if not the premier - molecular imaging technique. This paper gives an overview of the clinical applications of PET and dual modality CT-PET systems as well as the challenges in small-animal PET imaging.

Clinical applications of PET in oncology.

Positron emission tomography (PET) provides metabolic information that has been documented to be useful in patient care. The properties of positron decay permit accurate imaging of the distribution of positron-emitting radiopharmaceuticals. The wide array of positron-emitting radiopharmaceuticals has been used to characterize multiple physiologic and pathologic states. PET is used for characterizing brain disorders such as Alzheimer disease and epilepsy and cardiac disorders such as coronary artery disease and myocardial viability. The neurologic and cardiac applications of PET are not covered in this review. The major utilization of PET clinically is in oncology and consists of imaging the distribution of fluorine 18 fluorodeoxyglucose (FDG). FDG, an analogue of glucose, accumulates in most tumors in a greater amount than it does in normal tissue. FDG PET is being used in diagnosis and follow-up of several malignancies, and the list of articles supporting its use continues to grow. In this review, the physics and instrumentation aspects of PET are described. Many of the clinical applications in oncology are mature and readily covered by third-party payers. Other applications are being used clinically but have not been as carefully evaluated in the literature, and these applications may not be covered by third-party payers. The developing applications of PET are included in this review.

Positron emission tomography: a review of basic principles, scanner design and performance, and current systems

S N INCE THE INCEPTION of positron emission tomography (PET) several decades ago, PET canner design and performance have improved ramatically. The number of detector elements has ncreased from 20 to 20,000 and the axial field f view from 2 to 20 cm, the spatial resolution as improved from 25 to 5 mm, and the ensitivity has increased 1000-fold.1,2 At the ame time, the clinical applications of PET have rown dramatically as well.3-5 The current article eviews the technical basis of the remarkable dvance of this modality—the underlying princiles of PET and the basic design and performance haracteristics of PET scanners—emphasizing edicated “full-ring” devices and including multiodality (ie, PET-CT) and special-purpose (ie, mall-animal) devices.

Positron emission tomography imaging in evaluation of cancer patients.

Positron emission tomography (PET) is a diagnostic imaging technique that has progressed rapidly from being a research technique in laboratories to a routine clinical imaging modality. The most widely used radiotracer in PET is Fluorine18-fluorodeoxyglucose (F18-FDG), which is an analogue of glucose. The FDG uptake in cells is directly proportional to glucose metabolism of cells. Since glucose metabolism is increased many fold in malignant tumors PET has a high sensitivity and a high negative predictive value. PET with FDG is now the standard of care in initial staging, monitoring the response to the therapy, and management of lung cancer, colonic cancer, lymphoma, melanoma, esophageal cancer, head and neck cancer and breast cancer. Other indications of PET like bone tumor, ovarian cancer and cancer of unknown primary (CUP) has also been discussed in brief. The aim of this review article is to review the clinical applications of PET in various malignancies and only limited number of important studies will be discussed for this effort.

Evaluation of breast and gynecologic cancers by positron emission tomography.

D ESPITE AN increase in public awareness and the use of screening methods for early detection of cancer, breast, and gynecologic cancers, these cancers are responsible for approximately 66,500 deaths among American women annually (40,200 from breast cancer and 26,300 from gynecologic cancers). 1 Breast and gynecologic cancers represent the most common and second most common malignancies of women, respectively, accounting for 31% and 13% of all cancers in women. 1 In the United States, it is estimated that nearly 192,200 new cases of breast cancer and 80,300 new cases of gynecologic cancer will be diagnosed in 2001.1 Although conventional anatomic imaging methods have improved the detection and management of breast cancer, their role in the diagnosis and evaluation of gynecologic cancers has been less clear. Over the past decade, positron emission tomography (PET), a functional imaging modality, has been shown to have properties ideal for imaging patients with cancers. Currently, PET has become an essential tool in the diagnosis and staging of several types of cancers, and it also has an expanding role in predicting and assessing response to therapy. This review focuses on current and potential clinical applications of PET in the evaluation of breast and gynecologic cancers.

Positron emission tomography: establishing priorities for health technology assessment.

Positron emission tomography (PET) is an expensive diagnostic imaging technology. Despite the long history of PET development, the costs and effectiveness of its use in routine clinical practice remain unknown. Against this background of uncertainty regarding the clinical role of PET, the UK Standing Group on Health Technology requested a review of its current and potential role which would enable research priorities in this area to be established. This 3-month project had two explicit objectives: (1) to review the state of knowledge regarding the clinical applications of PET; (2) to determine the key health technology assessment (HTA) research questions relating to the use of PET in the UK. A literature review to ascertain the state of knowledge regarding the clinical applications of PET and a three-round Delphi study to inform the key HTA research questions relating to the use of PET in the UK were undertaken. The results of an earlier systematic review, published by the Veteran's Health Administration (VHA) in the USA in 1996, were used as the starting point for the literature review. The VHA review was updated and extended by means of MEDLINE and Cochrane Library database searches. Participants in the Delphi study were selected by discussion with five individuals in the UK with an interest in, and awareness of, developments in PET. As a result of their suggestions, 43 individuals were initially invited to participate, of whom two did not feel appropriately qualified. Questionnaires were sent by facsimile to all invited participants, who were asked to return the completed forms by facsimile within a week. The content and structure of the Delphi study was informed by the results of the literature review. The responses and comments of the participants were a major source of information for this report. Clinical applications for PET have been advocated in three broad disease groups: oncology, cardiology and neuropsychiatric disorders. There are currently four PET modalities that need to be considered when assessing its potential clinical role in the UK: full ring PET scanners operating in two or three dimensions (available at five sites); partial ring rotating PET scanners (one currently operating in the UK); coincidence imaging with modified gamma camera technology; and high-energy collimator imaging of 511 keV photons with modified gamma camera technology. There is a paucity of available evidence relating to the cost-effectiveness of the various PET modalities in all of the clinical indications for which the technology is currently being advocated. In addition, many existing reports on the diagnostic accuracy of PET are limited because they are liable to bias and often relate only to very small patient numbers. The results of the Delphi study indicated that the four most important research priorities for the NHS, in descending order of their importance, are: (1) the relative cost-effectiveness of (a) full ring PET, (b) gamma camera PET using coincidence imaging and (c) existing diagnostic strategies to determine staging prior to operative intervention for lung cancer; (2) partial ring PET compared with full ring PET in oncology (3) the relative cost-effectiveness of (a) full ring PET, (b) gamma camera PET using coincidence imaging and (c) existing diagnostic strategies to stage and monitor treatment response in breast cancer; (4) the relative cost-effectiveness of (a) gamma camera PET using coincidence imaging and (b) 511 keV collimated positron imaging for assessing myocardial viability when selecting patients for revascularisation surgery. Vignettes describing each of the research priorities are provided in the main report. The findings of this project, which was undertaken rapidly in order to inform HTA research prioritization in the UK, provide a contemporary overview of the potential clinical role for PET in the NHS. Evidence is needed that using PET as a diagnostic

Positron emission tomography in patients with primary CNS lymphomas.

This article reviews possible clinical applications of positron emission tomography (PET) in patients with CNS lymphomas. PET allows quantitative assessment of brain tumor pathophysiology and biochemistry in vivo. Therefore, it provides different information about tumors when compared to histological or neuroradiological methods. In a diagnostic setting, PET cannot differentiate between primary lymphomas of the CNS, brain secondaries, or malignant gliomas, since various brain tumors share biochemical alterations. In HIV patients with contrast-enhancing brain tumors, however, data from the literature suggest that PET with the tracer F-18 fluoro-deoxyglucose may help to discriminate neoplastic (CNS lymphoma) from inflammatory (e.g. toxoplasmosis) lesions. Assuming that tumor biochemistry is highly abnormal in the most malignant parts of tumors, PET may also assist in defining targets for stereotactic biopsy. With regard to treatment evaluation, the prediction of individual treatment response is among the most challenging clinical applications of PET. On the one hand, this could be achieved on the basis of measures like tumor perfusion, oxygen consumption, or hypoxia. On the other hand, PET tracer methods may allow to quantify the expression of gene products following gene therapy. However, in CNS lymphoma patients these topics have yet not been addressed with PET.

Basic Principles and Neurosurgical Applications of Positron Emission Tomography

Positron emission tomography (PET) is a technique for studying functional processes in the human body in vivo. The important clinical applications of PET in neurosurgery include localization of epileptic foci, diagnosis of brain tumors, preoperative brain mapping, and the study of plasticity of the brain following brain damage. The basic physics and neurosurgical applications of PET are presented.

State of the art in emission tomography equipment.

The current state of the art in single photon emission computed tomography (SPECT) and positron emission tomography (PET) equipment is based on developments over the last 35 years, including those items necessary to make the devices clinically useful. In SPECT, most of the development has involved rotating gamma cameras, since this device could also be used for conventional planar imaging. Recent advances involve the use of multiheaded SPECT cameras and have led to a substantial increase in image quality with these devices. Historically, attenuation correction in SPECT has been applied only to brain and abdominal studies. Currently, the application of nonuniform attenuation correction for cardiac studies, which typically requires acquisition of a transmission scan, has been investigated. Over the past 10 years, greater interest in the clinical application of PET has led to design changes in the equipment used for chemistry and scanning. Modern cyclotrons are typically smaller, self-shielded, and less complicated to run than older models. PET scanners can now image multiple planes over an extended axial field of view with approximately equal spatial resolution in all directions. Advancements in emission tomography have made these technologies more accessible for clinical application.

863 Clinical applications of FDG positron emission tomography in patients with soft tissue sarcoma

Various applications of positron emission tomography (PET) were studied in patients with soft tissue sarcoma: depiction of primary and recurrent lesions, determination of malignancy grade and evaluation of response to regional isolation perfusion. Twenty-nine patients with various types of soft tissue sarcoma were studied, 17 with a primary tumor and 12 patients with a local recurrence. The tumor size ranged from 1.0 to 31 cm. An IV dose of 370 MBq 18F-fluoro-deoxy-D-glucose (FDG) was administered. PET studies were performed in a dynamic and a “whole body” mode using a Siemens ECAT 951 camera. All 17 primary tumors and 11 of the 12 recurrent sarcomas were well visualized on the PET studies. The location of the recurrent lesions was clearly depicted in the presence of surrounding scar tissue and fibrosis. The glucose metabolic rate in the lesions was found to increase with increasing malignancy grade (P The decrease in glucose metabolic rate after TNF perfusion (20 patients) was found to provide information about the tumor response. In summary, several clinical applications of PET with FDG were established in patients with soft tissue sarcoma.

Clinical applications of positron-emission tomography in cancer.

Positron-emission tomography is a unique imaging technique that has shown promise for improving staging, treatment planning, and monitoring of cancer. When used in conjunction with a radioactive glucose analog, positron-emission tomography has proven useful for detecting malignant tissue and quantitating changes in tumor glycolysis during and after treatment. This article reviews the principles of positron-emission tomography and its clinical role in cancer treatment.

Preliminary clinical images from a prototype positron camera.

Recent developments in positron emission tomography (PET) have shown that the technique can produce high-resolution quantitative images superior to those obtained by single photon emission computed tomography (SPECT). However PET is presently only available at certain large research institutes with on-site radionuclide-producing cyclotrons and it is therefore used mainly for clinical research. The high cost of the detector systems and the lack of readily available radiopharmaceuticals are further constraints which limit the widespread clinical application of PET. In this short communication we present preliminary clinical images taken during an evaluation of a prototype Multiwire Proportional Chamber (MWPC) positron camera. Although these early images were taken with a limited sensitive area, a camera with a larger field of view is currently being developed. Such a positron camera would be used with generatorproduced as well as cyclotron-produced longer-lived positron emitting radionuclides to provide a P...