Molecular imaging examinations using positron emission tomography (PET) and single-photon emission computed tomography (SPECT) are frequently used in the brain because they can complement the anatomical information from magnetic resonance (MR) imaging and computed tomography (CT). By examining cellular function, disease is often detected at an earlier stage, or the extent of disease may be more accurately demonstrated with nuclear medicine techniques. Hybrid cameras combining PET…

This chapter reviews tumor scintigraphy using radiopharmaceuticals other than F-18 fluorodeoxyglucose (FDG), as well as therapeutic radiopharmaceuticals for specific malignancies ( Box 13.1 ). Theranostics is a topic of increasing importance as it relates to nuclear oncology. The term refers to a pharmaceutical that is labeled with one radionuclide for diagnostic imaging and another radionuclide for therapy, for example, Ga-68 dotatate and Lu-177 dotatate for neuroendocrine…

Background For decades, positron emission tomography (PET) imaging was largely limited to use in research. The development of dedicated PET cameras, the widespread expansion of cyclotron production facilities, and the approval of new radiopharmaceuticals have all contributed to the dramatic growth of clinical PET in recent years. PET agents often incorporate radioactive isotopes of atoms normally present in organic substances (e.g., oxygen-15, nitrogen-13, carbon-11, and the…

Over the years, radiopharmaceuticals and scintigraphic techniques have been developed to assess different aspects of renal function. Using a variety of radiopharmaceuticals, these techniques can answer clinical questions not possible with ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI). Some indications for nuclear scintigraphy are listed in Box 11.1 . These include problem-solving and quantification applications that break down roughly into issues related to function…

Liver, biliary, and splenic scintigraphy have played an important diagnostic imaging role in patient management since the 1960s. Today’s radiopharmaceuticals have mechanisms of uptake and localization that take advantage of the complex anatomy and physiology of the liver ( Table 9.1 ; Figs. 9.1 to 9.4 ). Although many of the radiopharmaceuticals, methodologies, and indications have changed, hepatobiliary and splenic scintigraphy continue to provide unique functional…

Thyroid Disease—Radionuclide Diagnosis and Therapy In 1941, the first patient was treated for thyroid cancer with radioiodine. Since then, radioiodine has proven invaluable in the assessment of thyroid disorders and treatment of thyroid cancer, Graves disease, and toxic thyroid nodules. Today, radioiodine I-123 and I-131 remain important diagnostic and therapeutic modalities, and the use of positron emission tomography (PET) iodine-124 is growing. Thyroid Anatomy and Physiology…

Introduction: The Ventilation–Perfusion Lung Scan Particles slightly larger than red blood cells can be radiolabeled and injected into a peripheral vein. After passing through the heart and central pulmonary arteries, they finally lodge in the peripheral lung capillaries, creating a map of pulmonary blood flow that can be imaged with a gamma camera. Similarly, inhalation of a radiolabeled gas or aerosol can allow ventilation imaging. These…

Made up of inorganic calcium hydroxyapatite (Ca 10 [PO 4 ] 6 [OH] 2) crystal and an organic matrix of collagen and blood vessels, the skeleton is constantly changing and remodeling. This physiological activity can be imaged with radioactive analogs of calcium, phosphate, or hydroxyl ions (OH – ) that can localize to the bone, with areas of growth or repair resulting in increased turnover. Whereas…

Molecular imaging (MI) allows noninvasive visualization and quantification of functions occurring at the cellular or molecular level. This can involve several different techniques ( Table 5.1 ), but tagging a targeted probe with a radioactive molecule is one of the most important. This label makes imaging and quantitation possible with only small (or tracer) amounts of the probe, helping to minimize the impact on the patient…

An unstable atom that undergoes radioactive decay in order to achieve stability is known as a radionuclide. The radiation these atoms emit can sometimes be used in medical imaging and therapy. Agents approved for such uses in humans that incorporate radioactive molecules are referred to as radiopharmaceuticals. Radiopharmaceuticals can portray physiology, biochemistry, or pathology in the body without causing any significant physiological effect. They are also…

Data Acquisition of Emission Tomographyn Conventional or planar radionuclide imaging suffers a major limitation in the loss of object contrast as a result of background radioactivity. In the planar image, radioactivity underlying and overlying the object of interest is superimposed on that coming from the object. The fundamental goal of tomographic imaging systems is a more accurate portrayal of the three-dimensional (3D) distribution of radioactivity in…

In nuclear medicine, radiopharmaceuticals given to the patient emit the radiation used to create images or perform therapy. In order to understand how these agents perform and what safety considerations are involved in their use, it is necessary to be familiar with some basic aspects of the physics behind radioactive decay. This chapter discusses radioactive molecules, different types of radioactive decay, and how these emissions interact…