Chap 1 Book Nucmed Questions and Answers

Chap 1 Book Nucmed Questions and Answers The science and clinical practice of nuclear medicine involve the administration of trace amounts of compounds labeled with radioactivity (_____) that are used to provide ____ information in a wide range of disease states. radionuclides, diagnostic In its most basic form, a nuclear medicine study involves injecting a compound, which is labeled with a _____-emitting or positron-emitting radionuclide, into the body. The radiolabeled compound is called a _____, or more commonly, a tracer or ____ gamma-ray, radiopharmaceutical, radiotracer .When the radionuclide decays, _____ or high-energy photons are emitted gamma rays An external, ____-sensitive gamma-ray "camera" can detect the _____ or photons and form an image of the distribution of the radionuclide position, gamma rays There are two broad classes of nuclear medicine imaging: _____ [which includes single photon emission computed tomography (SPECT)] and ______ [positron emission tomography (PET)] single photon imaging, positron imaging Single photon imaging uses radionuclides that decay by _____ emission. A ____ image is obtained by taking a picture of the radionuclide distribution in the patient from ____ particular angle. This results in an image with little depth information, but which can still be diagnostically useful gamma-ray, planar, one For the tomographic mode of single photon imaging (SPECT), data are collected from ____ angles around the patient. This allows ____ images of the distribution of the radionuclide to be reconstructed, thus providing the depth information missing from planar imaging. many, cross-sectional Positron imaging makes use of radionuclides that decay by ____ emission. it has a very short lifetime and, following annihilation with an ___, simultaneously produces two ____ photons that subsequently are detected by an imaging camera. positron, electron, high-energy , tomographic images are formed by collecting data from many angles around the patient, resulting in ____ images PET The power of nuclear medicine lies in its ability to provide exquisitely ___ measures of a wide range of____ processes in the body. sensitive , biologic Other medical imaging modalities such as _______, x-ray imaging, and _____ provide outstanding anatomic images but are limited in their ability to provide biologic information magnetic resonance imaging (MRI), x-ray computed tomography (CT) magnetic resonance methods generally have a lower limit of detection in the millimolar concentration range (≈____ per mL tissue), 6 × 1017 molecules whereas nuclear medicine studies routinely detect radiolabeled substances in the nanomolar (≈_____ per mL tissue) or picomolar (≈____ molecules per mL tissue) range 6 × 1011 molecules, 6 × 108 Examples of the diverse biologic processes that can be measured by nuclear medicine techniques include tissue ____, ______, the somatostatin receptor status of tumors, the density of dopamine receptors in the brain, and _____ perfusion, glucose metabolism, gene expression. Because _____ can easily detect very tiny amounts of radioactivity, and because ____ are able to label compounds with very high specific activity. it is possible to form high-quality images even with ____ or picomolar concentrations of compounds. radiation detectors, radiochemists, nanomolar The ___ for human studies is established through careful dosimetry for every new radiopharmaceutical that is approved for human use. safe dose The origins of nuclear medicine1 can be traced back to the last years of the ___ century and the discovery of radioactivity by _____ (____) and of radium by Marie Curie (____). 19th, Henri Becquerel 1896, radium 1898 Both x rays and ____ sources were quickly adopted for medical applications and were used to make ___ images in which the radiation was transmitted through the body and onto photographic plates. radium, shadow X rays soon became the method of choice for producing "____" because images could be obtained more quickly and with better contrast than those provided by ____or other naturally occurring radionuclides that were available at that time. radiographs, radium The biologic foundations for nuclear medicine were laid down between 1910 and 1945. In _____, _____ developed the principles of the tracer approach and was the first to apply them to a biologic system in 1923, studying the absorption and translocation of radioactive ___ in plants. 1913, Georg de Hevesy, lead nitrate The first human study employing radioactive tracers was probably that of ____ and ____ (____),4 who injected an aqueous solution of ___ intravenously and measured the transit time of the blood from one arm to the other using a ____ chamber as the radiation detector Blumgart, Weiss, 1927, radon, cloud In the 1930s, with the invention of the ____ by _____, it became possible to artificially produce new radionuclides, thereby extending the range of biologic processes that could be studied cyclotron, Lawrence