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Patients are encouraged to consult with the nuclear medicine department prior to a scan. The end result of the nuclear medicine imaging process is a "dataset" comprising one or more images. In multi-image datasets the array of images may represent a time sequence i. SPECT single photon emission computed tomography is the process by which images acquired from a rotating gamma-camera are reconstructed to produce an image of a "slice" through the patient at a particular position. A collection of parallel slices form a slice-stack, a three-dimensional representation of the distribution of radionuclide in the patient.
The nuclear medicine computer may require millions of lines of source code to provide quantitative analysis packages for each of the specific imaging techniques available in nuclear medicine. Time sequences can be further analysed using kinetic models such as multi-compartment models or a Patlak plot. Radionuclide therapy can be used to treat conditions such as hyperthyroidism , thyroid cancer , and blood disorders. In nuclear medicine therapy, the radiation treatment dose is administered internally e. The radiopharmaceuticals used in nuclear medicine therapy emit ionizing radiation that travels only a short distance, thereby minimizing unwanted side effects and damage to noninvolved organs or nearby structures.
Nuclear medicine is an important component of modern medicine. This easy-to- use book is designed to acquaint readers with the basic principles of nuclear. Nuclear medicine utilizes radioactive molecules (radiopharmaceuticals) for the diagnosis and treatment of disease. The diagnostic information obtained from.
Most nuclear medicine therapies can be performed as outpatient procedures since there are few side effects from the treatment and the radiation exposure to the general public can be kept within a safe limit. Common nuclear medicine unsealed source therapies. In some centers the nuclear medicine department may also use implanted capsules of isotopes brachytherapy to treat cancer. Commonly used radiation sources radionuclides for brachytherapy [3]. The history of nuclear medicine contains contributions from scientists across different disciplines in physics, chemistry, engineering, and medicine.
The multidisciplinary nature of nuclear medicine makes it difficult for medical historians to determine the birthdate of nuclear medicine. This can probably be best placed between the discovery of artificial radioactivity in and the production of radionuclides by Oak Ridge National Laboratory for medicine related use, in The origins of this medical idea date back as far as the mids in Freiburg , Germany, when George de Hevesy made experiments with radionuclides administered to rats, thus displaying metabolic pathways of these substances and establishing the tracer principle.
Possibly, the genesis of this medical field took place in , when John Lawrence , known as "the father of nuclear medicine", took a leave of absence from his faculty position at Yale Medical School , to visit his brother Ernest Lawrence at his new radiation laboratory now known as the Lawrence Berkeley National Laboratory in Berkeley , California.
Later on, John Lawrence made the first application in patients of an artificial radionuclide when he used phosphorus to treat leukemia. The history of nuclear medicine will not be complete without mentioning these early pioneers. Nuclear medicine gained public recognition as a potential specialty on December 7, when an article was published in the Journal of the American Medical Association by Sam Seidlin.
This is considered by many historians as the most important article ever published in nuclear medicine. Among the many radionuclides that were discovered for medical-use, none were as important as the discovery and development of Technetiumm. It was first discovered in by C. Segre as an artificial element to fill space number 43 in the Periodic Table.
The development of a generator system to produce Technetiumm in the s became a practical method for medical use. Today, Technetiumm is the most utilized element in nuclear medicine and is employed in a wide variety of nuclear medicine imaging studies. Widespread clinical use of nuclear medicine began in the early s, as knowledge expanded about radionuclides, detection of radioactivity, and using certain radionuclides to trace biochemical processes.
Pioneering works by Benedict Cassen in developing the first rectilinear scanner and Hal O. Anger 's scintillation camera Anger camera broadened the young discipline of nuclear medicine into a full-fledged medical imaging specialty. By the early s, in southern Scandinavia , Niels A. Lassen , David H. It allowed them to construct images reflecting brain activation from speaking, reading, visual or auditory perception and voluntary movement.
By the s most organs of the body could be visualized using nuclear medicine procedures. In , American Medical Association officially recognized nuclear medicine as a medical specialty. In the s, radiopharmaceuticals were designed for use in diagnosis of heart disease. The development of single photon emission computed tomography SPECT , around the same time, led to three-dimensional reconstruction of the heart and establishment of the field of nuclear cardiology. More recent developments in nuclear medicine include the invention of the first positron emission tomography scanner PET.
The concept of emission and transmission tomography, later developed into single photon emission computed tomography SPECT , was introduced by David E. Kuhl and Roy Edwards in the late s. Tomographic imaging techniques were further developed at the Washington University School of Medicine.
Townsend from University of Pittsburgh in About a third of the world's supply, and most of Europe's supply, of medical isotopes is produced at the Petten nuclear reactor in the Netherlands. The NRU started operating in The Canadian Nuclear Safety Commission ordered the National Research Universal reactor to be shut down on November 18, for regularly scheduled maintenance and an upgrade of the safety systems to modern standards.
The upgrade took longer than expected, and in December a critical shortage of medical isotopes occurred. The Canadian government passed emergency legislation allowing the reactor to restart on 16 December , and production of medical isotopes to continue. In mid-February, , the reactor was shut down once again due to a mechanism problem that extracts the isotope containing rods from the reactor. The reactor was again shut down in mid May of the same year because of a heavy water leak.
The reactor was started again during the first quarter of The NRU will cease routine production in the fall of , however the reactor will be available for backup production until March , at which point it will be shut down. The Chalk River reactor is used to irradiate materials with neutrons which are produced in great quantity during the fission of U These neutrons change the nucleus of the irradiated material by adding a neutron, or by splitting it in the process of nuclear fission. In a reactor, one of the fission products of uranium is molybdenum which is extracted and shipped to radiopharmaceutical houses all over North America.
The Mo radioactively beta decays with a half-life of 2. The Tcm then further decays, while inside a patient, releasing a gamma photon which is detected by the gamma camera. It decays to its ground state of Tc, which is relatively non-radioactive compared to Tcm. The most commonly used radioisotope in PET F , is not produced in any nuclear reactor, but rather in a circular accelerator called a cyclotron.
The cyclotron is used to accelerate protons to bombard the stable heavy isotope of oxygen O The O constitutes about 0.
The F is then typically used to make FDG see this link for more information on this process. A typical nuclear medicine study involves administration of a radionuclide into the body by intravenous injection in liquid or aggregate form, ingestion while combined with food, inhalation as a gas or aerosol, or rarely, injection of a radionuclide that has undergone micro-encapsulation. Some studies require the labeling of a patient's own blood cells with a radionuclide leukocyte scintigraphy and red blood cell scintigraphy.
Most diagnostic radionuclides emit gamma rays , while the cell-damaging properties of beta particles are used in therapeutic applications. Refined radionuclides for use in nuclear medicine are derived from fission or fusion processes in nuclear reactors , which produce radionuclides with longer half-lives, or cyclotrons , which produce radionuclides with shorter half-lives, or take advantage of natural decay processes in dedicated generators, i.
The most commonly used intravenous radionuclides are Technetium m technetiumm , Iodine and , Thallium , Gallium , Fluorine fluorodeoxyglucose , and Indium Labeled Leukocytes.
A patient undergoing a nuclear medicine procedure will receive a radiation dose. Under present international guidelines it is assumed that any radiation dose, however small, presents a risk.
The radiation dose delivered to a patient in a nuclear medicine investigation, though unproven, is generally accepted to present a very small risk of inducing cancer. In this respect it is similar to the risk from X-ray investigations except that the dose is delivered internally rather than from an external source such as an X-ray machine, and dosage amounts are typically significantly higher than those of X-rays. The radiation dose from a nuclear medicine investigation is expressed as an effective dose with units of sieverts usually given in millisieverts, mSv.
The effective dose resulting from an investigation is influenced by the amount of radioactivity administered in mega becquerels MBq , the physical properties of the radiopharmaceutical used, its distribution in the body and its rate of clearance from the body. Formerly, units of measurement were the curie Ci , being 3. The rad and rem are essentially equivalent for almost all nuclear medicine procedures, and only alpha radiation will produce a higher Rem or Sv value, due to its much higher Relative Biological Effectiveness RBE. Alpha emitters are nowadays rarely used in nuclear medicine, but were used extensively before the advent of nuclear reactor and accelerator produced radionuclides.
Anderson Cancer Center Pressler St. Footnotes Published online Sep.
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