Physics
Radionuclide Imaging and Therapy
Radionuclide imaging involves the use of radioactive substances to create images of the body's internal structures and functions. It is commonly used in medical diagnostics to detect diseases and monitor treatment effectiveness. Radionuclide therapy, on the other hand, uses radioactive substances to treat certain medical conditions, such as cancer, by targeting and destroying specific cells within the body.
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11 Key excerpts on "Radionuclide Imaging and Therapy"
eBook - ePubPractical Radiotherapy
Physics and Equipment
- Pam Cherry, Angela M. Duxbury, Pam Cherry, Angela M. Duxbury(Authors)
- 2019(Publication Date)
- Wiley-Blackwell(Publisher)
CHAPTER 13 The Use of Radionuclides in Molecular Imaging and Molecular RadiotherapyPaul Shepherd OBE and Terri GilleeceAim
The aim of this chapter is to introduce the fundamental principles and practice of the use of radionuclides in molecular imaging and molecular radiotherapy.13.1 Introduction
Radionuclides play a dual function in the management of cancer. Radionuclide imaging is used for the diagnosis, staging, and monitoring of cancer, and in radiotherapy or brachytherapy radionuclides have been at the forefront of cancer treatment for decades. A good example is the use of radioactive iodine in both the imaging and the treatment of thyroid cancers.A therapeutic radiographer is required to have an understanding of the physical principles underpinning and the potential hazards associated with the use of radionuclides in imaging and radiotherapy practice. Radionuclides are localised to the desired tissue by being chemically attached to, or incorporated into, a compound that is designed to follow a known biodistribution in the body. There are a number of different mechanisms by which this is achieved. The radionuclide and compound together is known as the radiopharmaceutical (RP ). By introducing RPs into the body that follow specific physiological pathways whilst emitting radiation, it is possible to detect and map penetrating radiation from outside the body to produce images or to use non‐penetrating radiation for therapy. In therapeutic applications the activities administered are much higher than for imaging. In recent years, methodologies have been developed specifically for tumour imaging (molecular imaging) and the targeting of tumours with radionuclides or molecular radiotherapy (MRT
eBook - PDF- Walter D. Loveland, David J. Morrissey, Glenn T. Seaborg(Authors)
- 2017(Publication Date)
- Wiley(Publisher)
93 4 Nuclear Medicine 4.1 Introduction The most rapidly expanding area of radionuclide use is in nuclear medicine. Nuclear medicine deals with the use of radiation and radioactivity to diagnose and treat disease. The two principal areas of endeavor, diagnosis and ther- apy, involve different methods and considerations for radioactivity use. (As an aside, we note that radiolabeled drugs that are given to patients are called radiopharmaceuticals.) Recent work in this area has focused on developing combinations of two isotopes in one delivery system: one isotope provides a therapy function and another isotope provides a diagnostic function, called theranostics. In diagnosis (imaging) emitted radiation from injected radionuclides is detected by special detectors (cameras) to give images of the body. A list of radionuclides commonly used in diagnosis is shown in Tables 4.1 and 4.2. At present, most nuclear medicine procedures (>90%) use either 99 Tc m or one of the iodine isotopes. Most diagnostic use of radionuclides is for imaging of specific organs, bones, or tissue. Typical administered quantities of radionu- clides are 1–30mCi for adults. Nuclides used for imaging should emit photons with an energy between 100 and 200 keV, which have small decay branches for particle emission (to minimize radiation damage) and have a half-life that is ∼1.5 times the duration of the test procedure and be inexpensive and readily available. 99 Tc m is used in more than 80% of nuclear medicine imaging because its 143 keV γ-rays produce excellent images with today’s gamma cameras, and it has a convenient 6 h half-life. In therapy, radionuclides are injected into the body and concentrated in the organ of choice and damage the tissue. Nuclear medicine combines nuclear and radiochemistry, pharmacy, medicine, and radiation biology in a challenging and satisfying career.
eBook - PDFNuclear Physics 2
Radiochronometers and Radiopharmaceuticals
- Ibrahima Sakho(Author)
- 2024(Publication Date)
- Wiley-ISTE(Publisher)
Once administered to a patient, the labeled substance becomes a radiotracer that travels to a biological tissue or organ that it selectively recognizes. The substrate (organic or biological carrier) to which the radioactive isotope is grafted is designed to promote a concentration of this isotope on the targeted tissue or organ. The radioactivity induced by the isotope is then either used to visualize its location (diagnosis), or to initiate damage to surrounding cells (therapy). The choice of a radioactive isotope (based on the nature of the radiation emitted, its physical properties (energy and half-life) and its chemical properties) will define the use of this molecule, known as a radiopharmaceutical [ZIM 06]. There are two major areas of application for nuclear medicine: – In vivo functional imaging. This type of imaging involves administering a radiotracer to the patient, enabling it to be detected externally. In this field, we use General Information on Radiopharmaceuticals Used in Nuclear Medicine Imaging 137 scintigraphies based on the emission of gamma rays or tomographies based on the emission of positrons. – Radiation therapy. In this field, X-rays or gamma photons are used to destroy cancer cells by breaking down their DNA. There are two types of this type of therapy: External radiation therapy and internal radiation therapy. External radiotherapy consists of directing ionizing radiation in high doses, 20–80 grays (Gy), depending on the tumor and organ, through the skin and tissues to destroy the tumor while sparing the surrounding healthy cells [INS 19]. Metabolic radiotherapy or internal vectorized radiotherapy treats benign (not serious) or malignant (serious) diseases. The radioactive isotope used is administered orally or by injection, and binds preferentially to the targeted diseased cells.
- Angela Newing(Author)
- 1999(Publication Date)
- ICP(Publisher)
Chapter 5 NUCLEAR MEDICINE Nuclear medicine covers the medical uses of radioactive isotopes primarily for diagnostic purposes but also, in a few instances, for therapy. For diagnosis, the aim is to be able to make a clinical diagnosis while giving the least practicable radiation dose to the patient. Diagnostic procedures can be divided into four general categories which depend upon either, localisation, dilution, diffusion (or flow), or biochemical and metabolic properties. Diagnostic radiology and nuclear medicine are complementary techniques. In general, diagnostic X-rays show body structure whereas isotope studies show function. Diagnostic nuclear medicine relies upon the use of artificially produced isotopes with short half lives in order that patient dose is minimised, and that repeat investigations are possible. The production of such isotopes, although not the very short lived ones used today, began in 1932 when the British physicists J. D. Cockroft and E. T. S. Walton built a high voltage particle accelerator capable of producing protons with sufficient energy to cause nuclear transformations. In the first Cockroft-Walton experiments, lithium nuclei, containing three protons, were bombarded with protons. Those nuclei which captured a fourth proton from the beam were transformed into beryllium nuclei which themselves split into two helium nuclei (alpha particles). Rutherford's classic experiments at the Cavendish Laboratory, Cambridge, in 1919, had established that alpha particles were capable of transforming one element into another. He used radium alpha particles to convert stable nitrogen into radioactive oxygen-15 which has a half life of two minutes. Shortly after the Cockroft-Walton accelerator was built, E. 0. Lawrence at the University of California in America, developed a circular accelerator called the cyclotron. This used a magnetic field combined with a rapidly oscillating voltage to accelerate nuclear particles along a spiral path, thus 125
eBook - PDF- Shan Xiang Wang, Adam de la Zerda(Authors)
- 2022(Publication Date)
- Wiley(Publisher)
Biochips and Medical Imaging, First Edition. Adam de la Zerda and Shan Xiang Wang. © 2022 John Wiley & Sons, Inc. Published 2022 by John Wiley & Sons, Inc. 295 14.1 Radioactivity A radionuclide is an atom with an unstable nucleus, which has excess energy that can be trans- ferred to either a newly created radiation particle or an electron. During this process of radioactive decay, the radionuclide also emits gamma rays and/or subatomic particles. Radionuclide imaging, or nuclear imaging, uses radionuclides and their radioactive decay to produce images of tissues (Figure 14.1), using either positron emission tomography (PET) or single photon emission computed tomography (SPECT). Unlike MRI, for which the body naturally produces a good signal without administration of an external contrast agent, nuclear imaging requires the injection of contrast agents or imaging agents since the body naturally is not radioactive enough to produce a detectable and specific signal. 14.1.1 Gamma Decay An atom or atom within a molecule that is in an unstable state (i.e. a radionuclide) can undergo three different types of radioactive decay: alpha, beta, or gamma. Beta and gamma decay are appli- cable for nuclear imaging. During gamma decay (Figure 14.2), nucleons rearrange themselves to a less energetic, more stable configuration, giving off electromagnetic energy in the form of high- energy (i.e. very short wavelength) gamma photons. For gamma imaging, a metastable parent atom is required, i.e. the atomic number (number of protons) Z does not change during decay: A z A z X X , where X is an atom, A is the mass number (number of neutrons and protons), and Z is the atomic number (number of protons). When a metastable atom undergoes gamma decay, the mass number (i.e. total number of protons and neutrons) does not change, but one electron moves from one shell to another, and thus emits high-energy gamma rays on the order of several keV.
- Rachel A. Powsner, Matthew R. Palmer, Edward R. Powsner(Authors)
- 2021(Publication Date)
- Wiley-Blackwell(Publisher)
239 Essentials of Nuclear Medicine Physics, Instrumentation, and Radiation Biology , Fourth Edition. Rachel A. Powsner, Matthew R. Palmer, and Edward R. Powsner. © 2022 John Wiley & Sons Ltd. Published 2022 by John Wiley & Sons Ltd. CHAPTER 18 This chapter is divided into two parts. The first part is a review of several common therapeutic radiophar‑ maceuticals and their biological mechanism of uptake. The second part reviews radiation protection practices for handling and administering these radiopharmaceuticals. Introduction Radiopharmaceuticals are compounds composed of biologically active radioisotopes bound to another ion, or radioisotopes bound by a linker molecule to a carrier molecule that has high affin‑ ity for a special target or function in an organ or tissue (Figure 18.1). If the radioisotope emits gamma rays, X‐rays, or positrons it is diagnostic; if it emits alpha or beta par‑ ticles it is therapeutic. Some radiopharmaceuticals can be both diagnostic and therapeutic. Paired diagnostic and therapeutic radiopharmaceuticals Most therapeutic radiopharmaceuticals are “paired” with a diagnostic radiopharmaceutical. This diag‑ nostic agent is used to characterize the target tissue or organ, predict the uptake and estimate the dosim‑ etry of its therapeutic counterpart prior to treatment. Several therapeutic and diagnostic radiopharma‑ ceuticals pairs are not structurally identical, but have similar or identical biologic uptake in an organ. Examples are 223 Ra‐dichloride (therapeutic) and 99m Tc‐phosphonate compounds (diagnostic). Another example is 90 Y‐microspheres (therapeutic) and 99m Tc‐ macroaggregated albumin ( 99m Tc‐MAA—diagnostic). When a thera peutic radiopharmaceutical and a diag nostic radiopharmaceutical are identical except for their radioisotopes, they are called theranostic .
eBook - PDFReviews Of Accelerator Science And Technology - Volume 2: Medical Applications Of Accelerators
Volume 2: Medical Applications of Accelerators
- Alexander Wu Chao, Weiren Chou(Authors)
- 2009(Publication Date)
- World Scientific(Publisher)
The advent of clinical PET for cancer diagnosis makes use of sophisticated tracers to unravel cancer biology. 4.2. Radionuclides for imaging Nuclear medicine imaging differs from other types of radiological imaging, in that the radiotracers used in nuclear medicine map out the function of an organ system or metabolic pathway and, thus, imaging the concentration of these agents in the body can reveal the integrity of these systems or pathways. This is the basis for the unique infor-mation that a nuclear medicine scan (described in Table 3) provides with various scanning proce-dures for the various organ/functional systems of the body. Table 3. Typical radioisotopes and their uses for imaging. Radioisotope Half-life Uses Technetium-99m 6 h derived from 99 Mo parent 66 h Used to image the skeleton and heart muscle, in particular; but also for the brain, thyroid, lungs (perfusion and ventilation), liver, spleen, kidneys (structure and filtration rate), gall bladder, bone marrow, salivary and lachrymal glands, heart blood pool, infection and numerous specialist medical studies. Cobalt-57 272 d Used as a marker to estimate organ size and for in vitro diagnostic kits. Gallium-67 78 h Used for tumor imaging and localization of inflammatory lesions (infections). Indium-111 67 h Used for specialist diagnostic studies, e.g. brain, infection, and colon transit studies. Iodine-123 13 h Increasingly used for diagnosis of thyroid function, it is a gamma emitter without the beta radiation of 131 I. Krypton-81m 13 s from 81 Rb 4.6 h 81m Kr gas can yield functional images of pulmonary ventilation, e.g. in asthmatic patients, and for the early diagnosis of lung diseases and function. Rubidium-82 65 h Convenient PET agent for myocardial perfusion imaging. Strontium-92 25 d Used as the “parent” in a generator to produce 82 Rb. Thallium-201 73 h Used for diagnosis of coronary artery disease and other heart conditions, such as heart muscle death and for location of low-grade lymphomas.
eBook - PDF- David Dowsett, Patrick A Kenny, R Eugene Johnston(Authors)
- 2006(Publication Date)
- CRC Press(Publisher)
16 Nuclear medicine: radiopharmaceuticals and imaging equipment Clinical nuclides and radiopharmaceuticals 469 Dosimetry 472 Planar imaging 478 Single photon emission tomography 483 Positron emission tomography 490 Comparison of other tomographic techniques 505 Further reading 506 Keywords 506 16.1 CLINICAL NUCLIDES AND RADIOPHARMACEUTICALS The parallel development of instrumentation and the chemistry of clinically useful isotopes has maintained nuclear medicine as a premier diagnostic imaging service. The distribution of labeled radiopharmaceu-ticals in the body allows imaging of organ function since these chemical substances are actively accumu-lated (e.g. MDP bone agents, liver colloid) or excreted (e.g. DTPA, EHIDA) by the target organ. Although several radionuclides are available for nuclear medicine the predominant one is 99m Tc; it complies with most of the requirements for an ideal clinical isotope. It is produced by a generator, which can be kept in the nuclear medicine radiopharmacy, and renewed at weekly intervals. It is immediately available, thereby allowing a nuclear medicine clinic to offer a continuous service. 16.1.1 99m Tc generator specifications Basic information on generator construction was given earlier in Chapter 15, Section 15.4.4. The tech-netium generator used for routine nuclear medicine purposes is commonly eluted each morning; Fig. 16.1 shows the decreasing activity of available 99m Tc A in equilibrium with 99 Mo and eluted 99m Tc over a 3 day period (curves B and C). Partial elution of the generator gives high activity in a small volume, which is useful for efficient label-ing of small samples (white cells and complex mole-cules). Specific concentration for small volumes is plotted in Fig.
eBook - PDF- Aamir Shahzad, Sajid Bashir, Aamir Shahzad, Sajid Bashir(Authors)
- 2019(Publication Date)
- IntechOpen(Publisher)
It is fundamental to remember that medicinal imaging thinks are performed to influence quiet care. Thus, a medicinal imaging methodology performed at bring down measurement is just “sensible” on the off chance that it answers the clinical inquiry. As such, a lower dosage 86 Nuclear Medicine Physics methodology that is lacking to answer the clinical inquiry conveys radiation dosage to the patient without the imperative advantage and is generally “not sensible.” The procedure of self-appraisal must be bolstered by a high level institutional responsibility regarding quality restorative imaging and the fitting conveyance of radiation measurement to patients expected to help the clinical administration of every patient. The institutional responsibility must incor-porate allotment of the fundamental assets to fulfill these assignments. Fundamental assets incorporate time for staff to commit to the procedure, and time on imaging frameworks to test potential measurement decreases strategies, where required. Budgetary designations may be expected to pay for administrations are not performed by staff or for substitution clinical scope while staff individuals commit time to the self-assessment. 1.6. Nuclear medicine Atomic drug is a branch of medicinal imaging that utilizations radiopharmaceuticals to look at the capacity and structure of organs and tissue capacity and structure. A radiopharmaceutical is the most part comprised of two sections: a pharmaceutical that objective a particular organ or tissue and a radioactive material (radionuclide) that emits little measures of radiation. 1.7. Nuclear medicine procedures Name of NM procedures are HIDA scan, Bone scan, DTPA renal scan, cardiac rest scan, car -diac stress scan, parathyroid scan, thyroid scan, DMSA and GI bleeding, etc. 1.8. Nuclear medicine scans 1.8.1. Bone scan Bone scan is also known as skeleton scan, is an imaging test. To diagnose the problem in bones, it uses very small amount of radioactive material.
eBook - PDFRadioisotopes
Applications in Bio-Medical Science
- Nirmal Singh(Author)
- 2011(Publication Date)
- IntechOpen(Publisher)
External radiation therapy delivers high-energy x-rays or electron or proton beams to a tumor from outside the body, often under imaging guidance. Internal radiation therapy (also called brachytherapy) places radiation sources within or near the tumor using minimally invasive procedures. Systemic radiation therapy delivers soluble radioactive substances, either by ingestion, catheter infusion, or intravenous administration of tumor-targeting carriers, such as antibodies or biocompatible materials, which carry selected radioisotopes. Although systemic radiation offers desirable advantages of improved efficacy as well as potentially reducing radiation dosage and side effects, in vivo delivery of radioisotopes with tumor targeted specificity needs to address many challenges that include: (i) the selection of radioisotopes with a proper half life; (ii) a delivery vehicle that can carry an optimal amount of radioisotopes and has favorable pharmacokinetics; (iii) suitable tumor biomarkers that can be used to direct the delivery vehicle into cancer cells; and (iv) specific tumor targeting ligands that are inexpensive to produce and can be readily conjugated to the delivery vehicles. In addition, a multifunctional carrier that not only delivers radioisotopes but also provides imaging capability for tracking and quantifying radioisotopes that have accumulated in the tumor is highly desirable. 2 Radioisotopes – Applications in Bio-Medical Science 226 Recent advances in nanotechnology have led to the development of novel nanomaterials and integrated nanodevices for cancer detection and screening, in vivo molecular and cellular imaging, 3 and the delivery of therapeutics such as cancer cell killing radio-isotopes. 4,5 An increasing number of studies have shown that the selective delivery of therapeutic agents into a tumor mass using nanoparticle platforms may improve the bioavailability of cytotoxic agents and minimize toxicity to normal tissues.
eBook - PDF- Paul G. Abrams, Alan R. Fritzberg(Authors)
- 2000(Publication Date)
- CRC Press(Publisher)
3 Metallic Radionuclides for Radioimmunotherapy Alan R. Fritzberg NeoRx Corporation, Seattle, Washington Claude F. Meares University of California, Davis, California I. INTRODUCTION Many elements have radioisotopes of radiotherapeutic potential. Based on consid- erations of type of emission, energy, half-life, production capability, and cost, a significant number have been evaluated for application to radioimmunotherapy. A listing of various of these radionuclides is provided in Table 1, adapted from Fritzberg and Wessels (1). As can be easily seen, the majority of the radionuclides that have been of interest are metals and a great deal of work has been carried out to stably attach them to antibody proteins in ways that do not interfere with the tumor targeting of the antibody. This chapter will describe the various ap- proaches used for the attachment of metals to antibodies, evaluations in vitro and in vivo, and a perspective on current status of metallic radionuclides in radiother- apy. As space and time limitations preclude an exhaustive review of all studies of therapeutic radionuclides, the chapter will focus on those that are representa- tive and have had significant developmental effort applied to them. Several re- views are available that describe properties and production of therapeutic radio- nuclides, and they are recommended for more details (2–4). Metal chemistry is organized by groups as related to their properties of oxidation levels, bonding characteristics, and size. The review will describe radio- nuclides as groups that are chemically related. Thus, yttrium-90 will be discussed in a section with other related radionuclides including lutetium-177, and imaging 57
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