Saha Physics and Radiobiology of Nuclear Medicine

3rd Auflage 2006
ISBN: 978-0-387-36281-6
Verlag: Springer US
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 320 Seiten, Web PDF

Reihe: Medicine

From a distinguished author comes this new edition for technologists, practitioners, residents, and students in radiology and nuclear medicine. Encompassing major topics in nuclear medicine from the basic physics of radioactive decay to instrumentation and radiobiology, it is an ideal review for Board and Registry examinations. The material is well organized, simplified, and written with clarity that makes the text very easy to comprehend. This third edition has been thoroughly updated and expanded, prompted by the success of the second edition. Supplemented with tables and illustrations throughout the book, each chapter provides the reader with well-delineated descriptions of the different aspects of physics and radiation biology related to nuclear medicine. It provides a quick reference book that is concise but comprehensive, and offers a complete discussion of topics for the nuclear medicine and radiology physician in training.

Zielgruppe

Professional/practitioner

Autoren/Hrsg.

Saha, Gopal B.

Inhaltsverzeichnis

Structure of Matter.- Radioactive Decay.- Kinetics of Radioactive Decay.- Statistics of Radiation Counting.- Production of Radionuclides.- Interaction of Radiation with Matter.- Gas-Filled Detectors.- Scintillation and Semiconductor Detectors.- Gamma Cameras.- Performance Parameters of Gamma Cameras.- Digital Computers in Nuclear Medicine.- Single Photon Emission Computed Tomography.- Positron Emission Tomography.- Internal Radiation Dosimetry.- Radiation Biology.- Radiation Regulations and Protection.

Leseproben

"6 Interaction of Radiation with Matter (p. 56)

All particulate and electromagnetic radiations can interact with the atoms of an absorber during their passage through it, producing ionization and excitation of the absorber atoms. These radiations are called ionizing radiations. Because particulate radiations have mass and electromagnetic radiations do not, the latter travel through matter longer distance before losing all energy than the former of the same energy. Electromagnetic radiations are therefore called penetrating radiations and particulate radiations nonpenetrating radiations.The mechanisms of interaction with matter, however, differ for the two types of radiation, and therefore they are discussed separately.

Interaction of Charged Particles with Matter

The energetic charged particles such as a-particles, protons, deuterons, and b-particles (electrons) interact with the absorber atoms, while passing through it.The interaction occurs primarily with the orbital electrons of the atoms and rarely with the nucleus. During the interaction, both ionization and excitation as well as the breakdown of the molecule may occur. In excitation, the charged particle transfers all or part of its energy to the orbital electrons, raising them to higher energy shells. In ionization, the energy transfer may be suf?cient to overcome the binding energy of the orbital electrons, ultimately ejecting them from the atom.

Electrons ejected from the atoms by the incident charged particles are called primary electrons, which may have suf?cient kinetic energy to produce further excitation or ionization in the absorber. The high-energy secondary electrons from secondary ionizations are referred to as delta (d-) rays. The process of excitation and ionization will continue until the incident particle and all electrons come to rest. Both these processes may rupture chemical bonds in the molecules of the absorber, forming various chemical entities. In ionization, an average energy of W is required to produce an ion pair in the absorber and varies somewhat with the type of absorber.

The value of W is about 35 eV in air and less in oxygen and xenon gases but falls in the range of 25–45 eV for most gases. The process of ionization, that is, the formation of ion pairs, is often used as a means of the detection of charged particles in ion chambers and Geiger–Müller counters described in Chapter 7. Three important quantities associated with the passage of charged particles through matter are speci?c ionization, linear energy transfer, and range of the particle in the absorber, and these are described next."