Radiation Health Physics

What is Radiation Health Physics Radiation Health Physics (RHP) is an interdisciplinary study of the physical aspects of radiation. Health physicists control the beneficial uses of radiation while protecting people and the environment from potential hazards. Professional Health Physicist may:

Measure radioactivity in water, soil, and air Design radiation detection equipment Calculate effective doses of radiation for cancer patients Provide radiation protection training and advice Recommend strategies for environmental cleanup

Radiation 1- The act or process of radiating: the radiation of heat and light from a fire. 2- Physics. Emission and propagation and emission of energy in the form of rays or waves. Energy radiated or transmitted as rays, waves, in the form of particles. A stream of particles or electromagnetic waves emitted by the atoms and molecules of a radioactive substance as a result of nuclear decay. 3- a-The act of exposing or the condition of being exposed to such energy. b-The application of such energy, as in medical treatment. 4- Anatomy. Radial arrangement of parts, as of a group of nerve fibers connecting different areas of the brain. 5 a-The spread of a group of organisms into new habitats. b-Adaptive radiation.

Definition Radiation and radioisotopes are extensively used medications to allow physicians to image internal structures and processes in vivo (in the living body) with a minimum of invasion to the patient. Higher doses of radiation are also used as means to kill cancerous cells. Radiation is actually a term that includes a variety of different physical phenomena. However, in essence, all these phenomena can be divided into two classes: phenomena connected with nuclear radioactive processes are one class, the so-called radioactive radiation (RR); electromagnetic radiation (EMR) may be considered as the second class. Both classes of radiation are used in diagnoses and treatment of neurological disorders.

Description There are three kinds of radiation useful to medical personnel: alpha, beta, and gamma radiation. Alpha radiation is a flow of alpha particles, beta radiation is a flow of electrons, and gamma radiation is electromagnetic radiation. Radioisotopes, containing unstable combinations of protons and neutrons, are created by neutron activation. This involves the capture of a neutron by the nucleus of an atom, resulting in an excess of neutrons (neutron rich). Proton-rich radioisotopes are manufactured in cyclotrons. During radioactive decay, the nucleus of a radioisotope seeks energetic stability by emitting particles (alpha, beta, or positron) and photons (including gamma rays).

Radiation—produced by radioisotopes—allows accurate imaging of internal organs and structures. Radioactive tracers are formed from the bonding of short-lived radioisotopes with chemical compounds that, when in the body, allow the targeting of specific body regions or physiologic processes. Emitted gamma rays (photons) can be detected by gamma cameras and computer enhancement of the resulting images and allows quick and relatively noninvasive (compared to surgery) assessments of trauma or physiological impairments.

Because the density of tissues is unequal, x rays (a high frequency and energetic form of electromagnetic radiation) pass through tissues in an unequal manner. The beam passed through the body layer is recorded on special film to produce an image of internal structures. However, conventional x rays produce only a two-dimensional picture of the body structure under investigation.

Tomography (from the Greek tomos, meaning "to slice") is a method developed to allow the detailed construction of images of the target object. Initially using the x rays to scan layers of the area in question, with computer assisted tomography a computer then analyzes data of all layers to construct a 3D image of the object.

Electromagnetic radiation In contrast to imaging produced through the emission and collection of nuclear radiation (e.g., x rays, CT scans), magnetic resonance imaging (MRI) scanners rely on the emission and detection of electromagnetic radiation. and detection of electromagnetic radiation. Electromagnetic radiation results from oscillations of components of electric and magnetic fields. In the simplest cases, these oscillations occur with definite frequency (the unit of frequency measurement is 1 Hertz (Hz), which is one oscillation per second). Arising in some point (under the action of the radiation source), electromagnetic radiation travels with the velocity that is equal to the velocity of the light, and this velocity is equal for all frequencies.

Another quantity, wavelength, is often used for the description of electromagnetic radiation (this quantity is similar to the distance between two neighbor crests of waves spreading on a water surface, which appear after dropping a stone on the surface). Because the product of the wavelength and frequency must equal the velocity of light, the greater the wave frequency, the less its wavelength.

Magnetic resonance Imaging MRI MRI scanners rely on the principles of atomic nuclear-spin resonance. Using strong magnetic fields and radio waves, MRIs collect and correlate deflections caused by atoms into images. MRIs allow physicians to see internal structures with great detail and also allow earlier and more accurate diagnosis of disorders.

MRI technology was developed from nuclear magnetic resonance (NMR) technology. Groups of nuclei brought into resonance, that is, nuclei absorbing and emitting photons of similar electromagnetic radiation such as radio waves, make subtle yet distinguishable changes when the resonance is forced to change by altering the energy of impacting photons. The speed and extent of the resonance changes permit a non-destructive (because of the use of low-energy photons) determination of anatomical structures.

MRI images do not utilize potentially harmful ionizing radiation generated by three-dimensional x-ray CT scans, but rely on the atomic properties (nuclear resonance) of protons in tissues when they are scanned with radio frequency radiation. The protons in the tissues, which resonate at slightly different frequencies, produce a signal that a computer uses to tell one tissue from another. MRI provides detailed three-dimensional soft tissue images. These methods are used successfully for brain investigations.