LAB 3: RADIATION: EVERYDAY APPLICATIONS IN LIFE The purposes of this lab session are for you to develop competencies in (1) the basic physical principles of radiation, and (2) the applications of radiation within the medical field. PRE-CLASS ASSIGNMENT BEFORE coming to class, you need to read this document L03 DOCU in its entirety. In addition, you should read pages 437- 443 (up to GENERAL PRINCIPLES FOR MINIMIZING RADIATION RISK IN MEDICAL USE) of the accompanying document entitled L03 DOCU2. Some of the material will be common to both documents, and some will be unique to each document. You need to print the worksheet for Lab #3 (L03 WORK) to work on during the lab section. At the beginning of class, you will need to take the quiz for Lab #3 and turn it in. To prepare for the quiz, you should be familiar with what radiation is, the different kinds of radiation, and the meaning of various radiation-related terms such as alpha, beta, gamma, x-ray, electromagnetic, ionizing, and non-ionizing. You should be aware of natural sources of radiation (e.g. sun, radon), and biological risks such as cell death and dna mutations. Last of all, understand the biological basis of the two doses measured in units of Gray (Gy) and Sievert (Sv). In particle, look at the brief topic “How do we quantify radiation?” on page 442 of L03 DOCU2 and a similar discussion towards the bottom of page 3 of L03 DOCU. You also need to turn in your lab report for Lab #2 at the beginning of class. What is radiation? Radiation is a form of energy that is emitted or transmitted in the form of rays, electromagnetic waves, and/or particles. The radiation is emitted from an unstable nucleus , which is referred to as radioactive. Not all nuclei are unstable and radioactive. An element may have some isotopes which are radioactive and some which are not. In some cases, radiation can be seen (visible light) or felt (infrared radiation), while other forms like x- rays and gamma rays are not visible and can only be observed directly or indirectly with special equipment. Although radiation can have negative effects both on biological and mechanical systems, it can also be carefully used to learn more about each of those systems. The motion of electrically charged particles produces electromagnetic waves. These waves are also called “electromagnetic radiation” because they radiate from the electrically charged particles. They travel through empty space as well as through air and other substances. Scientists have observed that electromagnetic radiation has a dual “personality.” Besides acting like waves, it acts like a stream of particles (called photons) that has no mass. The photons with the highest energy correspond to the shortest wavelengths and vice versa. The full range of wavelengths (and photon energies) is called the electromagnetic spectrum. The shorter the wavelength, the more energetic the radiation and the greater the potential for biological harm (Figure 1).
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- Spring '13
- Radiation, Ionizing radiation, Radiation Therapy Exposure