1. P4: Radiation for Life Lesson 13: Treatment (part 1)

2. Starter Electromagnetic Spectrum What radiation? Where? 1 2

3. Lesson Objectives Compare the production and properties of X- rays and gamma rays. Understand how radioactive materials are produced for medical uses.

4. Success Criteria Grade EGrade CGrade A Compare the properties of X- rays and gamma rays Understand how an X-ray image is produced Explain how X-rays and gamma rays are produced Recall that medical radioisotopes are produced by placing materials in a nuclear reactor Describe how materials can become radioactive by absorbing extra neutrons Key Words: X-rays gamma absorption wavelength electromagnetic wave exposure half-life diagnosis therapy

5. Nuclear radiation is radiation that emitted from the nucleus of an atom. It is used in medicine for: o Diagnosis (finding out what is wrong) o Therapy (treatment) There are three types of nuclear radiation. α, ,  but gamma radiation is usually used for diagnosis and for therapy because the other two do not penetrate bone. X-rays are also used for diagnosis and therapy and these are made by firing high speed electrons at metal targets. X-rays and gamma rays are both electromagnetic waves that have very short wavelengths. Both are very penetrating and can pass into the body to treat internal organs.

6. What are X-rays? Anyone who has been to hospital with a broken bone will have had an X-ray photograph taken. X-rays have a very short wavelengths between 0.1 and 10 nm. (The size of a water molecule is about 0.3 nm.) ultra- violet infrared X-rays 10 -3 10 -9 10 -6 10 -12 gamma rays wavelength of electromagnetic waves X-rays are a form of electromagnetic radiation that are very penetrating. In the electromagnetic spectrum, they are found between UV and gamma rays.

7. How are X-rays produced? X-rays are created when high-energy electrons suddenly lose energy. X-rays are produced artificially using a X-ray tube. high voltage cathode anode tungsten target X-rays lead shielding Electrons from the hot, negatively charged, cathode are fired at the positively charged tungsten target at high speed. When these high-energy electrons strike the target, some of their kinetic energy is changed into X-rays. Higher

8. What are X-rays used for? Imaging X-rays are very penetrating and can pass through many forms of matter. They are used in medicine, industry and security to take pictures of the inside of objects. Treating cancer Concentrated beams of short wavelength X-rays can be used to kill cancerous cells. Crystallography X-rays are used to work out the arrangement of atoms in various substances, including crystals.

9. What do X-rays do to cells?

10. X-rays – true or false?

11. What are gamma rays? Gamma rays are emitted by certain radioactive materials and have many uses in medicine. ultra- violet infrared X-rays 10 -3 10 -9 10 -6 10 -12 gamma rays wavelength of electromagnetic waves Gamma rays are the highest-energy form of electromagnetic radiation and are beside X-rays in the electromagnetic spectrum. Gamma rays have wavelengths between 0.001 and 0.1 nm (less than the size of an atom), which makes them the form of electromagnetic radiation with the shortest wavelengths.

12. What are gamma rays used for? Medical imaging A gamma scan is obtained by injecting a radioactive tracer, which concentrates in the area of the body being investigated. Gamma rays emitted from this area are detected by a gamma camera. Industrial imaging Gamma rays are even more penetrating than X-rays and can pass through denser materials. They can be used to examine metal castings and welded structures. Sterilizing Gamma rays are used to sterilize medical equipment because they are highly penetrating and kill all living cells.

13. How can gamma rays be used to treat cancer? Radiotherapy is the use of high-energy ionizing radiation, such as gamma rays, to kill cancer cells. The radiation dose may come from a radioactive source in a machine outside the body, which directs a beam of radiation at the cancer cells. Steps to reduce the effects on healthy tissue include: splitting the radiation dose into a number of treatments; rotating the beam of radiation so that healthy cells receive a lower dose than the cancer cells. Healthy cells can also be affected by the radiation applied to the body.

14. X-rays vs Gamma Rays X-rays are produced only when needed An x-ray machine allows the rate of production of the x-rays to be controlled The energy of x-rays can be changed. The higher the tube voltage the higher the energy of the electrons and therefore the higher the energy of the x-rays Some x-rays can have higher energy than some gamma rays. You can’t change the rate of production or energy of the gamma radiation emitted from a particular radioactive source. Higher

15. Plenary Write down 2 facts about X-rays and 2 facts about gamma rays. Explain briefly how X-rays are produced.

16. Success Criteria Grade EGrade CGrade A Compare the properties of X- rays and gamma rays Understand how an X-ray image is produced Explain how X-rays rays are produced Recall that medical radioisotopes are produced by placing materials in a nuclear reactor Describe how materials can become radioactive by absorbing extra neutrons Key Words: X-rays gamma absorption wavelength electromagnetic wave exposure half-life diagnosis therapy