1. Radiation all Around Us Radon gas, cosmic rays, medical x- rays, food and body chemicals

3. I dose = amount of radiation absorbed Measured in grays (Gy) 1 Gy = i joule of radiation energy absorbed by 1kg of body Alpha particles however, do 20x as much damage to cells as same dose of beta, gamma or X-rays Thus talk in dose equivalents measured in Sieverts (Sv), where

4. Dose equivalent = absorbed dose x Q (Sv)(Gy) where Q = 1 for beta, gamma and x-rays 20 for alpha

5. Protection against radiation? How can you reduce your exposure to radiation? Read txtbook pages196- 197 answer questions 1-5

6. Radiotherapy Treatment of cancer with high energy ionising radiation Cancer is the uncontrollable division of cells, forming a tumour Benign – does not destroy surrounding tissues or spread to other organs Malignant – destroys surrounding tissue; cells often break away and spread to other sites; referred to as cancer

7. How does radiotherapy work? Gamma rays, electrons or a beam of high energy X-rays Electrons often used externally – do not penetrate well X-rays have higher energy and penetrate tissues more easily and travel further. Used to treat tumours inside body Can be use on own, or in conjunction with surgery and chemotherapy

8. Normal cells also damaged but they quickly recover Cancer cells are dividing quickly, however and radiation will damage cells beyond repair when they are in mitosis Radiation beams carefully focussed on area to be treated Healthy tissue receives minimum of radiation Curative or Palliative Lesson 5 Radiation\An insight into Radiotherapy.avi Lesson 5 Radiation\An insight into Radiotherapy.avi Read txtbk pages 198- 199 answer questions 1-6

9. Alternatives to radiotherapy? Boron Neutron Capture Therapy (BNCT) Reserach and produce a summary of the basic principles of BNCT. What is its current status as a cancer therapy To be completed for HW