Diploma in Applied Science(Forensic Science)UNIT 20 MEDICAL PHYSICS TECHNIQUES
Diploma in Applied Science (Forensic Science)Unit 20 Medical physics techniquesAims and purposeThe aim of this unit is to enable learners to develop, through a practical vocational skillsapproach, an understanding of the important fundamental physics concepts behind medicalphysics techniques such as x-rays, ultrasounds, diagnostic imaging and magnetic resonanceimaging (MRI) and radiotherapy. Learners will also understand the importance of radiationsafety.Unit introductionDiagnostic medicine has come a long way since the time when the best diagnosis occurredduring the postmortem examination. Surgery today is faster, less invasive and more effectivethan ever – thanks in part to improvements in medical imaging technology. Imaging gives thedoctor a clearer understanding of the patient’s condition so treatment can be planned moreeffectively and therapy delivered more precisely.Nuclear medicine is providing hope for the cure of the most serious diseases, especiallycancer. Radioactive materials are used in this rapidly developing branch of medicine. At thecutting edge of developments in nuclear medicine is the precise targeting needed to get theradiation to the exact site of the cancer.Future prospects are even more exciting. Medical imaging is extending human vision into thevery nature of disease; at the cellular level it will permit diagnosis before symptoms evenappear. Surgery in the future will be bloodless, painless and non-invasive. It will be poweredby medical imaging systems that focus on the disease and use energy to destroy the targetbut preserve healthy tissue. Researchers are testing the use of high intensity ultrasound todestroy tumours identified and targeted while the patient lies in an MRI scanner.This unit introduces learners to some of the established practices in medical physics imaging.It aims to deliver the underpinning knowledge of several of the fundamental techniques andprovide a basic introduction to the more complicated theory of magnetic resonance imaging.Learning outcomesOn completion of this unit a learner should: 1. Know atomic structure and the physical principles of ionising radiation and ultrasound 2. Understand how radiopharmaceuticals are used in diagnostic imaging 3. Know the basic principles of magnetic resonance imaging 4. Understand the importance of radiation safety to the treatment of malignant disease with radiotherapy.
Diploma in Applied Science (Forensic Science)Task 1: Radiation and radioactivityYour work as a junior technician in the radiography section of a large hospital involvesworking closely with other highly qualified personnel, talking to patients undergoingradiotherapy and periods of personal study. You must show that you have a clearunderstanding of the terms used and an understanding of the basic science principlesinvolved in your department.P1 Describe radioactivity, including atomic structureP2 Describe the production of x-rays and ultrasoundM1 Explain the random nature of decay and how it relates to half-lifeD1 Analyse the effects of the operation and design of the tube/head on a typical x-rayspectrumYou need to complete the following task • Draw sequences which show what happens to radioactive elements when they lose: an alpha particle; a beta particle. What happens to an atom when gamma rays are emitted? P1 • Draw a fully labeled diagram demonstrating the principles of: an X-ray tube; production of ultrasound P2 • Using graph paper, show a decay curve and mark on: the axis showing the fraction of undecayed nuclei remaining, the axis showing time, half-life intervals, fractions of original number of undecayed nuclei remaining M1 • Use a suitable diagram to analyse what happens to the x-ray spectrum when the tube voltage is changed. Show some known x-ray peaks in your diagram. What do these peaks tell you. D1Grading tipsInclude labels of protons and neutrons in your answer and at least two element sequences foreach decay to achieve P1. To achieve M1 you could add a simple demonstration set ofresults using dice to illustrate the random aspect.Deadline:________28th January 2011________
Task 2: Radiopharmaceuticals and their usesAs a recent addition to the technical and nursing staff of a large city hospital, you must showthat you are familiar with the radiopharmaceuticals used and the way in which they aredetected within the body of a patient.P3 Describe the production and detection of radiopharmaceuticalsP4 Explain the role of pharmaceuticals within the operating principles of the gamma cameraM2 Compare the desirable biological properties and radiological properties of radionuclidesused for imagingD2 Evaluate the choice of radiopharmaceuticals for a range of clinical imaging requirementsYou need to complete the following task: • Make a list of the most common radiopharmaceuticals used in medicine, describe how they are produced and briefly describe what happens when these substances enter the body P3 • Explain how the gamma camera works using a fully labelled diagram P4 • Using your list for P3, provide details of what qualities you are looking for when choosing a suitable radiopharmaceutical. Remember that patients have to inhale or be injected with these substances M2 • Use information in this chapter (pg 374-377 Applied Science Level 3) and your own research to evaluate which radiopharmaceutical are best for a given purpose D2Grading tipsYou should include the formulas for your radiopharmaceuticals in your answer for P3 andwhat the images received by the gamma camera tells us for P4. Additional research isnecessary for M2 and D2, which should provide more information on the choices made bydoctors for particular radiopharmaceuticals in specific parts of the body. Health of the patientis vital and the image produced is very important.Deadline ________4th February 2011_________
Task 3: Investigating MRIYou are called upon to provide an explanation of the procedure of an MRI scan to a patient aspart of your duties as a technician within the radiology department of a major hospital.P5 Outline the process of magnetic reasonance imaging including the instrumentation andequipment usedM3 Explain the factors influencing signal intensity in MRID3 Evaluate the appearance of bone and soft tissue in an MRI scan and a conventional x-rayYou need to complete the following task • Describe how the MRI scanner works in simple terms and list the components with a brief description of each P5 • Provide an explanation of the principles of nuclear magnetic reasonance and how difference factors change the signal intensity M3 • Use a variety of images of the same body parts to evaluate the similarities and differences between x-ray and MR images D3Grading tipsTo achieve P6 your notes taken during the practical should be sufficient as long as they areneat. Work through your maths carefully, keeping track of your units (if any) and prefixes. Getthem checked by friends, or tutors to get P7. To complete M3, a graph may help. Is thechosen statistical method the most appropriate?Deadline _______11th February 2011__________
Task 4: Radiotherapy techniques and their dangersWorking in the x-ray department of a busy hospital means that you will need to attend regularspecific additional training sessions for health and safety as part of your continuedprofessional development.P6 Explain the principles and effects of radiation therapy including the equipment usedM4 Explain how excessive exposure to radiation can cause harmD4 Evaluate a range of therapy techniques, types of radiation available and equipment usedYou need to complete the following task • Provide a slide demonstration explaining the way in which x-rays are used to treat malignant disease. Provide a brief explanation of equipment which may be used P6 • Explain the physical effects of being exposed to a lot of radiation M4 • Evaluate the various types of radiotherapy practices that are currently in use and explain the function of equipment that allows these kinds of treatment D4Grading tips:List the components of the equipment which focus x-rays onto the target with a simpleexplanation of how they work and highlight what can happen to cells during radiotherapy forP6. Link the doses of radiation to the symptoms of radiation exposure and comment onpreventative measures to achieve M4. You will need to include specific radiation types usedfor particular diseases for D4 and the equipment used to produce and target the radiation.Deadline _______18th February__________
Outline of evidence requirementsAssessment Assessment Description Complete Assignment criteria Describe radioactivity, including P1 20.1 atomic structure Describe the production of x-rays P2 20.1 and ultrasound Explain the random nature of decay M1 20.1 and how it relates to half-life Analyse the effects of the operation D1 and design of the tube/head on a 20.1 typical x-ray spectrum Describe the production and P3 20.2 detection of radiopharmaceuticals Explain the role of pharmaceuticals P4 within the operating principles of the 20.2 gamma camera Compare the desirable biological properties and radiological M2 20.2 properties of radionuclides used for imaging Evaluate the choice of D2 radiopharmaceuticals for a range of 20.2 clinical imaging requirements Outline the process of magnetic reasonance imaging including the P5 20.3 instrumentation and equipment used Explain the factors influencing M3 20.3 signal intensity in MRI Evaluate the appearance of bone D3 and soft tissue in an MRI scan and 20.3 a conventional x-ray Explain the principles and effects of P6 radiation therapy including the 20.4 equipment used Explain how excessive exposure to M4 20.4 radiation can cause harm Evaluate a range of therapy D4 techniques, types of radiation 20.4 available and equipment used