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RADIATION PROTECTION IN RADIOTHERAPY. IAEA Training Material on Radiation Protection in Radiotherapy. Part 12: Quality Assurance PRACTICAL EXERCISE. IAEA Post Graduate Educational Course Radiation Protection and Safe Use of Radiation Sources. Objectives.
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RADIATION PROTECTION IN RADIOTHERAPY IAEA Training Material on Radiation Protection in Radiotherapy Part 12: Quality Assurance PRACTICAL EXERCISE IAEA Post Graduate Educational Course Radiation Protection and Safe Use of Radiation Sources
Objectives • To be familiar with the concepts of Quality Assurance as a multidisciplinary activity and its interrelation with radiation protection in radiotherapy. • To be familiar with Quality Assurance procedures as a tool for reviewing and assessing the overall effectiveness of a radiation protection program. • To be able to understand the need for and role of specific tests in the context of quality control and be able to identify appropriate national and international protocols for this task • To be aware of the need for involvement of professionals in a quality assurance program and for radiation protection Part 12, Practical 1
Part 12: Quality Assurance IAEA Training Material on Radiation Protection in Radiotherapy Practical 1: Develop a Weekly QC Check List for an isocentric external beam irradiation device in the participant’s environment IAEA Post Graduate Educational Course Radiation Protection and Safe Use of Radiation Sources
Why weekly? • Different frequencies may be possible and AAPM Task Group 40 recommends chiefly daily and monthly tests • Weekly checks are typically easy to schedule (e.g. each Friday at 4pm) • It is dependent on the user’s circumstances as to how often tests are performed Part 12, Practical 1
Contents + Objective • Learn how to determine necessary checks and prioritize them • Understand how to design appropriate tests for a particular parameter • Develop a sheet which may be useful at the home institution Part 12, Practical 1
What Minimum Equipment is Needed? • Paper • If checks are also to be performed in practice: • Radiographic film • Pointers • Graph paper Part 12, Practical 1
How to start? • Think of three groups to test: • Mechanical/optical • Dosimetry • Safety Part 12, Practical 1
How to decide on frequency for tests? • Likelihood of failure • Severity of the consequences if something goes wrong • Ease of the test - resources required A weekly check of an external beam irradiation unit typically takes about 2 hours Part 12, Practical 1
Questions? Let’s get started... Part 12, Practical 1
Some suggestions • Please don’t look before you try to produce your own list • Suggestions based on a document by C Blackwell and E McCullough for Mayo Clinic Part 12, Practical 1
Weekly Mechanical Checks • Gantry angle readout • Collimator angle readout • Field size symmetric fields • Field size asymmetric fields • MLC field definition • Couch height • Couch angle • Physical wedge interlock • Electron applicators interlock Part 12, Practical 1
Weekly optical checks • Optical distance indicator • Cross hair stability on collimator rotation • Cross hair stability on gantry rotation • Laser alignment to isocentre • Laser line orthogonality Part 12, Practical 1
Weekly radiation checks • Output check photons • Output check electrons • Photon beam symmetry • Photon beam flatness • Light radiation field coincidence Part 12, Practical 1
Weekly Safety Checks • Deadman switches • Door interlocks • Accessory mounts, trays, applicators • Emergency off buttons (one per week) • Touch guards Part 12, Practical 1
Weekly other checks... • Film processor - if applicable • Electronic portal imaging • Data transfer for MLC • Record and verify system • Dynamic wedge factors and profiles • ... Part 12, Practical 1
Handout Part 12, Practical 1
Please check your handout • Do you want to add activities? • Can you suggest tolerances in the last column? Part 12, Practical 1