Radiation dosimetry, protection and legislation
Radiation is present in the environment naturally and we are all exposed to some extent. The effect this radiation has on humans depends on the type, source and level of radiation and on the age of the patient. Legislation guides the dose limits for staff and the public and the dose reference levels (DRLs) for patients undergoing medical exposure. DRLs give an idea of the doses for standard-sized patients but the dose may be larger for larger patients. Strictly, there are no dose limits for patients but the key guiding principle for patient, staff and public doses is ALARP (As Low As Reasonably Practical).
This chapter covers the sources of radiation to staff, how the dose received is measured and how to protect against radiation exposure. In this chapter I have also included patient dose measurements and factors affecting exposure for X-ray, CT and nuclear medicine imaging.