RADT 1200 CH 37 & 39 QUESTIONS AND ANSWERS

RADT 1200 CH 37 & 39 QUESTIONS AND ANSWERS Entrance Skin Exposure (ESE) or Entrance Skin Dose (ESD) - Answer- •Most often reported & referred to as pt. dose , easy to measure Gonadal Dose-GSD Genetically Sig. Dose - Answer- •Important due to genetic responses, easy to measure Bone Marrow Dose - Answer- ave radiation dose to the entire active bone marrow •Important due to rad-induced leukemia, est. from ESE and cannot be directly measured. Thermoluminescence dosimeters (TLDs) - Answer- are used most often to measure ESE. TLDs - Answer- •Response is proportional to exposure dose TLDs - Answer- •Very accurate to within 5% TLDs - Answer- •Can be used to measure all levels experienced, even low doses TLDs - Answer- •Not used in most occupational monitoring due to no permanent record or re-readability is provided and an immediate, on the job readout is not possible. Three methods for estimating ESE - Answer- 1.Use of nomogram if technique is known or assumed 2.Medical physicist constructs nomogram for each radiographic unit 3.Physicist measures the output intensity during annual QC survey •Mean marrow dose - Answer- •Average dose to the entire active bone marrow •Mean marrow dose in United States - Answer- •Average over entire population for diagnostic x-ray is 1 mGyt/yr •Leukemia •Lymphoma •myeloma - Answer- •Risks from radiation dose to stem cells of bone marrow