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RT 244 Ch 35-38
Radio-biology chapters 35,36,37,38
| Question | Answer |
|---|---|
| What is the most common barrier used in shielding? | Lead (Pb) |
| What is the dose quantity that accounts for different types of radiation and the radiosensitivity of various tissue and organs? | effective dose |
| Diagnostic tube housing must be shielded so that radiation leakage may not exceed what? | leakage cannot exceed 100mR at 1 meter |
| Protective gloves worn and the bucky slot cover on a fluoro table must have a Pb equivalent of what? | .25mm |
| Scatter to the RT during fluoro is primarily caused by what? | the patient |
| Regarding an aluminum filter used in the beam of a diagnostic xray machine, what is its purpose? | 1.reduce dose to patient 2.makes image better |
| What is the required total filtration? | 2.5mm |
| How can you reduce gonadal dose? | 1.shielding 2.collimation 3.distance |
| Primary protective barrier must have a lead equivalency of at least what? | 2mm of Pb or 4 inches of masonary |
| Regarding the thickness of a protective barrier, what factors should be considered? | distance, occupancy factor, control, workload, use factor, kVp |
| Fluoro units, what is the minimum source to image receptor distance that can be used with a mobile unit? | 30cm |
| Fluoro units, what is the minimum source to image receptor distance that can be used with a stationary unit? | 38cm |
| What is the minimal thickness of the protective curtain between the fluoro and the operator? | curtain must be at least .25mm thick |
| What are the 2 types of secondary radiation? | 1.scatter from the patient 2.leakage from the tube |
| What are high risk areas for RTs to work in? | fluoro and mobile |
| Exposure time adjusted for constant mAs, should have a constant radiation intensity | linearity |
| What is the max variation for linearity? | 10% |
| How accurate must PBL (positive beam limitation) and collimators be? | must be accurate to 2% of the SID |
| The intensity of the xray beam at the table top of an image intensified fluoro unit does not exceed what? | 10 R/min |
| What is the efficiency of a 1.0mm Pb equivalent apron at 75 kVp? | 99% |
| OSL's use what type of crystals? | aluminum oxide |
| What is a cutie pie? | nickname for an ionization chamber-type survey meter |
| What is the GSD (genetically significant dose) in the US? | 20 mrad |
| Scintillation detectors are used in what modalities? | 1.nuclear medicine 2.CT 3.digital imaging systems |
| What types of crystals do scintillators use? | 1.thallium activated sodium iodide 2.thallium activated cesium iodide |
| After exposure to ionizing radiation, heating allows for the measurement of the intensity of the emitted light via the glow curve for what device? | TLD |
| TLD's use what type of crystal? | lithium fluoride |
| A common type of gas-filled radiation detector used to detect contamination is the? | Gieger Muller (counter) |
| For any given radiographic technique, the output radiation intensity should be constant from one exposure to another | reproducibility |
| How accurate does reproducibility need to be? | within 5% |
| Lithium fluoride provides a nearly ____?____ equivalent dose | tissue |
| What causes film badges to fog when left in your car? | heat and humidity |
| Dosimetry reports must include what? | current and cumulative exposure levels |
| What is the number one reason for retakes? | positioning errors |
| A beam passes thru a barrier of a TVL of 1 and a barrier of 1 HVL, which beam is most reduced? | the beam thru the 1 TVL |
| What is the monthly exposure limits during pregnancy? | .5mSv(50mrem) |
| What is the full term exposure limits during pregnancy? | 5mSv(500mrem) |
| What is the dose limit for skin and extremities? | 500mSv/yr(50rem/yr) |
| What is the does limit for the lens of the eye? | 150mSv/yr(15rem/yr) |
| What is the general population exposed to every year? | 100mrem/yr |
| What is a radiographer annual dose limit? | 5000mrem/yr |
| What trimester is associated with possible childhood malignancies? | 2nd and 3rd |
| When does resorption occur? | within the first 2 weeks |
| How do you figure out the max lifetime cumulative exposure for a person? | age x 1rem |
| Protective aprons must have a Pb equivalent of ___?____ and ___?___ PB equivalent is recommended. | .25mm and .5mm |
| Patient skin exposure can be measured indirectly by using a what? | nomogram |
| Acute skin effects from radiation exposure have been reported following what type of exams? | angiointerventional |
| An estimation of patient dose is reported as? | entrance skin exposure, bone marrow dose, gonadal dose |
| Bone marrow dose is measured as what? | as an estimate from ESE |
| The simplest way to measure patient dose is to measure the? | entrance skin exposure |
| The period of major organogenesis is during what time frame of pregnancy? | 2nd to 10th week |
| At the level of the tabletop, the intensity of the fluoro beam should not exceed ___?___ for each mA of operation at 80 kVp. | 2.1 R/min |
| How is exposure measured? | exposure rate x exposure time |
| The fluoro exposure control switch is always what type? | deadman |
| Who was Thomas Edison's assistant that died from radiation exposure? | Clarence Dally |
| 1 TVL(tenth value layer) = ? HVL(half value layer) | 3.3 HVL |
| What are the 3 types of possible malicious radiologic devices? | 1.Radiation exposure device (RED) 2.Radiologic dispersal device (RDD) 3.Improvised nuclear device (IND) |
| On a mobile xray machine how long is the cord on the exposure switch? | atleast 2m/6ft/183cm |
Created by:
Chrslarsen
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