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37 Cards in this Set
- Front
- Back
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What are the three protective methods? |
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What are the three ways workers are monitored? |
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The ____ the exposure time, the greater the dose. |
longer |
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The ____ should be as large as possible and the ____ should be as small as possible to reduce the exposure time. |
מוקד אמיתי מוקד מעשי |
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How does a short exposure time improve חדות? |
By reducing movement (improves חדות תנועתית) |
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Time exposure + Radiation ? |
Time exposure +Radiation + יחס ישר |
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What device can shorten exposure time? |
ישור מתח |
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Distance × 2 = Radiation × ? |
1/4 |
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Distance × 1/2 = Radiation × ? |
4 |
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Distance + Radiation ? |
Distance +Radiation - |
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What is the חוק הריבועים? |
Strength of radiation changes in opposite proportion to the square of the distance: Radiation strength = 1 / distance sqared |
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What are the two types of distance? |
FFD - focus film distance OFD - object film distance |
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What is FFD? |
FFD is focus film distance, or the distance between the tube and the film. |
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What is OFD? |
OFD - object film distance, the distance between the body part and the film. |
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What happens with a large OFD? |
Shade and magnification |
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If we double the FFD, the radiation has ___ the power. If we triple it? |
1/4, 1/9 |
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When do we raise the OFD? |
When we want magnification such as in mammogram. |
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To reduce radiation, distance should be as ___ as possible. |
great |
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How else can we use distance to reduce radiation? |
Not have any assistants in the room |
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How can we block radiation? |
Shielding with a lead apron or lead wall (thin lead = thick concrete) |
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When are thyroid shields mostly used? |
On surgeons who can not leave their patients |
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What size walls shield radiation? |
Concrete 15 mm or brick 25 mm |
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How thick are lead aprons? |
.25 mm but double to .5 |
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What is HVL? |
Half value layer--the thickness required to reduce radiation by 1/2. |
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What thickness should lead be to block all radiation? |
.5 mm |
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What are some types of shields and tags? |
Leaded glasses Thyroid collar Lead apron Over apron badge (eye tag) Under apron badge (whole body) Finger ring dosimeter |
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How often should a radiographer be checked? |
Once a year by dr + blood, urine Lenses every 3 yrs |
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How many vacation days does a radiographer get? |
32 |
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How does a radiation tag work? |
Wear on chest, measures whole body radiation |
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What enables נטור אישי? |
Whole body tag plus tag for exposed organs |
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How often do we switch tags? |
Once a month (each month different color) |
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How does the tag detect radiation? |
Tag is based on TLD, thermoluminescent dosimeter. Has 3 lithium fluoride גבישים, which behave like tissue. More exposure more e- movement. Not affected by temperature. |
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How is the tag checked? |
Heated to 300°c, lights up with more radiation. get a report each month. 5 REM a year allowed. |
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Which side of the tag goes our? |
Side with bumps |
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What are the rules of the tag? |
Chest tag under apron, others over. Don't leave in sun. Don't lend. |
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What is listed in the report? |
0 exposure if less than .1 msv (10 miliram). Added to yearly amount. Eye tags recorded separately. |
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What is considered a radiation incident? |
Exposure over 125 militant (1.25 msv) will be investigated. |
