Practical Radiation Safety

Question 1

How to reduce radiation exposure

Answer 1

Limit Time,
Increase distance,
Use shielding

These principles help minimize radiation exposure.

Question 2

What should be done to limit exposure time when using fluoroscopy?

Answer 2

Limit exposure time by using pulsed exposure if possible

This reduces the dose received by patients and operators.

Question 3

What happens to the radiation dose when the distance from the source is doubled?

Answer 3

The dose decreases
As distance from source increases

Doubling the distance reduces the area over which radiation is spread.

Question 4

In fluoroscopy, how should the x-ray tube be positioned relative to the patient?

Answer 4

Position the x-ray tube as far from the patient as possible

Must be at least 30 cm from the patient’s skin.

Position detector as close as possible to the patient

Question 5

What is the definition of Half Value Layer (HVL)?

Answer 5

The thickness required to reduce the dose to half what it is without the attenuation

HVL is crucial for radiation shielding.

Question 6

What materials are typically used for radiation shielding at lower diagnostic energies?

Answer 6

Lead

Lead has a high atomic number (Z) and is effective at these energies.

Photoelectric effect occurs- Hugh atomic no. And high frequency

Question 7

What is the primary concern regarding scatter radiation in fluoroscopy?

Answer 7

Most scatter is directed back towards the x-ray tube

This affects the positioning of the x-ray tube during procedures.

Stand opposite side of the x-ray source to prevent scatter exposure

Question 8

What type of personal protective equipment (PPE) will not protect you from the primary radiation beam?

Answer 8

Lead gloves

Lead gloves protect against scattered radiation, not the direct beam.

Question 9

True or False: PPE is effective against the primary radiation beam.

Answer 9

False

PPE should never be relied upon to protect from the primary beam.

Question 10

When should you notify radiation safety

Answer 10

Dosimeters is lost or damaged
Doses are above investigation levels
Staff member is reaching an annual limit

This is crucial for maintaining safety records.

Question 11

What is the purpose of a dosimeter?

Answer 11

Form of PPE

To measure the amount of radiation exposure

They do not protect from radiation but record exposure levels.

Have a duty to use them and take care of them

Question 12

What is the advantage of thermoluminescent dosimeters (TLD)?

Answer 12

They emit light when heated

TLDs can provide a permanent record of exposure.

Small devices
Can be worn on fingers

Reusable

Question 13

What happens to the dose received by staff when changing to a fluoroscopy low dose setting?

Answer 13

The dose is reduced by 50%

This significantly decreases radiation exposure during procedures.

Question 14

What is the effect of collimating the beam to a smaller size?

Answer 14

It reduces the dose received

For example, collimating from 10 cm x 20 cm to 10 cm x 10 cm can halve the dose.

Question 15

What is the impact of increasing distance from the radiation source on exposure?

Answer 15

It reduces the dose significantly

For instance, standing at 100 cm instead of 50 cm can reduce the dose by 90%.

Question 16

What should be done with lead aprons to ensure they remain effective?

Answer 16

Store them appropriately to limit creasing

Proper storage prevents damage and maintains their protective qualities.

Question 17

True or False: It is acceptable to pierce or bend a dosimeter.

Answer 17

False

Damaging a dosimeter can result in inaccurate readings.

Question 18

What is the advised maximum dose limit for fingers in the primary beam?

Answer 18

100 minutes for an entrance dose rate of 20 mSv/min

This limit is crucial for preventing occupational exposure injuries.

Question 19

What should be included in a PPE inventory?

Answer 19

Lead aprons, thyroid shields, and individual labels

This ensures accountability and proper maintenance.

Question 20

‘Acquisition’ meaning

Answer 20

Step back due to radiation dose

Question 21

Lead gloves and primary beam

Answer 21

Keep your hands well away from the primary beam

Lead gloves are not designed to protect hands from the direct beam. (Only scattered radiation)

You should never enter the primary beam

All operators fingers in the beam must be datixed

Wearing lead gloves in primary beam causes detector to pump up dose to get through the lead which pouts operator in higher danger

Question 22

Rad pads

Answer 22

Radiation protection shield that is placed directly over patient and gives operator protection from the scattered radiation

Question 23

Ceiling mounted screens

Answer 23

Use wherever possible

Place as close to the individual

Question 24

Film badges pros and cons

Answer 24

Pros:
Cheap
Permanent record
Range of doses
Acute or chronic exposure

Cons:
Not very sensitive
Can be fogged by heat
Larger than TLD
No longer routinely available

Question 25

How to wear dosimeters correctly

Answer 25

Must be work within the holder
Worn in radiation areas
Label showing wearers name visible
Between hip and shoulder
Do not wear it where it could be obscured by metal

Question 26

How to store dosimeters correctly

Answer 26

Keep away from hot pipes or radiators
Protect from chemicals
Do not piece bend or damage