Radiation Protection (Occupational and Patient)

Question 1

5 SC35 requirements for fluoroscopy exams

Answer 1

1. all fluoro exams should be carried out as rapidly as possible using minimum dose rates and xray field size
2. equipment operators must be trained in fluoro procedures
3. when using ABC, the operator must monitor the xray tube current and voltage so they don’t become high without realizing
4. mobile fluoro should only be used if it is impractical to move patient
5. cinefluorocopy (movie like fluoro, constant exposure) produces the highest patient doses and should not be used unless medically necessary

Question 2

Shielding in Fluoro Rooms

Answer 2

rooms require less wall shielding then gen rad because II is primary barrier (2mm lead equivalent)

Question 3

Accessory Equipment Shielding

Answer 3

• bucky slot cover (0.25 lead equivalent)
• protective curtain (0.25 lead equivalent)
• ceiling mounted shield

Question 4

Protective Apparel

Answer 4

• kV up to 100 requires 0.25 lead equivalent
• 101-149 kV requires o.35 lead equivalent
• 150 kV and up requires o.5 lead equivalent

Question 5

Maximum Exposure Rates

Answer 5

• 50 mGy/min for equipment not equipped with automatic intensity control
• 100 mGy/min for equipment that is equipped with automatic intensity control
• 150 mGy/min for equipment that is equipped with automatic intensity control and high level irradiation control the is activated

Question 6

Dose Area Product (DAP)

Answer 6

• related to tissue dose and volume of tissues irradiated
• must consider while area being irradiated (beam is an area beam unlike CT)
• expressed as cGmy-cm² , effective way to indicate risk
• lower DAP = smaller field size = collimation

Question 6

3 Cardinal Rules of Radiation Protection

Answer 6

1. minimize time
2. maximize distance
3. use shielding

Question 7

How to minimize beam on time

Answer 7

• communication: closed loop communication between tech and rad and other workers in the room
• audible time: when 5 minutes of fluoro on time reached, audible timer will sound
• dead man switch: switch must be actively pressed to expose
• pulsed mode: engaged as much as possible
• high level fluoro has audible sound when pressed
• last image hold

Question 8

Source to Skin Distance (SSD)

Answer 8

• 38 cm for stationary equipment
• 30 cm for mobile equipment
• 20 cm for special applications
• increased SSD = decreased ESE (good for patient, low dose)

Question 9

OID and dose

Answer 9

patient closer to II: lower dose, mag present

Question 10

Magnification and dose

Answer 10

mag mode increases patient dose