Rad Safety Exam 5

Radiation dose is measured in what unit

Gray (Gy)

Radiation exposure expressed as air KERMA is measured in __

Gray

What does KERMA stand for

Kinetic energy released in matter

When the radiation exposure is to radiologic technologists and to radiologists, the proper unit is __

Sievert (Sv)

The sievert is the unit of __; it is used for radiation protection purposes

Effective dose

Although exposure, dose, and effective dose have precise and different meanings, they often are used __ in radiologic because they have approximately the same numeric value following whole body exposure

Interchangeably

When properly used, __ refers to radiation intensity in air

Exposure (Gya)

__ measure the radiation energy absorbed as a result of radiation exposure

Patient radiation dose and tissue dose (Gyt)

__ identifies the biological effectiveness of the radiation energy absorbed

Effective dose (Sv)

Radiation regulations are expressed in __

Sievert (Sv)

Although the recommended dose limit for radiologic personnel is __, experience has shown that considerably lower exposures than this are routine

50 mSv/yr

The occupational radiation exposure of radiologic personnel engaged in general X-ray activity normally will not exceed __

1 mSv/yr

Who usually receives slightly higher radiation exposures and why? Radiologists or rad techs

Radiologists because they receive most exposure during fluoroscopy and are usually closer to the radiation source (the patient) during exposure

The highest occupational exposure of diagnostic X-ray personnel occurs during __ and _

Fluoroscopy and mobile radiography

What is the source of occupational radiation exposure during fluoroscopy

Scatter from the patient

During fluoroscopy, both the radiologist and radiographer are exposed to relatively (low or high) levels of radiation

High

Personnel exposure is related directly to the __

X-ray beam on time

A barium enema examination requires 2.5 min of fluoroscopic X-ray beam on time. If the radiologist technologist is exposed to 2.5 Gya/h, what will be his or her occupational radiation exposure

Exposure = exposure rate x time

2.5 Gya/h x 2.5 minutes

2.5 Gya/h x 0.0717 hour

= 0.1 mGya

T/F With some fluoroscopes, the X-ray tube is over the table and the IR is under the table. This offers some advantage of image QUALITY

T

T/F With some fluoroscopes, the X-ray tube is over the table and the IR is under this table. This causes personnel exposures to be higher because secondary radiation (scatter and leakage) levels are higher

T

What is the highest intensity of secondary radiation during any X-ray procedure

The entrance skin

It is best to position the X-ray tube (under or over) the patient during C-arm fluoroscopy

Under

Personnel engaged in interventional radiology procedures often receive __ exposures than those do in general radiologic practice because of longer fluoroscopic X-ray beam on time

Higher

The frequent absence of a protective curtain on the image-intensifier tower and the use of image capture also contribute to __ personnel exposures

Higher

__ exposure during interventional radiology procedures may be significant

Extremity

In IR, even with protective gloves, exposure of the forearm can approach the recommended dose limit of __ if care is not taken

500 mSv/yr

What must be provided for interventional radiologists?

Extremity occupational monitoring

Personnel exposures associated with mammo are __ because the low kVp of the examination results in less scatter radiation from the patient

Low

In mammo, usually a __ and _ are sufficient to provide adequate radiation protection

Long exposure cord and a conventional wall or window wall

T/F Rarely does a room that is used strictly for mammography require protective lead shielding

T

Dedicated mammography X-ray units have personnel protective barrier made of what 3 things as an integral component

Leaded glass, lead acrylic, and even plate glass

Personnel exposures in CT are (low or high)

Low

In CT, because the CT X-ray beam is finely collimated and only secondary radiation is present in the exam room, radiation levels are __ compared with those experienced in fluoroscopy

Low