rad bio Test 5 -chapter 10/11

Reports that have served as the resources for EfD limit recommendations

• NCRP report #11

• IRCP publication #60

RSO duties

• oversees day to day radiation safety operations in medical imaging

• Performs a yearly formal review of the departments radiation safety program

• Establishes radiation protection protocols for the department

• Implements and enforces the requirements of the radiation safety program

• Maintains and reviews personnel dosimetry reports

• Investigates and counsels persons exceeding dose limits

Parts of the code of standards for diagnostic cray equipment

• PBL

• Appropriate filtration

• Duplication of radiation exposures for any combination of mA, time, and kVp values to ensure reproducibility and linearity

• Beam limitation for fluoro

• Beam on indicators that alert those on the vicinity when an exposure is in progress with visual and audible signals

• Manual back up timer for the AEC

How does filtration contribute to radiation protection?

It absorbs the non diagnostic low energy photons that would contribute unnecessarily to patient exposure

When operating a c arm unit, why should the xray tube be kept under the patient whenever possible?

To reduce the amount of scatter reaching the head, neck, and chest of others in the room

Light field alignment should be within 2% of the SID on all sides

• So, at a 40” SID, light field alignment must be within 0.8 inches of the actual xray beam on all sides

• At a 72” SID, light field alignment must be within 1.44 inches of the actual xray beam on all sides

SID indicator accuracy must be within 2% or the SID

• so at a 40” SID, the SID indicator must be accurate to within 0.8 inches of the actual SID

• At a 72” SID, the SID indicator must be accurate to within 1.44 inches of the actual SID

True or false:

Reproducibility measures the consistency of output intensity for identical generator settings from one exposure to subsequent exposures. It must be within 5% accuracy

True

True or false:

Linearity measures the consistency of output radiation intensity at a selected kVp setting when changing from one mA and time combination to another. Some books define or as the ability of the different generators in an xray department to all produce the same exposure at the same technique setting. Linearity must be within 10% accuracy

To find the total cumulative EfD limit for an occupational worker

• multiply their age in years x 1 rem for rem measurement

• Multiply their age in years x 10 mSv for mSv measurement

True or false:

To find the collective effective dose (ColEfD), multiply the number of exposed persons x the average exposure. If the exposure is given in rem, answer in “man-rem”. If the exposure is given in sieverts, answer in “person-sieverts”

True

ICRP

• international commission on radiological protection

• Evaluates information on radiation induced biologic effects and provides radiation protection recommendations on occupational and public dose limits

NCRP

• national council on radiation protection and measurements

• Review regulations formed by the ICRP and then decide how to incorporate them into u.s. radiation protection criteria

NAS/ NRC-BEIR

• National Academy of Sciences / national research council committee on the biological effects of ionizing radiation

• Look at epidemiological data and review the studies of biologic effects due to exposure by ionizing radiation and report their findings to the ICRP for evaluation

UNSCEAR

• United Nations scientific committee on the effects of atomic radiation

• Look at epidemiological data and review the studies of biologic effects due to exposure by ionizing radiation and report their findings to the ICRP for evaluation

NRC

• nuclear regulatory commission

• Oversees the nuclear energy industry and enforces radiation protection standards

EPA

• environmental protection agency

• Facilitates the development and enforcement of regulations pertaining to radiation exposure control in the environment

FDA

• U.S. food and drug administration

• Conducts an ongoing product radiation control program, regulating xray equipment design and manufacture

OSHA

• occupational safety and health administration

• Regulate occupatIonal exposure to radiation to ensure the safety of the workers

Agreement states

• states that have entered into an agreement with the NRC to assume responsibility for ensuring radiation protection regulations through their health care facilities

150 mSv/15 rem

Lens of the eye (annual for the occupational worker)

0.5 mSv/ 0.05 rem

Pregnant radiation workers embryo-fetus (monthly)

1 mSv/0.1 rem

• nonoccupationally and frequently exposed individuals (annually)

• Individuals receiving education in an ionizing radiation learning environment (annually)

5.0 mSv/0.5 rem

• nonoccupationally and infrequently exposed individuals (annually) pregnant radiation workers embryo fetus (entire gestation)

500 mSv/50 rem

• localized areas of the skin, including the hands and feet (annual for the occupational worker)

0.01 mSv

Negligible individual dose (for the occupational worker)

Who is responsible for keeping occupational and non-occupational exposure as low as possible in the medical imaging department?

• Techs

• Radiologist

The effective dose limiting system is a set of numeric dose limits based on the risks of what two things?

1. Genetic effects

2. Cancer

Which act of 1981 provided federal regulation requiring the establishment of minimal standards for radiology school accreditation?

consumer patient radiation health and safety act of 1981

which NCRP report provides the most recent guidance on radiation protection?

116

Between stochastic and non-stochastic, which the following biological responses is deterministic?

Non stochastic

Between stochastic and non-stochastic, which the following biological responses which is probabalistic?

Stochastic

which biological response severity is dependent on the dose received?

Non stochastic/ deterministic

Which of the responses will not occur below the threshold level?

Non stochastic/ deterministic

Which of the following responses will most likely be seen in diagnostic imaging?

Stochastic

Which of those responses is most likely to be seen in the high dose range?

Non stochastic

between those 2 things, which response has an increased chance of occurring as dose goes up?

Stochastic

current radiation protection philosophy is based on what?

the assumption that a stochastic relationship exists between radiation dose and biological response. And another name for stochastic would be linear, non-threshold

Who would be the most radio sensitive? if I give you like an embryo fetus, a five-year-old, a 40 year old or an 80 year old, what would you tell me?

Embryo fetus

equivalent dose, we take into account what?

We multiply the radiation weighting factor times the dose

Effective dose

Multiply the tissue weighting factor

When a specific tissue or organ is being considered for risk and the effective dose limiting system, a _____ weighting factor is used

Tissue

I'm gonna give you a list of beam limiting devices. 
So between an aperture diaphragm, an extension cone, and an extension cylinder, Which one of those is best for restricting the beam for a greater distance from the source?

Extension cylinder

Which of these plus your normal, regular, everyday collimator, your double aperture collimator, which of those is the most popular form of beam restriction device?

Light localizing double variable aperture collimator

For mobile radiographic units, what is the patient's skin surface? What is the SSD? It should never be what? Closer than how many inches?

12 inches

mobile, C arm, the SSD must be at least what?

12 inches

SSD of stationary fluoro

15 inches

What is the unit used to describe luminance?

Nit/ candela per square meter

a 12 to 1 grid will yield ______ as much exposure to the patient as a non grid.

Five times

what should be kept as close to the patient as possible during fluoro in order to decrease skin dose?

Image intensifier

General purpose fluoro units should not have an entrance skin exposure rate that exceeds a maximum of how many milligray sub A per minute measured at tabletop with the image intensifier to 12 inches above the tabletop?

100 milligray sub a

Image receptor in a fluoro unit is a _____ barrier.

Primary

it must consist of how many millimeters of lead equipment equivalent?

2.5 mm lead equivalent

the primary responsibility for monitoring and documenting radiation exposure generally belongs to the ______ who was in on the exam.

Radiographer

why did we establish or why have they established dos limits? 
We're wanting to keep the risk of what, as low as possible?

Cancer

your ICRP and your NCRP. 
These are your proposal agencies. So what do proposal agencies do with effective dose and equivalent dose limits? Do they enforce them? 
Do they recommend them?

Recommend them

what does the NRC require us to have in our facility?

• RSO

• Radiation safety committee

what does ALARA mean?

As low as reasonably achievable

if we consistently apply ALARA, our effective dose limits and our equivalent dose limits will be kept how?

well below the minimum

The goal of radiation protection is to prevent what?

we want to prevent the occurrence of serious radiation induced conditions, like acute or chronic, deterministic effects and stochastic effects. and expose people to an acceptable degree in relation to the derived benefits

by practicing ALARA, can we ever completely eliminate stochastic effects?

No

True or false:

to reduce stochastic effects, the minimal amount of radiation possible should also be used along with lead shielding

True

the effective dose limits for occupational workers, do those include natural background radiation?

No

at a distance of one meter from the x-ray source, leakage radiation should not exceed what?

1 mGya per hour

True or false:

The luminance of the collimator box should be such that the RT has no difficulty making out the edges in the center of the light field

True

half value layer is the amount of absorbent material necessary to reduce the beam ____ to half of its original intensity

Quantity

Are compensating filters a form of radiation protection?

Yes

What will the use of a grid do to patient dose?

Increase patient dose

Any type of digital imaging, will allow fewer repeats due to improper what?

technique

will a higher KVP in digital affect the contrast?

No

Are CR plates very sensitive to scatter?

Yes

True or false:

Fluoro poses the greatest radiation exposure risk in digital imaging.

True

Anything that lowers patient dose, what will that do to tube longevity?

It’s going to increase tube longevity

For medical legal reasons, what do you do with your fluoro time?

Document it for every patient and it needs to be entered into the patient record

when you have your fluoro tube parked, can you x-ray?

No

Is any fluoro a high dose procedure?

Yes

What's HLCF stand for?

High level Control fluoroscopy

tell me about HCLF in patient dose. What's that do to patient dose

Increase substantially

So, let's say you're in a case, and you feel the fluoroing position has become distracted, and does not realize how much floral time he or she is using. What should you do?

Speak up kindly

the RT, you go up to do a surgery case and you notice some of the staff doesn't have their lead aprons on and they're not standing behind a lead barrier. What do you do?

you should say something to the unprotected staff member

If an excessive fluoro time is used on a surgery or fluoro case, the RT should notify who?

RSO

Who put forth the ALARA principle? 
Who put that in place?

NCRP

what is the acronym that is synonymous with Alara?

ORP

What does ORP stand for?

Occupation for radiation protection

When sperm or egg cells are damaged from ionizing radiation before conception, what do we call this?

Mutagenesis

before a medical imaging exam using radiation exposures ordered, the ordering physician must be sure that the ____ outweighs the ____

Benefits; risks

Effective dose limit is the upper boundary dose of ionizing radiation that results in a _____ risk of bodily injury or genetic damage

Negligible

what is the maximum radiation dose a worker can have in a year's time? in mSv. In one year's time, what is the most dose you can have?

50 mSv/ 5 rem

if a radiology department strictly adheres to radiation protection guidelines, personnel, do seminar reading, should be well below what fraction of the maximum effective dose limits?

1/10

The x ray tube is enclosed in a lead line metal protective housing to protect the patient and the radiation worker from what?

Leakage radiation

what do we call the electronic connection between the Bucky tray and the collimator lead shutters?

PBL

As you increase your collimation, what happens to patient dose?

Decreases

Which set of collimator lead shutters stops the off focus radiation?

first set, entrance set, or proximal shutters.

In the colimator box, what angle does the mirror sit at?

45 degrees

How well the size of the light field aligns to the size of the x-ray beam is what?

Congruence

How well the location of the light field aligns to the location of the x-ray being refers to What?

Alignment

What's total filtration equal to?

Inherent plus added filtration

As the tube gets older, what happens to filtration?

Increases

The NCRP requires that all x-ray tubes, capable of operating above 70 KDP, have a minimum total filtration of?

2.5 mm aluminum equivalent