Radiation Biology Exam III

Stochastic event

Which of the following terms involves a random effect of ionizing radiation?

1. manufacturing.
2. trade.
3. government.

Upper boundary safe radiation exposure limits for occupationally exposed persons are associated with risks that are similar to those encountered by employees in other industries that are generally considered to be reasonably safe. These industries include

NRC

Which of the following agencies is responsible for enforcing radiation safety standards?

460 mSv

Determine the cumulative effective dose (CumEfD) limit to the whole body of an occupationally exposed person who is 46 years old.

the current method for controlling the risk of biologic damage to radiation workers and the general public from radiation exposure.

The effective dose (EfD) limiting system is

ionizing radiation and potential risk.

The ALARA concept adopts an extremely conservative model concerning the relationship between

designated radiation safety officer of a health care facility.

The responsibility for maintaining radiation monitoring records for all personnel and for providing counseling for individuals who receive monitor readings in excess of allowable limits belongs to the

any organ in the human body is vulnerable to damage from exposure to ionizing radiation.

The ALARA concept adopts an extremely conservative model concerning the relationship between

decreases.

Whenever scattered radiation decreases, the radiographer’s exposure

50 mSv

The annual occupational effective dose that applies to radiographers during routine operations is _____

Should not

Medical imaging personnel ____ receive equivalent doses that are close to the annual occupational effective dose limit.

No larger than the image receptor

The radiographic beam should be collimated so that it is which of the following?

the high voltage

The protective tube housing serves as a shield against _____________________ entering the x-ray tube, thereby preventing electric shock while also facilitating the cooling of the x-ray tube.

5 minute

During a fluoroscopic examination, a resettable cumulative timing device measures the x-ray beam-on time and sounds an audible alarm or in some cases temporarily interrupts the exposure after the fluoroscope has been activated for what length of time?

1 mGy_a/hr

A diagnostic-type protective tube housing must be constructed so that leakage radiation measured at a distance of 1 m from the x-ray source does not exceed _______ when the tube is operated at its highest voltage at the highest current that allows continuous operation.

To reduce exposure to the patient’s skin and superficial tissues by absorbing most of the lower-energy photons from the heterogeneous beam

What is the purpose of radiographic beam filtration?

be an effective dose reduction technique.

When using digital fluoroscopy systems, making use of the last image hold feature can

• lower dose

• ease of use

• immediate imaging results

• manipulation of the image.

Digital radiography systems offer several advantages over computed radiography, including ____

NCRP Report No. 116

Gives all dose limits

ICRP

The ____ is considered the international authority on the safe use of sources of ionizing radiation and provides clear and consistent radiation protection guidance through its recommendations for occupational dose limits, and public dose limits

NCRP

______ is a nongovernmental, nonprofit, corporation that determines how to implement ICRP recommendations into U.S. radiation protection criteria

NRC

Federal agency regulating nuclear materials and facilities
• Issues licenses, conducts inspections, sets occupational dose limits
• Focus: Nuclear energy safety and byproduct materials

Agreement State

States authorized by the NRC to regulate radioactive materials locally
• Must follow or exceed NRC standards
• Focus: Medical, industrial, academic radiation use within the state

permit the contracting state to undertake the responsibility of licensing and regulating the use of radioisotopes and certain other radioactive materials within that state.

EPA

Sets environmental exposure limits for radiation
• Regulates radon, water, air, and waste contamination
• Focus: Protecting public health and ecosystems

FDA

Regulates radiation-emitting devices (X-ray, CT, lasers)
• Oversees food irradiation and device labeling standards
• Focus: Patient and consumer safety

OSHA

Enforces workplace safety for radiation outside the nuclear field
• Covers training, protective equipment, exposure limits
• Focus: Worker safety in healthcare, industry, and research

Public Law 90-602

Does not regulate the diagnostic x-ray user. It is strictly an equipment
performance standard

Consumer–Patient Radiation Health and Safety Act of 1981

Protects the public from unnecessary exposure to radiation

2.5%

Occupational Risk for radiography

1/10th

Personnel dosimeter readings should be below _____ of annual dose limit

Radiation Hormesis

is that there exists a beneficial aspect or result to groups of individuals from continuing exposure to small amounts of radiation.

NRC

Which of the following agencies is responsible for enforcing radiation safety standards?

270 (age x 10 mSv)

Determine the cumulative effective dose (CumEfD) to the whole body of an occupationally exposed person who is 27 years old.

Sigmoid threshold dose-response curve

Biologic effects such as cataracts that result from exposure to ionizing radiation appear to have which of the following?

Other industries that are generally considered reasonably safe

For radiation workers, such as medical imaging personnel, occupational risk may be equated with occupational risk in which of the following?

1 mSv

When exposed to radiation as part of their educational experience, 18-year-old students should not exceed an effective dose limit of ___ annually.

1. Developing an appropriate radiation safety program
2. Maintaining radiation-monitoring records for all personnel.

Responsibilities of a medical facility's radiation safety officer (RSO) include which of the following?

0.5 mSv, 5.0 mSv

To reduce exposure for pregnant imaging professionals and to control the exposure of the unborn during potentially sensitive periods of gestation, the NCRP now recommends a monthly equivalent dose limit not exceeding ___ per month to the embryo-fetus and a limit during the entire pregnancy not to exceed ___ after declaration of a pregnancy.

to decrease the x radiation dose to the patients skin and superficial tissue

What is the function of a filter in diagnostic radiology?

decrease the intensity of the primary beam by 50% of it's initial value.

HVL may be defined as the thickness of a designated absorber required to so which of the following?

a radiographic grid may be used more frequently during CR imaging.

 The photostimulable phosphor in the computed radiography imaging plate is more sensitive to scatter radiation before and after it is sensitized through exposure to a radiographic beam. Because of this increased sensitivity, which of the following is true?

at least 15 cm

to minimize skin exposure to electrons produced by photon interaction with the collimator, how far below the collimator should the patients skin surface be?

2.5 mm aluminum equivalent

which of the following aluminum equivalents for total permanent filtration meets the minimum requirement for mobile diagnostic and fluroscopic equipment?

Compensating filter

the trough, or bilateral wedge, filter, which is used in some dedicated chest radiographic units, is an example of which of the following?

1. limit the size of the fluroscopic field to include only the area of anatomy that is of clinical interest.
2. employ the practice of intermittent, or pulsesd, fluoroscopy to reduce the overall length of exposure

to decrease patient exposure during fluroscopic procedures, the fluroscopist can:

1 Gya/hr

A diagnostic type protective tube housing must be constructed so that leakage radiation measured at a distance of 1 m from the x ray source does not exceed ______ when the tube is operated at it's highest voltage at the highest current that allows contious operation.

1 m, 1 mGy/hr

Radiation leakage: at a distance of ___ from the x-ray source must not exceed ____

400 lbs

Supporting weight of the radiographic exam table is up to ____

2% of SID

Distance must be _____

1% of SID

Centering indicator must be within ____

collimator

is currently the predominant x-ray beam limitation device

15 cm

Skin paring: ____ below the collimator

not exceed 2% of SID

Coincidence between radiographic beam and the localizing light beam must _____

between 2% - 3%

PBL should be ____

0.5 mm Al

Requirement for minimum filtration below 50 kVp

1.5 mm Al

Requirement for minimum filtration between 50 kVp - 70 kVp

2.5 mm Al

Requirement for minimum filtration above 70 kVp

5% or less

Variance of reproducibility

10%

Variance of linearity

12 inches (30 cm)

Minimum SSD in mobile radiography + mobile fluoroscopy

15 inches (38 cm)

Minimum SSD in stationary fluoroscopy

3 - 4.5 mm Al

HVL in fluoroscopy ____ is considered acceptable when kVp ranges from 80 to 100

5 minutes

Cumulative timer for fluoroscopy

100 mGya/min

ESE for fluoroscopy

Maximum of 200 mGya/min

ESE for fluoroscopy HCL

2 mm lead equivalent

Primary protective barrier in fluoroscopy

dead-man type

Fluoroscopic exposure control switch must be of ____

Three times more

As a consequence of their anatomic location, the female reproductive organs receive about _____ exposure during a given radiographic procedure involving the pelvic region than do the male reproductive organs.

Effective Communication

An interaction that produces a satisfying result through an exchange of information.

PA

In which of the following projections will a young female patient receive a significantly lower dose to her breast tissue during a chest x-ray?

The patient’s skin and possibly the gonads, if they were in the included imaged area, receive a double radiation dose.

Any image that must be repeated because of human or mechanical error during the production of the initial image is considered to be a repeat image. What effect does a repeat image have on the radiation dose received by the patient?

an incorrectly placed shield within the collimated x-ray beam when an automatic collimator is used, can result in the lead in the shield obscuring anatomic information or interfering with the AEC system.

The reason for discontinuing patient gonadal shielding and fetal shielding in diagnostic radiology is based on research that the use of such shielding may jeopardize the benefits of the radiologic examination because

increases completed image quality by decreasing scatter.

an incorrectly placed shield within the collimated x-ray beam when an automatic collimator is used, can result in the lead in the shield obscuring anatomic information or interfering with the AEC system.

the radiation safety officer or the medical physicist should perform the calculations necessary to determine fetal dose.

In the event that a pregnant patient is inadvertently irradiated

High; low

Use of a ___ kVp and a ____ product of milliamperage and exposure time in seconds (mAs) reduces the patient dose.

She continues to perform her duties without interruption of employment, provided that she has received radiation safety counseling and follows established radiation safety practices.

When a radiologic technologist declares her pregnancy to her employer, which of the following is appropriate?

Medical physicist

Who should determine the exact shielding requirements for a particular imaging facility?

1. leakage radiation.
3. scatter radiation.

Secondary radiation includes:

Workload

_______________ is essentially the radiation output weighted time that the unit is actually delivering radiation during the week.

Tube housing, collimator, high-tension cables

Which part(s) of a diagnostic x-ray unit should not be touched while a radiographic exposure is in progress?

2 m

For mobile radiographic units, which are not equipped with remote control exposure devices, the cord leading to the exposure switch must be long enough to permit the radiographer to stand at least _____ from the patient, x-ray tube, and the useful beam to reduce occupational exposure.

90-degree angle

When performing a mobile radiographic exam, if the protection factors of distance and shielding are equal, the radiographer should stand at a _____ to the scattering object.

workload

Units of either mAs/wk or mA-min/wk are used to determine the _____ for a specific x-ray room.

1. Select the smallest technical exposure factors that will produce a diagnostically useful image.
2. Adequately and precisely collimate the radiographic beam to include only the anatomic area of interest.
3. Shield the patient's lower abdomen and pelvic region with a suitable protective contact shield.

A woman who is 3 months pregnant has been in a motor vehicle accident. The emergency room physician suspects there is injury to her cervical spine and thus feels justified in ordering an x-ray examination to aid in determining the extent of the patient's injury. Because the patient is pregnant, the radiographer should:

Both the late somatic effects and genetic effects of radiation.

Pediatric patients require special consideration and appropriate radiation protection procedures because they are more vulnerable to which of the following?

Lower entrance exposure dose to the anterior body surface, thereby significantly reducing the dose to the breast.

The use of the PA projection during a juvenile scoliosis radiographic examination results in which of the following?

1. Chest x-ray study as part of a preemployment physical

3. Whole-body multislice spiral CT

Which of the following examinations are considered to be unnecessary radiologic procedures?

Scatter Radiation

Greatest occupational hazard

0.5 mm

Maternity aprons should be ___

primary beam

Primary protective barrier protect from ___

1.6 mm lead

Primary protective barrier must consist ____ of lead

2.1 mm

Primary protective barrier must extend ___

scatter and leakage radiation

Secondary Protective barrier protects from ______

0.8 mm (1/32 in)

Secondary Protective barrier should consist ____ of lead

1.3 cm (1/2 in)

Secondary Protective barrier should overlap the primary protective barrier by _____

0.25 mm lead equivalent

A bucky slot shielding device of at least _____ must automatically cover the bucky slot opening in the side of the x-ray table during a fluoroscopic examination when the bucky tray is positioned at the foot end of the table.

2 m

For mobile radiographic units, which are not equipped with remote control exposure devices, the cord leading to the exposure switch must be long enough to permit the radiographer to stand at least ____ from the patient, the x-ray tube, and the useful beam to reduce occupational exposure.