Capstone Study

what is the largest artificial/manmade radiation

medical and dental xrays

what is the most radiosensitive cell in the body

lymphocyte

Similar absorbed doses of different kinds of radiation can cause different biologic effects.  This is a number assigned to different types of ionizing radiations so that their effect(s) may be better determined

quality factor

The correct use of a 1-mm lead equivalent shield will reduce the gonadal dose by 50% for females and ______% for males

95%

the following statement is TRUE

The greatest effect of irradiation will be observed if a large quantity of radiation is delivered in a short time to the whole body.

This is defined as the average annual gonadal dose to the population of child-bearing age, and is estimated to be 20 mrem.

genetically scientific dose (GSD)

Pregnant radiographers can wear an additional monitoring device at waist level to ensure monthly equivalent dose does not exceed ____ mSv or ___rem

0.5 mSv; 0.05 rem

f a radiographer cannot remain behind the protective barrier, to provide the MOST radiation protection, a lead apron of _____-mm lead-equivalent thickness should be worn.

1.0

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

workload

NCRP guidelines state that collimators must be accurate to within ___% of the SID.

2%

Equipment operated between 50 - 70 kVp must have at least _____ mm Al. equivalent for filtration.

1.5

NCRP recommends that lead aprons used in fluoroscopy must be at least

0.5mm lead

For a scoliosis series, what shield would be best utilized? (select two answers)

Shadow and Breast

The intensity of scattered radiation  ____ meter (s) from the patient is approximately 0.1% of the intensity of the primary beam.

1 meter

The NCRP recommends personal monitoring for individuals who might receive ___% of the occupational dose equivalent limit of 5 rem per year

10%

This type of monitoring device has the ability to measure radiation doses as low as 1 mrem.

OSL

This is the unit used to describe quantity of ionization in air

C/kg - (R) - Air Kerma

A 30-year old lifetime occupational exposure must not exceed

30 rem

Acute radiation syndrome (ARS) occurs when the whole body is exposed to at least ____ of ionizing radiation.

1 Gy (100 rad)

Permanent sterility in human germ cells occurs at

500 rad (5 Gy) - 600 rad (6 Gy)

This provides fuel for the cell metabolism

carbohydrates

These carry genetic information necessary for cell replication

Nucleic acids

Radiation induced chromosome damage may be evaluated during which of the following processes?

Metaphase

According to the NCRP, student dose for the age of 17 should not exceed ___ mSv per year.

1 mSv

The primary protective barrier of ___ -mm lead equivalent is required for an image intensifier. 

2

Mobile fluoroscopic units are required to have a minimal source to end of collimator assembly distance of

12 in

At a 90-degree angle to the primary x-ray beam, at a distance of 1 meter (3 feet), the scattered x-ray intensity is generally approximately ____ of the intensity of the primary x-ray beam.

1/1000

Fluoroscopic mA must not exceed ___, although image-intensified fluoroscopy usually operates between ___ and ___ mA.

5: 1 and 3

Which type of x-ray contributes to an increase in patient dose

low energy, long wavelength

If an individual receives 80 mR while standing 6 feet from a source of radiation for 2 minutes, which of the options listed below will most effectively reduce his/her radiation exposure.

standing 8 feet from the source for 1 min

Which equals 400 rem?

4000 mSv

The manifest illness known as gastrointestinal syndrome would occur following a dose of:

600 rads

The EPA recommends that action be taken to reduce the level of radon in the home if the radon concentration exceeds  ________  pCi/L

4

Air kerma is used to define radiation exposure or radiation delivered to a specific point.  The unit of measurement is

Gy(a)

Which of the following natural background radiations contributes to the largest amount of exposure to the general population each year

radon gas

The source-to-tabletop distance for a mobile fluoroscopic unit may not be less than

30 cm

Attenuation of a diagnostic x-ray beam would be the result of which of the following: (two answers)

photoelectric effect and compton effect

Doubling dose is the amount of radiation that causes the number of mutations in a population to double.  This is estimated to be ____ Sv for humans

1.56 Sv

The dose-response relationship of radiation induced cataracts is considered to be

nonlinear, threshold

Scattered beam intensity is about ________ of the intensity of the primary beam at a 90 degree angle at a distance of one meter.

1/1000

This is the amount of time the beam is 'on' and directed at a particular barrier

use factor

Early studies of the Japanese atomic bomb survivors demonstrated a relatively high incidence of:

leukemia

This personnel monitoring device can measure radiation doses as low as 100 µGy (0.1mSv).

Film badge

When this personnel monitoring device is returned to the laboratory for processing, the chips are stimulated with a laser light

OSL

This type of personnel monitoring device is most widely used.  Has increased sensitivity providing accurate readings as low as 10µSv (0.01 mSv)

OSL

This type of personnel monitoring device can measure doses as low as 50 µGy (0.05 mGy(a).

TLD

Most occupational exposure is received in all the following areas except:

Diagnostic

The process of cell division for germ cells is called

meiosis

This cytoplasm organelle acts as a transportation system to move food and molecules within the cell

endoplasmic reticulum

Skeletal anomalies occur within the _________ trimester

first

Damage to the nitrogenous bases will result in

mutation

Patient dose will increase during cine fluoroscopy with a

smaller field of view and increase frames per second

Radiation safety is especially important with interventional procedures because

the procedures are longer in time than c-arm procedures

Radiation output from an x-ray tube would be expressed in units of

roentgen (c/kg)

According to the NCRP, the annual occupational whole-body dose-equivalent limit is

5000 mrem

NCRP recommends _____ mm Pb equivalency  for routinely used lead aprons during fluoroscopy!! 

0.5

There are two types of cells in the body, genetic and somatic. Which one is all cells in the human body such as skin, nerve, muscle, etc., but NOT reproductive organs

Somatic

The most radiosensitive part of the cell cycle is the ______ phase.

M Phase

The most radioresistant tissues are

nerve and muscle

The high-dose effect occurring at doses from 1 - 10 Gy (100-1000 rad) is the

hematopoietic

Immature somatic cells are called

stem cells

The LD 50-30 dose with no medical support is approximately ______ rad

300

Fluoroscopy units must have dose rates of less than ______mSv/min ( ___ R/min) at the tabletop, unless there is an audible alarm that sounds during the high-dose-rate mode

100/10

Thyroid shields are available as a protective device and should have a lead content equivalent to

.5

How many individual chromosomes does a somatic cell contain

46

When cells are subjected to radiation exposure, ___% of the cells will recover and ___% will die.

90, 10

Linearity on an x-ray machine checks the mA calibration and must be accurate to within

10%

Primary and secondary walls must overlap at least

1/2”

Increasing the sampling frequency of the analog signal _____ the pixel density of the digital data and ____ spatial frequency of the digital image.

increases, improves

When the exposure factor mAs, increases, the IR exposure will _____ and the image contrast will ___.

increase proportionally, not change

Digital image receptors can respond to a ____ dynamic range.

wide

This is also called limiting spatial resolution that is the maximum number of lp/mm that can be recorded by the imaging system

nyquist frequency

as kVp increases, IR exposure _____, and spatial resolution ____

increase, does not change

T/F: Grid selectivity refers to the ratio of the exposure needed without a grid to the exposure needed with a grid.

false

Adding a grid to a pelvis image (no compensation in exposure factors) will ____ the IR exposure, will cause the image contrast to ______ (analog system only), and spatial resolution to be ____.

decrease, increase, not effected

The term "canting" refers to the

angle of the grid strips

Milliamperage and exposure time have an _____ relationship to maintain exposure to the IR.

inverse

this will not cause grid cutoff with a linear focused grid

angling the beam longitudinally with the long axis of the beam

In a digital system, increasing the pixel density and decreasing the pixel pitch ____ spatial resolution.

increases

This number ranges from 0 to 1 (0% - 100%), with 1 being the maximum spatial frequency.

modulation transfer function

Grid factor refers to the

the amount of change in exposure needed to maintain image receptor exposure

X-ray beam intensity changes with a change in SID, and the amount of change in intensity is determined by the

inverse square law

The ability of an image receptor system to resolve small structures is evaluated using a/an

line pair test tool

In this interaction of matter, the incoming photon interacts with an outer orbital electron, imparting some of its energy to the electron, ejecting it from orbit

Compton scatter

This grid error produces an overall decrease in exposure to the IR

angling the xray tube across the grid lines/angling the grid itself during exposure (off level error)