Cluster 1 Flashcards by Hannie Han

A transformer with a turn ratio of 1000:1 is:

● a step-up transformer

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The annual dose limit for radiation workers has been
reduced from 50mSv to 20mSv in 1990 according to
the recommendations of ICRP published as.

ICRP 60

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What is the expected image that will be displayed on
a radiograph exposed to 70 kVp, 100 mA, 100ms
from a full wave 3 phase x-ray unit?

36 deg arc

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Which of the following will serve to
increase theeffective energy of the x-ray beam?

increase in added filtration
increase in kilovoltage

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Radiographs from a particular single-phase,
full wave-rectified x-ray unit were overexposed,
usingknown correct exposures. a spinning top
test wasperformed at 200 mA, 0.05s, and 70
kvp, and eightdots (dashes) were visualized on
the finished film.which of the following is
indicated?

the 0.05s time station is inaccurate

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Comparing the mR output at 50mA @ 0.2s,
100mA@ 0.1s, and 200mA @ 0.05s while
increasing themAsusing different mA and s
combination is part of whichQC test?

Linearity

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If a high voltage transformer has 100 primary
turnsand 35000 secondary turns, and is supplied
by 220volts and 75 A, what are the secondary
voltage andcurrent?

214 mA and 77 kVp

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A branch of physics that describes the
motion oflarge objects such as planets,
universe, cars andplanes

classical mechanics

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Focal spot size is measured with a_____.

pinhole camera (most accurate but most difficult)

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Double-focus x-ray tubes have two______.

Filaments

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Congruence of the x-ray beam with the light field is tested using

radiopaque objects

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An automatic exposure control device can
operateon which of the following principles?

a photomultiplier tube charged by a
fluorescent screen -a parallel-plate
ionization chamber charged by x-ray
photons

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The introduction of AI,Cu And Sn filters into the x-ray beam causes

Low energy x-rays to be absorbed

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An electric generator is a device that
convertsmechanical energy to electrical energy
utilizing theprinciple of

Faraday’s law

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It is a principle that states that no electrons
in thesame atomic system may be assigned
identicalvalues.

Pauli’s exclusion

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The exposure rate to a body 2m from a
source ofradiation is 28R/hr. what distance from
the sourcewould be necessary to decrease the
exposure to7R/hr?

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The old concept of annual maximum
permissibledose (MPD) for the general
population isapproximately what portion of the
MPD for radiationworkers?

1/10

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An example of a derived quantity is a______.

volume

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What unit results when a coulumb is divided
by asecond?

ampere

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A frequency of 1MHz is:

1x106 cycles/s

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A single unit of electromagnetic radiation
is alsocalled a/an:

quantum

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The only difference between x-rays and
gamma raysis their

Origin

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The intensity of radiation on an object is
reducedwith distance because the radiation
.

is spread out over a greater area

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Photons tend to interact with matter their
wavelength.

equal in size to

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In the surface of an electrified object, the chargesconcentrate __ .

on the sharpest curvatures

Calculate the power loss (in kW) in a circuit wherethe current flowing is 100 amperes and the total lineresistance is 2 ohms.

20 kW

Variations in power distribution to the x-ray machineare corrected by the .

line voltage compensator

The first component to receive power in the x-raycircuit is the .

Autotransformer

The difference in the waveform between the primaryand secondary sides of the high voltage transformeris the

Amplitude

In modern imaging systems, the components forrectification are

solid state semiconductors

A three-phase, 6 pulse waveform has ripple.

14%

As an x-ray tube ages, the inside can become coatedwith tungsten, which can cause in the tube.

Arcing

What is the most common cause of tube failure?

Tungsten vaporization

The rotating anode is turned by a

magnetic field

The target of the rotating anode is usually coatedwith a alloy.

Tungsten

What is the formula for heat units for a 3 - phase, 6 -pulse x-ray machine?

1.35 × kVp × mA × seconds

The filament in an x-ray tube is about inlength

1- 2 cm

Extra focal or off-focus radiation is produced from

rebounding electrons

Characteristic k-shell x-rays have an effective energyof keV.

The half value layer (HVL) of an x-ray beam is ameasurement of beam

Quality

Any chromosome damage induced by radiationcould be seen during the

Metaphase

What is the annual effective dose limit recommended for occupational exposure?

5 rem (per year)

What is the total dose limit for the embryo and fetus?

0.5 rem (0.05 per month)

filtration is measured by measurements.

half value layer

the measured kVp should be within + - % of thekVp indicated in the console.

5 Measured kVp = 5%

Occupational radiation monitoring is required if theindividual may get of the recommended doselimit.

10%

During fluoroscopy the exposure to the collar is times greater than exposure to the trunk of thebody under a protective apron.

The preferred way to hold patients who are unable tosupport themselves is to use a

restraining device

If the output intensity of an x-ray machine is 6.4mR/mAs at 80 kVp, what is the patient's ESE for an examdone at 20 mAs at 80 kVp?

128 mR

Performing routine x-ray exams without indication isnot acceptable for

● preemployment physicals ● all hospital admissions ● annual routine physicals

The is the primary protective barrier for thefluoroscopic x-ray tube.

image intensifier

The bucky slot opening in the side of the table mustbe automatically covered with mm Pb duringfluoroscopy.

0.25

The intensity of scatter radiation 1 meter from thepatient is approximately of the intensity of theincident beam at the patient.

0.1%

Measuring the relationship between the output intensities of adjacent mA stations is a test o

● Linearity

Controlled area is one occupied primarily by

● radiology personnel ● Patients

Relative risk is

observed cases/expected cases

A dose of rads or more to a small area of thebody can cause skinerythema.

● 200

A person subjected to 5000 radsto the whole bodymay survive for before death occurs.

● 3 days

The LD50/60 for humans is approximately rads.

● 350

Ovaries are most radiosensitive during

● fetal growth ● early childhood

A type of DNA damage that may not be reversible isa

base change or loss

when H2O receives a free electron, it becomesunstable and dissociates into what free radical?

● H*

Two OH free radicals can join to form molecules

● hydrogen peroxide

. the principal radiation interactions within the humanbody are assumed to be

● indirect effects

the lethal effect of cell irradiation are measured by

● survival

the number of nuclear transformation occurring in a given quantity of material per unit time

● activity

what is the SSD of portable fluoroscope?

● atleast 30cm

the probability or frequent of the biologic responseto radiation dose , increases proportionally with dose: and there is no dose treshold

● stochastic

radiation dose that can be reduce the number ofsperm may delay/suppress menstruation

25 rad

. the latent period for gastrointestinal syndrome is

● 3- 5 days

protective aprons and gloves should be fluoroscopeto check for defect every

● once a year

if the radiologic technologist participates influoroscopy, then the occupational radiation monitorshould be positioned on the collar inside the protective apron

● false

the process by which a neutral atom or moleculeacquires a positive or negative charge

● ionization

refers to the number of ion pairs formed per cm oflathis any given medium

● specific ionization

the proper unit for the exposure of radiologic techand radiologist

● REM

it is an antimatter since it undergoes annihilation

● positron

area occupied primarily by radiology personnel andpatients

● controlled

Refers to the process/processes involved in the transformation of an unstable nucleus into other nuclear form

● radioactive decay

a quantity that reflects not only dose but also thevolume of tissue irradiation.

● dose area product

spontaneous abortion after irradiation during thefirst 2 weeks of pregnancy is more pronounced atradiation doses of:

● 25 rad

it is called the period of major organogenesis:

● 6-8 weeks of pregnancy

the maximum energy required to remove an electronfrom its orbit.

● ionization energy

which of the following statement is true?

● the higher the temperature, the greater theresistance of a uniform conductor

nucleons are made of bounded by gluons.

● Quarks

how many half-value layers will it take to reduce anx-ray beam whose intensity is 78 R/ minto an intensity ofless than 10 R/min?

● 3

in which of the following portions of the x-ray circuitis a step-down transformer located?

● filament circuit