Ch. 1 Intro to Imaging PRACTICE QUESTIONS

What is a cathode ray tube?

partial vacuum that produces an electron stream

Who discovered x-rays?

Roentgen

What was roentgen experimenting with when he discovered xrays?

cathode ray tube of crooked type

What was the first radiograph?

Roentgen's wife's hand on December 1895

What did Roentgen write about his discoveries?

three communications (informal papers)

What was Roentgen the first to be awarded?

nobel prize in physics 1901

What phenomenon did Roentgen investigate that led to discovery of xray?

Fluorescence of barium platinocyanide painted cardboard every time crookes tube was energized

What were the exposure times of early xrays?

30 minutiea

Why were early xrays inefficient?

30 minute exposure time

What is acute radiodermatitis?

radiation burns

How were images created in early xray machines?

photographic plates exposed to xrays

What were the side effects of early xray machines on the operator and patient?

radiation burns and electrocutions

Why did the scientific community initially think xrays were harmless?

did not immediate connect radiation burns to xray

thought they were sunburns

Who brought attention to the dangers of x-rays?

Thomas Edison

Why did Edison discontinue xray experiments?

Was injured with radiation burns

What was the only treatment for radiation burns in early xrays?

Amputation

Why did Clarence Dally (Edison's assistant) die?

from his injuries from experimenting with xray

What were early identifying factors of xray technologists?

amputations and gloved hands

What nearly eliminated acute radiodermatitis in 1900?

improved imaging plates, techniques

What is ionizing radiation?

radiation with enough energy to ionize atoms

What are the fundamental quantities of measure?

mass, length, time

How are derived quantities formed?

combining fundamental quantities

What are derived quantities?

velocity

acceleration

force

momentum

work

power

What are radiologic quantities?

dose

dose equivalent

exposure

radioactivity

What is the unit of measure of mass?

pound / kilogram

What is the unit of measure of length?

foot / meter

What is the unit of measure of time?

second

What is the unit of measure of velocity?

m/s

What is the unit of measure of acceleration?

m/s^2

What is the unit of measure of force?

N

What is the unit of measure of momentum?

kg*m/s

What is the unit of measure of work?

Joule (J)

What is the unit of measure of power?

Watt (W)

What is mass?

quantity of matter in a object

What is matter?

Anything that has mass and takes up space

What is intertia?

property of an object with mass that resists a change in its state of motion

When were xrays discovered?

November 8, 1895

What is mass in relation to inertia?

Mass is the measure of the amount of inertia that a body possesses

What is energy?

the ability to do work

What are the two states of energy?

potential and kinetic

What is potential energy?

energy in a stored state

What is kinetic energy?

energy being expended (doing work)

What forms can energy exist in?

electromagnetic

electrical

thermal

chemical

What is electromagnetic energy?

energy that exists as an electric and magnetic disturbance in space

Coulomb/kilogram (C/Kg)

Roentgen (R)

Gray (Gy)

Radiation absorbed dose (rad)

Sievert (Sv)

radiation equivalent man (rem)

Becquerel (Bq)

Curie (Ci)

What is the C/Kg a measure of?

number of electrons liberated by ionization per kg of air (output intensity/intensity in air)

How many electrons is 1 Coulomb?

6.24 x 10^18

What is R (roentgen) used to quantify?

radiation intensity (output intensity/ intensity in air)

How much is 1 R equal to?

radiation that will produce 2.08x10^9 ion pairs in a cubic centimeter of air

What is the Gy?

unit of absorbed dose

What is the Gy a measure of ?

quantity of radiation energy absorbed by tissues being irradiated (on target object)

What is the Gy used to quantify?

the biologic effects of radiation on humans and animals

What is Sv used to quantify?

occupational exposure or dose equivalent

What does the Sv specifically address?

different biologic effects of different types of ionizing radiation to which a radiation worker may be exposed

What is the quality factor of the energy range of radiation encountered in radiologic sciences?

1

What is Bq used to quantify?

radioactivity

What does the Bq specifically measure?

quantity of radioactive material (NOT the effect) number of individual atoms decaying per second

What is 1 Curie (Ci) equivalent to?

quantity of radioactive material in which 3.7x10^10 atoms disintegrate every second

Effective dose

expression of relative risk to humans of exposure to ionizing radiation

KERMA

Kinetic Energy Released per Mass Unit

What is KERMA used to quanitfy?

quantity of radiation energy delivered to a given point

Who was able to describe practically every property of xray knows today through their experiments?

Roentgen

What is the difference between KERMA and dose?

kerma is the measure of energy released at a given point, dose is the expression of amount of energy absorbed at a given point

What two categories can radiographic equipment be classified as?

mobile or permanently installed

What is MOBILE EQUIPMENT?

unit on wheels (can be taken bedside, er, surgery, wherever)

What is PERMANENTLY INSTALLED EQUIPMENT?

units fixed in place in a particular room specifically designed for the purpose of

What does a permanently installed equipment consist of?

tube

collimator

table

control console

tube stand

wall unit

What comprises the tube head assembly?

xray tube

collimator

tube stand

What is the xray tube?

special diode tube that converts electrical energy into xrays (and heat by product)

positive electrode

Anode

Negative electrode

cathode

What is the collimator used for?

restricts the xray beam to area of interest and helps localize beam to that area

What is the purpose of the tube stand/ mount?

gives mobility to the xray tube

What are the variants of tube mounts?

floor

floor-ceiling

floor-wall

ceiling

Why is the overhead tube assembly (ceiling mount) the most widely used in hospitals?

allows for maximum flexibility and movement

What does the table do?

for easy patient positioning, can be lowered and raised

What is the xray table?

has a 4-way floating top with electromagnetic locks

What is the fluoroscopy variation of the table?

motor moves the tabletop and the mechanism can tilt the table to position patient in trendelenburg positions

What does the wall unit consist of?

vertical rail assembly affixed to the wall and floor and a vertical bucky assembly

What does the wall units rail allow?

adjustment of bucky height

What is the control panel?

panel used by radiographer to select parameters (kilovoltage and milliamperage) that is applied to xray tube to produce xray

What does the control panel allow the radiographer to do?

fine-tune or modify exposure parameters to best image the area of body of interest

What does ALARA stand for?

As Low As Reasonably Achievable

What are the three cardinal principles for minimizing radiation dose?

shielding

time

distance

What does the ARRT do?

certifies individuals

write the standard of ethics (code of ethics/ rule of ethics)

What does shielding consist of?

the use of radiopaque materials to reduce exposure

What does ASRT stand for?

American Society of Radiologic Technologists

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