RADT 100 @ OCC - Exam 1

180 sec = ? sec

0.18 sec

If the original intensity is 200 mGy at 30 inches, what is the intensity at 65 inches?

42.6

If the frequency of a photon increases, its wavelength must...

decrease

Rank the following types of radiation, in order from most penetrating to least penetrating:

A. Xray

B. Alpha particles

C. Beta particles

Xray, Beta particles, Alpha particles

The binding energy of the 'K' shell in tungsten is _ keV

69

Which side of the x-ray tube is negatively charged?

Cathode

A gamma camera is used in which modality?

nuclear medicine

Occupational dose is measured by?

Sieverts

A charged particle in motion creates/induces a .....

magnetic field

Transformers work on _________ current.

alternating

The target of the typical xray is made of what metal?

tungsten

Pick the two types of xray production:

1. characteristic

2. photoelectric effect

3. bremsstrahlung

4. compton effect

characteristic; bremsstrahlung

like charges _, unlike charges _.

repel, attract

Which of the following electromagnetic radiations has the highest energy?

1. radiowaves

2. visible light

3. xrays

4. gamma rays

gamma rays

The ionized atom and the released electron are called an:

ion pair

xray voltages are measured in _ and xray currents are measured in _.

kVp, mA

The amount of background radiation the public receives is approximately _ mSv annually based on 2006 date

3.1 mSv

The atomic number is described as _

number of protons in nucleus

The external structure of the xray tube includes the support structure, the protective housing, and the _

glass envelope

As an xray tube ages, the inside can become coated with tungsten, which can cause _ in the tube

arcing

The filament is made of _

tungsten

thermionic emission at the filament creates a _

space charge

the rotating anode is turned by a _

magnetic field

The induction motor works by _

electromagnetic induction

When electrons bombard the target, _% of their kinetic energy is converted to heat

99%

The target of the rotating anode is usually coated with a _ alloy.

tungsten

The _ is the source of radiation in the xray tube

focal spot

High capacity tube rotors revolve at _ rpm.

10,000 rpm

The filament in an xray tube is about _ cm in length.

1-2 cm

A dual focus tube has two

filaments

The _ is/are outside the glass envelope

stators

The anode side of the tube has a _ charge

positive

The focusing cup has a _ charge

negartive

Like charges _____ and unlike charges _____

repel, attract

A _ is a source of direct current

1. wall socket

2. generator

3. spark

4. battery

battery

An alternating current is represented by a ____ line

sinusoidal

A charged particle in motion creates a _.

magnetic field

Rubber and glass are _

insulators (because they are nonconductors)

potential energy

the ability to do work by virtue of position

kinetic energy

the energy of motion; it is possessed by all matter in motion

chemical energy

the eenrgy released by a chemical reaction; at a molecular level

electrical energy

the work that can be done when an electron moves through an electric potential difference (voltage)

gravity

fundamental invisible force or attraction between any two objects that have mass or energy

weight

force on mass that is caused by the acceleration of gravity

expressed in Newtons: 1 N = 4.4 lb

mass

quantity of matter as described by its energy equivalence

thermal energy

The energy of motion at the molecular level

nuclear energy

the energy that is contained within the nucleus of an atom (E=mc2)

electromagnetic energy

type of energy that is used in xray imaging

includes: radio waves, microwaves, and ultraviolet waves

radiation

the transfer of energy through space

ionizing radiation

removal of an electron from an atom

properties of xrays

highly penetrating, electrically neutral, releases small amounts of heat, travels at speed of light, produce secondary & scatter radiation, travel in a straight line

Radiology emerged as a medical specialty because of the _ transformer and the _ xray tube

Snook, Coolidge

ALARA

As Low As Reasonably Achievable

filtration

metal aluminum filters inserted in the xray housing so that low energy xrays are absorbed before reaching the patient

collimation

The restriction of the size and shape of the x-ray beam in order to reduce patient exposure

matter

anything that occupies space

energy

ability to do work

xray voltages are measured in

kilovolt (kVp)

* 1 kilovolt is equal to 1,000 volt of electrical potential

xray current is measured in

milliampere (mA)

* (A) is a measure of electrical current

* milli = 1/1000 or .001

Air Kerma (Gya)

unit of radiation exposure

Gray (Gyt)

Unit of radiation absorbed dose (rad)

sievert (Sv)

unit of occupational radiation exposure and effective dose

becquerel (Bq)

unit of radioactivity

velocity (equation)

distance/time

force (equation)

mass x acceleration

work (equation)

force x distance

heat

kinetic energy of the random motion of molecules (conduction, convection, radiation)

Bohr atom

represents the atom as a nucleus surrounded by electrons in discrete electron shells

atomic number

whole number at the top representing the number of protons (this defines an element)

chemical symbol

a 1 or 2 letter representation of an element

atomic mass

the weighted average of the masses of the isotopes of an element

groups (columns)

there are 18 groups. Elements in the same group have the same number of valence electrons (electrons in the outer shell)

periods (rows)

7 periods. The period number indicates the number of electron shells an atom has

periodic law

elements in the same column exhibit similar chemical properties and repeating physical trends due to their outermost electrons

metals (in periodic table)

located on the left and center of the table. Typically they are shiny, malleable, ductile, and conductors of heat and electricity.

nonmetals (in periodic table)

located on the far right of table. Generally dull, brittle, and poor conductors.

metalloids/semimetals (in periodic table)

found along a staircase-like dividing line. Posess properties of both metals and nonmetals

alkali metals (group 1)

highly reactive, soft metals (n/a hydrogen)

alkaline earth metals (group 2)

reactive but harder and denser than alkali metals

transition metals (group 3-12)

hard, dense, & less reactive metals

Halogens (Group 17)

highly reactive nonmetals that often bond with metals to form salts

Noble Gases (Group 18)

unreactive, stable gases because their outer electrons are full

atomic radius (periodic trends)

decreases from left to right (as the nucleus pulls electrons closer) and increases as you move down (due to adding more electron shells)

ionization energy (periodic trends)

increases from left to right (harder to remove electron) and decreases moving down (easier to remove)

electronegativity (periodic trends)

increases from left to right and decreases fom top to bottom

fundamental particles of an atom _

electron, proton, neutron

atomic mass units (amu)

mass of a neutral atom of an element

atomic mass numbers (A)

number of protons plus number of neutrons in the nucleus

atomic number (Z)

the number of protons in the nucleus of an atom

isotopes

Atoms of the same element that have different numbers of neutrons

isobars

atomic nuclei that have the same atomic mass number but different atomic numbers

isotones

same number of neutrons, different number of protons

isomers

same atomic number and same atomic mass number

the smallest particle of an element is an _. The smallest particle of a compound is a _.

atom, molecule

radioactive half-life

time required for a quantity of radioactivity to be reduced to one-half its original value

types of atomic bonds

covalent, ionic

ionic bonding

occurs when an electron from one atom transfers to another atom

covalent bonding

two atoms are bonded by sharing some of the same electrons that revolve around both nuclei

wavelength equation

wavelength = velocity/frequency

frequency

number of wavelengths that pass a point of observation per second