MT1 - Nature of Radiation - 2 Qs Flashcards by F S

What is radiation?

The production and emission of energy through space or a material medium

How well did you know this?

Not at all

Perfectly

What are the 2 types of radiation?

Particulate (Corpuscular) Radiation

2. Electromagnetic (non-particulate) Radiation

How well did you know this?

Not at all

Perfectly

What kinds of particles are involved in particulate radiation?

Protons
Neutrons
Electrons
Alpha particles
Beta particles

How well did you know this?

Not at all

Perfectly

What types of energy are involved in elecromagnetic (EM) radiation?

Radi
TV
Radar
Infrared
Visible Light
UV
Gamma rays
X-RAYS*

How well did you know this?

Not at all

Perfectly

How are EM waves grouped/categorized?

According to wavelength in the EM spectrum

How well did you know this?

Not at all

Perfectly

At what speed to EM waves travel in air?

At the speed of light

How well did you know this?

Not at all

Perfectly

What is another term for electromagnetic waves?

Electromagnetic Radiation

How well did you know this?

Not at all

Perfectly

What is the mass and charge of electromagnetic Radiation?

EM waves have no mass and no charge

How well did you know this?

Not at all

Perfectly

How does wavelength correlate to frequency and energy?

Wavelength is inversely related to frequency and energy, therefore a shorter wavelength actually will have higher energy adn higher frequency (and vice versa)

How well did you know this?

Not at all

Perfectly

How are x-rays defined?

X-rays are EM radiation with wavelengths shorter than UV but longer than gamma radiation

How well did you know this?

Not at all

Perfectly

How are x-rays packaged?

As photons, packets, or weightless bundles

How well did you know this?

Not at all

Perfectly

Are the energies and wavelengths of x-rays variable or constant?

X-rays have variable wavelengths and energies

How well did you know this?

Not at all

Perfectly

Describe the effect of x-rays on biological molecules

X-rays cause ionization in biological molecules when they interact with the patient’s body.

How well did you know this?

Not at all

Perfectly

How are x-rays produced?

Highly accelerated electrons are suddenly brought to a stop by hitting a stationary object, thus causing a fraction of the kinetic energy possessed by the high speed electron to be converted to x-rays.

How well did you know this?

Not at all

Perfectly

Who was the 1st person to describe the structure of an atom?

Neils Bohr

How well did you know this?

Not at all

Perfectly

What are the 4 parts of an atom?

Nucleus
Electrons
Protons
Neutrons

How well did you know this?

Not at all

Perfectly

What part of the atom makes up over 99% of the mass?

Nucleus

How well did you know this?

Not at all

Perfectly

What determines the identity of an element?

The number of protons (Z number)

How well did you know this?

Not at all

Perfectly

What is Z number?

Z number is the atomic number, equivalent to the number of protons, which determines the identity of an element

How well did you know this?

Not at all

Perfectly

How do Z number and the number of electrons in a neutral atom relate?

Z number will be the same as the number of electrons in a neutral atom

How well did you know this?

Not at all

Perfectly

What is the A number?

A number is the atomic mass which is equal to the number of protons plus the number of neutrons

How well did you know this?

Not at all

Perfectly

What is the symbol designation for an element’s Z and A numbers?

Z number is written as subscript and A number is written as superscript

How well did you know this?

Not at all

Perfectly

How is the charge of an electron related to the charge of a proton?

Electrons have a negative charge equal in magnitude to the positive charge of a proton

How are orbital electrons arranged in the atom?

Electrons are arranged in definitive energy levels (shells or orbits) outside the nucleus at varying distances

How are electrons kept in their orbits?

By electrostatic attraction and centripetal force

How are orbits designated?

Orbits are lettered K, L, M, N, O, P and Q from innermost to outermost

What is the maximum number of orbits in a given atom?

7 orbits

Are orbits limited in the number of electrons they can hold?

Yes. There is a maximum number of orbits that each designated orbit can hold. K orbit can only hold 2 electrons, while Q, the outermost shell, can hold 98 electrons

Define binding energy

Binding energy is the attractive force that keeps electrons in their orbit

How are binding energy and the distance b/t the nucleus and an electron related?

Binding energy is inversely proportional to the square of the distance b/t the nucleus and the electron

Which electrons are most vs least tightly bound to the nucleus?

K shell electrons are most tightly bound while outermost electrons in the Q shell are least tightly bound

How is EM radiation created?

While moving an electron from an outer orbit to the one closer to the nucleus, energy is lost in the form of electromagnetic radiation

How can an electron be removed from its orbit?

To remove an electron from its orbit, an energy greater than the binding energy must be supplied

What electron shells are involved in x-ray production?

Electrons in K, L, and M shells

How are Z number and binding energy related?

The higher the Z number, the higher the binding energy for any particular shell

In particulate radiation, energy is transferred via _____

High velocity subatomic particle

What kind of energy is associated with particulate radiation?

Kinetic energy (KE) is associated with particulate radiation

How does KE relate to mass and velocity?

KE=1/2mV^2, therefore KE is DIRECTLY related to both mass and velocity

How is energy usually supplied when using particulate radiation?

Via electricity

What is the most common clinical application for particulate radiology?

Radiation therapy

What is linear energy transfer (LET)?

The rate of loss of energy of a particle as it moves along its path in an absorber

How is the mass and charge of a particle related to LET?

DIRECTLY related. The higher the mass and charge of a particle, the higher the RATE of TRANSFER of energy to the absorber

How is the velocity of a particle related to LET?

INVERSELY related. The lower the rate of velocity of a particle, the higher the rate of transfer for energy to an absorber

How is chemical composition (Z number), thickness, and density of the ABSORBER related to LET?

DIRECTLY related. Higher Z#, thicker and denser the absorber, the sooner the particle loses energy and is unable to travel.

What travels with the least amount of LET, alpha, beta, or x-ray particles?

X-rays have the least rate of LET and therefore travel furthest and weigh the least. The travel thru tissues and are recorded on an image receptor

What is another name for non-particulate radiation?

Electromagnetic radiation

Describe energy transfer with EM radiation?

Transfer of energy thru space as a combination of electrical and magnetic fields

Is EM radiation best described by wave theory or quantum theory?

Actually EM radiation is best described by a combination of both wave and photons (quanta)

Why do we use a focusing cup when taking radiographs?

Due to the wave nature of EMR, EMR travels in all directions from its source, thus a focusing cup is used to direct the EMR toward the patient.

Define wavelength

The distance between 2 successive crests of troughs. Measured in meters, or in the case of x-rays, measured in angstroms

Define frequency

Number of oscillations, vibrations, waves, or cycles per second

How does velocity relate to wavelength and frequency?

velocity = wavelength x frequency

Does velocity of EMR in air vary?

NO! Velocity of all EMRs in air is the same (3x10^10 cm/sec)

How are energy and velocity related?

Energy and velocity are directly related, therefore an increase in in velocity results in an increase in energy

How are energy and wavelength related?

Energy and wavelength are inversely related, therefore an EMR with longer wavelength will have lower energy