RAT Physics Exam 3

What is an after-loader?

A device in a Brachytherapy (tumor treatment in with radiation) that delivers the planned radiation dose to the treatment area

Plank's constant

photon energy frequency calculation

Basic properties of x-ray

Unaffected by gravity
Unaffected by electric & magnetic fields
Travels in straight lines
Are exponentially attenuated by matter
Cannot be focused

Linac

linear accelerator

Simulator

Computed Tomography Machine

brachytherapy radiation

A permanent or temporary implantation of small, sealed containers (seeds) of radioactive material directly into the tumor or in a cavity of the tumor.

Types of Brachytherapy

HDR & LDR

HDR Brachytherapy

temporary implantation of small, sealed containers (seeds) directly into the tumor or in a cavity of the tumor using after-loading device

LDR Brachytherapy

Emits low doses of radiation with seeds that stay inside permanently

Nuclear Medicine

Injection or ingestion of radioactive materials and recording of their uptake in the body using a gamma camera.

What does a patient emit from Nuclear medicine?

Gamma rays

HDR Unit Source

Iridium-192

What is NOT ionizing radiation?

MRI & Ultrasound

Electromagnetic Radiation consists of:

electric and magnetic disturbances that travel through space as waves

What is the most common form of radiation?

Visible Light

Penumbra

Fuzzy edge of soft X-ray

Ionizing Radiation

Knockout or add electrons to atoms

All radiologic equipment is based on:

The laws of electricity and magnetism

Etiology

the study of the causes of diseases

Epidemiology

the study of the distribution of mental or physical disorders in a population

Electromagnetic Radiation has characteristics of:

Particles & Waves

Diffraction

The bending of sound, which is a characteristic of waves

What is a term for scatter irradiation?

Diffraction

Scatter is diffraction that:

Adds to your patient dose

Characteristics of Electromagnetic Radiation:

wavelength, frequency, and velocity

The linear accelerator operates at:

3000 MegaHertz (mHZ)

Electromagnetic Radiation as a particle is called?

Photon

What is a photon?

Bundles of energy

What do photons exhibit?

Wave-particle duality

Isotopes are

atoms of the same element that have the same number of protons

Isomers are

compounds with the same molecular formula but different structures and properties

Isobars are

Elements that have both the same number of protons and neutrons

Isotones are

Atoms with the same number of neutrons

Velocity

How fast the radiation moves

Bohr Model

model of the atom in which negative electrons move rapidly around the positive nucleus in paths called orbits

Absorbed energy is measured in

Gray

Dose Equivalent is measured in

Sievert

Radioactivity is measured in

Becquerel (Bq) = 1 dps per second

Ionization in air is measured in:

Coulomb

4 forces of nature: strongest to weakest

Strong
Electromagnetic
Weak
Gravitational

Wavelength is measured in

meters (m)

Frequency is measured in

Hertz (Hz)

Coulomb Electrostatic Force

Holds the atom together

Electron binding energy

Energy needed to knock an electron out of orbital shells

Nuclear Binding Energy

Energy needed to break apart the nucleus

Inverse Square Law

the intensity of radiation is inversely proportional to the square of the distance from the source of radiation

What Linear Energy Transfer is proportional to?

Relative Biological Effectiveness

Why do we use X-ray and gamma rays in Radiation?

It gives patients a chance to heal themselves due to the Low LET & RBE it gives

What particle cannot break through paper?

Alpha

What particle has the highest LET & RBE?

Alpha

What particle has a higher LET & RBE than Gamma & X-Ray?

Beta

What particle gives off most of its energy as it travels?

Alpha

What is the only therapeutic imaging modality?

Radiation Therapy

What is brachytherapy?

Short Distance Radiation Therapy

What is an HDR Unit called?

After loading device

HDR Afterloader

Implant device in Brachytherapy that delivers the planned radiation dose to the treatment area, retracts it after a certain amount of time to remove the implants

Tandems

A long narrow tube that goes into the cervix, up into the uterus

Ovoids

egg-shaped bodies that are inserted into the fornices of vagina

Vagina Cylinder

Device used to give even dose distribution that is inserted into vagina, up to external os

Savi

Used for breast treatments, inserted into cavity in the breast that get expanded to treat breast internally using the channels connected to the source.

Where do mV energies come from?

Gantry

CT Bohr

Used for simulation process to create treatment plan using the images

C-Arm

A mobile fluoroscopy unit used in surgery or at the bedside

What are types of Diagnostic X-Ray Units?

Basic X-Ray
C-Arm
Portable X- Ray Unit

Different types of electromagnetic radiation/ energies are known as the:

Electromagnetic Spectrum

types of electromagnetic radiation

visible light, x-rays, gamma rays, ultraviolet and infrared light, microwaves, and radio waves

Radiation travels at

speed of light

The electromagnetic spectrum lists the different types of electromagnetic radiations varying in:

Energy
Frequency
Wavelength

Wavelength

distance from peak to peak

Frequency

The number of peaks in a second

Radiowaves

an electromagnetic wave that has the longest wavelength and has the least energy

Radio frequency is used in:

MRI

Microwaves

Electromagnetic waves that have shorter wavelengths and higher frequencies than radio waves.

infrared radiation

Heating elements with shorter wavelengths and higher frequency

Visible Light

electromagnetic waves that activates the cells in the eyes

What occupies a very narrow band in the electromagnetic spectrum?

Visible Light

Red visible light

lowest frequency, longest wavelength of visible light

Blue and Violet Light

Highest energy and shortest wavelength of visible light

What destroys airborne bacteria?

Ultraviolet Rays

What is responsible for the majority of skin cancers and sunburn?

Ultraviolet Rays

Properties of Electromagnetic Radiation

Consists of vibrations in electric & magnetic fields
No charge
No mass
Travels at the speed of light
Waves move in sinusoidal waveform

What happens as we move up the spectrum?

The wavelengths get smaller and the frequency vets higher

What is the basic electron volts that we deal with?

KeV & MeV

Anything that's an energy of 1 MeV is considered?

Therapeutic

A Diagnostic x-ray has an energy of?

1 KeV

What takes advantage of hydrogen ions?

MRI machine

What is the most abundant element in the body?

Hydrogen

What type of movement does an MRI machine perform?

Spin- magnetic movement

Spin magnetic movement

Takes hydrogen ions in the body, lines them up from pole to pole, and gives a soft tissue image

What are radio frequency coils used for?

To enhance magnets to get better imaging by realigning the hydrogen ions.

What contributed to different types of skin cancers?

UVA
UVB
UVC

What are 3 types of skin cancers?

basal cell carcinoma, squamous cell carcinoma, malignant melanoma

Etiology for Lung Cancer

Smoking

Etiology for head and neck cancer

Smoking and drinking

Etiology for cervical cancer

HPV, and promiscuity

How would you best describe a waveform?

Sinusoidal

wave-particle duality

X-rays, gammas and light can behave as both a wave and a particle

Wave particle duality can cause what?

Penumbra

The target in the linear accelerator is typically made of

Tungsten

What is produced from a source or a target?

X-ray