RADIATION PHYSICS AND CHARACTERISTICS (D1)

CHAPTER 1 and CHAPTER 2 in Bushong (D1)

Matter

_______ is anything that occupies space and has mass.

Matter

It is the material substance of which physical objects are composed.

atoms

All matter is composed of fundamental building blocks called ______, which are arranged in various complex ways.

mass

A primary, distinguishing characteristic of matter is ______, the quantity of matter contained in any physical object.

weight

_________ is the force exerted on a body under the influence of gravity.

Kilograms

Mass is measured in _______.

matter

________ is anything that occupies space.

Mass

It is the material substance having mass of which physical objects are

composed.

Mass

______ is the quantity of matter as described by its energy equivalence.

atoms and molecules

The fundamental, complex building blocks of matter are _____ and ______ .

Potential Energy

__________ is the ability to do work by virtue of position.

kinetic energy

is the energy of motion.

chemical energy

is the energy released by chemical reaction.

electrical energy

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

thermal energy (heat)

is the energy of motion at the molecular level

thermal energy (heat)

it is the kinetic energy of molecules and is closely related to temperature

nuclear energy

is the energy that is contained within the nucleus of an atom.

electric nuclear power plants

nuclear energy is the energy that is contained within the nucleus of an atom, we control the release and use of this type of energy in ___________.

atomic bomb

an example of uncontrolled release of nuclear energy is the ________.

electromagnetic energy

is perhaps the least familiar form of energy.

sound or diagnostic ultrasound

electromagnetic energy does not include ________ or __________ .

mass energy equivalence

this mass-energy equivalence serves as the basis for the atomic bomb, nuclear power plants, and certain nuclear medicine imaging modalities.

radiation

energy emitted and transferred through space is called _______?

radiation

electromagnetic energy is usually referred to as electromagnetic radiation or simply, _________.

exposed or irradiated

matter that intercepts radiation and absorbs part or all of it is said to be _______ or _______.

ionizing radiation

is a special type of radiation that includes the x-rays

ionizing radiation

is any type of radiation that is capable of removing an orbital electron from the atom with which it interacts.

Ionization

it occurs when an x-ray passes close to an orbital electron of an atom and transfer sufficient energy to the electron to remove it from the atom.

ion pair

the orbital electron and the atom from which it was separated are called an _________.

negative ion

the electron is a _________, and the remaining atom is a positive ion.

positive ion

the electron is a negative ion, and the remaining atom is a ________.

ionizing radiation

thus any type of energy that is capable of ionizing matter is known as ________.

x-rays, gamma rays and ultraviolet light

______,______, and _______ are the only forms of electromagnetic radiation with sufficient energy to ionize.

alpha and beta particles

examples of particle-type ionizing radiation are ______ and _____ .

rays

although alpha and beta particles are sometimes called ______, this designation is incorrect.

natural environmental radiation and man-made radiation

sources of ionizing radiation can be divided into two main categories:

3 millisieverts (mSv)

natural environmental radiation results in annual dose of approximately ________ annually.

3.2 mSV

man-made radiation results on _________ annually.

mSv or millisieverts

it is used to express radiation exposure of populations and radiation risk in those populations.

mSv or millisieverts

An ______ js the unit of effective dose.

1. cosmic rays

2. terrestrial radiation

3. internally deposited radionuclides

4. radon

natural environmental radiation consists of four components:

cosmic rays

_________ are particulate and electromagnetic radiation emitted by sun and stars.

altitude and latitude

on earth, the intensity of cosmic radiation increases with ______ and _______.

uranium, thorium, and other radionuclides in the Earth

Terrestrial radiation results from deposits of _____, ____ and ______.

geology of the local area

The intensity of the terrestrial sources of radiation is highly dependent on the ________.

potassium-40 ( 40K)

Internally deposited radionuclides, mainly ______, are natural metabolites.

Terrestrial Sources of Radiation

They have always been with us and contribute an equal dose to each of us.

Radon

The largest source of natural environmental radiation is

Radon

_____ is a radioactive gas that is produced by the natural radioactive decay of uranium, which is present in trace quantities in the Earth.

Radon

_____ emits alpha particles, which are not penetrating, and therefore contributes a radiation dose only to the lung.

alpha particles

Radon emits _______, which are not penetrating, and therefore contributes a radiation dose only to the lung.

Diagnostic x-rays

______ constitute the largest man-made source of ionizing radiation (3.2 mSv/yr).

computed tomography (CT) and high-level fluoroscopy

The increase during this 16-year period in sources of man-made radiation is principally attributable to the increasing use of _______ and __________.

3.2 mSv

The currently accepted approximate annual dose resulting from medical applications of ionizing radiation is _____.

0.1 mSv

Consumer products such as watch dials, exit signs, smoke detectors, camping lantern mantles, and airport surveillance systems contribute only ______ to our annual radiation dose.

discovered

X-rays were not developed; they were ______, and quite by accident.

Crookes tube

During the 1870s and 1880s, many university physics laboratories were investigating the conduction of cathode rays through a large, partially evacuated glass tube known as a ________.

William Crookes

when was xray discovered?

barium platinocyanide

On November 8, 1895, Roentgen was working in his physics laboratory at Würzburg University in Germany. He had darkened his laboratory and completely enclosed his Crookes tube with black photographic paper so he could better visualize the effects of the cathode rays in the tube. A plate coated with ___________, a fluorescent material, happened to be lying on a bench top several meters from the Crookes tube.

visible light

No ______ escaped from the Crookes tube because of the black paper that enclosed it, but Roentgen noted that the barium platinocyanide glowed.

fluorescence

The intensity of the glow increased as the plate was brought closer to the tube; consequently, there was little doubt about the origin of the stimulus of the glow. This glow is called ______.

early 1896

He produced and published the first medical x-ray image in ________. It was an image of his wife’s hand is a photograph of what is reported to be the first x-ray examination in the United States, conducted in early February 1896, in the physics laboratory at Dartmouth College.

Radiography

__________ uses film or a solid-state image receptor and usually an x-ray tube mounted from the ceiling on a track that allows the tube to be moved in any direction.

Fluoroscopy

______ is usually conducted with an x-ray tube located under the examination table. The radiologist is provided with moving images on a television monitor or flat panel display.

Computed Tomography

_______ uses a rotating x-ray source and detector array. A volume of data is acquired so that fixed images can be reconstructed in any anatomical plane—coronal, sagittal, transverse, or oblique.

30 minutes or longer

Early radiographic procedures often required exposure times of _________.

image blur

Long exposure time results in _________.

intensifying screen

One development that helped reduce this exposure time was the use of a fluorescent _______ in conjunction with the glass photographic plates.

Michael Pupin

______is said to have demonstrated the use of a radiographic intensifying screen in 1896, but only many years later did it receive adequate recognition and use

Charles L. Leonard

___________ found that by exposing two glass x-ray plates with the emulsion surfaces together, exposure time was halved, and the image was considerably enhanced.

1918

This demonstration of double-emulsion radiography was conducted in 1904, but double-emulsion film did not become commercially available until ______.

Belgium and other European countries

Much of the high-quality glass used in radiography came from ________

cellulose nitrate

The demands of the army for increased radiologic services made necessary a substitute for the glass plate. The substitute was ______, and it quickly became apparent that the substitute was better than the original glass plate.

1898

The fluoroscope was developed in _____ by the American inventor Thomas A. Edison

Thomas A. Edison

The fluoroscope was developed in 1898 by the American inventor _________

barium platinocyanide

Edison’s original fluorescent material was _________, a widely used laboratory material.

1904

Clarence Dally died in ____ and is counted as the first x-ray fatality in the United States.

Clarence Dally

He is counted as the first xray fatality in the United States.

diaphragm

Two devices designed to reduce the exposure of patients to x-rays and thereby minimize the possibility of x-ray burn were introduced before the turn of the 20th century by a Boston dentist, William Rollins. Rollins used x-rays to image teeth and found that restricting the x-ray beam with a sheet of lead with a hole in the center, a _______, and inserting a leather or aluminum filter improved the diagnostic quality of radiographs.

collimation and filtration

This first application of ______ and _______was followed very slowly by general adoption of these techniques. It was later recognized that these devices reduce the hazard associated with x-rays

Snook

_______ introduced a substitute high-voltage power supply, an interrupterless transformer, for the static machines and induction coils then in use.

interrupterless transformer

Snook introduced a substitute high-voltage power supply, an ___________, for the static machines and induction coils then in use.

Snook transformer

Although the _______was far superior to these other devices, its capability greatly exceeded the capability of the Crookes tube.

William D. Coolidge

After considerable clinical testing, ________ unveiled his hot-cathode x-ray tube to the medical community in 1913. It was immediately recognized as far superior to the Crookes tube.

Coolidgre Tube

It was a vacuum tube that allowed x-ray intensity and energy to be selected separately and with great accuracy.

Coolidge tube

X-ray tubes in use today are refinements of the _________.

Snook transformer and the Coolidge x-ray tube

Radiology emerged as a medical specialty because of the ________ and ________.

stationary grid (“Glitterblende”)

In 1913 Gustav Bucky (German) invented the ________

H. Potter (American)

In 1915 ________, probably unaware of Bucky’s patent because of World War I, also invented a moving grid.

1921

To his credit, Potter recognized Bucky’s work, and the PotterBucky grid was introduced in_______.

1950

In 1946 the light amplifier tube was demonstrated at Bell Telephone Laboratories. This device was adapted for fluoroscopy by ______ as an image intensifier tube

image intensifier tube

In 1946 the light amplifier tube was demonstrated at Bell Telephone Laboratories. This device was adapted for fluoroscopy by 1950 as an _________

solid-state image receptors

Today, image-intensified fluoroscopy is being replaced by __________.

1960s

Diagnostic ultrasonography appeared in the _______, as did the gamma camera.

1970s

Positron emission tomography and x-ray CT were developed in the _______.

1980s

Magnetic resonance imaging (MRI) became an accepted modality in the ____, and now digital radiography and digital fluoroscopy are rapidly replacing screen-film radiography and image-intensified fluoroscopy.

1904

The first x-ray fatality in the United States occurred in ______.

aplastic anemia and leukemia

Years later, it was discovered that blood disorders such as _______ and ________ were occurring in radiologists at a much higher rate than in others

latent harmful effects

Current studies suggest that even the low doses of x-radiation used in routine diagnostic procedures may result in a small incidence of ___________.

Filtration

Metal filters, usually aluminum or copper, are inserted into the x-ray tube housing so that low-energy x-rays are absorbed before they reach the patient. These x-rays have little diagnostic value.