Imaging Ch 1 Challenge Questions

The ability to do work or physically influence surroundings because of position, chemical state, or nuclear state.

energy

Secondary quantities that are derived from a combination of one or more of the three base quantities (e.g., volume, density, and velocity).

derived quantity

Any electromagnetic or particulate radiation that has sufficient energy to remove an electron from an atom.

ionizing radiation

1/1000 of a rad, where the rad (radiation absorbed dose) is 100 ergs of energy absorbed per gram of tissue.

air karma

Approximately 300 mrad/yr.

the average level of natural environmental radiation

The first heated filament x-ray tube was developed by a physicist, William Coolidge, in 1913.

the Coolidge tube

The production of continuous x-ray images in real time using a special x-ray imaging system, the fluoroscope, with continuous low mA. The fluoroscope was first demonstrated by Thomas Edison in 1898.

fluoroscopy

The rate of change of velocity (speed and/or direction) with time.

acceleration

the term applied to the chemistry of the body

biochemistry

A phosphor that glows when excited with x-rays. This is the phosphor with which Roentgen was experimenting when he discovered x-rays.

barium platinocyanide

Roentgen discovered x-rays in:

1895

Roentgen wins the first Nobel Prize in physics in which year?

1901

The Snook transformer was developed in which year?

1907

The Coolidge hot-cathode x-ray tube is introduced in which year?

1913

Describe how weight is different from mass.

Weight is determined by the force of gravity. Weight changes in value with position in a gravitational field such as that of the Earth or the moon. Mass is constant. It is independent of position and is determined by the object's energy equivalence.

Name four examples of electromagnetic radiation.

X-rays, gamma rays, visible light, radio waves (also microwaves, infrared radiation, ultraviolet radiation).

How is x-ray interaction different from that seen in other types of electromagnetic radiation?

X-rays interact at the electron level or nuclear level, ionizing an atom or ejecting a nuclear particle, respectively. Lower-energy electromagnetic radiation interacts with molecules, cells, and larger objects in a way that will usually elevate the temperature of the object.

What is the purpose of x-ray beam filtration?

To keep low-energy x-rays from reaching the patient. Such x-rays do not reach the image receptor. Filtration results in lower patient radiation dose.

Describe the process that results in the formation of a negative ion and a positive ion.

An x-ray, for instance, interacts with an orbital electron of an atom of tissue. The electron absorbs some energy from the x-ray and is released from the atom. The electron (negative ion) and resulting atom (positive ion) are called an ion pair.

What percentage of average radiation exposure to a human is attributable to medical x-rays?

Percentage = (39 mrem ÷ 360 mrem) × 100% = 11%.

What is the velocity of the mobile x-ray imaging system if the hospital elevator travels 20 m to the next floor in 30 s?

Velocity = Distance divided by time = 20 m/30 s = 0.67 m/s.

A radiographer has a mass of 58 kg. What is her weight on the earth? On the moon?

Weight on Earth = 58 kg × 9.8 m/s2 = 568 N. Weight on the moon = 58 kg × 1.6 m/s2 = 93 N.

The acronym ALARA stands for what?

As Low As Reasonably Achievable.

Name devices designed to minimize radiation exposure to the patient and the operator.

X-ray beam filtration, x-ray beam collimation, protective apparel and barriers, fluoroscopic cumulative timer, and the protective tube housing.

Liquid hydrogen with a boiling temperature of 77 K is used to cool some superconducting magnets. What is this temperature in degrees Celsius? In degrees Fahrenheit?

Temperature in °C = 77K - 273 = -196 °C. Temperature in °F = [(-196) × 1.8] -32 = -385 °F.

What are the three natural sources of whole-body radiation exposure?

Cosmic rays, terrestrial radiation, and internally deposited radionuclides.

What naturally occurring radiation source is responsible for radiation dose to lung tissue?

Radon 222, a gas.

How would you define the term "radiation"?

The transfer of energy from one area or medium to another.

What are the four special quantities of radiation measurement?

Exposure Air Kerma Gya (R); Absorbed Dose Gyt (rad); Effective Dose Sv (rem); and Radioactivity Bq (Ci).

Place the following in chronologic order of appearance:

a. Digital fluoroscopy

b. American Society of Radiologic Technologists (ASRT)

c. Computed tomography (CT)

d. Radiographic grids

e. Automatic film processing

d, b, e, c, a.

What are the three units common to the SI and MKS systems?

The three fundamental units of measurements common to the SI and MKS systems are: length (meters, m), mass (kilograms, kg), and time (seconds, s).