Week 1 :Concepts Week 1 :Concepts of Radiologic of Radiologic ScienceScienceRTEC 111RTEC 111

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Welcome to the field of Welcome to the field of medical imagingmedical imaging

Objectives:Objectives: Matter, energy, the electromagnetic Matter, energy, the electromagnetic

spectrum – ionizing radiationspectrum – ionizing radiation Relative intensity of ionizing radiation Relative intensity of ionizing radiation Discovery of x-radiationDiscovery of x-radiation Basic concepts of radiation protectionBasic concepts of radiation protection

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Matter and EnergyMatter and Energy

Matter = anything that has mass and Matter = anything that has mass and occupies space. occupies space.

Energy = the ability to do workEnergy = the ability to do work

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MatterMatter

A primary characteristic of matter is A primary characteristic of matter is “mass”.“mass”.

Mass = the quantity of matter contained Mass = the quantity of matter contained in any physical object. in any physical object.

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Mass vs WeightMass vs Weight

For our purposes mass and weight can For our purposes mass and weight can be considered the same.be considered the same.

In the strictest sense they are not the In the strictest sense they are not the same. same.

Mass = energy equivalenceMass = energy equivalence Weight = the force exerted on a body Weight = the force exerted on a body

under the influence of gravityunder the influence of gravity

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MassMass

Mass is measured in kilograms (kg).Mass is measured in kilograms (kg).

How many grams are in a kilogram?How many grams are in a kilogram?

Kilogram is the scientific unit of mass and Kilogram is the scientific unit of mass and is unrelated to gravitational effects.is unrelated to gravitational effects.

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kilokilo

Kilo stands for 1000Kilo stands for 1000

Kilogram = 1000 gramsKilogram = 1000 grams

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Building blocks of matterBuilding blocks of matter

AtomAtom MoleculesMolecules

ElementsElements CompoundsCompounds

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EnergyEnergy

Define Energy?Define Energy?

Energy can exist in several formsEnergy can exist in several forms

Energy can be measured in varied units Energy can be measured in varied units of measurement. The International of measurement. The International System (SI) = joules (J). In Radiology = System (SI) = joules (J). In Radiology = electron volt (eV) electron volt (eV) (ex: e- energy vs. kVp)(ex: e- energy vs. kVp)

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Several forms of EnergySeveral forms of Energy

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Potential energyPotential energy

Ability to do work Ability to do work by virtue of by virtue of position.position.

Ex: roller coaster Ex: roller coaster or stretch spring.or stretch spring.

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Kinetic energyKinetic energy

Energy of MotionEnergy of Motion Work because of Work because of

motionmotion

Ex: moving car, Ex: moving car, moving rivermoving river

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Chemical energyChemical energy

Energy released Energy released by chemical by chemical reactionreaction

Ex: energy from Ex: energy from the food we eat. the food we eat.

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Electrical energyElectrical energy

Electrons moving Electrons moving through an through an electrical potential electrical potential differencedifference

Ex: household Ex: household electricity – 110 electricity – 110 voltsvolts

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Thermal energy (heat)Thermal energy (heat)

Energy of motion at Energy of motion at the atomic and the atomic and molecular level. The molecular level. The kinetic energy of kinetic energy of molecules vibratingmolecules vibrating

Ex: Heat from an X-Ex: Heat from an X-ray tuberay tube

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Nuclear energyNuclear energy

Energy contained Energy contained in the nucleus of in the nucleus of an atoman atom

Ex: nuclear Ex: nuclear electric power electric power plantsplants

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Electromagnetic energyElectromagnetic energy

Not as familiar to us as other forms of Not as familiar to us as other forms of energy … but very important to energy … but very important to radiographersradiographers

Results from electric and magnetic Results from electric and magnetic disturbances in spacedisturbances in space

This energy is produced by the This energy is produced by the acceleration of a chargeacceleration of a charge

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Radio waves, microwaves, Radio waves, microwaves, ultraviolet, infrared, visible ultraviolet, infrared, visible

light… what else?light… what else?

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Electromagnetic energyElectromagnetic energy

Is often referred to Electromagnetic Is often referred to Electromagnetic radiation when it is traveling through radiation when it is traveling through space. space.

Radiation is the transfer of energyRadiation is the transfer of energy (usually through space)(usually through space)

When a guitar string vibrates it is said to When a guitar string vibrates it is said to radiate sound. radiate sound.

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Exposed or IrradiatedExposed or Irradiated

Matter that Matter that intercepts intercepts radiation and radiation and absorbs part or all absorbs part or all of it is exposed or of it is exposed or irradiatedirradiated

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Is all radiation harmful?

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X-raysX-rays

You will learn to You will learn to expose or irradiate expose or irradiate patients for patients for medical medical treatments or treatments or diagnosisdiagnosis

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X-Rays are Ionizing X-Rays are Ionizing radiationradiation

X-rays are a special type of radiation. X-rays are a special type of radiation.

X-rays are capable of removing an orbital X-rays are capable of removing an orbital electron from the atom with which it electron from the atom with which it interacts. interacts.

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IonizationIonization

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

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Ion pairIon pair

The orbital electron and the atom from The orbital electron and the atom from which it was separated are called an ion which it was separated are called an ion pair.pair.

The electron is a negative ion and the The electron is a negative ion and the atom is a positive ion. atom is a positive ion.

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What is Ionization? What is Ionization?

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Examples of Ionizing Examples of Ionizing RadiationRadiation

X-rays, gamma rays, and X-rays, gamma rays, and ultraviolet lightultraviolet light

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IonizationIonization

Some particles with high kinetic Some particles with high kinetic energy can cause ionization energy can cause ionization Ex: Alpha & Beta particlesEx: Alpha & Beta particles

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Sources of Ionizing Radiation

• Natural Environmental Radiation

• Man – made Radiation

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Natural radiation Natural radiation accounts for approximately

300 millirem (mrem)

3 sources of environmental radiation: cosmic rays, terrestrial radiation and internally deposited radionuclides. The largest source of natural radiation is radon.

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MEDICAL IMAGING

• Diagnostic Imaging– Medical xrays– Dental xrays

• GREATEST SOURCE OF MAN-MADE RADIATION

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Diagnostic x-rays 1990 the National Council on Radiation

Protection and Measurements (NCRP) 39 mrem/yr OR 0.39 mSv/yr

More recent NCRP estimates indicate nearly 320 mrem/yr OR 3.2 mSv/yr. Due to increasing use of multslice spiral CT and high-level fluoroscopy

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What does this information mean?How does this affect us?

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Is this a safe profession ?

• Natural radiation = 300 mrem/yr

• Average medical exposure = 50 mrem/yr 39 – 320 mrem/yr

• Technologists?

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How Medical X-Ray Began

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Crookes Tubes Were the beginning of the modern fluorescent

lamps and x-ray tubes.

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Historical Perspectives

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Collaborative EventsCollaborative Events

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First RadiographFirst Radiograph

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““Willie Rontgen”Willie Rontgen”

Honored in 1901 Honored in 1901 with the first with the first Nobel prize in Nobel prize in physics for his physics for his efforts.efforts.

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X-Ray Properties: Roentgen’s discovery Are highly penetrating, invisible rays which

are a form of electromagnetic radiation.

Are electrically neutral and therefore not affected by either electric or magnetic fields

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X-Ray Properties Can be produced over a wide variety of

energies and wavelengths (polyenergetic & heterogeneous).

Release very small amounts of heat upon passing through matter.

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X-Ray Properties Travel in straight lines.

Travel at the speed of light, 3 X 108 meters per second in a vacuum or 299,792,458 m/s.

or 29,979,245,800 cm/s

Can ionize matter.

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X-Ray Properties Cause fluorescence of certain crystals.

Cannot be focused by a lens.

Affects photographic film.

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X-Ray Properties Produce chemical and biological changes in

matter through ionization and excitation. Produce secondary and scatter radiation.

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Later years

Radiologist experienced much higher rates of blood disorders than in others

Began the study of RADIATION PROTECTION

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• Where is the RADIATION PROTECTION?

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Early years in Radiologic Technology

• Nurses or nurses aides taught how to “take an x-ray”

• NO special education• Only “ON THE JOB” training• Experience the best teacher

• The first Technologist is credited to be EDWARD C. JERMAN.

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In 30 years

• Developed from a technical trade to one of a professionalism

• Once thought that anyone could be trained to quickly = “push the buttons’

• To now where it is considered a profession that requires analytical thinking and problem solving

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Questions ?

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