Welcome to Radiology

Introduction and Chapter 1

What to Expect

• You are going to learn a lot in a short period of time.

• This is a very fast paced class, so you will need to keep up.

• If you ever have any concerns or questions, please let me know.

My contact information

• Please use it with care.• I prefer texts, but be sure to sign

who you are.• Krista D. Wilkerson, R.V.T.• 210-601-0170• kwilkerson@vettechinstitute.edu• Midnight_cobra@yahoo.com

Other things to know

• We will be dividing into groups for the lab portion of this course.

• 4-5 people per team.• I will assign the groups and will

have final say as to who will be in a group with one another.

• Groups will be assigned by Friday.

How I grade:• There will be a minimum of one

unannounced quizz per week.• I give homework on Friday that is due

on Monday.• Case reports will also be due on

Mondays.• Anything that is late will be penalized

10% a day.• Homework counts once, quizzes

twice, and exams 3 times.

Lab portion of class• Kennels do count in this class.• You will receive a lab participation grade.• If you are late to lab you are penalized 5

points.• If you are absent from lab you are penalized

10 points.• Your portion of the portfolio will be counted as

a percentage of your attendance.• Your final radiographic portfolio will count 3

times and consist of 10 radiographs that you wish for me to grade (we will go over this portion in detail as the class goes on).

Lab portion Continued

• First lab will be on Monday, September 19.

• You will be assigned a particular time in which you will be responsible for taking your radiographs of an assigned animal.

• IF YOU ARE PREGNANT OR BECOME PREGNANT DURING THIS CLASS, SEE ME IMMEDIATELY!!!!!!!!!!!!!!!!!!!

Tentative Course Schedule

• There will unannounced “pop” quizzes every week.

• There will be a “safety quiz” on September, 6. You must pass this quiz with an 80 or higher in order to participate in lab.

• Exam 1 will be Thursday, September 15 over chapters 1-12.

• Exam 2 will be on Wednesday, September 28 over chapters 13-17.

• Final exam will be October 19 and will be comprehensive.

• Final lab portfolio is due Tuesday, October 18.

Soo……..

• Lets have fun, learn a lot and DO THIS!!

Chapter 1

• Why is radiology important?

• What makes a good radiograph?

• What is a radiograph?

answers

• Radiology is important because it allows us to visualize inside an animal in a very non-invasive way.

• If a radiograph is diagnostic, then it is considered a “good” radiograph.

Diagnostic vs. Non-Diagnostic

So what is a radiograph?

• A radiograph is a visible image on x-ray film.

• Image receptors and detectors convert invisible ionizing radiation into a visible image.

• Understand the difference between a radiograph and an

x-ray.

X-rays

• X-rays are the electromagnetic radiation similar to visible light but of shorter wavelength.

• Remember a radiograph is the actual image.

What is Electromagnetic Radiation?• Method of transporting energy

through space and is distinguished by wavelength, frequency and energy.

• Different forms of electromagnetic radiation.• Radio waves, television waves, radar,

infrared waves, visible light, gamma rays, UV rays, etc.

2 Characteristics of Electromagnetic Radiation

• 1. Particles

• 2. Waves

Particles

• Essentially atoms.• What makes up

an atom?• Protons (positive

charge)• Neutrons (neutral

charge)• Electrons

(negative charge)

The Atom

• Nucleus has protons and neutrons

• Electrons are negative and travel around nucleus in orbits called shells.

Waves

• All radiant energy travels in wave form along a straight path and is measured by it’s wavelength.

• Wavelength- distance between 2 corresponding points on a wave.

Wavelength

• Shorter wavelength=high frequency=greater energy

• Longer wavelength=low frequency=lesser energy

• High frequency=more penetrating power the energy has through space and matter

• So x-rays with shorter wavelengths penetrate farther than x-rays with longer wavelengths.

Electromagnetic Spectrum

• Electromagnetic Radiation is grouped according to wavelength and frequency.

• This grouping is called the Electromagnetic Spectrum.

How are x-rays produced?

• When electrons are slowed or stopped by the atoms of a target area, x-rays are produced.

• This target area is inside the x-ray tube.

• Once the electrons strike the target area, an x-ray beam is created.

Inside the x-ray tube

Definitions

• X-ray beam- composed of bundles of energy that travel in waveform.

• Quanta- these bundles of energy, may also be called photons.

• Photons consist of pure energy and are “carried” by the wave.

Physical Properties of X-ray Electromagnetic Radiation• What have we learned so far?

• 1. Wavelength is a variable.• 2. X-ray electromagnetic radiation travels

in a straight line. Direction can be altered but will continue in a straight line.

• 3. X-rays have short wavelengths- so therefore penetrate objects. Can be absorbed by object but depends on the physical density of that object (the atomic #).

Properties continued…

• And more that we know..• 4. Fluorescence-property that can emit

visible light- some substances fluoresce after absorbing electromagnetic radiation of shorter wavelength (glow in the dark).

• Question: What is a form of electromagnetic radiation of short wavelength??

More Properties

• 5. X-rays produce an invisible image on photographic film that can be viewed when film is processed (this is why you can’t see the image before processing).

And more properties

• 6. X-rays can excite or ionize the atoms and molecules of the substances including gases through which they pass. • Excitation- when an electron is moved to

higher energy level within the atom• Ionization-when outer electron is removed

and leaves atom with a positive charge. • Question: Which process takes more

energy?

And still more properties

• 7. X-rays can affect living tissue.• Why do we wear protective

equipment?• Can cause chemical damage or changes

within or near cells.

How are x-rays generated?

• When electrons collide with matter.

• On our modern x-ray machines we have something called the x-ray tube.• X-ray tube consists of:

• Cathode-negatively charged electrode.• Anode-positively charged electrode.

Now time for the magic

• Electrons have a negative charge and are at cathode end of tube.

• Anode has positive charge so electrons want to travel to anode (opposite attract).

• When electrons (negative charge) collide with anode’s positively charged target, x-rays and heat are produced.

Collisions everywhere

• When this collision and magical event of x-ray formation occurs, do you think more heat or x-rays are produced?

answer

• Only 1 % of collision is x-rays, while other 99% is heat.

Brief History of x-rays

• 1890- Professor in Philadelphia discovered x-rays but did not feel that they were important.

• 1895- Wilhelm Conrad Roentgen discovered x-rays and realized their medical importance. He mistakenly discovered while working on cathode rays.

Let’s Review

• Questions??????