RTC 100--PowerPoint Presentation Topics Groups 7 & 8

The following topics will be presented on Thursday November 20, 2008.

Topic for Group 7

Provide details of the use of intensifying screens in Radiography. Use a diagram to discuss the details of the structure of an intensifying screen. Discuss the various screen-film combinations. Describe the handling and cleaning of intensifying screens. What is the result of poor film/screen contact? (Show an image) How is radiographic technique adjusted for variations in screen speed?


Topic for Group 8

Radiography has gone filmless. No film? Just as photography is now predominantly digital, radiography is heading in that direction as well. Discuss the major forms of digital radiography now in use. How do they compare to traditional (film or analog) radiography? For example, how has the introduction of filmless radiography affected Radiology department expenses, workflow, and number of repeats?

Do not get caught up with details of the technology or how digital radiography works. The intent of your presentation is to introduce the class to the current trend in imaging, and the advantages and disadvantages of going digital. Crucial questions that should be answered are: is it cost effective? Does it save on patient radiation dose? Does it expand the availability of images? Are there any adjustments that have to be made by the radiographer to their technique and the way imaging devices are handled? What about workflow? Are there any improvements in patient throughput when we go from film to filmless?

RTC 100 and RTC 201--Quiz 2

The second round of quizzes is scheduled for Friday, October 17th.

Check your e-mail for more details.

RTC 100--Power Point Topics: Groups 4-6

The following topics will be presented on Thursday November 13, 2008.

Topic for Group 4 (Christina)

What is the purpose of a radiographic Technique Chart? What are the four major exposure factors? Explain the adjustments that have to be made when each of the four factors is changed. In other words, what adjustments must be made to factors 2, 3, and 4 when factor 1 is increased or decreased?
What are the three major patient factors that influence technique selection? Show an example of a typical radiographic technique chart.


Topic for Group 5 (Mathew)

Answer the following questions in your presentation:
What factors are used to determine the quality of a radiographic image? What makes an image good, and conversely, what do people see when they look at an image and determine that it is bad?
Discuss the geometric factors and subject factors that affect image quality. Make sure to include images and diagrams to illustrate your answers and emphasize your key points



Topic for Group 6 (Winton)


List and discuss the three categories of Radiographic Image Artifact presented in chapter 15. Explain the causes of exposure artifacts using actual images to illustrate your answer. Describe the types of artifacts caused during film processing. Also discuss how improper handling and storage of film can cause artifacts. Show examples of the artifacts you discuss.

X-Ray Production--Bremsstrahlung and Characetristic X-Rays

Energy cannot be destroyed..its is tranformed from one type to another. This restatement of the principle of "conservation of energy" is demonstrated in the x-ray tube.

The electrons possess kinetic energy once they start to move. This kinetic energy is based on their velocity (K.E =1/2 x mass of the electron x velocity squared). When the electrons interact with the atoms of the anode target material their kinetic energy is transformed into electromagnetic energy (heat and x-rays).

The process is very inefficient---less than one percent of the kinetic energy results in x-rays.

Two types of x-rays are produced--Bremsstrahlung and Characetristic.





View the animations above. Distinguish between Bremss and Characteristic X-rays.

How is each type produced?

The diagram to the right shows the range of x-ray energies produced in a Tungsten target and their relative intensities. There are more photons at 59.3 kev, for example, than at any other energy level.

Distinguish between Bremsstrahlung and Characetristic x-rays on the diagram. Which type is more abundant? What is the range of energy values for each type?

X-Ray Production--The X-Ray Tube

X-rays are produced when fast moving electrons interact with atoms of a high atomic number target.

Whenever a potential difference is established between the cathode and anode of an x-ray tube the negatively charged electrons move rapidly from cathode to anode. The fancy physics term--potential difference simply means that the kilovolatge selected at the operator's console makes the anode highly positive with respect to the cathode.

Opposites attract---so the electrons at the cathode are strongly attracted to the anode and rush across at a very high velocity as soon as the potential difference is established (when you press the exposure button).

Whenever you select a higher kV the potential difference increases along with the energy of the electrons. This results in higher energy x-rays being produced.



In the video, the waveform diagram at the top of the screen shows how the voltage supply changes as the exposure progresses. The waveform shown is single phase, full wave rectified. The voltage varies in intensity from zero to peak intensity and back to zero in a repeating pattern.

Note that the x-rays produced (shown on the oscilloscope at the bottom of the screen) vary in intensity in a similar pattern to the voltage.

It is very important to understand how the various voltage waveforms (single phase or three phase) affect the quality and quantity of x-rays produced.

Electric Charge and Static Electricity

The existence of electric charge is based on the protons and electrons in the atom. The amount of charge on a single proton is equal to the amount of charge possessed by a single electron.

A proton and an electron have an equal amount but an opposite type (sign) of charge. Proton positve (+), electron negative (-). Thus, if an atom contains equal numbers of protons and electrons, the atom is described as being electrically neutral. On the other hand, if an atom has an unequal number of protons and electrons, then the atom is electrically charged (and in fact, is then referred to as an ion rather than an atom).

Any atom which contains less electrons than protons is said to be positively charged. Conversely, any atom which contains more electrons than protons is said to be negatively charged.

-Neutral or uncharged atom--Equal numbers of protons and electrons (p=e)
-Positively Charged Ion--Possesses more protons than electrons (Neutral atom lost electrons)
-Negatively Charged Ion--Possesses more electrons than protons (Neutral atom gained electrons)

The process of an electron leaving one material and moving to reside in another object is a common occurence. As clothes tumble in the dryer, electrons are leaving one bit of clothing and going to another. The object that loses the electrons will become positive, and the one that gains the electrons becomes negative.

When two dissimilar materials are rubbed together (friction) charges can build up in both materials. These charges are called electrostatic charges. Anyone who has felt the "zap" of an electric spark after walking across a carpet and then touching a metal door knob has experienced the effect of two objects rubbing together to create electrostatic charges.

These static charges can be useful, or a nuisance. They can even be downright dangerous. Watch the video clip below, and comment on what you see. (Post a comment on the blog by clicking the comment button at the end of this post)

What caused the dangerous event shown in the video?


In Radiography, electrostatic charges are sometimes discharged when the technologist handles the film before processing.

RTC 201--Power Point Presentation Topics

The following topics will be presented by the second year students on Friday, November 21, 2008. Grading Criteria for all Power Point presentations will be posted on this Web Log in a subsequent post. Keep checking in.

1. Discuss the structure of a human cell (There are many different types of cell in the human body so focus on the "generalized cell" that includes features from all cell types). Describe the purpose and function of each component of the cell. Include diagrams and images of the cell produced by the electron microscope.


2. The cell cycle is often described as a process of division allowing the duplication of cells. Discuss the various phases of the human cell cycle. Also, how does the process of Mitosis differ from the process of Meiosis

3. Discuss the effects of ionizing radiation on the human cell. Include the types of cell death, and other effects such as mitotic delay, reproductive failure, and interference of cell function

4. What is the role of each of the following organizations in Radiation Safety: (What are they responsible for, or what do they do)
-Nuclear Regulatory Commission
-National Council on Radiation protection and Measurements
-Food and Drug Administration
-International Council on Radiation Protection and Measurements
Which state agency in New Jersey is responsible for Radiation safety in the state? What is their role in ensuring that the public is protected.

5. Discuss the sources of radiation exposure to human beings. What percentage of exposure occurs from natural sources, and artificial sources? Compare the exposure levels from each of the following medical sources:
-diagnostic radiology (focus on CT and Fluoroscopy)
-dental radiology
-interventional radiology
-nuclear medicine
-radiation oncology

6. Discuss the various devices used to detect and/or measure radiation. Which device is used for each type of radiation and how does it work. Cover in detail the methods and types of personnel monitors. What are the dose limits for occupational, non-occupational, critical organs, embryo and fetus?

RTC 100--Power Point Presentation Topics

The following topics will be presented on Thursday November 6, 2008.

1. Take a picture of a typical x-ray operator's console. Discuss each of the dials, switches, displays, and buttons on or connected directly to the operator's console. What is the purpose of each component of the console, and how does it impact the production of x-rays and/or the appearance of the radiographic image?

2. Describe the various components of a typical x-ray tube. Make sure you have a clearly labeled diagram of the x-ray tube. What is the function of each component? What are the differences between a stationary anode tube and a rotating anode tube? Also discuss recent innovations in x-ray tube design. What design features have been introduced, and how do these new design features improve on what existed in the older tubes?

3. Take pictures of the equipment in your energized x-ray lab. (Table, bucky tray, vertical cassette holder, grid, generator, high tension cables, tube housing, collimator, etc.) Describe the purpose of each bit of equipment in your x-ray room. Your discussion should answer the questions what does it do, or what is it used for?