X-rays By: Jacob, Akram, Cameron Science biophysics ISP

History of x-rays x-rays were discovered in 1885 by accident by Wilhelm Conrad Roentgen, a German professor Roentgen noticed crystals close to a high-voltage cathode-ray tube with a fluorescent glow, that could be seen even when being covered Energy was being produced by the tube, penetrating the paper, causing the crystals to glow

History of X-rays Roentgen called them “X radiation” and further experiments showed the energy passed through soft tissue but not bone By World War One, they were already being used for medical purposes

Visible light vs. X-ray Visible light waves and x-rays are both forms of electromagnetic energy carried by particles called photons The difference is the energy level of the individual photons We see visible light, however our eyes are not sensitive to the shorter wavelengths of higher energy x-rays x-rays carry more energy then visible light and have a higher frequency

What’s an X-ray? An x-ray is a form of electromagnetic radiation Electromagnetic radiation: a wave pattern made of electric and magnetic fields that can travel through empty space

What’s an X-ray? Photons of x-rays are produced by the movement of electrons – when electrons move to a lower energy level they release energy in the form of photons X-ray photons can pass through a lot of things such as soft tissue but it cannot pass through bone =hTz_rGP4v9Y =hTz_rGP4v9Y

What are medical X-rays? Using x-rays we can take images for practical purposes Medical x-rays are images formed from the use of x-rays through x-ray machines Medical x-rays are used to generate images of tissues and structures inside the body X-rays pass through an x-ray detector on the other side of the patient

Example of medical X-ray An image forms that shows the “shadows” formed by objects in the body X-ray images are called radiographs

X-ray boards are used to observe medical x-ray images or radiographs

Why are x-rays used/purpose? They are effective and less invasive then surgery To observe the severity of an injury without having to go into the patient They can be used to detect and diagnose diseases To check for broken bones, injuries, cancer, e.t.c…

X-ray machine Contains an electrode pair – a cathode and an anode – inside a gas vacuum tube The cathode is a heating filament The machine passes current through filament, heating it up The heat in the filament then sputters electrons off the filament surface The positively charged anode, made of tungsten, draws electrons across tube

X-ray machine The voltage difference between the cathode and the anode causes electrons to fly through the tube and collide with a tungsten atom with a great deal of force, making the atom loose one of it’s electrons from one of it’s lower energy levels An electron from a higher energy level falls to the lower energy level, producing photons to form x-rays A camera records the x-ray light that passes through a patient’s body

X-ray machine

X-ray machine video

How do medical X-rays work? A patient is positioned so that their body part being examined is between an x-ray source and an x-ray detector When the machine is on, x-rays travel through the body and are absorbed differently by different tissues, depending on the radiological density of tissue Radiological density is determined by the density and the atomic number of the material being imaged Bones produce a high contrast on x-ray detectors because they contain calcium, which has a higher atomic number than most tissues

When are medical x-rays used and how? X-rays are used when they have to diagnose or treat diseases, observe injuries, check for injuries, e.t.c… X-ray radiography: detects bone fractures, certain tumors and abnormal masses, pneumonia, some types of injuries, calcifications, foreign objects, and dental problems

G

X-ray radiography is the most common use of medical x-ray imaging Mammography: radiography of the breast used for cancer detection and diagnostic

Radiation therapy: x-rays can be used to destroy cancerous cells and tumors by damaging their DNA X-rays can cause cancer but also treat cancer CT (computer tomography): combines x-ray technology and computer processing to create a series of cross- sectional images of the body

Risks of radiation therapy Even though x-rays can be used to treat cancer, it can also kill normal cells If x-rays are directed properly, normal cells should not be effected

X-ray risks It’s much easier and safer to look at a broken bone using x-rays than opening a patient Long-term exposure to x-rays can cause radiation sickness

Radiation sickness

X-ray risks X-rays are ionizing radiation – when x-rays hit atoms it can knock electrons off an atom to create an ion and free electrons collide with other atoms to create more ions An ion’s electric charge can cause unnatural chemical reactions inside cells or break DNA chains, which will either kill cells or the DNA will develop a mutation If a lot of cells die the body has an increased chance for developing diseases If DNA mutates, cells may become cancerous or lead to birth defects

X-ray preventions To prevent patients and doctors from being effected by x-rays they take every precaution possible Lead aprons are worn Lead aprons prevent x-rays from penetrating tissues where it is not desired

Ethical issues to ponder Is it smart to use something to treat diseases that may also cause the same disease? Is exposing patients to x-rays, which can have serious side effects, really a smart thing to do? How do we know that x-rays are always completely accurate? Could they be giving false diagnostics? How do we rein burst someone for a false diagnostic and who is to blame for one? The technology, the doctor? These issues may encourage patients to be hesitate to use this technology and/or not use it if possible

Annotated Bibliography Harris, T. How X-rays work [online publication]. Retrieved from the How Stuff Works Science site: Accessed on May 10 th, The online publication is a web article from How Stuff Works Science. It includes, and explains clearly, the history of X- rays, what an X-ray is, the X-ray machine, as well as the side effects of X-rays. No author listed. X-rays [online publication]. Retrieved from the National Institute of Biomedical Imaging and Bioengineering site: Accessed on May 10 th, The online publication is a web article from the National Institute of Biomedical Imaging and Bioengineering. It includes, and explains clearly, what medical x-rays are and how they work and are used, as well as the risks involved in medical x-rays. Lucas, J. What are X-rays? [online publication]. Retrieved from the Live Science site: what-are-x-rays.html. Accessed on May 10 th, what-are-x-rays.html The online publication is a web article from Live Science. It includes, and explains clearly, what x-rays are, the history of x-rays, x-ray sources and effects, x-ray imaging, x-ray therapy, and x-ray astronomy. No author listed. A deeper look into X-rays. [online publication]. Retrieved from the blogspot site: rays.blogspot.ca/2013/04/ethical-issues-of-x-rays.html. Accessed on May 11 th, rays.blogspot.ca/2013/04/ethical-issues-of-x-rays.html The online publication is a web article from Blogspot. It includes, and explains clearly, some ethical questions and issues associated with x-rays and their practice in the medical field.

The End