Waves and Technology Case Studies

UV Sterilization

MRI

XRay

Radiation Treatment

Case Study 2

Case Study 3

Case Study 4

Case Study 1

XRay

Case Study 1: X-rays Imagine that you are playing a competitive game of soccer and jump up to head a ball. You collide with another player and you both fall to the ground. Unfortunately, you come down on top of your wrist with your full body weight and are now in an extreme amount of pain. Just to be safe, you decide to go to the hospital to have your wrist examined. What do you think the doctors will look for? What machines and technology will they use to make this determination? Since their discovery in 1895, x-rays have played an important role in how we see into the body. X-rays are high-energy EM waves that can travel through softer tissue, such as muscle and organs, but are stopped by dense parts like bone and teeth. We can use this property of x-rays to discover issues such as broken bones, cancerous tumors, sicknesses such as pneumonia, and the location of foreign objects that may require removal. In fact, one of the first major uses of x-rays came shortly after their discovery, when army hospitals used them to find and remove bullets from soldiers wounded in battle. X-rays soon became such a cultural fascination that even shoe stores in the 1930s−40s would offer customers an x-ray of their foot when they came in for a shoe fitting! Eventually, it was discovered that the high energy carried by x-rays was destructive to the human body and safety measures were taken when they were used in hospitals, dentists, and doctor’s offices. If you have ever received an x-ray before, you might remember that a heavy cape was placed on you, and that the person taking the x-ray likely left the room before turning on the machine. The heavy cape—made of the metal lead—blocks x-rays so they are only directed toward the part of your body being examined. In the story given above, doctors were probably checking your wrist to determine if it was broken or sprained. An x-ray would assist in making this diagnosis because high-energy x-rays cannot travel through dense objects such as bone. However, if the bone were separated, such as in a break, it would show up on an x-ray and doctors could accurately prescribe treatment to help you heal properly.

Case Study 1

MRI

Case Study 2: MRI After several more weeks of struggling with this pain in your knee, you finally go to a doctor to find out what might be wrong. The doctor decides to schedule you for an MRI to determine if you might have a torn ligament or similar injury in your knee. While we have known about magnetic resonance, the technology used in an MRI, since the 1930s, when scientists noticed how magnetic fields interacted with the nuclei of atoms. However, it took a lot of additional work and another 40 years before the first MRI machine was built. Even after that, MRIs did not become popular with hospitals until the early 2000s because of their cost. MRIs have become more popular with doctors now that doctors understand the many ways they can be used. An MRI machine uses powerful magnets and radio waves to see cross-sections of the human body. The low energy and long wavelength of these radio waves allows doctors to see the charged particles in your body’s tissues without damaging them. Put another way, imagine you could look at highly detailed slices of the body, almost like a loaf of bread, but without having to do any cutting. This is what an MRI does, and it has allowed doctors to identify and treat a wide variety of conditions, from cancer to brain injuries. MRIs are generally safer for patients than procedures such as x-rays but are also incredibly expensive because they require a massive amount of electrical energy and the machines are costly to build and maintain. For this reason, doctors will try to recommend less costly treatments for patients unless an MRI is necessary. In the case study presented, an MRI might be helpful because it could help identify if anything in your knee is torn. If there are tears, an MRI scan will show doctors exactly where and help them determine the best course of treatment, such as targeted physical therapy or surgery.

Case Study 2

Radiation Treatment

Case Study 3: Radiation Therapy A person notices one day that they have a soft lump on one of their arms. This lump was not caused by an injury of any sort and seems to be getting larger as the days go by. The person finally schedules a doctor’s appointment and is seen later that week. After looking at the lump, the doctor decides to take a small portion of it, a procedure called a biopsy, and send it for testing. The test comes back positive, indicating the lump is cancerous. After going in for a few more tests, it is determined that the cancer was caught early, and immediate treatment begins. The patient is sent for radiation therapy and the tumor shrinks bit by bit after each additional treatment. Radiation therapy was discovered soon after x-rays, and in many cases, uses x-ray waves. In the early 1900s, doctors found evidence that x-rays could harm the human body, but they also discovered that these high energy EM waves seemed to harm cancer cells more than healthy cells. While early methods of radiation therapy were much less advanced than they are today, the process has essentially remained the same. When high energy EM waves like x-rays are directed at cancer cells, they create breaks in the cell’s DNA, making it unable to divide. In the case of cancer, this is a great thing because tumors are not able to grow, and the cancer is unable to spread. With repeated, successful treatments, the goal is to eventually destroy as many cancerous cells as possible without causing too much damage to normal, healthy cells. Today, modern advances in computer and machine technology allow doctors to target specific areas of the body for radiation treatment while limiting the danger to healthy tissue. Still, radiation therapy is not without its side effects, and this can include loss of hair, burns to the skin, nausea and vomiting, headaches, and loss of energy. For this reason, doctors try to limit radiation therapy so that a patient only receives it when absolutely necessary. In the case study presented, the patient was diagnosed with early-stage skin cancer and responded quickly to treatment. Radiation therapy is typically quite effective when treating early stages of cancer that form close to the outside of the body.

Case Study 3

UV Sterilization

Case Study 4: UV Sterilization Unlike the other three technologies you investigated in this exploration, UV sterilization is a public health technology that works behind the scenes to keep you safe. You don’t necessarily see UV systems because they are often in places like ventilation systems and water treatment plants. During the onset of the COVID-19 pandemic, UV lamps became more popular in restaurants, stores, and other public spaces to help disinfect the air without the use of chemicals. People have known that UV waves kill germs for over 150 years. In the 1870s, scientists noticed that sunlight significantly slowed the growth of bacteria, but it took many more years to understand that UV rays were responsible. In the 1930s, experiments were conducted by placing UV lamps in building ventilation systems. It was discovered that these lamps significantly lowered the transmission of diseases such as the measles. UV waves are effective in cleaning the air by destroying many forms of viruses and bacteria. In the 1950s, it was discovered that UV light was also effective in treating drinking water. Many modern water treatment systems use UV sterilization since it is safer and cheaper to use than chemicals such as chlorine. UV lamps are also effective in disinfecting hard smooth surfaces such as desks, tables, fruits and vegetables, phones, and more. So how does UV sterilization work? Similar to how x-rays in radiation therapy work, high-energy UV waves can destroy disease-causing microbes by causing breaks in the DNA of the microbes, preventing them from multiplying. Only the most energetic UV waves can do this, a band of wavelengths called UV-C. This form of UV radiation can also be harmful to the human body. For this reason, UV sterilization technology is best used when there is little to no exposure risk for people. There are still many ways that UV-C waves can be used safely to clean food and tools.

Case Study 4