Author: Isabella Ng
Editors: Roberto Bailey, Eric Lin
Artist: Kyra Wang
Biomedical imaging, a medical technology used to image tissues, first emerged in 1895. Since then, it has revolutionized the healthcare industry. Imaging can be divided into three broad categories: ultrasounds, MRIs, CT scans, and X-rays. They all have similar applications: diagnosing, monitoring, and treating medical conditions.
X-ray scans are one of the most common types of biomedical imaging and the oldest, discovered by Wilhelm Conrad Roentgen in 1895. An X-ray scan uses ionizing radiation, a high-energy electromagnetic radiation that is used to take images of the body. The images from X-rays can be useful in viewing dental cavities, bone damage, cancer growth, and much more. There are some risks associated with the use of X-rays, though, including an increase in the chance of developing cancer later in life and effects of radiation on tissue, such as cataracts, reddening, and hair loss. However, cancer risk is ultimately very low and depends on many factors, such as the age of the patient, radiation dose, and the body region of the X-ray.
Computed Tomography Scans, better known as CTs, use a more advanced form of X-ray technology to obtain detailed internal images of the body. These scans can diagnose conditions like blood clots, hemorrhages, or even cancer. Like X-ray scans, CT scans use X-rays and share the risks of ionizing radiation, as detailed earlier. The high energy wavelengths have been linked to DNA damage and possible mutation. Differing from a conventional X-ray with a fixed tube, a CT scanner uses a rotating X-ray tube in a circular manner, where the detectors pick up rays onto a computer. The CT’s computer then converts the information from the rays into a two-dimensional image. Advancements in CT scan techniques and novel applications to minimize radiation damage have been extensively researched recently. Researchers from the University College London have been working on a technique to split the X-ray beam into beamlets, aiming to minimize radiation dose while still delivering a high-quality image. Others, like Dr. Keith Cheng and his team from the Penn State College of Medicine, have dedicated decades of research to developing new 3D imaging techniques that combine CT scanning and histology to image patients on a cellular level. While traditional computer tomography technology is vital in a common medical setting, advancements and innovations have fueled its growth toward a new, accessible future.
The MRI is another type of imaging that works slightly differently. It uses strong magnetic fields and radio waves to take images of the body through cross-sections. Specifically, the MRI machine uses strong coils that create a magnetic field within a patient’s body, causing the hydrogen ions in the human body to align with the field. Then, a radio frequency pulse that affects hydrogen ions is emitted, causing the ions to spin in a different direction so that digital images can be taken. These machines use no ionizing radiation, so there are fewer risks and complications. MRIs are used mostly to look at soft tissues and the nervous system, like the brain. MRI scans take cross-sections of the part of the body that is being analyzed, and they can be as precise as a few millimeters in width. However, because MRI machines use such strong magnets, not everyone can get them. People with metal devices such as pacemakers, metal rods, or metal disks cannot receive MRIs because of the possible risks with the magnets in the machines.
The last type of imaging, broadly, is ultrasounds. Ultrasounds use high-frequency sound waves to view the inside of the body. They show movement of the organs as well as the blood vessels. Using a trained eye, an ultrasound can assist in detecting and viewing the breast tissue, the ocular structure, a fetus during pregnancy, bones, and the abdomen. Ultrasound imaging has few risks, especially because it uses non-ionizing radiation, which has fewer risks than X-rays. However, in rare cases, ultrasounds can create small pockets of gas or air in tissues or fluids, also known as cavitation. Because these gas pockets haven’t been studied long, scientists are still unsure of any possible long-term effects.
Biomedical imaging plays a crucial role in the healthcare world, with its high-quality visualization allowing for diagnosis and monitoring of numerous medical conditions. Though many of its techniques have harmful side effects from ionizing radiation, its benefits cannot be understated. The X-ray, CT scan, MRI, and ultrasound facilitate disease detection and treatment response. As the biomedical field and imaging techniques continue to evolve, a promising future with improvements in diagnostics and treatment is near.
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