Half A Century In CT: How Computed Tomography Has Evolved

Have you ever looked back at the decade of your life and thought about how different things were just ten, short years ago? Sometimes the difference even a year can make can be startling, but just imagine all the advancements that can be made in a year within the medical technology community. We always say, “One year in real life, is like 10 years in CT time.”

For now, let’s take a trip down memory lane and explore how CT has changed over the last 50 years.

  • In the early 1900s an Italian radiologist named Alessandro Vallebona invented tomography which used radiographic film to see a single slice of the body. As conventional tomography evolved, it was still considered ineffective when it came to imaging soft tissues.
  • Increased power and availability of computers in the 1960s sparked the research to create practical computational tomographic images.
  • In 1967 Sir Godfrey Hounsfield invented the first CT scanner at EMI Central Research Laboratories using x-ray technology. 
  • It was widely rumored that The Beatles record sales in the 1960’s helped fund the first CT scan’s development
  • In 1971 the first patient brain CT was performed in Wimbledon, England but it was not publicized until a year later.
  • In 1973, the first CT scanners were installed in the United States
  • By 1980, 3 Million CT examinations had been performed and by 2005, that number had grown to over 68 Million CT scans annually.
  • During the 1990’s “Portable/Mobile CT” scanners grew in popularity
  • By 2005, 90% of PET scanners were actually PET-CT fusion imaging scanners
  • According to a census report, by 2007 more than half of the CT scanners in the U.S. were multi-slice CT scanners with more than 64-slice capability.
  • A new generation CT scanner was developed in 2008 that could take images of beating hearts or coronary arteries in less than one second.
  • In 2009 at the International Symosium on Multidetector-Row CT, Dr. Mathias Prokop discussed the clinical implications of the 16 cm wide detector CT. The wider coverage per gantry rotation enabled more dynamic scanning and the ability to do multiple acquisitions in less time. Read More: Aunt Minnnie
  • The FDA launched their Initiative to Reduce Unnecessary Radiation Exposure from Medial Imaging in 2010, which brought more attention to reducing radiation dose with CT scans.

Biggest advancements in Computed Tomography in more recent years:

  • Overall improvements in speed, slice count, radiation dose and image quality
    • 20 Years ago, a CT exam could take 30 minutes or more. Now, a CT exam can collect images and information in less than 1-2 seconds.
    • Adaptive Statistical, model based, and hybred Iterative image reconstruction techniques (have contributed to 70% - 80% radiation dose reduction over past 4 years.
    • More dose efficient CT detector materials and larger detector dimensions have also helped lower CT patient radiation dose while improving image quality at the same time.
  • CT Perfusion imaging now enables radiologists to see  and quantify brain stroke and  a deeper understanding of changes in blood flow to the patient's brain. In combination with CT angiography, this new approach is potentiallyh disruptive technology for the rapid evaluation of acute stroke.  Read more about interpreting CT perfusion in the setting of acute ischaemic stroke. CT perfusion of tumor is also being used to evaluate the impact of modern cancer therapy regimens – much soner than with older techniques.
  • CT Angiography of Coronary Arteries –Modern single-heartbeat CT coronary angiography has shown very high specificity and high sensitivity for coronary artery disease. In the setting of low to moderate risk chest pain in an Emergency Room patient, the CT approach to triage saves much time and money. CT of congenital heart disease and for planning of atrial ablation of fibrillation are other advanced applications.The emerging field of CT evaluation of myocardial perfusion shows great promise for clinical impact.
  • PET/CT for Cancer Treatment Planning – The combination allows doctors to have a much more precise  understanding of the extent of a patients disease. With fusion imaging, doctors can see metabolic and anatomical information at once. It also provides a rapid assessment of response to therapy or myocardia perfusion.
  • CT Simulation – With the invention of 3D CT imaging and IMRT, CT simulation has become an essential tool  in stereotactic radiosurgery and for radiation targeting around sensitive structures or organs.
  • Emergency Department CT – CT has become the  first line of  rapid and accurate diagnosis  in emergency departments. With more CT exams available in or near ERs, it has made the emergency evaluation oftrauma,  acute chest pain, or other urgent conditions  more available. Additionally, low radiation dose CT has enabled physicians to increase quality of pediatric CT examinations, especially for cervical spine procedures and chest CTs.
  • 3D Printing – Detailed digital data sets from CT have strongly contributeds to The rise in popularity for medical applications of 3D printing to improve  medical care. Now, radiologists are able to have CT data printed in 3D to assist in surgical planning and prototyping implants. 

It’s clear that this rapidly changing niche in radiology has grown considerably year over year. If the past is any indication, in another 50 years computed tomography technology will be even more impressive. In a report published by the American Society of Radiologic Technologists (ASRT) William Eversman, MD, chairman of radiology at the Mayo Clinic in Scottsdale, Arizona was quoted saying; “In our lifetimes, I don't think that we will reach the technology of Star Trek, where you can wave a wand over someone and instantly diagnose them, but step by step, we're getting there."

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