Introduction
Ever since Godfrey Hounsfield developed the first clinical computed tomography (CT) scanner for scanning the head in 1971, computerized tomography has undergone tremendous technological development and has transformed the diagnostic capabilities in medicine. In 1990, the advent of spiral (helical) CT scanning lead to improved diagnostic capabilities. The latest innovation is the multislice CT in 1998. This essay analyses the history, advances, uses, and future of CT.
History
It was Gabriel Frank who first described the basic idea of tomography in 1940. In 1961, William H. Oldendorf performed a series of experiments based on principles similar to those used in CT. In 1963, David E. Kuhl and Roy Q. Edwards introduced transverse tomography with the use of radioisotopes. The mathematical formulation for reconstructing an object from multiple projections was made by J. Radon (Hsieh, 2003.)
Allan M. Cormack reported the findings from investigations of perhaps the first CT scanner that was built. In 1967, Godfrey N. Hounsfield developed the first clinical CT scanner in England. The first clinically available CT device was installed in the Atkinson-Morley Hospital in 1971, and a patient with a large cyst was scanned and the pathology was clearly demonstrated. For their pioneer work, Hounsfield and Cormack shared the Nobel Prize for Physiology and Medicine in 1979 (Hsieh, 2003.)
Advances
Some of the advances in CT scanners over the years include the development of spiral CT and multi-slice CT. The advantages of spiral CT are due to continuous data acquisition and short total scanning time. Spiral CT eliminates respiratory motion and interscan gaps. There is optimum visualization of small lesions. Intravascular contrast medium can be used more effectively. The detection of hepatic and pancreatic lesions is significantly improved (Prokop, Galanski, Van Der Molen, 2003.)
Multi-slice computed tomography can acquire more than one slice at a time. This is possible because the detector system is composed of more than a single row of detector elements (Uffmann & Prokop, 2001.)
There are many advantages of multi slice computed tomography like: reduced artifacts caused due to breathing and pulsation, the ability to get multiplanar sections through the lung parenchyma with a high resolution, and the possibility to simultaneously evaluate high resolution and standard imaging protocols from just a single data acquisition. Three-dimensional techniques like volume rendering and virtual bronchoscopy is also possible with multi-slice computed tomography (Uffmann & Prokop, 2001)
CT uses
A CT scan of the chest can detect infection, lung cancer, pulmonary embolism, and an aneurysm. CT scan of the abdomen can find cysts, abscesses, infection, tumors, an aneurysm, enlarged lymph nodes, foreign objects, diverticulitis, inflammatory bowel disease, liver and pancreatic tumors, pancreatitis, and appendicitis. CT scan of the kidneys, ureters, and bladder can find kidney stones, bladder stones, or blockage of the urinary tract. A CT scan of the pelvis can detect problems in the uterus, ovaries, and fallopian tubes, and in men, problems in the prostate gland and the seminal vesicles. CT scan of the brain can detect brain tumors (WebMD)
CT is also used to guide a needle during a tissue biopsy or to guide the proper placement of a needle to drain an abscess. It helps in staging the cancer.
Case study
A 36-year-old man presented with a history of generalized seizures and speech difficulty. An EEG, lumbar puncture was negative. A CT scan brain revealed a large left frontal lesion in the brain. At surgery, the lesion revealed to be a malignant glioma.
Future of CT
Cone Beam Computed Tomography (CBCT) utilizes a cone beam with multi-row areas detectors. The result is a real time 3-D image at high resolution. CBCT has the potential to dramatically improve speed and accuracy while lowering the radiation exposure and being more cost-effective (Sonka, Kakadiaris, Kybic, 2004.)
Conclusion
The first clinical CT scanner was developed by Godfrey Hounsfield in 1967. Over the years, CT scanner technology has advanced to include the development of spiral CT and multi-slice CT with numerous advantages of earlier generation of scanners. Currently, the CT scan is used to diagnose a wide variety of lesions in the chest, abdomen, urinary tract, pelvis, and brain. It is also being use to guide tissue biopsy and to stage cancer. In the future, the CT scanner is likely to undergo more development. The use of Cone Beam Computed Tomography (CBCT) will provide high-resolution 3-D images, while at the same time being more cost effective, faster, and safer.
References
- Hsieh J. Computed Tomography: Principles, Design, Artifacts, and Recent Advances. SPIE Press, 2003.
- Uffmann M, Prokop M. Multi-slice CT of the lung. Technique and clinical applications. Radiologe (2001) 41(3): 240-247.
- Sonka M, Kakadiaris IA, Kybic J. Computer Vision and Mathematical Methods in Medical and Biomedical Image Analysis. Springer, 2004.
- WebMD. Computed Tomography (CT) Scan of the Body.
- Prokop M, Galanski M, Van Der Molen A. Spiral and Multislice Computed Tomography of the Body: Computed Tomography of the Body. Thieme, 2003