The CAT-Scan celebrates 40th Birthday
For centuries, there were two kinds of doctors; one Doctor deliberated in “Internal Diseases”, called Internal Medicine, and he examined “into the inner parts of the human being, from the outside”. He discussed an awful lot with his colleagues, and apparently less so, with his patients. When successful, he was believed to be “smart’. He was the man, who was called “Doctor” in Europe for centuries.
The other man was the Surgeon, and for as many centuries, he deserved the title, “Mister.” He was also a “Barber” in the community, where, as we know, there were wars almost every season. So, barbers took care of wounds from the myriad of war victims in Europe or elsewhere. There was a French Barber/Surgeon by name of André Parre, who turned so famous that he was in demand in Kings’ palaces around Europe, and if one may add, he saw English Royals too.
It is common knowledge that it is only recently that centenarians, posing with unforeseen problems in health-care-delivery in the West, are pushed to the fore. A lot of diseases could not be diagnosed accurately until after death, where post-mortems oftentimes would clear the air. An example is the cause of death of “Catharina the Great” [Empress of Russia], whose autopsy report left no doubt as to her having suffered massive “Hypertensive Cerebral Hemorrhage”.
The 1896 discovery/invention of electromagnetic waves (X-Rays), by Conrad Roentgen (Austrian-born German), made the situation somewhat easier, but not necessarily much better. Then, there was the English Physicist, by name of Geoffrey Hounsfield, working for the British manufacturers of X-Ray machines and music-recording gadgets, EMI, as the company was called, had sustained G. Hounsfield, who for ten years had dabbled in various ways “to look at the inside of a closed box”, and identifying the contents without first having to open it. His luck, and that of the world, came together in 1972, when he was honoured with the Nobel Prize for Physics.
In principle, the Computerised Axial Tomography Scan (CAT-Scan, CT-Scan), is an x-ray imager, computerised and presented as “in three-dimensional”. The first series of the machine, designated as Head-Scanner [EMI-Scanner], were made to scan the human head only. It required half-hour to scan the whole head into 23/24 images or slides. The hair on the head, the scalp, the skull, outer-table, the marrow (the spongiosa), the inner-table, the sub-arachnoid space, the cortical brain, the white-matter, the ventricular system, filled with the cerebro-spinal-fluid (CSF), could all be delineated. That way, one would be given the chance to visualise normal structures, and situations such as hemorrhage into the brain-substance, or into the ventricles, or sub-arachnoid space, as well as a neoplasm into the brain substance, or extra-axially challenging the brain matter, could be delineated. All this is done non-invasively (not hurting or endangering the patient).
When desired, contrast-medium could be added intravenously (i.e. injecting into a vein) to enhance the images. The world Federation of Radiologists, and other disciplines (initially the realm of Brain-Surgeons), but subsequently, all branches of medicine invited would recognise all findings as (i) Isodense, like the brain tissue, (ii) hypodense, darker than the brain tissue, and finally, (iii) hyperdense, more intense than the brain tissue. It all has something to do with properties called for “convenience” CT-Units, or Hounsfield Units (after the inventor). All structures found in the body would conform to one or a mixed category. That way, all structures, “whole body” could be conveniently scanned.
About 1972, the unit-price of US$7.5 million, plus its care requiring fine-tuned maintenance, made the machine, for a decade or two, not attainable in many places of the world. Today, being available as “used machines”, plus more nations having acquired the capability of manufacturing them, the CAT-Scan has become commonplace, even in third-world countries, where governmental, as well as private institutions, may not shy away from acquiring them, its application is fairly common-place.
All disciplines welcome the CAT-Scan, especially, Neurosurgery – the field the CAT-Scan indeed was initially designed for. Orthopedic Surgery, abdominal surgery, and practically all fields, including Veterinary, have found a place for the CAT-Scan. It is likely that the CAT-Scan, now with capabilities of shielding the subjects from possible radiation-effects, would not be missing from any hospital where diagnostics are necessary around the clock. The normal population is being taught to come aboard. It is an invention whose 40th Birthday is being celebrated with the inventor’s head, raised high! Happy Birthday to us All!
Kofi Dankyi Beeko, MD, e-mail: Dankyi_b@yahoo.com
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