Physics and Medicine

In historical times, medicine was not quite the scientific discipline it is today.  People took potions and other remedies, many of which were based on common plants, in the vague hope they would get better.  Often they did.  Sometimes it was with the aid the herbal remedies, which have since been shown scientifically to be effective.  Indeed many modern drugs are simply artificially made chemicals that have come from plants.  For example, many heart conditions are treated by Digitalis, a compound isolated from the leaves of foxgloves.  Taxol, a cancer-fighting drug, is derived from the Yew, which is a highly poisonous plant.

Plants did not evolve this for our benefit.  They were much cruder.  The idea was to poison any animal that was foolish enough to eat them.

Some procedures were mere quackery.  At best they had a placebo effect, meaning that the patient felt better because s/he had taken something to make them better.  At worst they were highly dangerous or fatal.

Nobody knew the risks of infection; bacteria were not discovered until the 19th Century.  Many diseases were put down to "bad air", not surprising given the squalid conditions that many people lived in.

Surgery was virtually a death sentence, only carried out in extreme cases.  The surgeon opened up his patient (with no anaesthetic) with knives that were derived from a barber's razor.  He wore an apron to protect his clothing.  Amputations were carried out with a joiner's saw.  If the patients did not die of shock, death was a high probability due to infection. 

Operations were a public spectacle; the operating theatre was just that.  A couple of hundred people could watch with a certain amount of schadenfreude the patient undergoing his torture.

Hospitals were pretty disgusting places.

In the Nineteenth Century, many far sighted people worked hard to improve things, for example, Joseph Lister who discovered aseptic technique.  Pharmacists such as William Beecham and Jesse Boot researched into the chemistry of drugs. 

Physicists came onto the medical scene with optical devices.  And Wilhelm Röntgen pioneered the use of X-rays to take shadow pictures of bones.

Today, medical physics departments are vital in all modern hospitals.  They are involved with:

• Radiography and radiotherapy;
• The manufacture of prostheses (artificial limbs);
• Instrument calibration.

In this unit, we are going to see how physics principles are applied to modern medicine.