WAR ON CANCER

Gisborne Times, Volume LXXI, Issue 11383, 8 December 1930, Page 3

WAR ON CANCER

THE RADIUM WEAPON

ITS DISCOVERY AND USE

DR,. LEAHY’S EXPOSITION AT NAPIER.

A most arresting address on the uses of radium in connection with cancer research was given to members of the Napier Rotary Club at Napier by Dr! J. P. Leahy. In his address,. Dr Leahy said:

The much -ftilked of substance radium was discovered in 189 S by Madame Curie working on uranium residues! Bccqueral soon after 'discovered its destructive, action on body tissues through getting a burn from inadvertently carrying some 'radium in his waistcoat pocket, and though this action was soon applied to skin diseases it was only later that tho possibilities of what is known as radium therapy began to be appreciated. The revolutionary conception involved in the discovery of radium was that an element could decay .and in, the. process of decay become transformed into an entirely different substance. This has' been established in the case of certain elements, including radium. Radium is formed by the decay of uranium and the important gas radon by the decay of radium. The half lifetime of radium is 1750 years, the half lifetime of radon is 3.55 days. It is indeed to the decay of radium and radon that wo owe the surgical possibilities of radium. The evolution of uranium began perhaps when our world was a glowing nebula, and during its decay it becomes several other elements, ending by becoming lead. It exists for a few days only as radon, and for these few days perhaps—wo are not quite .sure — it offers us a euro for cancer.

RADIO ACTIVE RAYS

Radio active substances, such as radium and radon, emit certain particles and rays having different powers of penetrating matter. Tho Alpha rays have' a velocity of 10,000 miles a second, hut in spite of this tremendous velocity have little power of penetration, and “are stopped by a thin sheet of paper. The Beta rays are projected with a velocity of 180,000 miles a second, falling just short /of the velocity of light. All, but a small percentage of Beta 'l-ays are stopped by a thin sheet of platinum or one quarter inch..of body tissue. Their special action is therefore very local, most often they are objectionable or not wanted, and are cut off by screens. The third kind of ray, the Gamma rays, travel with -the velocity of light, and their powers of penetration are so great that they are scarcely affected by the screens which stop the Beta rays. They can pass through several inches of lead, and are only reduced 50 per cent in passing through four inches of body itssue. It is thus upon the Beta and Gamma rays that the surgical action of radium depends. The Beta rays are destructive in their effect on body tissue cells and are chiefly used for surface application, but the Gamma rays, on the other hand, have two remarkable effects—they stimulate the activity of "health}' tissue cells and have a definite selective action on some forms of cancer cells, probably at the moment of their multiplication causing them to disintegrate and disappear, and so destroy them.

The total effect of Beta and Gamma rays when they can be suitably applied is to cause the disappearance of certain malignant tumours and replacing them by a harmless scar and thus curing the disease.

PROPERTIES •OF RADON

The decay of radium is so slow, half of its life being 1750 years, that it may he regarded as a constant source of radiation. It decays into radon at a constant rate and in many instances it is more conveient to use radon rather than the element radium itself, and the whole situation is then entirely changed. The properties of this extraordinary substance is still more remarkable than the radium from which it originates. Radon, tho emanation from radium, is the very spirit through which radium exercises its power. It is a heavy inert gas and decays with such rapidity that in 3.85 days' half of it has vanished. So long as it is in contact with radium its decay is made up by its production from radium so that after a certain time, equilibrium of production and decay is established. This time is one month, and at this stage radium has reached its maximum radio activity; the measurement of tbe radio activity of one milligram of radium at this stage is called a millicurie.

Tho gas radon can l-e packed ill tiny containers carrying with Jt what for all practical purpose? is tiio entire radio-activity power, of the radium which is left behind and which for the time being is practically inert. The total volume of the radon gas is only a minute fraction of that of tho radium from (which, it arose, so that if you purchased a gram of radium (about 18 grains) costing £12,000, waited patiently for a month and with the most delicato plant and precautions pumped off the gas you would ho rewarded with 0.6 cubic millimetres of radon. But that tiny bubble might euro 50 cases of cancer before it expires.

The great convenience of radon is then obvious. It carries all the powers of radium for' a few ; days, its bulk is infinitesimal and its money , value nil, It can he sealed in tiny tubes inserted into cancer growth and left to dissipate while the patient can be sent ■ homo without risk to himself or loss of radium capital /to the hospital or institute., i From tho foregoing, we have now bofore us the reason for the use of radium in cancer. The cancer cell, is' a body tissue cell which -wants to grow and reproduce itself indefinitely and wildly invading and .destroying normal healthy tissue cells regardless of . their/importance to the person concerned, Radium can attack the cells of gome oanoers even at a depth from the surface) of

course, the larger the area afiected the longer must be the close of radium used. Radon is practically as useful as the radium itself, and more generally useful. Experiments hare recently been made with large doses of radium called the radium bomb—four grains or 72 grains of raduim embedded in a block of lead weighing over a ton as a protective screen against the rays for the people working with it. Such a bomb would cost £50,000 and its utility is not yet proved.

THE NEED FOR FUNDS

In conclusion, the British Empire Cancer Campaign is to fight cancer by research into cause and cure, to treat it. surgically or by radium, radon lead or any way research may point. To educate the public so that early diagnosis and treatment (when there are only a small lot of cells to be killed) is the rule, and to establish clinics for the treatment and study of cancer. This means a lot of money. An adequate supply of radium and the establishment of emanation plants for . pumping of radon gas is very expensive, and the salary of the research worker must be found.