History of the Department of Radiology

[From the 1958-1959 Hya Yaka/Yearbook]

Department of Radiology

In the Department of Radiology we are anticipating with enthusiasm the possibilities in the new school. Dental Radiology is one of the more recent specialties and as such, is in a phase of development. A chang ein premises at this time, therefore, lends itself to the adoption of ideas which have been formulating over the past years and are now crystalizing.

One cannot delve too far back into history on this subject, because, "as every student knows," it was not until 1895 that Roentgen first discovered the existence of X-rays. It was some years before X-rays were in general use as a diagnostic aid in medicine and still later that they were adapted to dentistry.

Some of the earlier types of apparatus looked home-made by present day standards, and it was necessary for the operator to adjust the degree of the vacuum in the tube before the radiographs could be taken. this was achieved by making contact between two wires and causing an electrical discharge inside the tube. The dangers also were as fully realized as they are today, and I know of one gentleman who, in his earlier days, foreseeing a great future for this medium, experimented with radiographs of the skull, perhaps the forerunner of cephalometry. Unfortunately, he used a member of his staff for his experiments; some weeks after, the "volunteer" was seen to have a round bald patch on his head, and until his hair grew again the dentist had his mistake always before his eyes. There were, of course, other cases of over-exposure which had more tragic consequences.

In more recent times there was the apparatus in which the wire, carrying a high voltage (usually around 55,000 volts) from the transformer at the base, to the tube, was a bare wire. It was considered that no insulation was adequate against such a high voltage and therefore it was advisable to have the danger displayed conspicuously rather than have the hidden danger of inadequate insulation. One does not need to search so far into the past in order to remember this apparatus, and indeed, at this present moment there is one languishing in an oubliette of the present dental school.

The concept of a shock-proof apparatus was established with the advent of the small X-ray tube and small transformer. It then became possible to enclose both of these in one casing, and one no longer feared the firework display which could be caused by high voltage wire touching the electric light installation.

The department in this school developed as an off-shoot of the main clinic, but the records do not reveal the date when this occurred. One of the earliest names associated with X-rays in this school was Dr. F. Price, and another early worker in this field was Dr. R. D. Thornton. Later, radiology came under the direction of Dr. W. E. Willmott, a photograph of whose hands is displayed in the present intra oral room, and it was either during the time of Dr. Willmott or during the time of his successor, Dr. Richardson, that we were established as a separate department. Dr. Richardson remained as the Head of the department until 1945, and he was succeeded soon after by Dr. J. E. Moser, who held this position until his death in 1955. Dr. M. N. Rockman was then established in this appointment, which he held until 1957.

In the present department the oldest inhabitant is Dr. D. B. McAdam who was first appointed in 1953. For the past twelve years we have been fortunate in that Dr. Worth has travelled from Victoria every year in order to give the series of lectures on which the teaching of interpretation has been based.

In dental radiology at the present time, with one exception, we are in a period of modification of existing materials and equipment, for example, the improvement that has occurred in the quality of X-ray films over the past few years. The exception to which I referred is the increased awareness of the dangers associated with radiation. The knowledge that radiations are dangerous is not new, and there were papers on this subject as long ago as the early years of this century, and again about ten years ago there were some excllent articles on this theme. This aspect, however, has been brought into greater prominence recently because of two factors; firstly the increase and the potentially greater increase in general background radiation due to the instroduction into the life of man of atomic and nuclear reactions, and secondly the greater realization of the implications of genetic changes in human beings which can be brought about by all radiations.

It is for this reason that in the Radiology Department today one hears so much talk of filtration of rays, limiting cones and changes in kilivoltage, and it is for this reason also that in the new department the walls of all the surgeries will be lined with lead.

The department at the new school will probably be as modern and as up-to-date as any that exists today, and it has been designed not only to cope with the present situation but with an anticipation of the future. There will be ten individual surgeries for intra oral radiography in which will be housed apparatus for cephalometric surveys of a high degree of accuracy, and equipment for undertaking skull and general work. In addition to the normal requirements of radiography, there will be a teaching clinic room and a spare processing room to be used in cases of emergency, and for any special projects which may be undertaken.

It is always difficult to speculate on the future and it is no exception when speculating on possible trends and changes in this field, but, bearing in mind present research and the dental application of radiology in other fields, one can perhaps hazard a few guesses.

In the next few years we may see a still greater improvement in the X-ray films which are manufactured. Perhaps an emulsion will be produced for use with the higher kilovoltage apparatus, maintaining speed and at the same time giving greater contrast. This could facilitate interpretation of radiographs and enable the student to understand more fully the structures which he is viewing.

An adaptation of general medical radiology which we may see in dental use in the future is image intensification. This utilizes the principle of the television tube, and a weak image is increased in brightness by electronic activity.

An apparatus is designed for dental work which has recently appeared on the market is the Rotagraph. This combines tomography with panoramic viewing an done is able to view on a flat surface a curved plane of a large mass. The practical application of this in dentistry is that theoretically one is able to view the whole of the mandible and maxilla on one film. In actual practice, this result is obtained by rotating the patient in one direction and the film in the opposite direction whilst a narrow beam of X-rays is directed at the patient. At some future date we may see such an apparatus in our new department.

Another adaptation which we may see in use in dentistry in the future is the point source of radiation from radio active material. This has been used in industry and gneral research for the detection of flaws and cracks in different materials, and in medicine it has been used experimentally. It has been suggested that it is not outside the bounds of possibility that a radio active material could be contained in the head of an instrument about the dimensions of a pencil, and could be covered by a protective substance, except for one small oepning. This could then be used either intra orally or extra orally with a film appropriately placed. 

We have briefly passed through dental radiology and have finished in the realm of speculation. Perhaps we should get our feet on the ground again and consider the main aim of the department in the past, the present, and the future, and that is to equip the student to cope as efficiently as possible with all the problems in the field of dental radiology which he may encounter when in practice.

[Dr. H. G. Poyton]