Introduction

This is a Global Textbook of Radiology; but is diagnostic imaging truly "Global", and is it available, as it should be, to everyone?

Unfortunately, the answer to both questions is "NO", because only about one third of humanity has easy access to diagnostic imaging, even at its most simple and therefore most important level. Yet, and here is the contradiction that all radiologists must face, every student and trainee physician in any medical school quickly learns that most fractures, real or suspected, need to be radiographed. Many patients with a cough will need a chest x-ray and it is of benefit to many pregnant women to have at least one ultrasound examination. The list of patient complaints that leads to some form of imaging would be very long and impressive, if it were not taken for granted that imaging is part of good, standard, health care. Diagnostic imaging should not be a rare privilege, but should be the right of any patient when his or her doctor believes that it will assist in accurate diagnosis and result in better treatment (Figs. 1 and 2).

The World Health Organization (WHO) is a specialized agency of the United Nations, with its headquarters in Geneva, Switzerland, and six Regional Offices serving different areas of the world. Almost every one of the 189 member states has a WHO representative readily available to help the health authorities when requested. WHO is particularly concerned with providing "Health for All". Its programmes include public health and prevention (e.g. water supplies, environmental sanitation and vaccines), as well as the treatment, and if possible, control of the vast numbers of communicable diseases and the increasing morbidity and

Figure 1. Diagnostic imaging should be available to everyone who needs it. Radiography of the hand of a Maasai girl in Kenya. (Photo: Diane Gibson)	Figure 2. Diagnostic imaging should be available wherever it is needed. A patient in Yemen looking at his own radiograph. (Photo: WHO)

mortality from accidents and injuries. Any physician can provide a list of health problems in which diagnostic imaging will play an important role, often providing the only way to make the correct diagnosis. Several important publications, including "The hospital in rural and urban districts" (WHO Technical Report Series 819, Geneva, 1992) make it clear that diagnostic imaging for the most common illnesses is an essential part of the resources in any hospital to which patients will go for diagnosis and treatment.

So what has WHO done about this serious deficiency, apart from publishing various books and papers, holding conferences or lecturing at radiological meetings? Since the 1960' s, WHO has, through expert committees and advisors, worked with the x-ray industry on the design of imaging equipment for developing countries, and of equal importance, on the improvement of image quality, safety and the availability of imaging services. Training programmes for radiologists have been set up in cooperation with the International Society of Radiology (ISR), and the training and work of radiographers/x-ray technicians and sonographers have been studied with their international organizations. Radiation therapy has not been neglected but is not part of this textbook.

This lengthy and often frustrating process has resulted in universally applicable guide lines which are of importance to all radiologists. There are minimum specifications for equipment, together with technical manuals which, if followed, will prevent the waste of money caused by the wrong choice of equipment and technique. Image quality will be improved compared with much that is available today, because it has been shown that the radiographs produced by a WHO specified radiographic system are comparable to or even of better quality than images at prestigious university departments. Equipment does not have to be complex and expensive to produce good images.

Why is diagnostic imaging so important?

Table 1. Worldwide estimated percentage distribution of Disability Adjusted Life Years (DALY) lost, by major categories for 1990. Source: World Development Report 1993, Investing in Health. Published for the World Bank by Oxford University Press, Inc.

     
Table 1 shows the worldwide estimated percentage distribution of disability-adjusted life years (DAL Y) lost, by major categories for 1990.

DALY loss, the number of disability-adjusted life years lost, is a way of describing the difference between the actual age at death and the expectation of life at that age in a low-mortality population in combination with an adjustment for the severity of disabilities in the same population. DALY loss thus can be used as a measure of the burden of disease.

The importance of diagnostic imaging is that it makes possible the accurate diagnosis of much of the disease and trauma responsible for these deaths and disabilities. Whenever adequate therapeutic services are available, the years of disability and life lost can be reduced.

Yet, nearly 100 years after the discovery of x-rays about two thirds of the world' s population does not have access to the most essential diagnostic imaging service. The fundamental principle of "Health for All" is equity, which demands that this universally recognized diagnostic modality be made available to all who need it. There can then be quick and accurate diagnosis, less hospitalization, prompt return of the patient to home or workplace, and additionally and most importantly, less pain and suffering.

Philip E.S. Palmer, Thure Holm and Gerald P. Hanson