Ultrasound imaging market
Ultrasound is a versatile, non-invasive, low-cost, realtime technique used extensively by both hospital and office-based physicians. There are over 150,000 ultrasound instruments installed throughout the world, performing more than 135 million scans per annum. The true utility of ultrasound will be fully realised with the advent of safe and efficacious medical diagnostics which will pass through the vessels of the microvasculature, persist within the blood-pool for some minutes, enhance acoustic properties and thus produce brighter and clearer images of anatomical structure and physiology.

The latest generation of medical diagnostic products are well placed not only to improve image quality significantly but also offer the potential to show perfusion of the myocardium, or how well the heart muscle is being supplied with blood. Such utility will significantly strengthen the role of ultrasound in the evaluation of coronary artery disease (CAD), which is the single most important disease entity in the industrialised world in terms of both mortality and morbidity. During 2000 good progress was made towards this goal but this is still very much state of the art and we remain some way from a reliable, robust approach which is available to cardiologists everywhere. However, advances in instrument hardware, software and imaging techniques continue to be made at an impressive pace and we can envisage a time when contrast-enhanced ultrasound becomes part of the routine assessment of patients with heart disease.

Focus on disease³

3. Source: Pharmaceutical Research and Manufacturers of America, 2000 data.

The future
Medical imaging has come a long way since it was discovered that X-rays could be used to image bones in the living body. The ability to scan entire human bodies in a matter of seconds while identifying disease-induced abnormalities with pinpoint accuracy is now taken for granted. Medical diagnostic products have already advanced to a stage where they are an integral part of modern healthcare and their importance will continue to grow in future years. This growth will be driven primarily by two factors.

First, imaging is particularly well suited to the diagnosis and management of many age-related diseases such as cardiovascular disease, cancer and neurological disease. These diseases are becoming increasingly prevalent as the percentage of elderly people in the population rises. Heart disease, cancer and neurological diseases such as depression, stroke and Alzheimer's disease are among the most common diseases in the western world and represent the highest cost burden to the healthcare system. Accordingly, there is tremendous social and political pressure to develop earlier and more reliable diagnostic tests to assist in the treatment and prevention of these diseases.

Second, as medicine moves to treatment at the molecular level, so the vital importance of complementary molecular diagnostic products will be seen and the opportunities they offer continue to expand. We have already progressed from looking at the anatomical level (the whole organs, tumours) to the cellular level (disease-related changes in the cell, such as a reduction in the number of dopamine transporters in the brain in Parkinson’s disease). We are now at the point where medical diagnostic products can visualise biochemical events at the molecular level, for example, measuring the metabolism of glucose molecules in cells.

Advances such as these will expand the role of imaging beyond diagnosis. We will be able to detect disease earlier (disease screening), monitor its progression (disease staging), select the best therapy for a patient and monitor therapeutic efficacy. The human genome project is opening the possibility of identifying individuals at higher risk of inheriting certain diseases. Through selective screening of these ‘high risk’ individuals, using medical diagnostic products, disease onset will be detected at a much earlier stage than is possible today. This will enable earlier therapeutic intervention which, given the widely held belief that it is less expensive to pay for disease prevention than it is to pay for treatment, could help to reduce healthcare costs and improve quality of life.

Radiotherapy market
There are numerous applications for radioisotopes in therapeutic medicine, including the treatment of cancerous and non-cancerous tumours and the relief of pain from secondary cancer tumours and arthritis. Two applications are presented below.

Brachytherapy
In use for almost 100 years, brachytherapy requires the implantation of a solid radioactive source either temporarily or permanently into a tumour that it then irradiates and kills, for example, in the treatment of breast, prostate, head and neck cancers.

Although the use of these techniques is well established, there has been a dramatic increase in the use of brachytherapy for treating prostate cancer since the mid 1990s, when clinical data demonstrating the success of this treatment was first published. This has now become the largest single market for radioisotopes in therapy.

The rapid expansion in the use of brachytherapy has enticed many new competitors into the field. In the most established market (the US) there are now more than 10 active competitors. At present in the US, approximately 25 per cent of men who are diagnosed with early stage prostate cancer receive seed implantation treatments. This follows the early diagnosis of the disease and the widespread availability of this treatment option with its excellent clinical results. In Europe and other countries this option is not widely available, although publicity and good clinical results are generating a sharp increase in demand.

Systemic radioisotope therapy
Systemic radioisotope therapy has been used for more than 50 years and is defined as an injection or oral administration of a radioisotope which concentrates in a specific part of the body where it produces a therapeutic effect. Examples are the use of iodine 131 for thyroid tumours and strontium 89 for relieving pain in secondary bone cancers.

The future
Novel applications for radioisotope therapy continue to emerge. Vascular brachytherapy for the prevention of restenosis following angioplasty has received FDA (Food and Drug Administration) approval for routine clinical use in the US.

There is also great scientific and commercial interest in the clinical development of radiolabelled monoclonal antibodies for the treatment of several types of cancer. Antibodies target specific tumour cells and then attach to them, allowing their radioactive component to destroy them while sparing the surrounding healthy cells.