tool to fight cancer can be seen through a series of historical milestones. The main principle guiding the historical development of radiotherapy as a medical discipline has been the search for strategies to deliver a higher radiation dose to a defined volume at the site of the tumour, while minimizing the dose to healthy tissues and organs. The effort to reach this goal has included strategies such as the use of hyperbaric oxygen, the exploration of radiosensitizers and radioprotectors, brachytherapy, particle therapy and others. Modern radiotherapy makes use of highly precise collimating devices, and also offers the possibility of modulating the radiation fluence of an individual beam. Radiotherapy using charged particles such as protons or carbon ions is also a promising strategy (see Chapters 11 and 12). Radiotherapy is one of the three pillars of cancer treatment, which also include surgery and systemic therapies. Radiotherapy is highly cost effective (see Chapter 18); while the acquisition of radiotherapy equipment usually represents a significant initial capital investment, the equipment has a long useful life during which a large number of patients can be treated. Radiotherapy has had a role in cancer cure, alone or in combined schedules with both forms of treatment mentioned previously. In addition, radiotherapy is highly effective in the palliation of cancer symptoms such as pain, bleeding and organ obstruction (see Chapter 23). The optimal therapy for patients with certain types of cancer detected early for example, cancer of the uterine cervix and corpus, breast and testicle, and early cutaneous melanoma will result in five year survival rates of up to 75%. By contrast, five year survival rates for patients with cancer of the pancreas, liver, stomach and lung are normally less than 15%. Some of the cancers common in developing countries are highly responsive and potentially curable with radiotherapy. These include cervical cancer, as well as breast, head and neck, oesophageal and rectal cancers. Hence the important role of adequate radiotherapy services in these countries. Since the initial cost of establishing and maintaining such facilities is relatively high, they are normally initially located in the capital city or other urban or highly populated centres. Facilities are then expanded and new facilities are established in the periphery when additional resources become available. 16 Radiotherapy should be an important part of any national cancer control plan or programme. In fact, the overall clinical outcomes of radiotherapy are optimized when radiotherapy services coexist with effective prevention and early detection programmes, and good quality surgery. The reasons for this are easy to understand. In countries that have been able to implement and sustain effective early detection and screening programmes, more cancer patients are diagnosed when their disease is in the early, curable stages; smaller tumours or precancerous lesions are amenable to being cured by surgery alone or radiotherapy. Therefore, in this scenario, radiotherapy can yield optimal clinical outcomes. Conversely, in countries where there is no availability of prevention or early detection programmes, and referral systems and specialized surgical services are weak, most patients present with advanced stages of the disease and are beyond cure. In these situations, the role of radiotherapy is limited to offering the best palliation possible, but the chances for cure will be much more limited. Access to radiotherapy services has a number of dimensions, which include availability of the service, geographical accessibility, affordability, accommodation, and awareness of physicians and patients. Physicians and patients need to be aware that radiotherapy services are available in their country and that cancer is a potentially curable disease when diagnosed early. Cultural traditions and popular and religious beliefs have an impact on access to radiotherapy services and should be taken into account. This factor has not been sufficiently explored and addressed in oncology research. 1.3. A PACKAGE CONCEPT FOR RADIOTHERAPY SERVICES The optimal use of a teletherapy machine in terms of effectiveness and safety occurs when it