Insufficient technical understanding, poor selection and poor planning result in procurement of X-ray equipments that breakdown quickly. Some guidelines are given in this article for planning and procuring x ray equipment for district level hospitals. First of all, it is essential to have an X-ray room and a dark room ready before ordering the equipment. Otherwise, the equipment would lie in the sun and moisture leading to early repairs. The X-ray room should be at least 16 feet 20 feet with a ceiling height of 10 16 feet. It should be painted with light shade of colour. Wooden panel shutters are advisable. Flourescent light is not recommended as it leaves an after glow. Dark room should be adjacent to X-ray room with light tight windows and an exhaust. Powerline also should be ready before equipment is ordered. It is extremely important to check the voltage drop and electrical requirements of the equipment before ordering. It is better to order a machine which can tolerate a higher voltage drop as it will function more reliably under poor line conditions than the one which tolerates only a low voltage drop.

BCG vaccination (prevention) and Case-finding followed by treatment (cure) are two universally accepted methods for controlling tuberculosis. BCG trials in selected populations have provided some information on the protective value of BCG, generally over short periods of time (below 20 years) and mainly among younger populations. Efficacy of different drug regimens for treatment of tuberculosis are well established and a number of studies on the effectiveness of different types of treatment programmes on the patient population are available. However, the manner in which BCG and treatment affect the four epidemiological indices of prevalence & incidence of infection and prevalence & incidence of disease in the community, over a period of time, has not been reported in detail.

This paper describes a simple set of models which can be used to predict the trend from these indices under different types of TB programmes (including no programme) which can be depicted as a combination of 5 programme parameters. How these models can be used for planning and assessment of programmes have been demonstrated by some examples. The trend in the incidence of disease obtained from this model is similar to that reported by Waaler et al in 1974. Unlike earlier models, the present model starts with cases and the calculations involved are simple enough to be handled by calculators and computer facilities are not necessary.