INVESTIGATIONS TO OPTIMIZE THE TECHNIQUE IN THE RADIOLOGICAL EXAMINATION OF THE LUNG OF THE ADULT HORSE

Investigations to optimize the technique in the radiological examinati on of the lung of the adult horse Standardised X-rays of lungs of 15 h orses which did not show any signs of pulmonary disease were made. The horses were between 1,5 and 7 years of age. Their weight ranged from 280 kg to 720 kg. In all these horses the following measurements were taken: hight at the garrot, diameter of the thorax, circumference of t he thorax and thickness of the thoracic wall. The measurements of the thorax were taken from two different locations. The thickness of the t horacic wall was measured by means of sonography. The latero-lateral X -rays were taken on two regions of the thorax of every horse: the caud o-ventral and the caudo-dorsal region. For each picture the mAs-value was individually chosen in relation to the size of the horse. All othe r instrumental settings like kV-value (here 125 kV), film-focus-distan ce (150 cm), beam direction, and phase of respiration (end of inspirat ion) were helt constant. For each horse three X-rays were taken with d ifferent mAs-values for the caudoventral and the caudodorsal region of the thorax. The quality of each X-ray picture was estimated by a stan dard procedure: the derails and the sharpness of the structures were e valuated and the best X-ray picture made was selected for further anal ysis. The optical density of two areas of these selected pictures was measured with a densitometer and compared with values of investigation s on human patients. Finally the relationship between parameters of bo dysize and optimal mAs-value of the best pictures was statistically de termined.