It has been suggested that 3 to 5% of total lung cancer deaths in the UK may be associated with elevated radon concentration. Radon gas levels can be assessed using CR-39 plastic detectors which are often assessed by 2-D image analysis of surface images. 3-D analysis has the potential to provide information relating to the angle at which alpha particles impinge on the detector. In this study we used a "LEXT" OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan) to image tracks on five CR-39 detectors. We were able to identify several patterns of single and coalescing tracks from 3-D visualisation. Thus this method may provide a means of detailed 3-D analysis of Solid State Nuclear Track Detectors.