Abstract: 
The present invention relates to a device (2) and a method (100) for determining at least one final twodimensional image or slice for visualizing an object of interest in a threedimensional ultrasound volume. The method (100) for determining at least one final twodimensional image, the method comprises the steps: a) providing (101) a threedimensional image of a body region of a patient body, wherein an applicator configured for fixating at least one radiation source is inserted into the body region; b) providing (102) an initial direction, in particular by randomly determining the initial direction within the threedimensional image; c) repeating (103) the following sequence of steps s1) to s4): s1) determining (104), via a processing unit, a setdirection within the threedimensional image based on the initial direction for the first sequence or based on a probability map determined during a previous sequence; s2) extracting (105), via the processing unit, an imageset of twodimensional images from the threedimensional image, such that the twodimensional images of the imageset are arranged coaxially and subsequently in the setdirection; s3) applying (106), via the processing unit, an applicator pretrained classification method to each of the twodimensional images of the imageset resulting in a probability score for each of the twodimensional images of the imageset indicating a probability of the applicator being depicted, in particular fully depicted, in the respective twodimensional image of the imageset in a crosssectional view; and s4) determining (107), via the processing unit, a probabilitymap representing the probability scores of the twodimensional images of the imageset with respect to the setdirection; wherein the method comprises the further step: d) determining (108), via a processing unit and after finishing the last sequence, the twodimensional image associated with the highest probability score, in particular from the imageset determined during the last sequence, as the final twodimensional image. The invention provides an efficient way to ensure that the ultrasound volume has the required clinical information by providing the necessary scan planes having the object of interest e.g. the applicator (6) in a threedimensional ultrasound volume.
