An imaging apparatus for imaging an introduction element (17; 117) within a living being, wherein the introduction element (17; 117) is adapted to be inserted into the living being for performing a biopsy of an inner part of the living being or for introducing a radiation source into or next to the inner part of the living being for performing a brachytherapy, wherein the introduction element (17; 117) comprises at least one ultrasound receiver (21; 121, 221, 321) arranged at a known location of the introduction element (17; 117), wherein the imaging apparatus comprises: - an ultrasound probe for being inserted into the living being, wherein the ultrasound probe is adapted to emit ultrasound signals for acquiring ultrasound data of the inner part of the living being, wherein the ultrasound probe is a 3D ultrasound probe for acquiring ultrasound data of a 3D region, - a first tracking unit for tracking the location of the introduction element (17; 117) within the living being and within the 3D region based on a reception of the emitted ultrasound signals by the at least one ultrasound receiver (21; 121, 221, 321), - an image providing unit for providing a pre-interventional 3D image showing the inner part of the living being, which indicates a diseased condition of the inner part of the living being, - an introduction element guide for being attached to the ultrasound probe and for guiding the introduction element (17; 117), - a second tracking unit for tracking the location of the introduction element guide, - an imaging unit for generating an indicator image showing the inner part of the living being and an indicator of the introduction element (17; 117) based on the tracked location of the introduction element (17; 117), wherein the imaging unit is adapted to generate an ultrasound image showing the inner part of the living being based on the acquired ultrasound data and to register the pre-interventional 3D image with the ultrasound image, wherein a site where the biopsy was performed or where the radiation source was introduced by means of the introduction element (17; 117) is indicated in the indicator image, wherein the imaging unit is adapted to determine a slice within the living being including the tracked location of the introduction element (17; 117) based on the tracked location of the introduction element (17; 117) and the tracked location of the introduction element guide and to generate as the indicator image a slice image of the determined slice, wherein the slice image is generated from the registered pre-interventional 3D image or as a fused image from the registered pre-interventional 3D image and the currently generated ultrasound image, wherein the tracked location of the introduction element (17; 117) is indicated in the slice image, and - a display for displaying the indicator image. - an ultrasound probe for being inserted into the living being, wherein the ultrasound probe is adapted to emit ultrasound signals for acquiring ultrasound data of the inner part of the living being, wherein the ultrasound probe is a 3D ultrasound probe for acquiring ultrasound data of a 3D region, - a first tracking unit for tracking the location of the introduction element (17; 117) within the living being and within the 3D region based on a reception of the emitted ultrasound signals by the at least one ultrasound receiver (21; 121, 221, 321), - an image providing unit for providing a pre-interventional 3D image showing the inner part of the living being, which indicates a diseased condition of the inner part of the living being, - an introduction element guide for being attached to the ultrasound probe and for guiding the introduction element (17; 117), - a second tracking unit for tracking the location of the introduction element guide, - an imaging unit for generating an indicator image showing the inner part of the living being and an indicator of the introduction element (17; 117) based on the tracked location of the introduction element (17; 117), wherein the imaging unit is adapted to generate an ultrasound image showing the inner part of the living being based on the acquired ultrasound data and to register the pre-interventional 3D image with the ultrasound image, wherein a site where the biopsy was performed or where the radiation source was introduced by means of the introduction element (17; 117) is indicated in the indicator image, wherein the imaging unit is adapted to determine a slice within the living being including the tracked location of the introduction element (17; 117) based on the tracked location of the introduction element (17; 117) and the tracked location of the introduction element guide and to generate as the indicator image a slice image of the determined slice, wherein the slice image is generated from the registered pre-interventional 3D image or as a fused image from the registered pre-interventional 3D image and the currently generated ultrasound image, wherein the tracked location of the introduction element (17; 117) is indicated in the slice image, and - a display for displaying the indicator image.