Among other things, there is disclosed embodiments of devices for assisting in aiming and inserting percutaneous medical tools or devices. A mandrel portion with a sharpened end has two or more guiding or directing members attached to it. The guiding or directing members at least partially define spaces that form part of a channel that is oriented parallel to the longitudinal axis of the mandrel portion, and one or both can be easily visualizable using imaging technology. The clinician can insert the aiming or guiding device into the patient, use imaging technology along the axis of the channel of the device to see whether the device is accurately placed, and if so, the guiding or directing members can be used to guide the percutaneous insertion of a medical tool or device.
