A guide for placing a landmark(s) in a patient tissue comprises a central portion defining at least one guiding bore configured to receive and guide a tool for placing the at least one landmark in the patient tissue. Extended portions project away from the central portion, each of the extended portions having respective lower base surfaces contoured to mate with the patient tissue, at least the respective lower base surfaces being customized as a function of preoperative imaging of the patient tissue, whereby the guide is specific to the patient.