To measure the target position in the body with high accuracy and quickly from the ultrasound image.The position measuring apparatus 1 includesThree dimensional moving model creation part 12 which creates three-dimensional moving model which shows three-dimensional position of body tissue according to respiration, andA first ultrasonic sensor group 141 disposed along a first direction in which the target moves the body in response to respirationA second ultrasonic sensor group 142 disposed sparsely along the second direction crossing the first direction andBased on a first ultrasonic image obtained from a signal of a first ultrasonic sensor groupA position calculating section 153 for calculating a first position of the targetThe second ultrasonic image obtained from the signal of the second ultrasonic sensor group is compared with the three-dimensional movement model.A position calculating unit 155 for calculating a second position of the targetA target three-dimensional position calculation unit 156 for calculating a three-dimensional position in a target body from a first position and a second position, and.Diagram【課題】超音波画像から高精度かつ速やかに体内の目標位置を測定すること。【解決手段】位置測定装置１は、呼吸に応じた体内組織の３次元位置を示す３次元移動モデルを作成する３次元移動モデル作成部１２と、目標が呼吸に応じて体内を移動する第１方向に沿って配置される第１超音波センサ群１４１と、第１方向と交差する第２方向に沿って疎に配置される第２超音波センサ群１４２と、第１超音波センサ群の信号等から得られる第１超音波画像に基づいて、目標の第１位置を算出する位置算出部１５３と、第２超音波センサ群の信号等から得られる第２超音波画像と３次元移動モデルとを照合して、目標の第２位置を算出する位置算出部１５５と、第１位置と第２位置とから目標の体内における３次元位置を算出する目標３次元位置演算部１５６と、を備える。【選択図】図１
