Positioning accuracy and precision of a three degrees-of-freedom manipulator guided by tilting collimator scintillation camera

In our previous studies we have considered a possible use of a manipulator for biomedical applications guided by the so-called tilting-collimator (TC) scintillation gamma-ray camera. The imaged gamma-ray emitting object is localized exploiting our patented method to determine the camera-toobject distance using a TC camera (patent No RM 2006 A 000216, UIBM Roma). Thus the three coordinates of the object are obtained without moving either the camera or the object. A manipulator coupled to the TC camera and designed for simple operations such as e.g. biopsy has been constructed. It has been realized as a three-segmented arm compounded by three mutually perpendicular linear actuators. The manipulator guidance and motion control are conducted by a computer after processing the images obtained for two different collimator positions of the TC camera. Accuracy and precision tests f the manipulator positioning have been conducted using tissue-equivalent phantom which contained small spherically shaped avities filled with a solution of 99mTc. The tests measurements show that the instrument possesses satisfactory accuracy and recision for camera-toobject distances ranging from 0 up to 10cm and can be used for in-vivo small-object studies such as monitoring of the biodistribution of radiopharmaceuticals, needle biopsy, tissue sampling, etc. © 2008 IEEE