Design and development of a prototype of dual modality PET/optical breast cancer margin specification imager

This thesis is an attempt to develop a prototype of a breast cancer imager to assess the margins of excised breast tissue. This device is proposed to be used to assure that the entire cancerous lesion has been removed by imaging the intensity of a radio labeled tracer and inspecting for a noncancerous margin in the volume of the tissue sample. The dual modality PET/optical breast cancer specification imager uses a pair of small PET detectors to measure the bioactivity of an excised sample of tissue. A co-registered optical image is taken to allow the surgeon to visually correlate the position of the lesion images obtained with the PET imager within the physical limits of the specimen, and to verify if margins are sufficient. This assists the surgeon in deciding if additional tissue removal is required. The hardware and software required to operate the optical modality was designed and developed as a part of this thesis. Various phantoms were tested and it was demonstrated that 3D reconstruction of volume can be calculated for objects with perfect convex surfaces and irregular convex surfaces of different sizes using the optical modality. By performing error analysis it was found out that the 3D surface can be reconstructed with an accuracy of ±1 mm. A calibration procedure was followed to merge the PET and optical volumes. Fusion of PET and optical volumes and margin evaluation of the merged volume was successful. It is proved that dual modality imager can be used for margin analysis and is potential enough for further research in this direction.