A high-resolution hybrid gamma-optical camera for intraoperative imaging
Lees, J.E. . 2016
Introduction
The development of compact low profile gamma-ray detectors has allowed the production of a small field of view, handheld imaging device which could be used at the patient bedside and in operating theatres. The combination of an optical and a gamma camera, in a co-aligned configuration, provides an optical image overlaid with a scintigraphic image. This innovative introduction of hybrid imaging offers assistance in localising the site of uptake in procedures such as sentinel node detection. The hybrid camera concept can be extended to a multi-detector design which provides depth estimation of the gamma-emitting source.
Materials and Methods
The hybrid camera consists of a 1500 mm thick CsI(Tl) columnar scintillator coupled to an electron multiplying CCD with a tungsten pinhole collimator which gives a 40mm x 40mm nominal field of view for the 8mm x 8mm CCD detection area. An optical camera is aligned so as to provide the same field of view as the gamma camera. Optical and gamma images are taken simultaneously and fused to produce dual-modality images providing information from the gamma camera within an optical context. Images were obtained in laboratory simulations using a range of bespoke phantoms. Clinical images from patients attending the nuclear medicine clinic were also taken.
Results
The characteristics of the hybrid camera compared favourably with other portable SFOV cameras currently in use. High quality images from phantoms show that the hybrid system is particularly suited for sentinel lymph node detection. Experimental simulations demonstrated the ability to differentiate between adjacent hot sources (1:100 activity ratio) in close proximity, as would be required for differentiation of sentinel nodes from the injection site. Estimation of depths of radioisotope sources in a simple phantom were also achieved.
We report on clinical results from lymphoscintigraphy, thyroid imaging and lacrimal drainage studies that show that the site of uptake could be visualised in the patient.
Conclusion
The hybrid camera has been used to produce dual-modality images in both laboratory simulations and in the clinic. In addition we have shown that the hybrid camera concept can be extended to estimate the position and depth of radionuclide distribution within an object.
A novel hand-held hybrid optical-gamma camera (HGC) has previously been described that is capable of displaying co-aligned images from both modalities in a single imaging system. Here, a dedicated…
OBJECTIVE: To examine the imaging capability of a novel small field of view hybrid gamma camera (HGC) using 125I seeds prior to surgical use.
Over recent years, in the field of nuclear medicine, advances in the development of small field of view (SFOV) gamma cameras have been increased.