Objectives
The Hybrid Compact Gamma Camera (HCGC) [1] has been developed to provide additional localisation information during procedures such as sentinel lymph node biopsies. These procedures trace radiopharmaceuticals, from an injection site to sentinel nodes, through lymphatic vessels. In this experiment, the performance of the HCGC for lymphatic vessel drainage imaging has been investigated.


Materials and Methods
Lymphatic vessels were simulated with a 0.55mm internal diameter cannula containing 99mTc with an activity of up to 3MBq/cm. A micro vial containing 60MBq of 99mTc (0.4ml) was used to simulate the injection site. The phantom was imaged through a range of depths of scattering material; spatial resolution and detectability were investigated. The effect of the presence of background was also investigated.


Results
Fused optical and gamma images showed good alignment of the two modalities allowing localisation of activity within the vessel and injection site. At an imaging distance of 10cm, the resolution of the HCGC was not degraded at a separation of more than 1.5cm (variation <5%) from the injection site. Even in the presence of the injection site the targeted lymphatic vessel was detectable with an acquisition time of less than 2 minutes.


Conclusion
The performance of the HCGC in this study shows that it is well suited for lymphatic vessel drainage imaging. The anatomical context provided by the optical camera aids the physical localisation of radiopharmaceutical uptake. Further evaluation will be carried out with the aim of using the camera in a surgical theatre setting.


1.Lees, J.E., D.J. Bassford, O.E. Blake, P.E. Blackshaw, and A.C. Perkins, A Hybrid Camera for simultaneous imaging of gamma and optical photons. Journal of Instrumentation, 2012. 7(6).Report abuse »