Objective: To estimate the depth of radioisotope distribution in relation to patient anatomy using a portable hybrid gamma camera which combines optical and gamma imaging. This additional information could be of particular help in optimising surgical procedures for resection of lymph nodes and tumours.

Method: The Hybrid Gamma Camera (HGC) was used to image phantoms filled with ⁹⁹ᵐTc to simulate radioactive uptake in nodes.
Gamma and optical images were recorded simultaneously and fused in a combined image. The distance between the simulated skin surface and the radiolabel in the nodes was determined from the images, and compared with the measured depth of the source below the surface.

Result: Good agreement was found between the calculated and measured source depths. Surface distance measurements were accurate to within 3% (at 200mm from the collimator face) and depth measurements within 10%. The phantom simulations have shown that this simple technique could provide a useful estimation of depth for radiolabelled distributions prior to clinical procedures. Suggestions for improving this technique will be discussed.

Conclusion: A method to calculate the depth from surface to source using the HGC has been described. There is a linear relationship between the calculated and measured distances from the camera to the source and/or the surface. This technique could allow surgeons to determine the depth and location of radiopharmaceutical uptake immediately prior to an operation without 3D SPECT imaging.


J E Lees, S L Bugby, A P Bark, DJ Bassford, PE Blackshaw, AC Perkins, A Hybrid Camera for locating gamma sources in the environment, JInst 8 (2013) P.10021 Report abuse »