Hybrid optical-gamma camera for intraoperative imaging: A flexible phantom to assess system performances for sentinel node detection

Conference Paper

Ng, A.H. . 2015

• نوع عمل المنشور: Poster presentation
• اسم المؤتمر: International Conference on Clinical PET-CT and Molecular Imaging (IPET 2015 ): PET-CT in the era of multimodality imaging and image-guided therapy
• عنوان المؤتمر: Vienna
• تاريخ المؤتمر: الاثنين, تشرين اﻷول (أكتوبر) 5, 2015
• المنظمة الراعية: IAEA

مستخلص المنشور

Introduction:
There is an increasing interest of the applications of handheld gamma cameras in sentinel lymph node biopsy (SLNB) in a broad range of cancers. A prototype hybrid optical-gamma camera has been developed through collaboration between the Space Research Centre at the University of Leicester and Medical Physics at the University of Nottingham. The camera system provides real-time, high resolution fused optical-gamma images highly suited to intraoperative procedures. We have also developed standard methods for assessing the performance of the camera system prior any surgical applications.
 
Material and methods:
A sentinel node phantom was developed to simulate the localisation of nodes in the presence of high injection site activity. The phantom was fabricated using polymethyl-methacrylate (PMMA) and assembled in a cube shape measuring 120 x 130 x 110mm. Syringes with small volumes of 99mTc were used to simulate activity in the injection site (approx. 3ml) and node (approx. 0.1ml) at node-to-injection site ratio of 1:100. These were placed at different separations and depths to simulate the uptake at different anatomical sites in the body. Image acquisition were carried out using the prototype camera system (CsI(Tl) columnar scintillator coupled to a charge-coupled device (CCD), 1 mm-diameter tungsten pinhole collimator) and compared with a portable gamma camera (Crystalcam, Germany).
 
Results:
Phantom studies simulating the SLNB procedures have showed that the camera system could detect low-activity in nodes up to the depth of 45 mm from the phantom surface by visual examination of images. Profile analysis demonstrated the limits of node detection over a range of depths and node-to-injection site separations. Further comparisons have been made between images captured by both imaging devices.
 
Conclusion:
The phantom was a useful tool to assess the performances of camera systems in a simulated clinical environment. The results show that the system would be suitable for use in intraoperative procedures, included but not limited to SLNB for example patients with breast cancer. In addition, the co-aligned hybrid images provided good evidence of localisation of radiopharmaceutical distribution and its anatomical features, thus providing added value in intraoperative procedures.