Gamma Camera Imaging with Rotating Multi-Pinhole Collimator. A Monte Carlo Feasibility Study

In this work, we propose and analyze a new concept of gamma ray imaging that corresponds to a gamma camera with a mobile collimator, which can be used in vivo, during surgical interventions for oncological patients for localizing regions of interest such as tumors or ganglia. The benefits are a much higher sensitivity, better image quality and, consequently, a dose reduction for the patient and medical staff. This novel approach is a practical solution to the overlapping problem which is inherent to multi-pinhole gamma camera imaging and single photon emission computed tomography and which translates into artifacts and/or image truncation in the final reconstructed image. The key concept consists in introducing a relative motion between the collimator and the detector. Moreover, this design could also be incorporated into most commercially available gamma camera devices, without any excessive additional requirements. We use Monte Carlo simulations to assess the feasibility of such a device, analyze three possible designs and compare their sensitivity, resolution and uniformity. We propose a final design of a gamma camera with a high sensitivity ranging from 0.001 to 0.006 cps/Bq, and a high resolution of 0.5–1.0 cm (FWHM), for source-to-detector distances of 4–10 cm. Additionally, this planar gamma camera provides information about the depth of source (with approximate resolution of 1.5 cm) and excellent image uniformity.

Development of Image Reconstruction Algorithm in Realtime for Compton Camera Systems

Compton Camera is a imaging technique that uses the principle of Compton scattering interaction to reproduce the distribution image of the radiation source. Compton Camera is a 3-D imaging technique, which has a high sensitivity, wide viewing angle and a range of shooting energy that is much higher than the transmissive imaging technique. In addition, the Compton Camera imaging technique does not use a mechanical collimation system, so it is compact in size, suitable for mobile applications, security control, radiation source detection and medical applications. In this paper, the authors built an image reconstruction algorithm for Compton Camera imaging equipment using data from Monte Carlo simulation. The image quality and the parameters of the algorithm will be evaluated in detail to determine the practical applicability.

Comparing the cost-effectiveness of three diagnostic test strategies for angle closure in a developing country

Background/Aims The appropriate roles for alternative diagnostic tests in detecting primary angle closure of the eye are uncertain. This study evaluated the cost-effectiveness of Scheimpflug camera imaging, the van Herick technique and gonioscopy to identify primary angle in a developing country. Methods This cross-sectional diagnostic study included participants aged >40 years with suspected primary angle closure in the developing country of Brazil. All participants underwent Scheimpflug camera imaging, a van Herick test and gonioscopy. The diagnostic ability of these tests was evaluated using a receiver operating characteristic curve. Costs of interventions were derived using the Brazilian Hierarchical Classification of Medical Procedures. The cost-effectiveness of the tests were compared using an incremental cost-effectiveness ratio. Results Gonioscopy was confirmed to be the most accurate diagnostic test for primary angle closure, closely followed by the van Herick test. The accuracy of Scheimpflug camera imaging was considerably lower, largely because of its low sensitivity. The incremental cost-effectiveness ratio demonstrated that Scheimpflug camera imaging was also the least cost-effective, as it was considerably more expensive but with less clinical benefits. Conclusions Because of its relatively low accuracy and high costs, Scheimpflug camera imaging is not as cost-effective as gonioscopy nor the van Herick test as a means of diagnosing primary angle closure in a developing country.