Tehran University of Medical Sciences Frontiers in Biomedical Technologies 2345-5837 1 4 2014 12 30 265 270 EN Hojjat Mahani Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran, Iran AND Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran. Alireza Kamali-Asl Radiation Medicine Engineering Department, Shahid Beheshti University, Tehran, Iran. Mohammad Reza Ay Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran AND Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran. 2015 10 13 2015 10 13 Purpose: Mechanical calibration of camera plays an important role in nuclear imaging to acquire a more qualified and quantized scintigram. The objective of this work was to quantitatively evaluate planar resolution and sensitivity of a tilted Anger camera using a Monte Carlo simulation. Methods: For this purpose, spatial resolution and system sensitivity of a tilted-head, LEHR collimated gamma-camera were evaluated using Monte Carlo simulation. To do so, tilt-angle of camera’s head was considered to vary from -10 to 10 degrees from the baseline. The Monte Carlo simulated data were validated by means of a comparison with experimental data. In addition, the performance of the system was analyzed both in spatial and frequency domains. Results: Spatial resolution, in terms of FWHM, for simulated and measured point-spread functions (PSFs), at the rest-position has a value of 7.22 mm and 7.43 mm, respectively. The results also show that the spatial resolution monotonically increases as the absolute value of tilt angles increases, up to a degradation factor of 2.02 for a typical scintillation-camera. System sensitivity exhibits a constant behavior for all tilt-angles with a maximum statistical fluctuation of 2%. Conclusion: While a head tilt has no effect on the sensitivity of the camera, it can result in a poor and spatially variable planar spatial resolution and contrast of the images provided by the tilted-scanner. https://fbt.tums.ac.ir/index.php/fbt/article/view/24 https://fbt.tums.ac.ir/index.php/fbt/article/download/24/23