<div class="__aliyun_email_body_block"><div  style="clear:both;"><span  style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14.0px;color:#000000;"></span><p  class="MsoNormal" style="margin:.0px;text-align:justify;font-size:15.0px;font-family:DengXian;color:#000000;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;text-indent:.0px;text-transform:none;widows:2;text-decoration-thickness:initial;text-decoration-style:initial;text-decoration-color:initial;"><span  style="margin:.0px;padding:.0px;border:.0px;outline:.0px;font-family:Arial,sans-serif;">Dear CASToR Users and Developers,</span></p>We design a small-caliber PET system that has serious DOI parallactic error. With the help of CASToR, right now I reconstructed 7 point sources placed in different offsets which showed in the attachment. Obviously, the point on the far right deteriorated seriously. Since I used 0.79mm(crystal size) FWHM isotropic Gaussian kernel function as PSF in castor-recon command, detector responses caused by different incident angles are not considered. So I need to design a dynamic PSF with single-photon incidence response instead of Static symmetric Gaussian distribution as the PSF to generate the system matrix on the fly. </div><div  style="clear:both;"><span  style="font-family:Tahoma,Arial;">Does anyone know how I can make this? Because I just find out how to change the standard normal distribution into another static distribution function, fail to relate <span  style="color:#000000;font-family:Tahoma,Arial;font-size:14.0px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;text-align:start;text-indent:.0px;text-transform:none;widows:2;background-color:#ffffff;text-decoration-thickness:initial;text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline;">the current LOR to </span></span><span  style="font-family:Tahoma,Arial;">the distribution function. Any reply will be appreciated.</span></div><div  style="clear:both;"><span  style="font-family:Tahoma,Arial;"></span><span  style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14.0px;color:#000000;"><br  style="outline:none medium;color:#000000;font-family:Tahoma,Arial;font-size:14.0px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;orphans:2;text-align:start;text-indent:.0px;text-transform:none;white-space:normal;widows:2;word-spacing:.0px;"><span  style="color:#000000;font-family:Tahoma,Arial;font-size:14.0px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;text-align:start;text-indent:.0px;text-transform:none;widows:2;background-color:#ffffff;text-decoration-thickness:initial;text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline;">Thank you in advance,</span><br  style="outline:none medium;color:#000000;font-family:Tahoma,Arial;font-size:14.0px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;orphans:2;text-align:start;text-indent:.0px;text-transform:none;white-space:normal;widows:2;word-spacing:.0px;"><span  style="color:#000000;font-family:Tahoma,Arial;font-size:14.0px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;text-align:start;text-indent:.0px;text-transform:none;widows:2;background-color:#ffffff;text-decoration-thickness:initial;text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline;">Dimitris Thanasas</span></span></div></div>