Imaging Simulation Of Internal Contamination In Lungs

According to application classification,nuclear radiation imaging system is mainly divided into two types,industrial gamma camera and medical gamma camera.The industrial gamma camera is mainly used in far field imaging,the imaging object size is large,the ray energy is high,and the medical gamma camera mostly uses low energy gamma ray,and the energy span is too small,so it can not be used for many kinds of energy ray imaging.The imaging of pulmonary contamination is between industrial and medical applications.It is necessary to image the medium and high energy gamma rays,but also to obtain better spatial resolution and detection efficiency by near-field imaging.Therefore,this paper designs a radiation imaging system for lung contamination in the event of a nuclear accident.,the radionuclides deposited in the lungs are radiographed with high energy gamma rays.The main results are as follows:(1)A method for modeling thoracic radiation sources in adult male patients with pulmonary contamination was developed.The method can be used to fill the lungs evenly and radionuclides can be placed in the chest cavity with different shapes of radioactive sources.(2)According to the lung size of adult male,a modified uniform redundancy array(MURA)collimator and a parallel beam(PB)collimator.The material of the collimator is tungsten,the density is 19.35g/cm~3,and the basic unit of opening is the square hole of 8.8mm.The size of the collimator is 100cm×100cm×1.93 cm.The size of the collimator is 2 mm,the thickness of the pore spacing is 1.2 mm,the material is tungsten,and the size is 30cm×30cm×10 cm.Both collimators can be used for imaging of lung radiation sources.Finally,the imaging of pulmonary contamination is considered synthetically.The MURA collimator is chosen for the measurement requirements.(3)According to the coding design rules of MURA collimator,the corresponding detector array model is designed.The maximum likelihood algorithm is used to retrieve the data obtained from the simulated detector,and the distributed image of the radioactive source is obtained.