Abstract:
The purpose of this research is to develop the combined transmission and emission technique for computed tomography which would be useful for nondestructive inspection by modification of the available gamma ray transmission scanning system. A 30 mCi Cs-137 gamma source was used as the transmission source, meanwhile a 2 muCi Cs-137, a 5 and a 500 muCi Ir-192, a 180 muCi Tc-99m, an 865 muCi I-131 were filled in 10 test objects used as the emission sources. A 2"x2" Nal(TI) scintillation detector with 3 mm beam collimator and a multichannal analyzer (MCA) were used in measuring the transmitted and emitted photons. The data acquisition system was continuously controlled by a microcomputer via the previously developed interface card. The maximum dimension and weight of the specimen that could be tested by this system were 30 cm in diameter and 500 g respectively. From the 10 specimens testing using the combined transmission and emission technique, quality of the computed tomographic images were found to be satisfactory.