It is my pleasure duty my heartiest gratitude to all authorities of the University of Trieste, IAEA (International Atomic Energy Agency), ICTP (International Centre for Theoretical Physics), CRO, Aviano (Centro di Riferimento Oncologico) and BAEC (Bangladesh Atomic Energy Commission) to give me the opportunity and for their administrative, technical and financial support to carry out this program. It is my pleasant duty to my heartiest gratitude to my supervisor Prof. Chiovati Paola and co-supervisor Dr. Cristina Cappelletto (Medical Physicist, Department of Medical Physics, CRO) for their constant inspiration, affectionate cordial guidance, for providing the facilities of this department, for suggesting on my obstacles and allow me to carry out my research work. I would like to express my sincere gratitude to the team of Medical Physicists and Dosimetrists at the Department of Medical Physics, CRO, Avaino for their cordial and continuous cooperation and constant encouragement in this course. Any omission in this brief acknowledgment does not mean a lack of gratitude.