The ionizing radiation has hazardous health effects upon human exposure. Different types of cancers are reported to be arising on account of overt exposure to ionizing radiation like X-rays. This study reports occupational exposure as well as general exposure to the public and persons visiting radiology department in hospitals of Kathmandu city for diagnostic and therapeutic purposes. A portable environment radiation monitor was used to quantify the total radiation in places of work in the X-ray departments of 13 hospitals located in different parts of city. The findings show increased exposure and in some instances very high levels of unintentional exposure to radiation. DOI: 10.3126/kuset.v3i2.2895 Kathmandu University Journal of Science, Engineering and Technology Vol.3, No.2, August 2007, pp 31-34

Proton beam therapy is a promising technique to cure various types of cancer diseases in the human body. Employing this technique, the prostate cancer cells are damaged primarily leaving the surrounding cells unaffected. Initially, the position of the prostate cancer is determined then the energy required to damage cancerous cells is calculated computationally. The energy loss to the damaged cells and other layers of the human body via which the proton beam travels is calculated separately with high accuracy. It is found that 65 MeV energy of proton beam when interacts with various layers, particularly with cancerous cells, the maximum energy is imparted to these cancerous cells to destroy them effectively. TRIM data shows that 99.96% of the energy of proton is lost in the process of ionization by ion and 0.02% in ionization by recoils and only 0.01% energy is lost by production of phonon by ion and 0.02% by recoils. 65 MeV of the energy deposited on various layers viz. skin, connective tissue, soft muscles and prostate are approximately 0.384 MeV (i.e. 0.595%), 6.585 MeV (i.e. 10.20%), 14.654 MeV (22.71%), and 42.896 MeV (66.49%) respectively with the calculation error 0.74%. Ion range and lateral distribution calculation enable us to visualize the overall picture of the process of the simulation. SRIM data illustrates that more than 99% of the energy of the proton is lost during the ionization process while phonon production is almost negligible. The energy of proton beam deposited on various layers viz. skin, connective tissue, soft muscles and prostate cancerous cells among them the prostate cells receive the maximum energy. This technique not only cures prostate cancer effectively but also ensures that it has no side effects and the surrounding tissues or cells remain unaffected.