1. Medical uses of Radio active isotopes: Radiation from radio active isotopes is used in medicine to treat cancer, some of radio active isotopes are: 1. Cobalt – 60 – its symbol 60 27 C, its β&γ emission, its widely used as external source of radiation for cancer therapy with t 1/2 5.3 years. 2. Iodine – 131 – 131 53 I, its β & γ emission, its used in treatment of thyroid gland cancer with ty 2 :8 days. 3. Iodine – 123 – 123 53 I: its symbol, its β – emission, its used in treatment of thyroid cancer with ty 2 13.3hr.

2. 4. Phosphorous – 32 – 32 15 P, its β emission, with ty 2 143days used in treatment of leukemia, also in detection of skin cancer and the brain surgery. 5. Sodium 24: 24 11 Na, its β & γ emission with ty 2 : 15.0 hr, its used in checking the proper function of circulating system. 6. Iron – 59 – 59 26 Fe, its β & γ emission with ty 2 : 45.6 days. Its used in determination of red blood cell formation and life time. 7. Technetium – 99 - 99 43 Tc, its β-emission with ty 2 : 6.1 hr. Its used in scanning of brain, kidney and lungs. Its used in scanning of brain, kidney and lungs.

3. Radio active isotopes used in human must be chosen carefully:- First: the half life must be long enough to do its job (to destroy the abnormal cells). Second: no isotopes that emits α- particles are used because α-particle are large and cause damage to all tissues and organs. Nuclear reaction and energy: 1/ Nuclear fission: when nuclei of several isotops like 235 u, 236 u, 244 Pu are bombarded with neutrons, they undergo nuclear fission to form smaller, more stable nucleus, are bombarded with neutrons, they undergo nuclear fission to form smaller, more stable nucleus,

4. Example: 1 0 n + 235 92 u 236 92 u 94 36 Kr + 139 56 Ba+3 1 0 n + energy unstable stable unstable stable nucleus nucleus + 94 36 Kr energy Ba 139 56 Ba 10n10n 10n10n 10n10n unstable nucleus

5. This n.f produce great amount of energy E.x: when one Kg of 235 u is fissional, it produce amount of energy equals 20,000 tons of T.N.T. This n.f produce great amount of energy E.x: when one Kg of 235 u is fissional, it produce amount of energy equals 20,000 tons of T.N.T. 2/ Nuclear fusion reaction:- This reaction allows us to obtain energy without forming dangerous radioactive products involve fusing two or more nuclei to make a heavier nucleus:- This reaction allows us to obtain energy without forming dangerous radioactive products involve fusing two or more nuclei to make a heavier nucleus:-Ex.:- Deuterium 2 1 H + 2 1 H 4 2 H In this reaction two nuclei of deuterium (stable isotopes of Hydrogen) are forced together to form a helium nucleus, which is also stable. In this reaction two nuclei of deuterium (stable isotopes of Hydrogen) are forced together to form a helium nucleus, which is also stable.

6. This reaction needed temp at least 10,000,000ْC to provide the energy to force the two positive nuclei close enough to fuse. This reaction needed temp at least 10,000,000ْC to provide the energy to force the two positive nuclei close enough to fuse. This fusion reaction occurs in two places 1- The sun, whose heat and light are produced by fusion reaction. 2- Hydrogen bomb.