Atomic number Mass number Isotopes-stable isotopes-unstable isotopes Radio-active halflife Units of Radio-activity-Roentgen-RAD-REM-Becquerel(bq)
METHODS OF PRODUCTION PILE PRODUCED ISOTOPES (NUCLERA REACTOR) CYCLOTRON – PRODUCED ISOTOPES RADIO ISOTOPES GENERATOR
Most of the R-A materials prepared in nuclear pile Uranium fission rxn produces large supply of neutrons Neutrons in rxn are a mixture of fast neutrons and thermal Thermal neutrons are obtained by fast neutrons thru a moderator n γ Rxn . Target nuclie captures thz thermal neutron to yield a radioactive nucleus in an excited state Surplus energy emitted as γ-radiation
Eg. 2311Na +n 23 Na 14 23 Na +γ 14 1 neutron for each uranium atom undregoes fission and other neutrons are used to produce PLUTONIUM by interaction with 238U These neutrons are either lost or used to interact with specific target which have been inserted into “neutron activation”1. Radio-active material thru Fission process2. Radio-active material thru Neutron activationFISSION Reactions :238 92 U+ 10n 131 50 Sn + 10642 Mo + 10n+ 1 0n131 50 Sn and 10642 Mo are radio active nuclides
NEUTRON ACTIVATIONWhen simple neutron is captured or during transmutation process neutron activation occurs a radio-activated phosphorus, 32P can be prepared from stable phosphorus , 31p by neutron capture
Radio-activewhich are neutron deficient are produced by cyclotron Obtained by bombarding targer nuclie with protons deuterons α particle
During investigation , hazards to patients can be reduced by using isotopes Such isotope can be supplied in form of long lived parent that decay to isotope required Parent nuclide prepared in form of suitable ion – absorbed to the ion exchange column The whole assembly is known ass Radio- isotope generator This long lived parent results in production short lived daughter Whicj is “eluted” or “milked” from column
Eg. Technetium 99m 99m Tc generator sonsist of column containing alumina on which Molybdenum 99 is absorbedin form of ammonium molybdate Radioactive decay of 99 Mo produces 99mTc which is eluted from the column This isotope is produced for brain , liver and in thyroid scanning and is safer It has short life and does not emit beta radiations.