radiopharmaceuticals introduction isotopes types of radioisotopes measurement of radioactivity handling and storage of radioactive material applications

1. RADIOPHARMACEUTICS
(Radio Isotopes in pharmacy)
By : Muskaan
CHANDIGARH
UNIVERSITY

2. CONTENTS
 INTRODUCTION
 ISOTOPES
 TYPES OF RADIONEUCLIDES
 PRODUCTION OF RADIOISOTOPES
 MEASUREMENT OF RADIOACTIVITY
 HANDLING AND STORAGE OF
RADIOACTIVE MATERIALS
 APPLICATIONS OF RADIOISOTOPES

3. INTRODUCTION
Radioactive substances are having a common
property of emmitting rays or particals which affect
photographic plates even when they are protocted
from visible direct light and also bring about
discharge of electrified bodies
About 40 radioactive elements are known which are
arranged in families such as
Uranium series, thorium series and actinium series.
Rays emmit by radioactive substances :
 Alpha rays
 Beta rays
 Gamma rays

4. ALPHA RAYS
These rays or particals have the least
penetrating power
They carry two Positive charge
These particals are emmited by certain
radioisotopes especially those of heavy metals

5. BETA RAYS
These have been of two types
 Electrically positives ( Positrons )
 Electrically nagetive ( Negatrons )
They are having greater penetrating power
than that of alpha rays
They have less ionizing power than alpha
particals

6. GAMMA RAYS
 They have no mass or charge
 These having more penetrating power than alpha
and beta rays
 These are not affected by magnetic force and are
having the speed of light
 Gamma rays are produced during disintegration of
radioactive substance along with beta radiation and
nuclear fission
 Poor ionizing power

7. ISOTOPES
Isotopes are atoms with the same number of
protons, but differing numbers of neutrons. In
other words, the have different atomic weights.
Isotopes are different forms of a single element
RADIO ISOTOPES : Isotopes that have been
undergoes nuclear change and rearrangement
that cause the emission of radioactive radiation.

8. The neucleus obtained after the nuclear changes or rearrangements
may be that of different element which may be stable.
The originalnuclide is called the parent and the product is called the
decay and daughter nuclide.
This phenomenon of nuclear changes is termed as disintegration and
Radioactive decay
STABILITY OF ISOTOPES
The naturally occuring nuclides are having favourable ratio of protons
and neutrons in most elements. Any deviation from the natural ratio, i.e
increase or decrease in the number of neutrones alters the atomuc
number . And the stability of the neucleus. Thus the stable ratio for
potassium is 1: 1.115. If one more neutron is added to the neucleus, the
ratio is disturbed and the nuclide becames unstable.

9. TYPES OF RADIONEUCLIDES
 Natural radioneuclides
Artificial radioneuclides

10. NATURAL RADIONEUCLIDES
Natural radioneuclides include about 40 high
atomic weight elements such as uranium
238 , radium 226 , which may be alpha ,
beta , gamma emmiters and also some
moderate weight elements such as
potassium 40 , rubidium 87 etc .

11. PRODUCTION OF
RADIOISOTOPES
 REACTOR IRRADIATION
A reactor is having an arrangement of fissionable
material in a mordrater which slows down the fast
neutrones to thermal energies .
The fissionable materials like uranium is taken in the
form of rods which are arranged in a lattice pattern
and hence the neutron flux is maximum in the centre
where there is most uranium
Eg: Co+n – Co + γ

12. • CYCLOTRON IRRIDATION
While the reactors are able to produce a flux of neutrons and
gamma
rays , accerelating machines can use many other types of
bombarding
Particles which have been charged particles.
They have to be accerelated to high velocities so as to
overcome the
Repulsive force of the neucleus
Mg + H ----- Na + He

13. MEASUREMENT OF
RADIOACTIVITY
 Ionisation Chamber
 Propotional chamber
 Geiger-Muller counters
 Scintillation Counters
 Autoradiography
 Solid state detector

14. Ionisation Chamber
These are available in various shapes and
sizes. An ionisation chamber consist of
chambers filled with gas and fitted with two
electrodes kept at different electrical
potentials and a measuring device to indicate
the flow of electric current. Radiation brings
about ionization of gas moleculeus or ions
which cause emission of electrons which in
turn reveals the change in electric current.

15. PROPOTIONAL COUNTERS
These are the modified ionization chambers
in which an applied potential
ionization of primary electrons causes
thunderous bursting or production of more free
electrons which got carried to the anode . The
voltage range over the which gas amplified
occurs is called the propotional region and the
working in this region called propotional
counters

16. GEIGER – MULLER
COUNTER
A G-M counter is having the ionising gas and also
having quenching vapour whose functions have
been
1. To prevent the spurious pulses that may get
produced due to the positive ions reaching the
cathode
2. to absorbs the photons emitted by excited
atoms and moleculeus returning to their ground
state .
Both chlorine and
bromine are generally employed as quenching
agent . Ethyl alcohol and ethyl formate are
used as organic quenching agent. The filling
gas pressure has been much below the
atmospheric pressure for avoiding the use of

17. Scintillation Counters:
 The various types of rays can be counted and
measured easily
 For counting Beta particles crystal of
anthracene release pulses of photons that
are detected by an adjacent photo multiplier
tube. Liquid solutions of stibene in Xylene are
good scintillators for Beta particles.
 For the measurement of Gamma rays, large
crystals of sodium iodide are preferred

18. Autoradiography
It is more useful in detecting and
determining gamma radiations in
physiological studies of plants and
animals

19. Solid state detector
These detectors have replaced
conventional ones due to
1. High resolution
2. Compactness
3. Easy interpretation of output signal

20. HANDLING AND STORAGE OF
RADIOACTIVE MATERIALS
 For any work with an open radioactive source wear
disposable gloves
 worn a full-length lab coat
 Do not eat or drink in any room where radioactive
materials are kept
 Do not store food, beverages, or medicines in
refrigerators, freezers or cold rooms where
radioactive materials are used or stored.
 Disposal of radioactive materials should be carried
out with great care

21. APPLICATIONS OF
RADIOISOTOPES
 Radioisotopes in Therapeutic
 Radioisotopes in diagnosis
 Research
 Sterelisation

22. THANK YOUTHANK YOU