Importance of Nuclear medicine !! Reactors Fission of 235 U n+ 235 U 99 Mo + xn + other fission products Neutron activation of 98 Mo n + 98 Mo 99 Mo

• Cyclotron Institute, Texas A&M University, College Station, TX, USA.

• Princess Nora Bent Abdulrahman University, Riyadh, Saudi Arabia.

Study of the Production of Mo and Tc Medical Radioisotopes Via Proton Induced Nuclear

Reaction on natMo

Presented By: Abeer AlharbiThe 11th international conference on Nucleus-Nucleus collisions

A. Alharbi San Antonio,05/28/2012

Importance of Nuclear medicine !!

Radiopharmaceuticals are used extensively in the field of nuclear medicine in three main branches.

1. The largest and the most common type involve diagnostic procedures

2. The second deals with radionuclide techniques that are used for the analysis of concentration of hormones, antibodies, drugs and other important substances in samples of blood or tissues.

3. The third is radiation therapy

In order to keep the exposure dose for the patient as low as possible, the

optimization of nuclear reaction for the production of radioisotope is very

important.

It involves the selection of:

• the Projectile energy range,• the time of irradiation • the cooling time after the EOB: that will maximize the yield of the produced medical radioisotope and minimize that of

the radionuclide impurities.


99Mo is produced through two different methods:

99mTc is produced through the decay of 99mMo via beta decay with a half life of 66 hours. It is interesting to note that 4.52 % of these transitions result in the prompt emission of a 140.5

keV γ-ray from the 7/2+ state of 99mTC.


Imp

ort

an

ce o

f N

ucl

ear

med

icin

e !

!

ReactorsFission of 235U

n+235U→99Mo + xn + other fission products

Neutron activation of 98Mo n + 98Mo→99Mo

Accelerators

Photo-fission of 238UPhoton+238U→99Mo + xn + other fission products

100Mo transmutation Photon + 100Mo→ 99Mo + n

Direct 99mTc production P + 100Mo→ 99mTc + 2n

The usual production of 99Mo for nuclear medicine depends on: • The neutron induced fission of 235U, which results in expensive but high specific

activity 99Mo , or• The (n,γ) nuclear reaction with 98Mo, 24% using natural Molybdenum, resulting in

inexpensive but low-specific activity 99Mo.

Why this study is important ?

• Currently, only five nuclear reactors produce 99mTc (T1/2

= 6.02 h), which is a vital part of diagnostic tests for heart disease and cancer.

It accounts for over 80% of all diagnostic nuclear medicine procedures world wide.

(The horse of nuclear medicine)

• According to the latest survey the world demand for production of 99Mo/ 99mTc is estimated to be around 6000 Ci/week and further growth is predicted.


SPECT - Single photon emission computed tomographyis performed by using a gamma camera to acquire multiple 2-D

images for the radio tracers inside the body, from multiple angles, which yields a 3-D dataset .

The Scanner SPECT image


PET - Positron emission tomography


As a positron-emitting radionuclide decays it emits a positron, which promptly combines with electron resulting in the simultaneous emission of two identifiable gamma rays in

opposite directions each with 511 keV ENERGY .

Giving a map of functional processes in the body

Animal imaging using 96Tc.


Motivation!!

They show relatively large deviations in the maximum value of the cross sections and in the energy position of the maximum as well as in the shape of the excitation function.

Beam condition Target Goal of the Experiment The importance for the studied

medical isotope

Protons @40MeV/u

40 nAnatMo

A study of the yield and the excitation functions for the longer lived medical radioisotopes and the attendant impurities for the production of the

99Mo.

96Tc which is used for animal studies with 99mTc.

Protons @40MeV/u

50 nAnatMo

A study for the production of the important

diagnostic medical radioisotope 99Tc (relatively short lived) and 99M (the

generator system) along with some attendant impurities.

99Mo is the parent for 99mTc generator used for brain, liver, lungs, bones, thyroid, kidney,

antibodies, red blood cells and heart imaging.

natMo(P,X)

Monitor

Reaction

Projectile Targets Main studied reactions Energy range (MeV)

Protons natTi natTi(p,X)48V 40-5

Protons natCunatCu(p,X)62ZnnatCu(p,X)63ZnnatCu(p,X)65Zn

40-1240-440-2

Protons natAl27Al(p,X)22Na27Al(p,X)24Na

40-2540-25

Experimental W

ork

Experimental Setup

The Experimental setup

@ MDM cave


The K500 superconducting

cyclotron, Texas A&M Cyclotron Institute was used in the MDM cave.

Experimental Setup

A photograph for foils and the special aluminum target holders used in the experiment.


1- Activation techniqueExperim

ental Setup


40 MeV of

protons with

20 nA’s intensity

Two experiments have been done:1- To measure the short lived radioisotopes (irradiated for 30 m)2-To measure the longer lived radioisotopes (irradiated for 50 m)

2- The Stacked foil technique: EXPERIMEN

TAL TECH

NIQ

UE

stacks were made of several groups of targets(40 foils in each experiment)

(natMo, 50 µm) and monitor foils (natAl, 125 µm and natCu, 125 µm) that acted also as

beam degraders, the energy step was kept within (0.5-2 MeV).


99Mo99mTc 96Tc

95Nb

The produced medical radioisotopes in this study are:


(p,xn) (p,pxn) (p,αXn) … etc

natMo(p,X)

Used for SPECT imaging for: Brain, heart , liver, lungs, bones, thyroid and kidney imaging. Also for cerebral blood flow, antibodies, and red blood cells.

99Mo99mTc 96Tc

95Nb

90Mo

The produced medical radioisotopes & the impurities in this study are:


94Tc 89m,gNb90Nb

(p,xn) (p,pxn) (p,αXn) … etc

natMo(p,X)

93m,gTc

Nu

cle

ar d

ata

Monitor reactions were used to determine the beam energy and intensity

Mon

itor re

actio

ns

Excitation functions of the monitor reactions compared with the recommended cross-sections

by the IAEA.

EXPERIMEN

TAL RESULTS

Determination of the actual proton beam Energy:

Nu

cle

ar d

ata

Decay Data & Q-Values for some of the contributing Reactions in the

desired Medical radioisotopes production process (1)

Nu

cle

ar d

ata

Decay Data & Q-Values for the contributing Reactions in the

desired Medical radioisotopes production process (2)

TA

MU

, 2010

A calibrated Gamma ray spectrum with the identified γ-lines natMo (p,X)

810.

6

98N

b77

8.63

99M

o

849.

29

94Tc

907.

83

95N

b

1130

.23

96

Tc

765.

7

95Tc

1173

.24

60

Co

1332

.5

60Co

661.

62

137 C

s

509.

47

An

nihi

latio

n

483.

56

87

Y39

1.83

93m

Tc

140.

51

(99M

o +

99m

Tc +

90N

b)

369.

5

99M

o

312.

64

96

Nb

202

.29

95

Tc

178.

73

99

Mo

Exp

erim

en

tal re

su

ltsSeparation of complex decay of mixture of

activities for 140 keV gamma line

99Mo, T½= 65.9 h99mTc,T½= 6.01 h90Nb, T½= 14.6 h

The individual activities of those overlapped γ-rays were analyzed using the difference in half-lives of the contributing nuclides by plotting the γ-ray emission rate as a function of

time.

Activ

atio

n fo

rmu

la

Whereas:

M : Target molecular weight

I : Beam intensity

Tγ : net area under each γ peak

C : The target density

f : The abundance

Iγ : gamma line intensity

Resu

lt & d

iscussio

ns

Excitation function for natMo(p,X)99Mo nuclear reactions calculated from the

measured cross sections in this work:


Theoretical simulations using Talys code has been done.

Resu

lt & d

iscussio

ns

Excitation function for natMo(p,X)95gTc nuclear reactions calculated from the



Theoretical simulations using Talys code has been done.

Resu

lt & d

iscussio

ns

Excitation function for natMo(p,X)99mTc nuclear reactions calculated from the



The Integral Yield of the Radionuclide Product

Whereas:

P : is no. of protons/ μA.hN : is number of target nuclei in cm2

ρ : is surface density in gm/cm2

)1()(10))(()./( 227 tdiff ePcmNmbEhAKBqY

M

NN A

14.6 hr

51.5 min 43.5 min

65.9 hr

Resu

lt & d

iscussio

ns

Integral Yields for the natMo(p,x) nuclear reactions calculated from the excitation functions measured in this work:


The optimum way to get the maximum yield of 99Mo and the minimum contribution of

the impurities is to irradiate with protons @ 26-29 MeV and wait for 8 Hours after the

EOB.

NN

, 2012

Stacked foil activation technique used to measure the cross section for the contributed nuclear reactions.

some monitor reactions have been measured by inserting some foils into the stack .

Theoretical simulations using Talys code.

The integral target Yield for all reactions have been calculated .

The optimum way to get the maximum yield of 99Mo and the minimum contribution of the impurities is to irradiate with protons @ 26-29 MeV and wait for 8 Hours after the EOB.

A considerable discrepancies still exists among the available literature data for the production of medical

99mTc radionuclide, which demands more experimental data to obtain a recommended data set.

Summary

U. S. Department of Energy.

Texas A&M University, Cyclotron institute.

Fulbright program.

Princess Nora University.

TA

MU

Acknowledgment

The Collaborators from TAMU:

M. McCleskey,

A. Aspiridon,

G. Tabacaru,

B. Roeder,

E. Simmons,

A. Banu,

L. Trache,

R. E. Tribble

TH

AN

K Y

OU

Thank You for

your attention


Documents

Importance of Nuclear medicine !! Reactors Fission of 235 U n+ 235 U 99 Mo + xn + other fission products Neutron activation of 98 Mo n + 98 Mo 99 Mo