Upload
adriel
View
36
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Study of the Production of Mo and Tc Medical Radioisotopes Via Proton Induced Nuclear Reaction on nat Mo. Presented By: Abeer Alharbi The 11 th international conference on Nucleus-Nucleus collisions. Cyclotron Institute, Texas A&M University, College Station, TX, USA. - PowerPoint PPT Presentation
Citation preview
• 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.
A. Alharbi San Antonio,05/28/2012
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.
A. Alharbi San Antonio,05/28/2012
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.
A. Alharbi San Antonio,05/28/2012
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
A. Alharbi San Antonio,05/28/2012
PET - Positron emission tomography
A. Alharbi San Antonio,05/28/2012
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.
A. Alharbi San Antonio,05/28/2012
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
A. Alharbi San Antonio,05/28/2012
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.
A. Alharbi San Antonio,05/28/2012
1- Activation techniqueExperim
ental Setup
A. Alharbi San Antonio,05/28/2012
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).
A. Alharbi San Antonio,05/28/2012
99Mo99mTc 96Tc
95Nb
The produced medical radioisotopes in this study are:
A. Alharbi San Antonio,05/28/2012
(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:
A. Alharbi San Antonio,05/28/2012
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:
A. Alharbi San Antonio,05/28/2012
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
measured cross sections in this work:
A. Alharbi San Antonio,05/28/2012
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
measured cross sections in this work:
A. Alharbi San Antonio,05/28/2012
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:
A. Alharbi San Antonio,05/28/2012
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
A. Alharbi San Antonio,05/28/2012