Dr. Hossein Mozdarani
International Journal of Radiation Research
2322-3243
4
2
2006
9
1
Radiotherapy techniques for intracranial tumours
53
62
EN
Mohammad Amin
Mosleh-Shirazi
ABSTRACTIntracranial tumours often require radiotherapeutic approaches that differ from other sites. Their specific requirements merit a specialized discussion. A brief review of radiotherapy techniques to treat intracranial tumours is presented with emphasis on the author’s own experience and work, where appropriate. A clinical introduction is presented first followed by a description of both conventional and modern techniques. Examples from clinical practice are also given. The issues discussed include direct simulation, 2D and 3D treatment planning, the use of CT and other imaging modalities, field shaping and non-coplanar techniques. In the modern radiotherapy era, simple conventional techniques still have a role to play in routine clinical practice. As new technologies are introduced into relatively under-resourced centres, they should be used judiciously and appropriately to maximize benefit to the whole patient population.
Dr. Hossein Mozdarani
International Journal of Radiation Research
2322-3243
4
2
2006
9
1
Radiological risk assessment of use of phosphate fertilizers in soil
63
70
EN
K.
Kant
S.B.
Upadhyay
R.G.
Sonkawade
S.K.
Chakarvarti
ABSTRACT
Background: The radiological impact of the use of phosphate fertilizers in soil
is due to the internal irradiation of the lung by the alpha particles, short
lived radon-thoron progeny and the external irradiation of the body by gamma
rays emitted from radionuclides in situ. This paper describes the results of
gamma spectrometric measurements of the concentration of the natural
radionuclides namely 226Ra, 232Th and 40K in the soil samples collected from the
fields where a variety of phosphate fertilizers are being used by the farmers to
enhance the crop yield. Materials and Methods: The experimental work utilizes
actual measurements of 226Ra, 232Th and 40K using gamma spectrometry and radon
concentration and exhalation rates measurements using solid state nuclear track
(LR-115, Type- II plastic) detectors to asses a first order exposure risk for
the persons working in the fields where lot of fertilizers are being used to
enhance crop yield in terms of occupational exposure. Results: The concentration
of Radium, Thorium and Potassium in the mixed soil sample from crop fields is
16.2±0.22, 68.1±1.44 and 875.0±9.68 Bq/kg, where as in barren soil sample is
9.1±0.13, 59.4±1.45 and 668.4±8.01 Bq/kg respectively. The radium equivalent
activity (Raeq) in the mixed soil sample from crop fields is 225.9 Bq/kg, where
as in barren soil sample is 193.1 Bq/kg. The values of absorbed dose and annual
effective dose (indoors and outdoors) are found to vary from 90.87 nGyh-1 to
119.71nGyh-1, 0.45mSv/y to 0.59mSv/y and 0.11mSv/y to 0.15mSv/y respectively in
soil sample from crop fields, whereas the value of absorbed dose and annual
effective dose (indoors and outdoors) is 92.29 nGyh-1, 0.45mSv/y, 0.11
respectively in soil sample collected from barren land. The radon concentration
and exhalation rates have also been reported. Conclusion: The activity
concentration, exhalation rate and absorbed dose were found to increase
substantially with the use of phosphate fertilizers and it varies from sample to
sample. The radium equivalent activities in all the soil samples were found to
be lower than the limit (370 Bq/kg) set in the Organization for Economic
Cooperation and Development (OECD) report and the dose equivalent is within the
safe limit of 1mSv/y.
Dr. Hossein Mozdarani
International Journal of Radiation Research
2322-3243
4
2
2006
9
1
60Co γ-ray attenuation coefficient of barite concrete
71
75
EN
F.
Bouzarjomehri
T.
Bayat
M.H.
Dashti R
J.
Ghisari
N.
Abdoli
ABSTRACT
Introduction: Recently uses of
medium and high energy x-rays has been increased in Iran and radiotherapy
centers along with a variety of accelerators have been installed in some
provinces. In the other hand there is no sufficient skill in designing and
making radiotherapy treatment rooms. This study was conducted to evaluate the
efficacy of different mixtures of barite concrete for shielding the radiotherapy
rooms. In this way we emphasized on determining the size and amount of barite
aggregations to achieve the maximum radiation attenuation which leads to
minimizing wall thickness in treatment room.
Materials and Methods: To
increase concrete density, the barite aggregation was added to concrete.
Different size variations of barite aggregates mixed with different water/cement
ratio were examined. The dimension of cubic concrete specimens for compression
strength test was 15×15×15 cm. The rectangular barite concrete blocks with
different compressions as used for strength test with cross section of 10×10 cm
and thicknesses from 5 to 40 cm were used for radiation attenuation test. For
this test concrete specimens were irradiated by gamma beam of 60Co
(Phoenix Theratron). The transmission radiation through the blocks was measured
by a Farmer ionization chamber (FC65P) in Yazd radiotherapy center.
Results: Our findings showed
that in all specimens the highest mean compression strength was related to the
specimens with equal ratio of fine to coarse barite aggregates but the lowest
HVL was obtained from mixtures with fine to coarse ratio of 35/65. The concrete
sample with a 0.45 water/cement ratio, 350 kg/m3 cement and equal
amounts of fine and coarse barite sands had nearly minimum half value layer(HVL)
and maximum compression strength, so this sample was considered as the best
barite concrete sample.
Conclusion: Since HVL of the
barite concrete specimens with the same compression strength is markedly lower
than the conventional concrete and we have a plenty barite mines in our country
it is recommended to use barite concrete with the best mixture condition based
on our findings for shielding the radiotherapy rooms.
Dr. Hossein Mozdarani
International Journal of Radiation Research
2322-3243
4
2
2006
9
1
A New Approach for Quantitative Evaluation of Reconstruction Algorithms in SPECT
77
80
EN
E.
Raeisi
H.
Rajabi
S.M.R.
Aghamiri
ABTRACT
Background: In nuclear medicine,
phantoms are mainly used to evaluate the overall performance of the imaging
systems and practically there is no phantom exclusively designed for the
evaluation of the software performance. In this study the Hoffman brain phantom
was used for quantitative evaluation of reconstruction techniques. The phantom
is modified to acquire tomographic and planar image of the same structure. The
planar image may be used as the reference image to evaluate the quality of
reconstructed slices using the companion software developed in MATLAB.
Methods and Materials: The designed
phantom is composed of 4 independent 2D slices that may be placed juxtapose to
form the 3D phantom. Each slice is composed of objects of different size
and shape e.g. circle, triangle, and rectangle. Each 2D slice was imaged at the
distances from 0 to 15 cm from the collimator surface. The phantom in 3D
configuration was imaged acquiring 128 views of 128×128 matrix size.
Reconstruction was performed using different filtering condition and the
reconstructed images were compared to the corresponding planar images. The
modulation transfer function, scatter fraction and attenuation map were
calculated for each reconstructed image
Results: Since all the parameters of the
acquisition were identical for the 2D and the 3D imaging. It was assumed that
the difference in the quality of the images was exclusively due to
reconstruction condition. The planar images were assumed to be the most perfect
images that could be obtained with the system. Comparing the reconstructed
slices to the corresponding planar images yielded the optimum reconstruction
condition. The results clearly showed that Wiener
filter yields superior quality image among the entire filter tested. The extent
of the improvement has been quantified in terms of universal image quality
index.
Conclusion: The
phantom and the accompanying software were evaluated and found to be quite
useful in determining the optimum filtering condition and mathematical
evaluation of the scatter and attenuation in tomographic images.
Dr. Hossein Mozdarani
International Journal of Radiation Research
2322-3243
4
2
2006
9
1
A study of densitometry comparison among three radiographic processing solutions
81
86
EN
V.
Changizi
E.
Jazayeri
A.
Talaeepour
ABSTRACT
Background:
The radiographic image accuracy depends on the X-ray film information
visibility. Good visibility is found by good contrast. Radiation exposure
parameters (kVp, mAs) and film processing conditions have impact on contrast. In
dentistry radiography machines, exposure time and processing procedure are set
by radiographer. No optimized exposure time and processing conditions may lead
to incorrect diagnosis and re-exposure of the patient. Therefore, we studied the
performance of the three different available processing solutions with dental
X-ray film. Materials and Methods: Dental intraoral E-speed films, size 2
(Kodak company, USA) were used in this study. These films were developed in a
manual processor using three different brands of processing solution: 1) Taifsaz
(Iran), 2) Darutasvir (Iran) and 3) Agfa (Germany) for temperatures of 25oC,
28oC and 30oC at the three different exposure times, 0.2
s, 0.25 s and 0.35 s. Performance was evaluated with respect to base plus fog,
relative contrast and relative speed. Results: Darutasvir processing
solution as the cheapest one showed higher base plus fog density at 25oC
and 30oC than that of Taifsaz and Agfa solutions. Also, Darutasvir
solution was found to have better relative contrast than that of the others,
except for 30oC at 0.25 s. Relative speed was higher in Darutsavir
solution than Agfa for 25oC at three exposure times used in this study, for 28oC
at 0.2 s and for 30oC at 0.35 s. Taifsaz Processing solution was in
the second order with respect to tested conditions. Conclusion:
Comparison among available X-ray film processing solutions for different
temperatures at different exposure times can help to maintain image quality
while patient exposure and film cost are kept considerably low.
Dr. Hossein Mozdarani
International Journal of Radiation Research
2322-3243
4
2
2006
9
1
Prospective evaluation of endo venous laser therapy for varicose vein complications. The first report from Iran
87
91
EN
J.
Salimi
F.
Yourdkhani
K.
Moosavi
ABSTRACT
Background: In recent years, the endovenous laser therapy (EVLT) has been
proposed to treat the incompetent greater saphenous veins (GSV) to increase
patient comfort,and to reduce cost as well as risk. EVLT causes vein wall
thickening, luminal contraction and vein fibrosis. The purpose of this article,
as the first report from Iran, is to review our experience and outline the early
results and complication of EVLT. Materials and Methods: 22 patients (13
females and 9 males, mean age: 40.6±11 years, range: 25-64) underwent EVLT of
incompetent GSV segments with 810-nm diode laser with an average energy of 89.2
J/cm (range, 50-123 J/cm). Success rate was defined as absence of reflux
throughout the entire treated segment on follow-up doppler ultrasound (DUS) and
clinical resolution of symptoms. Results: Short-term results in the EVLT
of 22 GSV indicate a 100% rate of closure. Self-limiting complication were
occurred in 18% of patients and included moderate ecchymosis and paresthesias in
3 (13.5%), and 1 (4.5%) patients, respectively. No major complications such as
deep vein thrombosis and pulmonary embolism were occurred. DUS demonstrated 21
(95%) and 19 (90.9%) occluded GSVs at 12 weeks, and 24 weeks respectively.
Conclusion: The early results of our experiences are excellent. EVLT of the
incompetent GSV with an 810 nm diode laser appears to be an extremely safe
technique. EVLT is a very effective and safe with best cosmetic results and rare
side effects.
Dr. Hossein Mozdarani
International Journal of Radiation Research
2322-3243
4
2
2006
9
1
Simulation of gamma irradiation system for a ballast water treatment
93
97
EN
T.P.
Faez
S.
Sarkar
ABSTRACT
Background:
Invasion by different kinds of ballast water microorganisms is one of
the most important marine environment problems around the world
therefore preventing the invasion of these unwanted and harmful
stowaways is one of the main strategies of responsible agencies. Some
of these methods such as ocean exchange, heating, filtration, hydro
cyclones, UV irradiation and chemical treatment, have various problems such
as technical deficiency, high costs, lack of safety and environmental
side effects. Materials and Methods: A novel system of treatment
by Gamma irradiation is designed to irradiate the blast water uniformly and
effectively. To determine the dose distribiution as a function of distance from
the irradiation source, the MNCP code was used. The systems used for source
implant in this simulation were Paterson-Parker, Paris and Network systems. In
each system, Sivert-integral and inverse square law were used in Matlab program
to determine the dose distribiution. Results: Results of initial
laboratory tests on offshore water samples of Siri Island indicated
that the appropriate dose for deactivation of organisms of water
samples is approximately one kGy. It has been demonstrated that the dose
can be provided by twenty five 100,000 Ci line sources of 60Co
in a triangle implant arranged in a 1x1x1 m3 cubic shape
water pipe. In order to increase efficiency and radiation safety,
water passed from two other coaxial and bigger cubes, after passing
from the first cube. A one meter thick wall of concrete around the
cubes was adequate to shield the system completely. Conclusion: The
main advantages of this system such as high efficiency, safety,
reliability, minimum environmental adverse effects, proves that this
novel method not only can be used for ballast water treatment, but is
also effective for drinking water purification.
Dr. Hossein Mozdarani
International Journal of Radiation Research
2322-3243
4
2
2006
9
1
Derived intervention levels for mostly consumed foodstuffs in Iran
99
103
EN
A.A.
Fathivand
J.
Amidi
ABSTRACT
Background: Measures to protect the public following an accidental release
of radionuclides to the environment will depend on the circumstances including
the extent of the potential hazards. The projected levels of risk are an
important precondition in emergency planning. The levels can be expressed in
terms of concentration levels in the environment or in foodstuffs. These derived
intervention levels (DILs) can be determined for the range of important
radionuclides that could be released to the environment in the event of a
nuclear accident. Materials and Methods: Derived intervention levels for
90Sr, 131I, 134Cs + 137Cs, 238Pu
+ 239Pu + 241Am and 103Ru + 106Ru
radionuclide groups were calculated for infants (17 years)
for mostly consumed foodstuffs in Iran. Calculations of DILs were based on
recommendations from international, national organizations and average food
consumption rate data for Iran. Results: From our research it was found
that DILs for foodstuffs consumed in Iran for above mentioned radionuclide
groups except for Ruthenium group are equal to 387, 250, 1023 and 2.8 Bqkg-1
respectively. Conclusion: The comparison of DILs for foodstuffs consumed
in Iran and DILs adopted in the new food and drug administration (FDA)
Compliance Policy Guide (CPG) which are 160, 170, 1200, 2 Bq.kg-1 for
90Sr, 131I, 134/137Cs, 238/239Pu
plus 241Am radionuclide groups respectively, shows agreement with
cesium and plutonium group and higher values for strontium and Iodine group. In
the case of nuclear accident or radiological events that might affect our
country calculated DILs can be used to prevent or reduce exposure due to
consumption of foodstuffs.