2024-03-29T19:08:25+03:30
http://ijrr.com/browse.php?mag_id=30&slc_lang=en&sid=1
30-619
2024-03-29
10.1002
International Journal of Radiation Research
Int J Radiat Res
2322-3243
2345-4229
10.61186/ijrr
2010
8
2
Dosimetry limitations and pre-treatment dose profile correction for sliding window IMRT
G.
Grigorov
grigor.grigorov@grhosp.on.ca
J.C.L.
Chow
N.
Yazdani
Background: This work investigated the
dosimetry limitations of the random and systematic
uncertainties of sliding window (SW) intensity
modulated radiation therapy (IMRT). Materials and
Methods: A Varian 21EX linear accelerator, Pinnacle3
treatment planning system and radiographic film
dosimetry was used. The limitations of the SW were
studied using beam modulation ranging from 2 to
100 MU/beam, DR from 100 to 600 MU min-1, LV
from 1 to 5 cm s-1 and field size up to 12 × 12 cm2.
The random and systematic errors were investigated
using clinical and flat beams, as well as beams of
high profile modulation including linear, exponential,
and sinusoidal profiles. Results: The leading edge
and plateau of the SW profiles have a significant
deformation for higher DR and for beams of < 10
MUs/beam. It was found that the error is directly
proportional to the DR and LV, and inversely proportional
to the number of MU/beam. Conclusion: The
high DR and LV are limiting factors, producing
random profile deformation when SW beams of small
number of MU/beam are delivered. A very good
agreement was found between the planned and
delivered geometrical and clinical dose profiles when
beams > 10 MUs irradiated by a DR from 100 to 600
MU min-1 and LV from 1 to 5 cm s-1. After the
proposed correction, an average difference < 0.5%
for clinical profiles was measured for beams
irradiated with DR = 600 MU min-1 and LV= 5 cm s-1.
It was concluded that this correction methodology
may serve as a pre-treatment Quality Assurance tool
for SW IMRT beams. Iran. J. Radiat. Res., 2010 8 (2):
61-74
IMRT
sliding window
pre-treatment QA and pre-treatment dose correction.
2010
9
01
61
74
http://ijrr.com/article-1-619-en.pdf
30-620
2024-03-29
10.1002
International Journal of Radiation Research
Int J Radiat Res
2322-3243
2345-4229
10.61186/ijrr
2010
8
2
Hepatoprotective efficacy of Grewia asiatica fruit against oxidative stress in swiss albino mice
K.V.
Sharma
sharma.krishna.v@gmail.com
R.
Sisodia
Background: The radioprotective effect of Grewia
asiatica fruit (GAE) which contains anthocyanin type
cyanidin 3- glucoside, vitamin C, A, minerals,
carotenes and dietary fibers etc was studied.
Materials and Methods: For study Swiss albino mice
were divided into five groups-1. Control (vehicle
treated) 2. GAE treated (700 mg / Kg. b.wt / day for
fifteen days), 3. Irradiated (5 Gy), 4. GAE + Irradiated
and 5. Irradiated + GAE treated. Results: The
irradiation of animals resulted in a significant
depletion in the DNA and RNA level at all intervals
studied viz 1-30 days in comparison to control group.
Treatment of mice with GAE before and after
irradiation caused a significant elevation in liver DNA
and RNA level in comparison to irradiated mice.
Photomicrograph of liver histology also showed that
pre and post supplementation of GAE provides
protection against radiation. Similarly counting of
different type hepatocytes also showed that GAE
protect the liver against radiation. Conclusion: Thus
biochemical and histopathological results proves that
GAE has the potential against radiation. Iran. J.
Radiat. Res., 2010 8 (2): 75-85
Radioprotection
mice liver
DNA
RNA
liver histology
hepatocyte count.
2010
9
01
75
85
http://ijrr.com/article-1-620-en.pdf
30-621
2024-03-29
10.1002
International Journal of Radiation Research
Int J Radiat Res
2322-3243
2345-4229
10.61186/ijrr
2010
8
2
A CVH-based computational female pelvic phantom for radiation dosimetry simulation
H.
Nan
S.
Jinlu
Z.
Shaoxiang
H.
Qing
T.
Li-wen
G.
Chengjun
X.
Tang
S.B.
Jiang
Z.
Xiao-lin
zxlcqu@yahoo.com
Background: Accurate voxel phantom is needed
for dosimetric simulation in radiation therapy for
malignant tumors in female pelvic region. However,
most of the existing voxel phantoms are constructed
on the basis of Caucasian or non-Chinese population.
Materials and Methods: A computational framework
for constructing female pelvic voxel phantom for
radiation dosimetry was performed based on Chinese
Visible Human (CVH) datasets. First, several organs
within pelvic region were segmented from CVH
datasets. Then, polygonization and voxelization were
performed based on the segmented organs and a 3D
computational phantom is built in the form of a set of
voxel arrays. Results: The generated phantom can be
converted and loaded into treatment planning system
for radiation dosimetry calculation. From the
observed dosimetric results of those organs and
structures, we can evaluate their absorbed dose and
implement some simulation studies. Conclusion: A
voxel female pelvic phantom was developed from
CVH datasets. It can be utilized for dosimetry evaluation
and planning simulation, which would be very
helpful to improve the clinical performance and
reduce the radiation toxicity on organ at risk (OAR).
Iran. J. Radiat. Res., 2010 8 (2): 87-91
Phantom
pelvis
radiation
dosimetry
simulation.
2010
9
01
87
91
http://ijrr.com/article-1-621-en.pdf
30-622
2024-03-29
10.1002
International Journal of Radiation Research
Int J Radiat Res
2322-3243
2345-4229
10.61186/ijrr
2010
8
2
Evaluation of the physical characteristic of Cerrobend blocks used for radiation therapy
A.
Taherkhani
M.
Mohammadi
mohammadi@umsha.ac.ir
M.S.
Saboori
V.
Changizi
Background: In Radiation Therapy, the sparing of
normal tissues can be performed using either
multi-leaf collimators or Cerrobend blocks. The
current work focuses on the physical characteristics
of Cerrobend blocks including attenuation coefficient,
effective penumbra width and isodose curves undulation
in penumbral regions. Materials and Methods: All
measurements were performed using a dual energy
linac and the Cerrobend blocks designed and
fabricated using a commercial Cerrobend material.
Data were collected using a calibrated ionization
chamber as well as EDR2 films. Results: The results
showed that the attenuation coefficient was found to
be 0.4475 and 0.4276 cm-1 for photon beams 6MV
and 15 MV, respectively, and a potential air bubble
with a diameter greater than 3 mm affects beam
attenuation significantly. The optimum Cerrobend
block width was found to be around 16 mm. The
isodose curves scalloping achieved for secondary
collimator jaws, were also similar. Conclusion: If
Cerrobend blocks are used as a basic method to
protect normal tissues, its physical characteristics will
be recommended to be taken into account comprehensively.
Iran. J. Radiat. Res., 2010 8 (2): 93-101
Beam collimation
block-cutter
Cerrobend blocks
shielding.
2010
9
01
93
101
http://ijrr.com/article-1-622-en.pdf
30-623
2024-03-29
10.1002
International Journal of Radiation Research
Int J Radiat Res
2322-3243
2345-4229
10.61186/ijrr
2010
8
2
Measurement of 226Ra, 228Ra, 137Cs and 40K in edible parts of two types of leafy vegetables cultivated in Tehran province-Iran and resultant annual ingestion radiation dose
V.
Changizi
changizi@sina.tums.ac.ir
Z.
Jafarpoor
M.
Naseri
Background: The sources of radioactivity in the
environment have natural, terrestrial and extraterrestrial,
and anthropogenic origins. Plants may get radioactive
nuclides in two ways: (i) by the deposition of
radioactive fallout, (ii) by absorption from the soil.
Materials and Methods: The Concentrations of the
natural radionuclides (226Ra, 228Ra, 40K) and the
artificial radionuclide (137Cs) in leek and parsley in
Tehran province-Iran were determined using HPGe.
Also the effective dose due to the ingestion of such
vegetables by the population of Tehran province was
studied. Results: The average value of radionuclide
concentrations in parsley samples were measured
177.69 ± 12.47 mBq kg-1 fresh for 226Ra 349.62 ±
28.42 mBq kg-1 fresh for 228Ra 187364.6 mBq kg-1 fresh
for 40K. The average value of radionuclide concentrations
in leek samples were measured 94.31 ± 6.46
mBq kg-1 fresh for 226Ra 207.47 ± 19.46 mBq kg-1 fresh
for 228Ra 174555 ± 1704.21 mBq kg-1 fresh for 40K.
The concentrations of 137Cs in most of Parsley and
Leek samples were below the minimum detectable
activity (MDA). Conclusion: The Average 226Ra and
228Ra activities in 29 leek and parsley samples were
about 2.63 and 6.78 times the reference values,
respectively. The annual effective dose resulting from
the studied radionuclides for the adult population in
Tehran province were found to be safe in comparison
with normal background areas. Iran. J. Radiat. Res.,
2010 8 (2): 103-110
226Ra
228Ra
40K
137Cs
leafy vegetable
HPGe
effective dose.
2010
9
01
103
110
http://ijrr.com/article-1-623-en.pdf
30-624
2024-03-29
10.1002
International Journal of Radiation Research
Int J Radiat Res
2322-3243
2345-4229
10.61186/ijrr
2010
8
2
New approach for attenuation correction in SPECT images, using linear optimization
A.
Vahidian Kamyad
M.H.
Noori Eskandari
M.
Naji Midani
M.
Hajizadeh Saffar
hajizadeh@mums.ac.ir
Background: Photon attenuation as an
inevitable physical phenomenon influences on the
diagnostic information of SPECT images and results
to errors in accuracy of quantitative measurements.
This can be corrected via different physical or
mathematical approaches. As the correction
equation in mathematical approaches is nonlinear, in
this study a new method of linearization called ‘Piece
Wise Linearization’ (PWL) is introduced and to
substantiate its validity for SPECT image
reconstructions, a phantom study is performed.
Material and Methods: A SPECT scan of a homemade
heart phantom filled with 2 mCi 99mTc was acquired
by dual head Siemens E.Cam gamma camera
equipped with LEHR collimator. Row data of the scan
were transferred in DICOM format to a pc computer
for reconstruction of the images using MLEM
iterative algorithm in Matlab software. Results:
Attenuation map of the phantom µ(x) were derived
using PWL with linear optimization approach. Based
on that, the attenuation corrected SPECT image of
the phantom were reconstructed and compared with
non-corrected image, using MLEM iterative algorithm.
Comparison of the corrected and non-corrected
images confirmed with CT attenuation correction
method. Conclusion: Attenuation correction in SPECT
image can be achieved successfully, using emission
data and piecewise linearization with linear
optimization approach. The corrected image of f(x)
and attenuation map µ(x) of the heart phantom
using this approach promise acceptable image
quality for diagnostic clinical use. Iran. J. Radiat. Res.,
2010 8 (2): 111-116
Piece wise linearization
linear optimization
SPECT image
attenuation correction.
2010
9
01
111
116
http://ijrr.com/article-1-624-en.pdf
30-625
2024-03-29
10.1002
International Journal of Radiation Research
Int J Radiat Res
2322-3243
2345-4229
10.61186/ijrr
2010
8
2
A proton induced X-ray emission (PIXE) analysis of concentration of trace elements in varicose veins
K.
Moosavi
kmoosavi@aeoi.org.ir
S.
Vatankhah
J.
Salimi
M.
Moradi
Background: Proton induced X-ray emission
(PIXE) has been applied as reliable and improved
techniques in this study to compare concentration of
various trace elements in normal and abnormal
varicose veins. Materials and Methods: Five samples
from normal veins and 13 samples from varicose
veins bombarded by 2.0 MeV energy proton beams
produced by a Van de Graff accelerator in vacuum.
Two specimens from each sample, approximately
1cm, were processed for PIXE (proton induced X-ray
emission) analysis. Both qualitative and quantitative
analyses of potassium, iron, copper and zinc
concentration were performed with respect to
calcium concentration. Results: The concentration of
potassium and iron in the varicose vein group has
been significantly higher than the normal group.
Copper and zinc concentration were also higher in the
varicose veins, and the elevation of bromine was
seen in the normal group. Conclusion: PIXE analysis
showed higher concentrations of trace elements in
veins derived from varicos patients compared to
normal group. The difference in normal and abnormal
vein might be independent of age. Iran. J. Radiat. Res.,
2010 8 (2): 117-121
Varicose vein
trace elements
PIXE.
2010
9
01
117
121
http://ijrr.com/article-1-625-en.pdf
30-626
2024-03-29
10.1002
International Journal of Radiation Research
Int J Radiat Res
2322-3243
2345-4229
10.61186/ijrr
2010
8
2
Comparison of Singh index accuracy and dual energy X-ray absorptiometry bone mineral density measurement for evaluating osteoporosis
M.R.
Salamat
N.
Rostampour
rostampour@umsha.ac.ir
Sh.J.
Zofaghari
H.
Hoseyni-Panah
M.
Javdan
Background: The Singh index is an inexpensive
simple method to evaluate bone density, commonly
used to assess osteoporosis is based on the radiological
appearance of the trabecular bone structure
of the proximal femur on a plain antero-posterior (AP)
radiograph. The purpose of this study was to compare
between Singh index and bone mineral density measurement
using dual energy X-ray absorptiometry
(DXA). Materials and Methods: Three orthopedists
evaluated radiographs of 72 patients suspected with
osteoporosis. The inter-observer agreements of the
Singh index were obtained by using kappa statistics.
The bone mineral density (BMD) of proximal femur
was measured by DXA in all patients, and then
the BMD results were compared with those of Singh
index by using reference radiographic charts of the
Singh index method. Dual-energy X-ray absorptiometry
was used to measure bone mineral density. A
Norland XR46 system was used for the investigations.
Results: The inter-observer agreement kappa values
were 0.01, 0.07 and 0.09 (mean value: 0.05) and the
strength of the observer agreements was negligible.
The obtained osteoporosis prevalence among the
studied patients was 38.9%. Conclusion: The
inter-observer variation was large, there was no any
correlation between the Singh index and bone
densitometry. So, the index cannot be used for
evaluating and osteoporosis diagnosis, because of its
low reliability. Iran. J. Radiat. Res., 2010 8 (2): 123-128
Singh index
BMD
osteoporosis
DXA
bone density.
2010
9
01
123
128
http://ijrr.com/article-1-626-en.pdf