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Modeling and dose calculations of a pure beta emitting 32P coated stent for intracoronary brachytherapy by Monte Carlo code
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O. Kiavar   , M. Sadeghi |
| , msadeghi@nrcam.org |
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Abstract: (10337 Views) |
| Background: Recently, different investigators
have studied the possibility of radiation therapy in
restenosis prevention and have shown promising
results. In this study a unique radioactive source for
intra vascular brachytherapy (IVBT) was investigated.
The two-dimensional dose distribution in water for a
32P IVBT stent has been calculated. The pure beta
emitter source 32P has been coated on Palmaz-
Schatz stent. The dosimetric parameters required by
the AAPM TG-60 formalism are discussed and
calculated. Materials and Methods: The dose distribution
of the activated stent was determined by Version
4C of the (MCNP) Monte Carlo radiation transport
code in water and it was verified by TG-60 experimental
results. Dosimetric parameters such as anisotropy
function, F(r, θ), and the radial dose function, gL(r),
around the Palmaz-Schatz stent at distances from
0.18 to 0.9 cm have been calculated. The Palmaz-
Schatz stent with 3.5 mm external diameter and 14
mm length is coated with a thin layer of 32P. Results:
The Monte Carlo calculated dose rate at the
reference point is found to be 17.85 Gy. The results
were compared with previously published paper for
an actual same source. The difference between these
two data sets is in acceptable range. There were
almost little differences (less than 0.05%) in values
among them. Conclusion: The dosimetry parameters
such as, geometry function, G(r,θ), anisotropy
function, F(r,θ) and radial dose function, g(r), were
determined according to TG-60 protocols and listed in
tabular format. High dose variants were visible near
the 32P stent surface, but these values decreased
with depth in vessel layers rapidly. There are an
acceptable agreement between the calculated data
in this study and other published data for the same
source. However, the observed differences between
the calculated and measured values could be
explained by the measurement uncertainty and the
geometry modeling during the simulations. Iran. J.
Radiat. Res., 2012 9(4): 257-263
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| Keywords: Coronary stent, radioactive stent, intravascular brachytherapy, 32P, MCNP4C |
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Full-Text [PDF 442 kb]
(1949 Downloads)
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Type of Study: Short Report |
Subject:
Radiation Biology
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