Evaluation of Lung Density and Its Dosimetric Impact on Lung Cancer Radiotherapy: A Simulation Study
Background: The dosimetric parameters required in lung cancer radiation therapy are taken from a homogeneous water phantom; however, during treatment, the expected results are being affected because of its inhomogeneity. Therefore, it becomes necessary to quantify these deviations. Objective: The...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Shiraz University of Medical Sciences
2019-02-01
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| Series: | Journal of Biomedical Physics and Engineering |
| Subjects: | |
| Online Access: | http://jbpe.ir/Journal_OJS/JBPE/index.php/jbpe/article/view/430/305 |
| Summary: | Background: The dosimetric parameters required in lung cancer radiation therapy
are taken from a homogeneous water phantom; however, during treatment, the expected results are being affected because of its inhomogeneity. Therefore, it becomes
necessary to quantify these deviations.
Objective: The present study has been undertaken to find out inter- and intralung density variations and its dosimetric impact on lung cancer radiotherapy using
Monte Carlo code FLUKA and PBC algorithms.
Material and Methods: Density of 100 lungs was recorded from their CT
images along with age. Then, after PDD calculated by FLUKA MC Code and PBC
algorithm for virtual phantom having density 0.2 gm/cm3
and 0.4 gm/cm3
(density
range obtained from CT images of 100 lungs) using Co-60 10 x10 cm2
beams were
compared.
Results: Average left and right lung densities were 0.275±0.387 and 0.270±0.383
respectively. The deviation in PBC calculated PDD were (+)216%, (+91%), (+)45%,
(+)26.88%, (+)14%, (-)1%, (+)2%, (-)0.4%, (-)1%, (+)1%, (+)4%, (+)4.5% for
0.4 gm/cm3
and (+)311%, (+)177%, (+)118%, (+)90.95%, (+)72.23%, (+)55.83%
,(+)38.85%, (+)28.80%, (+)21.79%, (+)15.95%, (+)1.67%, (-) 2.13%, (+)1.27%,
(+)0.35%, (-)1.79%, (-)2.75% for 0.2 gm/cm3
density mediums at depths of 1mm,
2mm, 3mm, 4mm, 5mm, 6 mm, 7 mm, 8mm, 9mm,10mm, 15mm, 30mm, 40mm,
50mm, 80mm and 100 mm, respectively.
Conclusion: Large variations in inter- and intra- lung density were recorded.
PBC overestimated the dose at air/lung interface as well as inside lung. The results
of Monte Carlo simulation can be used to assess the performance of other treatment
planning systems used in lung cancer radiotherapy. |
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| ISSN: | 2251-7200 2251-7200 |