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Investigation of the reproducibility of bladder dose- volume histogram (DVH) in prostate tomotherapy using the center of mass of the bladder in daily megavoltage computed tomography (MVCT) images
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F. Goli-Ahmadabad   , S.R. Mahdavi , A. Nikoofar , A. Zare-Sadeghi , H. Vazirinasab , S. Bagherzadeh , G. Esmaili , N. Hasani N. Hasani |
| Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran , srmahdavi@hotmail.com |
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Abstract: (117 Views) |
Background: The DVH is the most used radiotherapy formulation. DVH plays a fundamental role in determining dose constraints and side effects. Volume also plays the main role in calculating DVH. In prostate treatment, there is no comprehensive consensus on determining the association between bladder volume (BV) and side effects. Our aim is to investigate the reproducibility of bladder DVH (DVHB). D50%BV (dose received by 50% of BV) is used to analysis DVHB. Materials and Methods: We contoured the bladder of 467 daily MVCT images of fifteen prostate cancer patients who underwent tomotherapy. Using R software 4.2.3, the correlation between the bladder center of mass (XCM, YCM, ZCM), BV with D50%BV were modeled by the mixed model. Two prediction models were presented for D50%BV, the first model was based on BV and (XCM, YCM, ZCM), the second model was based on BV. Results: Statistical analyses revealed that independent factors YCM, ZCM, and BV have a significant influence on the response variable D50%BV. According to mixed model, YCM has a positive correlation with D50%BV, while ZCM or BV has a negative correlation. XCM does not significantly affect D50%BV. Akaike Information Criterion (AIC) index indicated that first model has a higher goodness of fit than second one. Conclusion: Our findings demonstrate that bladder location also affects D50%BV, in addition to BV. It can be concluded that DVHB is not always repeatable as a scientific claim. |
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| Keywords: Prostate cancer, tomotherapy, DVH (dose volume histogram), bladder, reproducibility, mixed model. |
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Full-Text [PDF 1876 kb]
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Type of Study: Original Research |
Subject:
Radiation Biology
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