Model
Digital Document
Publisher
Florida Atlantic University
Description
Since the release of the Cyberknife Multileaf Collimator (CK-MLC), it has been a constant
concern on the realistic dose differences computed with its early-available Finite Size
Pencil Beam algorithm (FSPB) from those computed by using industry well-accepted
algorithms such as the Monte Carlo (MC) dose algorithm. In this study dose disparities
between FSPB and MC dose calculation algorithms for selected CK-MLC treatment plans
were quantified. The dosimetry for planning target volume (PTV) and major organs at risks
(OAR) was compared by calculating normalized percentage deviations (Ndev) between the
two algorithms. It is found that the FSPB algorithm overestimates D95 of PTV when
compared with the MC algorithm by averaging 24.0% in detached lung cases, and 15.0%
in non-detached lung cases which is attributed to the absence of heterogeneity correction
in the FSPB algorithm. Average dose differences are 0.3% in intracranial and 0.9% in
pancreas cases. Ndev for the D95 of PTV range from 8.8% to 14.1% for the CK-MLC lung
treatment plans with small field (SF ≤ 2x2cm2). Ndev is ranged from 0.5-7.0% for OARs.
concern on the realistic dose differences computed with its early-available Finite Size
Pencil Beam algorithm (FSPB) from those computed by using industry well-accepted
algorithms such as the Monte Carlo (MC) dose algorithm. In this study dose disparities
between FSPB and MC dose calculation algorithms for selected CK-MLC treatment plans
were quantified. The dosimetry for planning target volume (PTV) and major organs at risks
(OAR) was compared by calculating normalized percentage deviations (Ndev) between the
two algorithms. It is found that the FSPB algorithm overestimates D95 of PTV when
compared with the MC algorithm by averaging 24.0% in detached lung cases, and 15.0%
in non-detached lung cases which is attributed to the absence of heterogeneity correction
in the FSPB algorithm. Average dose differences are 0.3% in intracranial and 0.9% in
pancreas cases. Ndev for the D95 of PTV range from 8.8% to 14.1% for the CK-MLC lung
treatment plans with small field (SF ≤ 2x2cm2). Ndev is ranged from 0.5-7.0% for OARs.
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