TITLE:
Clinical Comparison of Pencil Beam Convolution and Clarkson Algorithms for Dose Calculation
AUTHORS:
Abdulhamid Chaikh, Jean-Yves Giraud, Jacques Balosso
KEYWORDS:
Treatment Planning; Dose Distribution; Isodose; Monitor Unit; PBC; Clarkson
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.4 No.10,
December
24,
2013
ABSTRACT:
Purpose: The purpose of
this work is to study and quantify the differences in calculated dose computed
with two algorithms available in treatment planning systems: Pencil Beam
Convolution and Clarkson. Material and Methods: Four different types of treatment cases were analyzed: lung,
head and neck, brain and prostate. For each case, the volume definition was
based on a clinical CT-scan acquisition. The patients were
treated with 3-dimensional radiation therapy. For each patient, 2 treatment
plans were generated using exactly the same configuration of beams. In plan 1
and plan 2, the dose was calculated using the Clarkson and Pencil Beam Convolution algorithms,
respectively, without heterogeneity correction. To evaluate the treatment
plans, the monitor units, isodose curves, dose volume histograms and quality
index were compared. A statistical analysis was carried out using Wilcoxon
signed rank test. Results: The difference observed for monitor
unites was 1.2% for lung and less than 1% for head and neck, brain and
prostate. Wilcoxon test showed that there was “no statically significant
difference, (p > 0.05)”. The
dosimetric parameters derived from dose volume histograms were higher for
organs at risks using Clarkson compared to Pencil Beam Convolution algorithm inviting clinician to make “safer”
prescriptions. For quality index there was no statistically significant difference between
both algorithms for all quality indexes, (p > 0.05). Conclusion: The clinical evaluation of a treatment plan should be made regarding the
calculation algorithm which, in turn, is linked to the experience of the
clinician.