Dosimetric Analysis of Physical and Enhanced Dynamic Wedge and Its
Implicaton in 3D-Conformal Radiotherapy Planning
Shahnawaz Ansari
*
, Subrat Satpathy, Anil Kumar, Santosh kumar, Nimish Kumar and BK Singh
Apollo Hospitals Bilaspur (C.G), Bilaspur, Chhatsgarh, India
*
Corresponding author: Ansari S, M.Sc (Physics), D.R.P, Apollo Hospitals Bilaspur (C.G), Bilaspur, Chhatsgarh, India, Tel: 8968708521; E-mail:
ansarisnz05@gmail.com
Received Date: November 15, 2017; Accepted Date: January 08, 2018; Published Date: January 18, 2018
Copyright: © 2018 Ansari S, et al. This is an open-access artcle distributed under the terms of the Creatve Commons Atributon License, which
permits unrestricted use, distributon, and reproducton in any medium, provided the original author and source are credited.
Citaton: Ansari S, Satpathy S, Kumar A, kumar S, Kumar N, et al. (2018) Dosimetric Analysis of Physical and Enhanced Dynamic Wedge and Its
Implicaton in 3D-Conformal Radiotherapy Planning. J Biomedical Sci. Vol.7 No.1:1.
Abstract
Background: Across the history of radiotherapy, wedges are
generally used to modify the shape of isodose lines to
achieve desired clinical dose coverage to the target and to
reduce the hot spot as well.
Aim: The main aim of this study was to analyse and
compare the dosimetric propertes of Varian’s physical and
enhanced dynamic wedges, and their dosimetric impact on
radiotherapy plan (3D-Conformal).
Materials and Methods: All plans were generated and
evaluated in Varian’s eclipse planning system. For comparing
the isodose line alteraton, the plans were prepared in
water phantom with feld of size 10 cmx 10 cm. Wedges of
angle 15°, 30°, 45° and 60° were used for generatng
isodose lines in the current study. All wedge factors were
measured in water phantom using FC65 farmer type
chamber.
Discussion: In the current study, the dosimetric
characteristcs of EDW and PW were analyzed and
compared. For analyzing the impact of EDW and PW, 22
patents were taken into consideraton, and 50 Gy dose was
prescribed to PTV in 25 fractons.
Conclusion: The analysis of EDW and PW shows slightly
diferent dosimetric features. EDW gives beter target’s
coverage, less hyper dose and comparatvely less MUs as
compare to PW. Hence the use EDW in 3D-conformal
radiotherapy plan is a prudent practce.
Keywords Isodose line; Physical wedge; Enhanced
dynamic wedge
Background
Across the history of radiotherapy, wedges are generally used
as tssue compensator and beam modifer to improve the dose
coverage to the target. In enhanced dynamic wedge, the
required dose distributon is being achieved by sweeping acton
one of the collimator jaws in two directons (IN and OUT)
[1].Wedge flters are used to modify the shape of isodose curves,
for that two beams are being deployed at diferent angles with
small hinge angle at the target volume without creatng a
hotspot. The wedge angle refers to the angle through which the
isodose curves are tlted, relatve to their normal positon
perpendicular to the beam axis at reference depth. The
internatonal commission on radiaton units and measurements
(ICRU) recommendaton for reference depth is 10 cm [2]. The
presence of wedge flter in the beam path reduces the beam
intensity and this must be taken into account during treatment
planning. It is generally assumed that for wedged felds of
diferent size, a single wedge factor measured for a reference
feld size is valid for calculaton. Plta et al. examined feld size
dependence of a wedge factor using the Varian Clinac -4 wedge
flters and Philip’s SL75/5 auto wedge [3].
The Physical wedges (PW) have been the primarily means of
producing the wedged felds. The required wedged dose profles
can also be achieved by computer control moton of one of the
jaws. This kind of wedge is called dynamic wedge [4], which was
frst introduced by Varian medical system in early 1990s in linear
accelerator [5]. The dynamic wedge provides a range of angle
like 15°, 30°, 45°, and 60° for symmetrical feld size up to 20 cm
width. Capability of dynamic wedge is signifcantly improved by
introducing the concept of Varian’s enhanced dynamic wedge
(EDW). Now the EDW provides wedge angle of 10°, 15°, 20°, 25°,
30°, 45°, and 60° for both symmetrical and asymmetrical feld
sizes up to 30 cm width. A number of studies have been
conducted on PW and EDW [6-8]. Many studies related to
comparison of Varian’s PW and EDW stll have not been
reported [9-12].The dosimetric impact of enhanced dynamic
wedge factors (EDWF) for symmetrical and asymmetrical photon
felds have been discussed in many literatures. Physical wedge is
going to out of phase in future. Hence it is essental to analyze
and understand the features of enhanced dynamic wedge so
that users can use it judiciously.
Aim
The main aim of this study was to analyze the dosimetric
propertes of Varian’s physical and enhanced dynamic wedge,
Research Article
iMedPub Journals
http://www.imedpub.com/
DOI: 10.4172/2254-609X.100080
Journal of Biomedical Sciences
ISSN 2254-609X
Vol.7 No.1:1
2018
© Under License of Creative Commons Attribution 3.0 License | This article is available from: http://www.jbiomeds.com/
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