Lineer Hızlandırcıların Doz Doğrusallığının ve Doz Hızının Tedavi Kalitesine Etkisinin Değerlendirilmesi
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Abstract
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Abstract
BACKGROUND: The aim of this study is to
evaluate the dose linearity of linear
accelerators and the effect of dose rate on
treatment quality, after dosimetric calibration
of the Elekta Synergy Platform linear
accelerator device with reference dose of
100MU at reference dose rate of
400MU/min for 6MV and 15MV ionizing
radiation energies to 1Gy, to evaluate if the
differences statistically significant of the
dosimetric changes at different doses at
different dose rates used for treatment by
taking measurements at determined doses
(2MU~500MU) at other dose rates
(100MU/min ~ 600MU/min) METHODS: In this study, PTW brand RW-3
solid water equivalent phantom was used in
the clinical inventory is placed on the
treatment table in 10 cm thickness to
minimize the back scattering, the solid water
equivalent phantom source phantom
surface distance (ssd) is adjusted to 100 cm
and PTW brand TM30013 Model Farmer
Type Ion chamber, one of the ion chambers
used as standard in absolute dose
measurements of high-energy photon and
electron beams in radiotherapy is placed at
a depth of 10 cm, dosimetric readings were
made by PTW T10021 Model Unidos
Webline electrometer which has high
sensitivity at dose and dose rate was used
to measeure ,the each reading was
repeated 5 times, 2MU~500MU irradiations
for 100, 200, 300, 400, 500, 600MU/min
dose rates of Elekta Synergy Platform
device.RESULT: In Elekta Synergy Platform
device, for 6MV and 15 MV energies, at all
doses and dose rates set in the
measurements there is a difference of
±2%≤5MU at low doses , while this
difference is below ±0.5% ≤ (5U~500MU) at
high doses at electrometer readings.
DİSCUSSION: With the present results, it
has been seen that the Synergy Platform
linear accelerator produced by Elekta
company is compatible with AAPM Task
Group 142 in terms of X-ray MU linearity
and provides appropriate dosimetric results
for all other dose rates and doses with the
energy calibrations made at the specified
reference dose and dose rate and it
performed very well according to the
reference range specified in Task Group
142.