Introduction: Radiotherapy
is one of the important treatment modalities in cancer treatment. To maintain
the treatment procedure accuracy, the phantom is an essential tool for absolute
dosimetry conformation and Quality Assurance routine cheek up. This work aims
to study the absorbed dose of various phantoms and hence to make a comparison
of the result with the IAEA recommendation (TRS 398) for daily QA of Linac. Materials
and Methods: The experiment has been done at the Institute of Nuclear
Medical Physics (INMP), AERE, Savar, Dhaka, under the Bangladesh Atomic Energy
Commission. For external beam radiation, 6 MV and 15 MV photon beams of Varian
Clinac iX Linear Accelerator (Linac) were used. One dimensional (1D) water
phantom, solid water phantom, and MatriXX with MULTICube phantom and associate
accessories were used to experiment. Results: We have measured and
compared the absorbed dose data of the phantoms. The variation of sold water
phantom from the 1D water phantom is +2.8% at 6 MV and +3.5% at 15 MV. The
variation MatriXX with MULTIcube phantom from the 1D water phantom is +8.0% at
6 MV and +3.2% at 15 MV. This study revealed that the 1D water phantom was the
best absolute dose conformation among the other phantoms and the deviation was
within the acceptable limit (±5%), except MatriXX with MULTICube Phantom for
low energy beam (8%). Conclusion: It was observed that the accuracy of
dose estimation was better in the 1D water phantom rather than the other two.
It is also known that the 1D water phantom is low cost but needs a long time to
set up for the experimental arrangement. Solid water or MatriXX with MULTICube
phantom can be used to overcome this problem, which takes only a few minutes
for setup and is comparatively faster than 1D water phantom.
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