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Nuclear Science and Technology | Progress Report 203
The comparison between Varian AAA uncertainties below 2 %, validating the results.
and ACUROS XB dose calculation Figure 39 presents the anthropomorphic skull
algorithms for VMAT treatment planning 3D printed phantom.
of brain multiple metastases
3D Phantoms
The Optically Stimulated Luminescence dosim-
etry has become one of most used techniques Attenuation coefficient determination
for radiation dosimetry nowadays. The “Ala- of printed ABS and PLA samples in
bama Technique” demonstrates plan quality diagnostic radiology standard beams
and provides a practical, systematic approach
to the treatment planning technique for single IAEA code of practice TRS-457 states that stan-
isocenter cranial radiosurgery with volumetric dard phantoms should offer the same primary
modulated arc therapy (VMAT) used in meta- attenuation and scatter production as relevant
static carcinoma treatments. An anthropomor- body section of a representative patient. Mate-
phic skull 3D printed phantom was submitted rial cost, availability and dimensional stability
to a CT scan and planed five target volumes. In must also be considered. The goal of this study
order to compare, two dose calculations were was to determine the attenuation coefficient
performed in the Varian Eclipse with VMAT of printed ABS and PLA samples in standard
planning with “Alabama Technique” using X-ray beams, verifying if phantoms printed
the Varian’s AAA and Acuros XB algorithms. with these materials could be an easier-handle
The treatment was delivered with a VARIAN substitute for PMMA, enabling the creation
True Beam linear accelerator with Multileaf of different designs in an easier and cheaper
Collimator HD and 6 MV photon beam was way. Results show that PMMA presents higher
used. Landauer nanoDot dosimeters were po- attenuation coefficient, followed by PLA and
sitioned inside each of the five target volumes ABS, which means that thinner PMMA layer
planned and the experimental dosimetry re- creates higher radiation attenuation.
sults were compared with the two calculation
algorithms. The experimental results using the Equivalence between Solid Water and printed
OSLDs show agreement of 97.26 %, 99.12 %, PLA plates for 6 MV clinical photon beam – An
99.99 %, 95.94 % and 98.79 % for the targets 1 assessment using thermoluminescent dosimetry
to 5 respectively for the ACUROS XB calculated
doses. The findings of this work indicate that Three dimensional models of anatomical
ACUROS XB calculates more accurate doses structures, produced by rapid prototyping are
compared with AAA, with all the experimental being adopted for medical application as he-
agreements better than 96 %. The intrinsic pre- modynamics studies and maxillofacial surgery
cision and uncertainty of the InLight system planning. Models with geometrical accura-
device is sufficient to sustain the dosimetry cy can be achieved using medical images as
MRI or CT and produced using polyurethane,
Figure 39-
Landauer nanoDot polylactic acid and epoxy resins. By changing
dosimeters and materials and densities, it is possible to achieve
anthropomorphic
skull 3D printed the desired tissue-equivalence. This work was
phantom. developed in order to analyze the equivalence
between the printed PLA and the Solid Wa-
ter plates by using the thermoluminescence
