Radiotherapy Dosage.

This research demonstrates that a 3D printed bolus can be customized for electron
radiation therapy. Both extruder and powder based printers were used, along with, paraffin
wax, super stuff, and H20. The plan dose coverage and conformity for the planning target
volume (PTV), was such that the distal side of the PTV was covered by the 90% isodose
line. The structure is read, and converted into an STL file. The file is sent to a slicer to
print. The object was filled with parafin wax, superstuff or water and sealed. Materials
Hounsfield units were analyzed, along with the structure stability. This method is evaluated
by scanning the 3D printed bolus. The dose conformity is improved compared to that with
no bolus. By generating a patient specific 3D printed bolus there is an in improvement in
conformity of the prescription isodose surface while sparing immediately adjacent normal
tissues.

The purpose of this study is to verify and validate the dose at various points of
interest in accelerated partial breast irradiation (APBI) treated with the Strut Adjusted
Volume Implant (SAVI) applicator using Thermoluminescent Dosimeters (TLDs). A set
of CT images were selected from a patient’s data who had received APBI using the SAVI
applicator. The images were used to make 3D models. TLDs were calibrated for
Brachytherapy. Various points of interest were marked out and slots were carved in the 3D
models to fit the TLDs. CT scans were taken of the 3D models with expanded SAVI
applicator inserted. A plan was made following B-39 protocol. The TLDs were read and
the absorbed doses were calculated and compared to the delivered doses. The results of this
study show that the overall average reading of the TLDs is within expected value. The TPS
shows overestimated dose calculations for brachytherapy.