Complete Dosimetric Characterization of an In-House Manufactured SFRT Grid Collimator by 3D Printing with PLA-W...

Area of Science:

• Medical Physics
• Radiotherapy Technology
• 3D Printing in Medicine

Background:

• Small-field dosimetry is crucial for non-conventional radiotherapy but faces challenges with miniaturized, complex collimators.
• Accurate dose assessment is hindered by penumbra overlap in closely spaced beamlets, limiting conventional methods.
• 3D printing with tungsten-doped PLA enables fabrication of advanced, miniaturized grid collimators.

Purpose of the Study:

• To perform a comprehensive dosimetric characterization and commissioning of a 3D printed grid collimator.
• To evaluate the accuracy and stability of dose distributions for various beamlet configurations.
• To assess the long-term performance and clinical feasibility of these novel collimators.

Main Methods:

• Measurements followed the IAEA TRS-483 protocol for small-field dosimetry.
• Used micro-ionization chambers, diode detectors, and EBT3 films for dose distribution evaluation.
• Conducted long-term stability assessments over one to two years, including structural integrity and modulation performance.

Main Results:

• The 3D printed collimator demonstrated high manufacturing precision with minimal deviation in radiation field size.
• Output factors varied predictably with the number of beamlets, and depth of maximum dose remained stable.
• Long-term evaluations showed no significant changes in full width at half maximum (FWHM) or volumetric parameters, confirming reliability.

Conclusions:

• 3D printed grid collimators using PLA-W filaments are dosimetrically accurate and stable.
• These systems offer a clinically feasible solution for non-conventional radiotherapy applications.
• Accessible 3D printing technology enables reliable, in-house manufactured collimators with lasting performance.