GafChromic(®) EBT3 films for patient specific IMRT QA using a multichannel approach

Area of Science:

• Medical Physics
• Radiation Oncology
• Dosimetry

Background:

• Gafchromic EBT3 films offer an attractive option for patient-specific quality assurance (QA) in radiation therapy.
• However, their routine use has been limited by complex processing and characterization challenges.

Purpose of the Study:

• To evaluate Gafchromic EBT3 films for pre-treatment patient-specific QA.
• To compare multichannel dosimetry with single-channel dosimetry for EBT3 film analysis.
• To adapt existing protocols for practical clinical application.

Main Methods:

• Irradiation of EBT3 films using linac and TomoTherapy, obtaining calibration curves.
• Exposure of films to simple and complex clinical plans (IMRT, VMAT).
• Digitization using an Epson 10000XL scanner and analysis with FilmQA™ Pro software.

Main Results:

• A single calibration curve is effective for each film lot for both linac and TomoTherapy beams.
• Multichannel optimization significantly enhances gamma passing rates in dose map comparisons.
• This approach improves the accuracy of measured dose distributions.

Conclusions:

• The proposed protocol, combined with multichannel optimization, makes EBT3 films a practical and dependable detector for patient-specific QA.
• Addressing previous limitations, EBT3 films are now suitable for routine clinical implementation.
• This advancement enhances the reliability of pre-treatment QA in radiation oncology.