Day 1 : Poster Presentations (Theme: Patient Safety)

Event Title

Dosimetry of small fields in radiation therapy

Presenter Information

Asad Yousuf, Aga Khan University

Location

Auditorium Pond Side

Start Date

26-1-2013 10:30 AM

Abstract

Background: The field-in-field technique, using a number of static small fields, offers a useful alternative to Intensity Modulated Radiation Therapy in dose optimization in radiotherapy. This work investigates the dosimetry of small fields in such a technique.

Methods: A series of MLC-defined square and rectangular fields of various sizes were generated for 6 MV photon beams. Each field was irradiated with a set number of monitor units, and the measured doses output factor at points of interest in a solid water phantom were measured using ion chamber (Pin Point 0.16cc, Semiflex 0.3cc)and OSL dosimetry.

Results: Mesurement from differnt chmabers and OSL were compared, results from OSL are in agreement as predicted for very small field in range of 1x1 cm2, 2x2 cm2, 3x3 cm2

Conclusions: Field in Field technique include significant number of small fields, In Radiation Oncology new radiation technology IMRT will strat soon, which calculate dose Fluence with no of small beamlet. Powerful system calculate the dose fluence for us but before treating the patient dose verification is essential component of quality assurance. Our work allow us to design the protocol of IMRT quality assurance program.

Key words: Small Field, OSL; optical luminescence dosimetry, Pinpoint Chamber, Semiflex Chamber, IMRT;Intensity Modulation Radiation Therapy

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Jan 26th, 10:30 AM Jan 26th, 12:00 PM

Dosimetry of small fields in radiation therapy

Auditorium Pond Side

Background: The field-in-field technique, using a number of static small fields, offers a useful alternative to Intensity Modulated Radiation Therapy in dose optimization in radiotherapy. This work investigates the dosimetry of small fields in such a technique.

Methods: A series of MLC-defined square and rectangular fields of various sizes were generated for 6 MV photon beams. Each field was irradiated with a set number of monitor units, and the measured doses output factor at points of interest in a solid water phantom were measured using ion chamber (Pin Point 0.16cc, Semiflex 0.3cc)and OSL dosimetry.

Results: Mesurement from differnt chmabers and OSL were compared, results from OSL are in agreement as predicted for very small field in range of 1x1 cm2, 2x2 cm2, 3x3 cm2

Conclusions: Field in Field technique include significant number of small fields, In Radiation Oncology new radiation technology IMRT will strat soon, which calculate dose Fluence with no of small beamlet. Powerful system calculate the dose fluence for us but before treating the patient dose verification is essential component of quality assurance. Our work allow us to design the protocol of IMRT quality assurance program.

Key words: Small Field, OSL; optical luminescence dosimetry, Pinpoint Chamber, Semiflex Chamber, IMRT;Intensity Modulation Radiation Therapy