Small Field Dosimetry and Calibration

This umbrella project combines two complementary initiatives aimed at strengthening dosimetric precision and calibration capabilities within the King Faisal Specialist Hospital and Research Center (KFSHRC). Together, they enhance national expertise in small field radiotherapy dosimetry and support the hospital’s role as a regional reference in radiation standards.

The first component focuses on the establishment of calibration capabilities for small volume ionization chambers at KFSHRC’s Secondary Standards Dosimetry Laboratory (SSDL). Using a modified Cobalt-60 calibration unit equipped with conical collimators, the project develops and validates calibration procedures in terms of absorbed dose to water, ensuring traceability and accuracy for small field measurements. The second component involves testing and implementing the IAEA–AAPM TRS-483 Code of Practice for reference and relative dosimetry of small static fields used in advanced radiotherapy modalities, including CyberKnife, TomoTherapy, TrueBeam, and Versa HD. Conducted under the IAEA Coordinated Research Project (CRP), this study establishes validated datasets of field output factors and correction coefficients across multiple systems and beam qualities. Collectively, these efforts aim to optimize clinical dose delivery, improve patient safety, and align local calibration standards with international best practices — marking a major step toward precision radiotherapy and global compliance in small field dosimetry.

Alhanouf Aldosari, Haya Alarifi, Rachid Ayad, Salma Al-Ahmadi, Mamdouh Alhawiti, Tabuk University, International Atomic Energy Agency (IAEA) CRP Working Group.