MONITORING OF HIGH-ENERGY PHOTON FLUENCE IN CLINAC USING Zn AND Cr PHOTOACTIVATION

Area of Science:

• Medical Physics
• Nuclear Physics
• Radiation Dosimetry

Background:

• Accurate monitoring of high-energy photon dose is essential in radiation therapy for patient safety and to assess radiation effects on microelectronics.
• The Varian 21EX 23MV CLINAC is a medical linear accelerator used for cancer treatment.

Purpose of the Study:

• To investigate the feasibility of employing the photoactivation technique for monitoring high-energy photon fluence.
• To assess the suitability of specific nuclear reactions for dosimetry in a clinical setting.

Main Methods:

• Utilized the photoactivation technique with the Varian 21EX 23MV CLINAC.
• Employed the 52Cr(γ,n)51Cr and 66Zn(γ,n)65Zn nuclear reactions for activation analysis.
• Measured the resulting 51Cr and 65Zn isotopes to determine photon fluence.

Main Results:

• Successfully demonstrated the use of 51Cr for short-term (80 days) photon fluence monitoring.
• Successfully demonstrated the use of 65Zn for long-term (110 days) photon fluence monitoring.
• Validated the photoactivation technique as a viable dosimetry method.

Conclusions:

• The photoactivation technique is effective for monitoring high-energy photon fluence in radiation therapy.
• 51Cr and 65Zn are suitable isotopes for short-term and long-term dosimetry, respectively.
• This method enhances radiation protection and aids in understanding radiation effects on devices.