Dosimetric properties of new formulation of PRESAGE® with tin organometal catalyst: Development of sensitivity and stability to megavoltage energy
Davood Khezerloo1, Hassan Ali Nedaie2, Abbas Takavar1, Alireza Zirak3, Bagher Farhood1, Nooshin Banaee4, Eisa Alidokht5
1 Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
2 Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences; Radiotherapy Oncology Department, Cancer Research Centre, Cancer Institute, Tehran, Iran
3 Laser and Optics Research School, NSTRI, 4Department of Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
4 Department of Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
5 Department of Optics and Photonics, Shahid Beheshti University, Tehran, Iran
Hassan Ali Nedaie,
Radiotherapy Oncology Department, Cancer Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran
Source of Support: None, Conflict of Interest: None
Aim:Tin-base catalyst is one of the widely used organometallic catalysts in polyurethane technology. The purpose of this study was to evaluate the effect of tin organometallic catalyst in the radiation response and radiological properties of a new formula of PRESAGE ®.
Materials and Methods: In the study, two types of PRESAGE were fabricated. A very little amount of dibutyltindillaurate (DBTDL) (0.07% weight) was used as a catalyst in the fabrication of new PRESAGE (i.e., PRESAGE with catalyst), which components were: 93.93% weight polyurethane, 5% weight tetrachloride, and 1% weight leucomalachite green (LMG). For PRESAGE without catalyst, 94% weight polyurethane, 4% weight tetrachloride, and 2% weight LMG were used. Radiochromic response and postirradiation stability of PRESAGEs were determined. Also, radiological characteristics of PRESAGEs, such as mass density, electron density, mass attenuation coefficient, and mass stopping power in different photon energies were assessed and compared with water.
Results: The absorption peak of new PRESAGE compared to PRESAGE without catalyst was observed without change. Sensitivity of new PRESAGE was higher than PRESAGE without catalyst and its stability after the first 1 h was relatively constant. Also, Mass attenuation coefficient of new PRESAGE in energy ranges <0.1 MeV was 10% more than water, whereas the maximum difference of mass stopping power was only 3%.
Conclusions: Tin organometallic catalyst in very low concentration can be used in fabrication of radiochromic polymer gel to achieve high sensitivity and stability as well as good radiological properties in the megavoltage photon beam.