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. 2022 Oct 1;12(5):489-496.
doi: 10.31661/jbpe.v0i0.1912-1008. eCollection 2022 Oct.

Investigating the Sensitivity of New Formulation MAGAT and NIPAM Polymer Gels in the Radiation Therapy Dosimetry

Negin Javaheri  1 , Mehran Yarahmadi  2 , Abdollah Refaei  3 , Ali Aghamohammadi  3
Affiliations

Investigating the Sensitivity of New Formulation MAGAT and NIPAM Polymer Gels in the Radiation Therapy Dosimetry

Negin Javaheri et al. J Biomed Phys Eng. .

Abstract

Background: Normoxic polymer gels have been used as a three dimensional (3D) dosimeter in radiation therapy, recently. The sensitivity of these gels is important in dosimetry and their improvement can be also useful.

Objective: In this study, different modalities of gel reading were used and the structure of gel changed due to the best improvement of sensitivity. The sensitivities of the new formulation of Methacrylic acid gel (MAGAT) and N-isopropyl acrylamide (NIPAM) polymer gel dosimeters were studied using two different reading methods of magnetic resonance imaging (MRI) and X-ray computed tomography (X-ray CT).

Material and methods: In this experimental study, in addition to making the NIPAM polymer gel dosimeter, a new formulation of normoxic polymer gel dosimeter, which named MAGAT gel, was investigated. The gels were irradiated with 6 MV in low doses, including1, 1.5, 1.75, 2 and 2.5 Gy. MRI and X-ray CT did the reading of gel dosimeters a day after irradiation using an elevated protocol.

Results: The dose sensitivities of 0.92 HGy-1 and 0.47 HGy-1 were obtained for new MAGAT and NIPAM polymer gel dosimeters, respectively, based on the X-ray CT reading modality. The use of MRI reading modality and the dose sensitivities were 0.74 S-1Gy-1 and 0.27 S-1Gy-1 for new MAGAT and NIPAM polymer gel dosimeters, respectively.

Conclusion: The new formulation of MAGAT polymer gel with a suitable protocol of gel reading has a better response.

Keywords: Magnetic Resonance Imaging; Methacrylic Acid; Polymer Gel; Radiation Dosimeters; Radiation Therapy; X-Ray Computed Tomography.

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Conflict of interest statement

None

Figures

Figure 1
Figure 1
The scanning of irradiated polymer gel vials by 1.5T magnetic resonance imaging (MRI)
Figure 2
Figure 2
R2 dose-response of new MAGAT polymer gel dosimeter.
Figure 3
Figure 3
The computed tomography (CT) numbers with the dose for the new MAGAT polymer gel dosimeter.
Figure 4
Figure 4
R2 dose-response of NIPAM polymer gel dosimeter.
Figure 5
Figure 5
The computed tomography (CT) numbers with the dose for the NIPAM polymer gel dosimeter.
See this image and copyright information in PMC

References

    1. Yarahmadi M, Wegener S, Sauer OA. Energy and field size dependence of a silicon diode designed for small field dosimetry. Med Phys. 2017;44:1959–64. doi: 10.1002/mp.12195. - DOI - PubMed
    1. Haghparast A, Amiri F, Yarahmadi M, Rezaei M. The peripheral dose outside the applicator in electron beams of an Elekta linear accelerator. Australasian Physical & Engineering Sciences in Medicine. 2018;41:647655. doi: 10.1007/s13246-018-0660-9. - DOI - PubMed
    1. Baldock C, De Deene Y, Doran S, Ibbott G, Jirasek A, Lepage M, et al. Polymer gel dosimetry. Phys Med Biol. 2010;55:63. doi: 10.1088/0031-9155/55/5/R01. - DOI - PMC - PubMed
    1. Parwaie W, Yarahmadi M, Nedaie HA. Evaluation of MRI-based MAGIC polymer gel dosimeter in small photon fields. Int J Radiat Res. 2016;14:57–63. doi: 10.7508/ijrr.2016.01.009. - DOI
    1. Fong PM, Keil DC, Does MD, Gore JC. Polymer gels for magnetic resonance imaging of radiation dose distributions at normal room atmosphere. Phys Med Biol. 2001;46:3105–13. doi: 10.1088/0031-9155/46/12/303. - DOI - PubMed

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