Comparison of non-electrophoresis grade with electrophoresis grade BIS in NIPAM polymer gel preparation.

INTRODUCTION: The main objective of this study was to investigate the possibility of replacing electrophoresis cross-linker with non-electrophoresis N, N'-methylenebisacrylamide (BIS) in N-isopropyl acrylamide (NIPAM) polymer gel and its possible effect on dose response. METHODS: NIPAM polymer gel was prepared from non-electrophoresis grade BIS and the relaxation rate (R2) was measured by MR imaging after exposing the gel to gamma radiation from Co-60 source. To compare the response of this gel with the one that contains electrophoresis grade BIS, two sets of NIPAM gel were prepared using electrophoresis and non-electrophoresis BIS and irradiated to different gamma doses. RESULTS: It was found that the dose-response of NIPAM gel made from the non-electrophoresis grade BIS is coincident with that of electrophoresis grade BIS. CONCLUSION: Taken all, it can be concluded that the non-electrophoresis grade BIS not only is a suitable alternative for the electrophoresis grade BIS but also reduces the cost of gel due to its lower price.

Dosimetric properties of N-isopropylacrylamide polymer gel using nonelectrophoresis grade BIS in preparation.

INTRODUCTION: Unlike availability of the different grades of N, N'-methylenebisacrylamide (BIS), electrophoresis is recommended in literature as a crosslinking agent in gel preparation. As the cost of non-electrophoresis grade BIS is much less than that of electrophoresis, the dosimetric characteristics of the of the polymer gel using non-electrophoresis BIS is evaluated in terms of photon energy and dose rate. MATERIALS AND METHODS: To compare the response of this gel with the one that contains electrophoresis grade BIS, two sets of N-isopropylacrylamide (NIPAM) gel were prepared using electrophoresis and non-electrophoresis BIS and irradiated to different gamma doses. RESULTS: It was shown that the dose-response of NIPAM gel made from non-electrophoresis grade BIS is coincident to that of electrophoresis grade BIS. The study of dose response of NIPAM with non-electrophoresis grade BIS as a function of beam energy revealed no dependence on radiation energies of 1.25 MV from 60 Co and 6 MV and 18MV from linear accelerator. It was found that dose rate has no influence on dose response of NIPAM gel with non-electrophoresis BIS. CONCLUSION: Substitution non-electrophoresis grade BIS not only reduces the cost of gel preparation without any adverse effect on its dose response, but also its lower background increases the dynamic range of dose linearity.

Capability of NIPAM polymer gel in recording dose from the interaction of (10)B and thermal neutron in BNCT.

The capability of N-isopropylacrylamide (NIPAM) polymer gel to record the dose resulting from boron neutron capture reaction in BNCT was determined. In this regard, three compositions of the gel with different concentrations of (10)B were prepared and exposed to gamma radiation and thermal neutrons. Unlike irradiation with gamma rays, the boron-loaded gels irradiated by neutron exhibited sensitivity enhancement compared with the gels without (10)B. It was also found that the neutron sensitivity of the gel increased by the increase of concentration of (10)B. It can be concluded that NIPAM gel might be suitable for the measurement of the absorbed dose enhancement due to (10)B and thermal neutron reaction in BNCT.

Role of gel dosimeters in boron neutron capture therapy.

Gel dosimeters have acquired a unique status in radiotherapy, especially with the advent of the new techniques in which there is a need for three-dimensional dose measurement with high spatial resolution. One of the techniques in which the use of gel dosimeters has drawn the attention of the researchers is the boron neutron capture therapy. Exploring the history of gel dosimeters, this paper sets out to study their role in the boron neutron capture therapy dosimetric process.