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Accurate assessment of the radiation absorbed dose delivered to a tumor and different organs is a potentially importance issue in clinical radiotherapy. The aim of this study is to evaluate the effectiveness of the Fricke Xylenol Gel dosimeter (FXG) to the gamma radiation from Co-60. With this aim, the dose response of FXG and its behavior have been investigated. The sensitivity and accuracy of FXG were validated by irradiating FXG with the gamma radiation at 1-200 Gy. To evaluate the long- and short-term consistency and reproducibility of FXG, the optical density was measured at 24, 48 and 120 h after irradiation. Light absorbance spectra were analyzed from 350-700 nm. Spectrophotometric measurement of FXG demonstrated the linearity up to 30 Gy, and then gradually reached a plateau. FXG showed a good stability over a period of 120 h after exposure to gamma radiation. FXG showed a high reproducibility which is in comparable to that of obtained from the ionization chamber. The FXG showed high accuracy, sensitivity and reproducibility, thus enabling determination of absorbed dose from the external beam radiotherapy.

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A colorimetric liquid sensor based on a poly(vinyl alcohol)/silver nanoparticle (PVA/AgNPs) hybrid nanomaterial was developed for gamma radiation in the range of 0–100 Gy. In this study, gamma rays (Cobalt-60 source) triggered the aggregation of AgNPs in a PVA/silver nitrate (AgNO3) hybrid solution. The color of this solution visibly changed from colorless to dark yellow. Absorption spectra of the PVA/AgNPs solution were analyzed by UV-Vis spectrophotometry in the range of 350–800 nm. Important parameters, such as pH and AgNO3 concentration were optimized. The accuracy, sensitivity, stability, and uncertainty of the sensor were investigated and compared to the reference standard dosimeter. Based on the spectrophotometric results, an excellent positive linear correlation (r = 0.998) between the absorption intensity and received dose was found. For the accuracy, the intra-class correlation coefficient (ICC) between the PVA/AgNPs sensor and the standard Fricke dosimeter was 0.998 (95%CI). The sensitivity of this sensor was 2.06 times higher than the standard dosimeter. The limit of detection of the liquid dosimeter was 13.4 Gy. Moreover, the overall uncertainty of this sensor was estimated at 4.962%, in the acceptable range for routine standard dosimeters (<6%). Based on its dosimetric performance, this new PVA/AgNPs sensor has potential for application as an alternative gamma sensor for routine dose monitoring in the range of 13.4–100 Gy.