Formaldehyde increases MAGIC gel dosimeter melting point and sensitivity

Fernandes, Juliana P.; Pastorello, Bruno Fraccini; Araújo, Dráulio Barros de; Baffa, Oswaldo

doi:10.1088/0031-9155/53/4/n04

Cited by 62 publications

(21 citation statements)

References 22 publications

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“…The amount of 500 ml of the MAGIC-f gel was fabricated (based on its original constituents [27]). In this study, a method based on several gel tubes was used to calibrate the gel dosimeter, in which several calibration tubes were put at 10 cm depth of a big container filled with distilled water to provide a uniform medium around them when irradiated.…”

Section: Methodsmentioning

confidence: 99%

Investigation of the gold nanoparticles effects on the prostate dose distribution in brachytherapy: gel dosimetry and Monte Carlo method

Khosravi¹,

Hashemi²,

Rahmani³

et al. 2016

jcb

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PurposeIn this work, gold nanoparticles (GNPs) were embedded in the MAGIC-f polymer gel irradiated with the 192Ir brachytherapy sources.Material and methodsAt the first plexiglas phantom was made as the human pelvis. The GNPs were synthesized with 15 nm in diameter and 0.1 mM (0.0197 mg/ml) in concentration by using a chemical reduction method. Then, the MAGIC-f gel was synthesized. The fabricated gel was poured into the tubes located at the prostate (with and without the GNPs) locations of the phantom. The phantom was irradiated with 192Ir brachytherapy sources for prostate cancer. After 24 hours, the irradiated gels was read by using Siemens 1.5 Tesla MRI scanner. Following the brachytherapy practices, the absolute doses at the reference points and isodose curves were extracted and compared by experimental measurements and Monte Carlo (MC) simulations.ResultsThe mean absorbed doses in the presence of the GNPs in prostate were 14% higher than the corresponding values without the GNPs in the brachytherapy. The gamma index analysis (between gel and MC) using 7%/7 mm was also applied to the data and a high pass rate achieved (91.7% and 86.4% for analysis with/without GNPs, respectively).ConclusionsThe real three-dimensional analysis shows the comparison of the dose-volume histograms measured for planning volumes and the expected one from the MC calculation. The results indicate that the polymer gel dosimetry method, which developed and used in this study, could be recommended as a reliable method for investigating the dose enhancement factor of GNPs in brachytherapy.

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Section: Methodsmentioning

confidence: 99%

Investigation of the gold nanoparticles effects on the prostate dose distribution in brachytherapy: gel dosimetry and Monte Carlo method

Khosravi¹,

Hashemi²,

Rahmani³

et al. 2016

jcb

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“…As the gelatin cools to below 32 Celsius, the gelatin stock is titrated with formalin (Sigma Aldrich) at 1.4 mL per 40 mL of water. This amount of formalin is known to cross-link gelatin such that the melting temperature is increased above the 31 Celsius temperature of the ultrasound tomography water bath [9]. …”

Section: Methodsmentioning

confidence: 99%

Imaging Performance of Quantitative Transmission Ultrasound

Lenox

Wiskin

Lewis

et al. 2015

International Journal of Biomedical Imaging

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Quantitative Transmission Ultrasound (QTUS) is a tomographic transmission ultrasound modality that is capable of generating 3D speed-of-sound maps of objects in the field of view. It performs this measurement by propagating a plane wave through the medium from a transmitter on one side of a water tank to a high resolution receiver on the opposite side. This information is then used via inverse scattering to compute a speed map. In addition, the presence of reflection transducers allows the creation of a high resolution, spatially compounded reflection map that is natively coregistered to the speed map. A prototype QTUS system was evaluated for measurement and geometric accuracy as well as for the ability to correctly determine speed of sound.

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“…Other investigators have added formaldehyde to increase the melting point of MAGIC gels. 19 We found that when glucose was added, the melting point of the gel increased 5°C, which would allow its convenient uses in most air-conditioned treatment rooms without introducing additional toxicity. The only drawback was a slightly increased gel density, which is still closer to tissue density when compared to PMMA, and is considered very acceptable in our application.…”

Section: Discussionmentioning

confidence: 99%