A new polymer gel for magnetic resonance imaging (MRI) radiation dosimetry

Pappas, E.; Maris, Thomas G.; Angelopoulos, A.; Paparigopoulou, M; Sakelliou, L.; Sandilos, P.; Voyiatzi, S.; Vlachos, L.

doi:10.1088/0031-9155/44/10/320

Cited by 133 publications

(82 citation statements)

References 22 publications

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“…Polymer gels have been well studied for their dosimetric characteristics 14 , 15 , 16 . In this study, Vinylpyrrolidone‐based polymer gels were used.…”

Section: Methodsmentioning

confidence: 99%

Dosimetric validation for an automatic brain metastases planning software using single‐isocenter dynamic conformal arcs

Liu

Pappas

et al. 2016

J Applied Clin Med Phys

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An automatic brain‐metastases planning (ABMP) software has been installed in our institution. It is dedicated for treating multiple brain metastases with radiosurgery on linear accelerators (linacs) using a single‐setup isocenter with noncoplanar dynamic conformal arcs. This study is to validate the calculated absolute dose and dose distribution of ABMP. Three types of measurements were performed to validate the planning software: 1, dual micro ion chambers were used with an acrylic phantom to measure the absolute dose; 2, a 3D cylindrical phantom with dual diode array was used to evaluate 2D dose distribution and point dose for smaller targets; and 3, a 3D pseudo‐in vivo patient‐specific phantom filled with polymer gels was used to evaluate the accuracy of 3D dose distribution and radiation delivery. Micro chamber measurement of two targets (volumes of 1.2 cc and 0.9 cc, respectively) showed that the percentage differences of the absolute dose at both targets were less than 1%. Averaged GI passing rate of five different plans measured with the diode array phantom was above 98%, using criteria of 3% dose difference, 1 mm distance to agreement (DTA), and 10% low‐dose threshold. 3D gel phantom measurement results demonstrated a 3D displacement of nine targets of 0.7±0.4 mm (range 0.2 ~ 1.1 mm). The averaged two‐dimensional (2D) GI passing rate for several region of interests (ROI) on axial slices that encompass each one of the nine targets was above 98% (5% dose difference, 2 mm DTA, and 10% low‐dose threshold). Measured normalD95, the minimum dose that covers 95% of the target volume, of the nine targets was 0.7% less than the calculated normalD95. Three different types of dosimetric verification methods were used and proved the dose calculation of the new automatic brain metastases planning (ABMP) software was clinical acceptable. The 3D pseudo‐in vivo patient‐specific gel phantom test also served as an end‐to‐end test for validating not only the dose calculation, but the treatment delivery accuracy as well.PACS number(s): 87.53.Lv, 87.55.km, 87.55.Qr

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“…Polymer gels have been well studied for their dosimetric characteristics 14 , 15 , 16 . In this study, Vinylpyrrolidone‐based polymer gels were used.…”

Section: Methodsmentioning

confidence: 99%

Dosimetric validation for an automatic brain metastases planning software using single‐isocenter dynamic conformal arcs

Liu

Pappas

et al. 2016

J Applied Clin Med Phys

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“…BANG (bisacrylamide nitrogen gelatine) has been commercialised with multiple formulations, such as BANG-1 33 that is made with powdered acrylamide and BANG-2 6, 36 that uses acrylic acid as a monomer with sodium hydroxide to alter the pH. Other gels of reduced toxicity exist, such as PABIG (polyethylene glycol diacrylate bis gelatine) 37 and VIPAR (N-vinyl pyrolidone argon gel) [38][39][40] . Fong et al developed a normoxic gel dosimeter, MAGIC (methacrylic acid, ascorbic acid in gelatine initiated by copper), which does not require an oxygen-free environment to be prepared 41 .…”

Section: Gel Dosimetersmentioning

confidence: 99%

The effective atomic number of dosimetric gels

Taylor

Franich

Trapp

et al. 2008

Australas. Phys. Eng. Sci. Med.

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Radiological properties of gel dosimeters and phantom materials are often compared against each other and against water or tissue by consideration parameters including their effective atomic number, Zeff. Effective atomic numbers have been calculated for a range of ferrous-sulphate and polymeric gel dosimeters using mass attenuation coefficient data over the energy range 10 keV to 10 MeV. Data is presented relative to water to allow direct comparison over a range of energies. These data provide energy specific values of Zeff which improves on the practice of applying a power-law based formula to estimate an energy independent value. For applications that require a single value of Zeff, the data presented here allows the choice of a value appropriate to the energy of the photon source or a spectrum-weighted average. Studying the variation of Zeff, which is equivalent to taking into account the variation of mass attenuation coefficients with photon energy, it is found that gels typically match water better than water matches human tissues. As such, the subtle differences in effective atomic number between water and gels are small and may be considered negligible. Consideration of the mean disparity over a large energy range shows, broadly, BANG-1 to be the most water equivalent gel.

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“…Using Eq. [3], the temperature, t, of a pixel or region in the image can be found from its T 1 ([3a]) or T 2 ([3b]) value:…”

Section: Temperature Predictionmentioning

confidence: 99%

Temperature dosimetry using MR relaxation characteristics of poly(vinyl alcohol) cryogel (PVA‐C)

2001

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A new polymer gel for magnetic resonance imaging (MRI) radiation dosimetry

Cited by 133 publications

References 22 publications

Dosimetric validation for an automatic brain metastases planning software using single‐isocenter dynamic conformal arcs

Dosimetric validation for an automatic brain metastases planning software using single‐isocenter dynamic conformal arcs

The effective atomic number of dosimetric gels

Temperature dosimetry using MR relaxation characteristics of poly(vinyl alcohol) cryogel (PVA‐C)

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