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A new commercial 2D ionising radiation dosimeter (2Day.QA®) was developed. This work aims to introduce the basic functions of 2Day.QA®.The dosimeter is made mainly of a linear polysaccharide consisting of β(1 → 4) linked d-glucose units and radiation active substances, which make it environmentally friendly. For 2Day.QA® irradiation, radiotherapy ionising radiation sources were used. The analysis of 2Day.QA® was performed using three scanners: Vidar® Red LED Dosimetry Pro Advantage™, Vidar® VXR 12-plus™ and HP Scanjet G3010 flatbed scanner. The stability of 2Day.QA® was tested. Exemplary applications of 2DayQA® for QA studies of accelerator light and radiation field coincidence and brachytherapy source position were carried out.The dosimeter responded to the lowest applied dose of 0.95 Gy and saturated at over 94.9 Gy. The quasi-linear dose response is below 20 Gy. Vidar® Red LED Dosimetry Pro Advantage™ has proven to be superior to other scanners at determining dose effects in 2Day.QA®. The stability of the non-irradiated 2Day.QA® is at least 18 months. After 18 months of storage, the dosimeter reacted to irradiation. In the case of the irradiated samples, a slight color drift related to the absorbed dose was observed. Tests of the use of 2Day.QA® to control the quality of the accelerator light and radiation field coincidence and brachytherapy source position have shown that it can be used for such applications.The study reveals the potential of 2Day.QA® for 2D radiation dosimetry and concludes with recommendations for the use of the dosimeter for radiotherapy QA tests.

This work presents an approach to the fast determination of a medical accelerator irradiation isocenter as a quality assurance (QA) procedure in radiotherapy. The isocenter determination tool is the tissue equivalent high-resolution 3D polymer gel dosimeter (PABIGnx) in a dedicated container combined with kilovoltage imaging systems and the polyGeVero-CT software package (v. 1.2, GeVero Co., Poland). Two accelerators were employed: Halcyon and TrueBeam (Varian, USA), both equipped with cone beam computed tomography (CBCT) and iterative reconstruction CBCT (iCBCT) algorithms. The scope of this work includes: (i) the examination of factors influencing image quality (reconstruction algorithms and modes), radiation field parameters (dose and multi-leaf collimator (MLC) gaps), fiducial markers, signal averaging for reconstruction algorithms and the scanning time interval between consecutive scans, (ii) the examination of factors influencing the isocenter determination, image processing (signal averaging, background subtraction, image filtering) and (iii) an isocenter determination report using a 2D and 3D approach. An optimized protocol and isocenter determination conditions were found. The time and effort required to determine the isocenter are discussed.

This work presents the features of the PABIG

Purpose The purpose of this work was to examine the suitability of VIPARnd polymer gel-9.4 T magnetic resonance microimaging system for high spatial resolution dose distribution measurements. Methods The VIPARnd samples (3 cm in outside diameter and 12 cm in height) were exposed to ionizing radiation by using a linear accelerator (Varian TrueBeam, USA; 6 MV x-ray beam). In the calibration stage, nine gel dosimeter vials were irradiated in a water phantom homogenously to the doses from 1.5 to 30 Gy in order to obtain R2-dose relation. In the verification stage, two gel dosimeter vials were irradiated in the half beam penumbra area of 10 × 10 cm radiation field using the amount of monitor units appropriate to deliver 20 Gy at the field center. The gels were imaged on a vertical 9.4 T magnetic resonance (MR) microimaging scanner using single slice and multislice (9 slices) multiecho (90 × 7 ms) sequences at the spatial resolutions of 0.2-0.4 × 0.2-0.4 × 3 mm3 and 0.2-0.4 × 0.2-0.4 × 1 mm3 respectively. The gels were subjected to microimaging during the period of two weeks after irradiation. The reference data consisted of the dose profiles measured using the diode dosimetry, radiochromic film, ionization chamber, and the water phantom system. Results The VIPARnd -9.4 T MR microimaging system was characterized by the dose sensitivity of 0.067 ± 0.002 Gy-1 s-1 at day 3 after irradiation. The dose resolution at 10 Gy (at P = 95%) was equal to 0.42 Gy at day 3 after irradiation using a single slice sequence (0.2 × 0.2 × 3 mm3 ) and 2.0 Gy at day 4 after irradiation using a multislice sequence (0.2 × 0.2 × 1 mm3 ) for one signal acquisition (measurement time: 15 min). These values were improved by ~1.4-fold when using four signal acquisitions in the single slice sequence, and by ~2.78-fold for 12 signal acquisitions in the multislice sequence. Furthermore, decreasing the in-plane resolution from 0.2 × 0.2 mm2 to 0.4 × 0.4 mm2 resulted in a dose resolution of 0.3 Gy and 1 Gy at 10 Gy (at P = 95%) for one signal acquisition in the single slice and multislice sequences respectively (measurement time: 7.5 min). As reveals from the gamma index analysis the dose distributions measured at days 3-4 postirradiation using both VIPARnd verification phantoms agree with the data obtained using a silicon diode, assuming 1 mm/5% criterion. A good interphantom reproducibility of the polymer gel dosimetry was proved by monitoring of two phantoms up to 10 days after irradiation. However, the agreement between the dose distributions measured using the diode and polymer gel started to get worse from day 5 after irradiation. Conclusion The VIPARnd -9.4T MR microimaging system allows to obtain dose resolution of 0.42 Gy at 10 Gy (at P = 95%) for a spatial resolution of 0.2 × 0.2 × 3 mm3 (acquisition time: 15 min). Further studies are required to improve a temporal stability of the gel-derived dose distribution.

In this work, a method for the measurement of one-dimensional (1D) UV radiation dose is described. It comprises a new tablet dosimeter that measures the dose using reflectance spectrophotometry. The tablet dosimeter elaborated is a solid structure with a cylindrical form and has been manufactured with polycaprolactone (PCL) doped with a representative of tetrazolium salts: 2,3,5−triphenyltetrazolium chloride (TTC). The PCL used makes the dosimeter biodegradable and therefore proecological. The TTC dopant is distributed uniformly in the whole PCL tablet, and the whole tablet changes color to red under UVC irradiation. The intensity of this color increases if the PCL–TTC tablet absorbs higher doses. The color of the tablet is stable for at least 30 days after irradiation. It is proposed that the PCL-TTC tablet be used for measurement with reflectance spectrophotometry in order to determine the reflectance of light versus the absorbed dose in a fast and easy manner. On this basis, the PCL-TTC tablet could be characterized by providing information on its dose range, which amounted to 0–2 J/cm2. Moreover, other parameters were derived, such as dose sensitivity, quasilinear dose range, and dose threshold. The morphology of the tablets studied using scanning electron microscopy revealed their high porosity, which however did not influence the reflectance measurements with the aid of the chosen instrument. UVC irradiation at a dose (15 J/cm2) much above the PCL-TTC tablets’ dose range did not alter the morphology of the tablets. The PCL-TTC tablet read with reflectance spectrophotometry is shown to be a promising and fast method for 1D UV dose measurements.

Purpose Advanced 3D dosimetry is required for verifications of complex dose distributions in modern radiotherapy. Two 3D polymer gel dosimeters, coupled with magnetic resonance (MR) imaging (3 T MRI) readout and data processing with polyGeVero® software, were tested for the verification of calculated 3D dose distributions by a treatment planning system (TPS) and ArcCHECK®–3DVH®, related to eradication of a lung tumour. Methods N-vinylpyrrolidone-containing 3D polymer gel dosimeters were used: VIC (containing ascorbic acid and copper sulfate pentahydrate) and VIC-T (containing tetrakis(hydroxymethyl)phosphonium chloride). Three remote centers were involved in the dosimeters preparation and irradiation (Poland), and MRI (Austria). Cross beam calibration of the dosimeters and verification of a 3D dose distribution calculated with an Eclipse External Beam TPS and ArcCHECK®–3DVH® were performed. The 3D-to-3D comparisons of the VIC and VIC-T with TPS and ArcCHECK®–3DVH® along with ArcCHECK®–3DVH® versus TPS dose matrixes were performed with the aid of the polyGeVero® by analyzing dose profiles, isodoses lines, gamma index, gamma angle, dose difference, and related histograms. Results The measured MR-relaxation rate (R2 = 1/T2) for the dosimeters relates to the dose, as follows: R2 = 0.0928 ± 0.0008 [Gy−1 s−1] × D [Gy] + 2.985 ± 0.012 [s−1] (VIC) and 0.1839 ± 0.0044 [Gy−1 s−1] × D [Gy] + 2.519 ± 0.053 [s−1] (VIC-T). The 3D-to-3D comparisons revealed a good agreement between the measured and calculated 3D dose distributions. Conclusions VIC and VIC-T with 3T MRI readout and polyGeVero® showed potential for verifications of calculated irradiation plans. The results obtained suggest the implementation of the irradiation plan for eradication of the lung tumour.

This paper aims to explain the phenomenon of laser light trapping (LLT) in a 3D polymer gel dosimeter. A VIC-T polymer gel dosimeter containing 17% N-vinylpyrrolidone, 8% N,N′-methylenebisacrylamide, 12% tert-butyl alcohol, 5% gelatine, 0.02% hydroquinone and 14 mM tetrakis(hydroxymethyl)phosphonium chloride was used in this study. It was exposed to green laser light with a wavelength of 532 nm. A film was recorded during the exposure. After exposure, Raman spectroscopy was used to study the reactions taking place inside the dosimeter. The obtained results were used to explain what the LLT phenomenon is, what are the consequences for the dosimeter in which such a phenomenon occurs, and what dosimeter components play an important role in the occurrence of LLT. In addition, the conditions under which 3D polymer gel dosimeters can be measured using optical computed tomography at short wavelengths of visible laser light are indicated.

This work reports a modification of a fibrous cellulose material (paper) by the addition of polyacrylonitrile (PAN) fibres doped with 10,12–pentacosadiynoic acid (PDA). The fibres are sensitive to ultraviolet (UV) light. When the paper containing PAN–PDA is irradiated with UV light it changes colour to blue as a consequence of interaction of the light with PDA. The colour intensity is related to the absorbed dose, content of PAN–PDA fibres in the paper and the wavelength of UV radiation. The features of the paper are summarised after reflectance spectrophotometry and scanning microscopy analyses. All the properties of the modified paper were tested in accordance with adequate ISO standards. Moreover, a unique method for assessing the unevenness of the paper surface and the quality of printing was proposed by using a Python script (RGBreader) for the analysis of RGB colour channels. The modification applied to the paper can serve as a paper security system. The modified paper can act also as a UV radiation indicator.

This work reports on the surface-modified woven fabrics for use as UV radiation sensors. The cotton and polyamide fabrics were printed with radiochromic hydrogels using a screen-printing method. The hydrogels used as a printing paste were composed of water, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) as a gel matrix and nitro blue tetrazolium chloride as a radiation-sensitive compound. The development of the hydrogels’ colour occurs after exposure to UV radiation and its intensity increases with increasing absorbed dose. The features of the NBT-Pluronic F-127 radiochromic hydrogels and the fabrics printed with the hydrogels were examined using UV-Vis and reflectance spectrophotometry as well as scanning electron microscopy (SEM). The effects of NBT concentration and UV radiation type (UVA, UVB, UVC) on dose responses of the hydrogels and printed fabrics were also examined. The results obtained reveal that the fabrics printed with NBT-Pluronic F-127 hydrogels can be potentially useful as UV radiation sensors.

In this work we discuss UV and ionising radiation induced processes in the flat foils (films). The foils were made from poly(vinyl alcohol) (PVA) and either 10,12-pentacosadiynoic acid (PDA) or a representative of tetrazolium salts − 2,3,5-triphenyl tetrazolium chloride (TTC). Also, we proposed a very attractive modification of the surfaces of the foils by vapour deposition of parylene C. This lead to an alteration of the UV dose response of the foils and improved their water-resistance thus making them potentially useful for radiation dose measurements when immersed in water. The TTC- and PDA-containing foils were shown to respond to ionising radiation in a high dose range of up to 3 kGy. The PDA foils were of a higher dose sensitivity and much lower dose threshold than those containing TTC. Whereas the TTC-containing foils were of irreversible character, those containing PDA showed high reversibility both to UV and ionising radiation. Basic features of such reversible-foil dosimeters are presented. Additionally, the mechanism of radiation induced changes in the TTC- and PDA-PVA films is analysed by using UV–vis spectrophotometry and Raman spectroscopy techniques.

In this work, we present for the first time three-dimensional (3D) gel dosimeters for 3D UV dose distribution measurements. These new gel dosimeters are aqueous compositions containing 2,3,5-triphenyltetrazolium chloride or 4,4′-benzylidenebis(N,N-dimethylaniline) (leucomalachite green) and poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127), which form a physical gel matrix. The unique feature of these gels is their high transparency and colourlessness, comparable to crystal clear water. This differentiates them from 3D gel dosimeter compositions that are made of gelatine and used for radiotherapy dosimetry purposes only. If UV irradiated, the gels become coloured (red or green); the colour depends on the radiation sensitive compound in the composition. Both gels were examined versus UVA (range: 315–400 nm; a peak at 369 nm), UVB (range: 280–360 nm; a peak at 306 nm) and UVC (253.7 nm) irradiation. The typical parameters of such dosimeters were derived after obtaining their calibrations: linear dose range, dynamic dose range, dose threshold and dose sensitivity, as well as the UV subranges to which the gels were the most sensitive. The 2,3,5-triphenyltetrazolium chloride gels were the most sensitive to UVA radiation, whereas the leucomalachite green gels were sensitive to UVB. The highest dose sensitivity of the gels was obtained for 3 mmol/dm3 2,3,5-triphenyltetrazolium chloride and 7 mmol/dm3 leucomalachite green, which amounted to 3.60 ± 0.12 and 42.85 ± 1.53 cm2/J, respectively (the linear dose range was equal to 0.15–0.9 and 0–0.3 J/cm2; respectively, and the dynamic dose range was equal to 0–2 and 0–5 J/cm2, respectively). The 2,3,5-triphenyltetrazolium chloride gels were more sensitive to UVA but less sensitive to UVB and UVC than the leucomalachite green gels. Additionally, the gel dosimeters were examined with respect to their temporal stability, dose response for fractionated and non-fractionated doses as well as the repeatability and spatial stability of the dose distribution. The spatial stability results obtained suggested that 2,3,5-triphenyltetrazolium chloride gels keep the dose distribution integral for over 10 days after irradiation, contrary to the leucomalachite green gels that lose it soon after irradiation. However, this does not disqualify the leucomalachite green gels from use as 3D radiation dosimeters, on the condition that they are measured in 3D soon after irradiation. The proposed gel dosimeters can be used as UV dose sensors, 1D UV dosimeters or 3D high resolution dosimeters.

This work reports on the results obtained for VIC-T dosimeter for radiotherapy dosimetry (17 % (w/v) N-vinylpyrrolidone, 8 % (w/v) N,N′-methylenebisacrylamide, 12 % (w/v) tert-butyl alcohol, 5 % (w/v) gelatine, 0.02 % (w/v) hydroquinone and 14 mM tetrakis (hydroxymethyl) phosphonium chloride (THPC)) measured with a spiral computed tomography (CT). Optimal spiral CT protocol, CT measurements conditions and image processing are provided. Basic features of VIC-T are discussed such as a calibration relation and dose resolution with respect to former N-vinylpyrrolidone containing dosimeters. Both adopted data processing performed with a new polyGeVero®-CT software package and its features are reported.

This work reports on the first results obtained for a new 3D lung mimicking dosimeter. The dosimeter comprises 3% (w/w) acrylamide, 3% (w/w) N,N′-methylenebisacrylamide, 10 mM tetrakis (hydroxymethyl) phosphonium chloride (THPC), 25% (w/w) poly(ethylene oxide)-block-poly (propylene oxide)-block-poly (ethylene oxide) (Pluronic F-127) in presence or absence of sodium chloride. The approach to the manufacturing of the dosimeter both in the presence of air and argon relied on the preparation of a foam using the surface-active properties of Pluronic F-127. The resistance of Pluronic F-127 matrix to irradiation was analysed using differential scanning calorimetry; however, the foam dosimeter after irradiation was measured by using Raman spectroscopy, scanning electron and optical microscopy as well as computed tomography. Preliminary investigation revealed the following: (i) sodium chloride improves the thermal properties of the foam dosimeter in a low temperature region and impacts on the foam density, (ii) the dosimeter prepared in presence and absence of air responds to irradiation, however, its dose response is improved in absence of air, (iii) the preparation method applied allowed for decreasing the density of the dosimeter relative to solid gel dosimeter towards the density of lungs tissue and lungs in exhale. The results obtained pointed to a potential of this new dosimeter in 3D radiotherapy dosimetry related to eradication of lung tumours.

This work concerns a new potassium iodide based radiochromic gel dosimeter with Pluronic F-127 gel matrix. The optimal dosimeter composition obtained in this work comprises 200 mM potassium iodide as a radiation sensitive colour changing compound, 200 mM fructose, 50 mM gluconic acid δ-lactone and 25% (w/w) poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) as a physical gel matrix. The potassium iodide changes from colourless to yellow colour upon ionizing radiation and the intensity of colour increases with an increase of radiation dose. The dosimeter after irradiation was measured using UV-Vis spectrophotometry to derive basic characteristics related to dose response: threshold dose, linear and dynamic dose response, dose sensitivity as well as stability over time after irradiation. Water equivalence was also analysed with respect to other similar 3D radiochromic gel dosimeters for a broad photon energy range. The results obtained indicate that the KI-Pluronic F-127 radiochromic gel dosimeter shows potential for use in 3D radiotherapy dosimetry.

A new radiochromic dosimeter was examined with Raman spectroscopy and an optical approach for assessment of 3D dose distribution integrity. The acronym of the dosimeter is Fricke-XO-Pluronic F-127, where XO denotes xylenol orange; Pluronic F-127 is a copolymer matrix of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide), and the dosimeter contains the components of a Fricke dosimetric solution. Two dosimeter samples in cuvettes were partially irradiated such that a radiation dose was absorbed at the bottom of the cuvettes. After irradiation, one sample was stored upside down such that the irradiated part was at the top and another one was stored with the irradiated part at the bottom. Two diffusion coefficients of ferric ion complexes with XO ([XO-Fe]+3) were calculated. They were compared with those for similar dosimeter, however with gelatine matrix instead of Pluronic F-127. The results obtained indicate an impact of the gravitational force on the diffusion of [XO-Fe]+3ions over time after irradiation and thus a possibility of severely undermining the integrity of a dose distribution in irradiated dosimeter. The conclusions drawn suggest the necessity of examination of different 3D Fricke dosimeter compositions for anisotropic diffusion of ferric ions.

This work reports the first results obtained using a new 3D radiochromic gel dosimeter. The dosimeter is an aqueous physical gel matrix made of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127, PEO-PPO-PEO) doped with a representative of tetrazolium salts, 2, 3, 5-triphenyltetrazolium chloride (TTC). There were several reasons for the choice of Pluronic as a gel forming substrate: (i) the high degree of transparency and colourlessness; (ii) the possibility of gel dosimeter preparation at both high and low temperatures due to the phase behaviour of Pluronic; (iii) the broad temperature range over which the TTC-Pluronic dosimeter is stable; and (iv) the non-toxicity of Pluronic. A reason for the choice of TTC was its ionising radiation-induced transformation to water-insoluble formazan, which was assumed to impact beneficially on the spatial stability of the dose distribution. If irradiated, the TTC-Pluronic gels become red but transparent in the irradiated part, while the non-irradiated part remains crystal clear. The best obtained composition is characterised by 500 Gy and a dynamic dose response much greater than 500 Gy (7.5% TTC, 25% Pluronic F-127, 50 mmol dm-3 tetrakis). Temporal and spatial stability studies revealed that the TTC-Pluronic gels (7.5% TTC, 25% Pluronic F-127) were stable for more than one week. The addition of compounds boosting the gels' dose performance caused deterioration of the gels' temporal stability but did not impact the stability of the 3D dose distribution. The proposed method of preparation allows for the repeatable manufacture of the gels. There were no differences observed between gels irradiated fractionally and non-fractionally. The TTC-Pluronic dose response might be affected by the radiation source dose rate-this, however, requires further examination.

This work presents an improvement of the VIPARnd ('nd' stands for 'normoxic, double', or VIP) polymer gel dosimeter. The gel composition was altered by increasing the concentration of the monomeric components, N-vinylpyrrolidone (NVP) and N,N'-methylenebisacrylamide (MBA), in co-solvent solutions. The optimal composition (VIPARCT, where 'CT' stands for computed tomography, or VIC) comprised: 17% NVP, 8% MBA, 12% t-BuOH, 7.5% gelatine, 0.007% ascorbic acid, 0.0008% CuSO4 × 5H2O and 0.02% hydroquinone. The following characteristics of VIC were achieved: (i) linear dose range of 0.9_30 Gy, (ii) saturation for radiation doses of over 50 Gy, (iii) threshold dose of about 0.5 Gy, (iv) dose sensitivity of 0.171 Gy-1 s-1, which is roughly 2.2 times higher than that of VIP (for nuclear magnetic resonance measurements). It was also found that VIC is dose- rate-independent, and its dose response does not alter if the radiation source is changed from electrons to photons for external beam radiotherapy. The gel responded similarly to irradiation with small changes in radiation energy but was sensitive to larger energy changes. The VIC gel retained temporal stability from 20 h until at least 10 d after irradiation, whereas spatial stability was retained from 20 h until at least 6 d after irradiation. The scheme adopted for VIC manufacturing yields repeatable gels in terms of radiation dose response. The VIC was also shown to perform better than VIP using x-ray computed tomography as a readout method; the dose sensitivity of VIC (0.397 HU Gy-1) was 1.5 times higher than that of VIP. Also, the dose resolution of VIC was better than that of VIP in the whole dose range examined.

This work reports on a radiochromic dosimeter for dose distribution measurement after irradiation with UV light. The dosimeter is composed of a 25 % copolymer of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) that forms a physical gel matrix. The matrix is infused with leuco crystal violet (LCV, 2 mM), 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X-100, 4 mM) and trichloroacetic acid (TCAA, 17 mM). This dosimeter was exposed to UVA, UVB and UVC radiation and the radiochromic reactions were followed with reflectance spectrophotometry and Raman spectroscopy. Exposition of the dosimeter to all UV light subranges caused LCV to convert to CV molecules absorbing visible light and affecting the dosimeter that changes colour to blue. The intensity of colour was related to absorbed UV dose. The dosimeter is the least sensitive to irradiation with UVA and the most sensitive to irradiation with UVB. The main dose-response characteristics of the dosimeter were obtained: threshold dose, linear and dynamic dose range, dose sensitivity as well as the stability over time after irradiation and stability of recorded dose distribution. Overall, the dosimeter coupled with reflectance spectrophotometry is effective in measuring doses in 1D, whereas using 3D optical scanning techniques should expand its application to 3D dosimetry. This work also provides an approach to using the LCV-Pluronic F-127 dosimeter for measurements of 2D dose distribution with a flat-bed optical scanner as a readout method. LCV-Pluronic F-127 may also be useful for solar radiation measurements.

This work reports on the characteristic of a 3D polymer gel dosimeter with poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) gel matrix. The dosimeter (acronym: VIP3-Pluronic F-127) comprises 4% (w/w) N-vinylpyrrolidone (NVP), 4% (w/w) N,N′-methylenebisacrylamide (MBA), 4% (w/w) tert-butanol, 10 mM tetrakis (hydroxymethyl)phosphonium chloride (THPC) and 25% (w/w) Pluronic F-127. A medical ionizing radiation source was used for irradiation of VIP3-Pluronic F-127 and the dosimeter was measured with a nuclear magnetic resonance (NMR, 0.47 T) relaxometer. The mean dose sensitivity of VIP3-Pluronic F-127 amounted to 0.1873 ± 0.0091 Gy−1 s−1, the intercept was equal to 1.3614 ± 0.0511 s−1, the linear dose response was in the range of 1–20 Gy, the dynamic dose range was of 1–50 Gy and the threshold dose was of ~1 Gy. The manufacturing process of VIP3-Pluronic F-127 was repeatable and the dosimeter was stable for at least 8 days after irradiation (no measurements for longer period were performed). It was also found that the dose response of VIP3-Pluronic F-127 is independent of the radiation dose rate and energy, and type of radiation (photons and electrons). The results obtained indicate that VIP3-Pluronic F-127 is promising as a polymer gel dosimeter for use in radiotherapy dosimetry.

The subject of this work are microfibres that are made of polyacrylonitrile (PAN) doped with nano-particles of 10,12-pentacosadiynoic acid (PDA) with a mean hydrodynamic diameter of ca. 22 nm, as measured by dynamic light scattering (DLS). Two kinds of microfibres were obtained from a DMF solution (multifilaments – a bunch of 250 microfibres): glossy (diameter: ~ 11–15 µm) and lustreless (diameter: ~ 27–31 µm). The fibres responded to ionising radiation by colour changing from white to dark blue or dark blue-brown thanks to the PDA nanoparticles; the colour intensity was related to the absorbed dose of radiation. The chemical changes inside the fibres were followed with the aid of Raman spectroscopy. Reflectance spectrophotometry was chosen for characterisation of the fibres by reflectance [%] versus absorbed dose [Gy] relations, which revealed that the lustreless fibres were more susceptible to irradiation. The fibres responded to high-dose ranges and were saturated at about 8 and 15 kGy, for lustreless and glossy fibres, respectively. The fibres were very stable; they did not change their colour after irradiation within at least 30 days. The dose response of the fibres was independent of the dose rate and the way the dose was delivered: in fractions or non-fractioned. The PAN-PDA fibres were used for flat woven textile preparation to serve as 2D radiation dosimeter. An approach to 2D dose distribution analysis using the PAN-PDA textile samples is presented.

Sophisticated techniques employed in radiotherapy for irradiation of tumours require comprehensive dosimetry allowing for precise, high resolution measurements of radiation dose distribution in three dimensions and verification of treatment planning systems. Polymer gel dosimetry has been shown to be a unique technique for three-dimensional high resolution measurements of absorbed radiation dose distributions. If exposed to ionizing radiation, radical polymerisation and crosslinking of monomeric components take place in a 3D polymer gel dosimeter, leading to the formation of large polymeric structures that scatter visible light. This feature allows for optical observation of the effects of the absorbed dose and its distribution. Presently, magnetic resonance imaging is employed the most often for analysis of 3D polymer gel dosimeters. However, much attention is also being given to the development of optical computed tomography since this technique is hoped to serve as a substitute for expensive and not easily available magnetic resonance imaging. The optical scanner presented in this work consists of a laser diode, a scanning system and a signal detector. A 3D polymer gel dosimeter is measured in an immersion liquid in order to reduce deflection of the light from the dosimeter phantom. The very first results were obtained with the newly constructed scanner for PABIGnx 3D polymer gel dosimeter, which was inhomogeneously irradiated with 192Ir brachytherapy source. The results have been contrasted with those for magnetic resonance imaging and are presented in this work together with the description of the optical scanner. Currently, optimization of the optical scanner is performed.

This work discusses the substitution of a gelatine physical gel matrix with a matrix made of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) in five 3D radiotherapy polymer gel dosimeters: MAGAT, PAGAT, NIPAM, VIPARnd (VIP) and VIPARCT (VIC). The current research outcomes showed that not each polymer gel dosimeter could be manufactured with Pluronic F-127. Two of the polymer gel dosimeters (PAGAT and VIP) containing the Pluronic F-127 matrix allowed for some proper dose response for radiotherapy dosimetry (a response to a dose range of e.g. 0‒50 Gy). The new best performing Pluronic-based polymer gel dosimeters were characterised by improved nuclear magnetic resonance properties, when being compared to gels with gelatine matrix at the same monomer content. These are: (i) a ~33% higher dose sensitivity; (ii) a comparable or slightly higher linear and dynamic dose range and (iii) a lower (new VIP composition, VIP3) or equivocal (new PAGAT composition, PAGAT2-Pluronic) dose threshold. However, there might be optimised gelatine based polymer dosimeters demonstrating even better sensitivity. UV-vis spectrophotometry measurements revealed that Pluronic matrices ensure six-times lower (VIP3-Pluronic) and eight-times lower (PAGAT2-Pluronic) absorbance (at 400 nm) of non-irradiated gels compared to gelatine matrices, which makes the new polymer gel dosimeters optically improved in comparison to their corresponding gelatine-based compositions. The differences in absorption reduce for higher wavelengths. Differential scanning calorimetry measurements revealed the following temperature stability ranges for the gels: (i) VIP with gelatine matrix: 0 °C‒26 °C, (ii) VIP3 with Pluronic matrix: 13.8 °C-55.2 °C, (iii) PAGAT2 with gelatine matrix: 0 °C-80 °C and (iv) PAGAT2 with Pluronic matrix: 21.4 °C-55.2 °C. In conclusion, Pluronic F-127 is an attractive co-polymer to serve as a substitute for the gelatine matrix in some 3D polymer gel dosimeters.

This work is a follow-up study for a recently-proposed 3D radiochromic gel dosimeter that contains a tetrazolium salt and a physical gel matrix made of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127). Several tetrazolium salts were examined in this work, including tetrazolium violet, blue tetrazolium chloride, nitro blue tetrazolium chloride (NBT), tetranitro blue tetrazolium chloride (tNBT) and thiazolyl blue tetrazolium bromide (TBTB). The salt-containing gel dosimeters were compared with the first Pluronic gel composition that contained 2,3,5-triphenyltetrazolium chloride (TTC) as the radiation-sensitive component (dose sensitivity of 0.0023 (Gy cm)−1). The Pluronic gels with NBT and tNBT outperformed the other gels, including the TTC-containing gel, with respect to their dose sensitivity and low dose-response. The NBT gels were found to have better stability over time than tNBT gels. Sensitization of the gels to ionizing radiation was examined by addition of tert-butyl alcohol and sodium formate. The best composition was 0.0818% NBT (1 mM), 25% Pluronic F-127 and 0.136 × 10−2% sodium formate. This gel dosimeter was insensitive to changes in dose rate for photons of different energies. The mean dose sensitivity amounted to 0.0047 ± 0.1 × 10−4 (Gy cm)−1. A diversion in the dose-response was observed for the gel irradiated with electrons. Additional characteristics of the NBT gel were a linear-dose range and a dynamic-dose range between

In this work a method of preparing UV-sensitive fibres is presented. The fibres are made of polyacrylonitrile by wet spinning and 2,3,5-triphenyltetrazolium chloride (TTC), 4,4′,4″-tri-di-β-hydroxyethyloaminotriphenyloacetonitrile (HHEVC) and 10,12-pentacosadiyonic acid (PENTA) are used as dopants. Preparing the fibres is a two-step process, allowing for the preparation of two kinds of fibres with different characteristics: glossy and lustreless. When the fibres are UV irradiated they change colour, to yellow for TTC and blue for HHEVC. Those with the PENTA dopant undergo a complex colour change since at lower doses blue colour formation is initiated but at higher absorbed doses a red colour appears that finally leads to a brown colour in the fibres. The colour formation and its intensity are related to the absorbed dose and the wavelength of UV radiation. The fibres possess different morphologies and mechanical properties that depend on the preparation method. XRD analysis revealed a distinct difference between the glossy and lustreless fibres in that the former are of higher crystallinity that translates into better mechanical properties of the fibres. The impact of the dopants on the crystallinity and mechanical properties of the fibres is also discussed. One possible application of the fibres is for UV absorbed dose detection. Nevertheless, they were designed to serve as elementary units to be further manufactured into a flat textile as a 2D radiation dosimeter.

In this work, a reactive inkjet printing (RIP) has been proposed as an useful method for the deposition of reduced graphene oxide (RGO) layers on different textile fabrics - polyacrylonitrile, poly(ethylene terephthalate), and polypropylene. Under the RIP process, the RGO layers were grown on fabrics by printing of graphene oxide (GO) suspension and simultaneously reduced by L-ascorbic acid. This strategy is a simple and one step process to grow conductive layers of RGO on textile substrates at large scale without any post treatment and does not require any corrosive reagent during the process. Thus, obtained binder-free RGO on textile fabrics can be readily used directly as an electrode material. The applicability of the selected textile fabrics modified by RIP deposition of RGO for energy storage application was tested. For this, a flexible all-solid-state supercapacitor was constructed using two RGO coated textile fabrics as electrodes separated by gel electrolyte (poly(vinyl alcohol)/H3PO4 electrolyte). The as-obtained supercapacitor exhibited an area specific capacitance of 13.3 m F/cm2 (79.9 F/g) at a current density of 0.1 mA/cm2, and delivered an energy density of 1.18 mW h/cm2 and the power density of 4.6 mW/cm2.

This work reports results related to the manufacturing and optimisation of a leuco crystal violet (LCV)-Pluronic F-127 radiochromic gel dosimeter suitable for 3D radiotherapy dosimetry. A feature of this gel is that the natural gelatine polymer, which is most often used as a matrix in 3D dosimeters, is substituted with Pluronic F-127 synthetic copolymer (poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide). Pluronic F-127 ensures a higher transparency than gelatine, which may be beneficial for optical computed tomography readout, and improves the thermal properties in the temperature range above ~30 °C at which the gelatine physical gel converts to a solution. The optimal composition obtained comprises 2 mM LCV, 4 mM 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X-100), 17 mM trichloroacetic acid (TCAA) and 25% Pluronic F-127. Its main dose-response features are 4‒150 Gy linear dose range (150 Gy was the maximal dose applied to gels in this work), 0.0070 Gy-1 cm-1 dose sensitivity (derived from absorbance (600 nm) = f (dose) for 6 MeV electrons, 0.88(3) Gy s-1 and 0.0156 Gy-1 cm-1 derived from optical density (Δµ) = f (dose) for 6 MV x-rays, 0.1010 Gy s-1), low initial colour (initial absorbance = 0.0429) and a diffusion coefficient of crystal violet (CV) in LCV-Pluronic of 0.054 ± 0.023 mm2 h-1. Raman spectroscopy was used to characterize LCV-Pluronic chemical changes after irradiation. Differential scanning calorimetry (DSC) revealed that LCV-Pluronic is stable in temperatures between approximately 11 °C and 56 °C. Irradiation of LCV-Pluronic gel impacts on its first sol-gel transition temperature and the thermal effect of this process-both increased with absorbed dose, which might be related to the degradation of Pluronic. LCV-Pluronic is a promising 3D dosimeter for ionising radiation applications. Further work is needed to improve LCV-Pluronic response in the low dose region, and characterize potential effects of pH, temperature during irradiation, and radiation quality/dose rate on dose response characteristics.

A co-polymer of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127, PEO-PPO-PEO) was proposed as a physical gel matrix, substituting gelatine for three-dimensional polymer gel dosimeters and as a matrix for the preparation of new radiochromic gel dosimeters. Two polymer gel dosimeters and seven radiochromic gel dosimeters were obtained with this new matrix. In this review we summarise the main advantages of using Pluronic F-127 for manufacturing radiation dosimeters and the best performing new Pluronic dosimeters.

NVP-containing three-dimensional polymer gel dosimeters for radiotherapy dosimetry have been developed for more than 20 years. There have been 11 main modifications of the originally proposed VIPAR polymer gel dosimeter that altogether have amounted to 12 gel dosimeter formulae. This communication is to summarise the main chemical changes made to the VIPAR dosimeter over these years of research. The newest NVP-polymer gel dosimeters are also introduced.

This work reports on the impact of tetrakis(hydroxymethyl)phosphonium chloride (THPC) on the properties of a VIC gel dosimeter (VIC is an abbreviated acronym of VIPARCT). THPC was used as a substitute oxygen scavenger in VIC (17% N-vinylpyrrolidone, 8% N,N'-methylenebisacrylamide, 12% tert-butyl alcohol, 7.5% gelatine, 0.02% hydroquinone and an oxygen scavenger of 0.007% ascorbic acid and 0.0008% CuSO4 × 5H2O). THPC reduced the gelation time of VIC from hours to minutes. The best composition (VIC-T) contained 14 mM THPC and a reduced gelatine concentration (5%) with respect to VIC, which allowed for gelation in about 3 min. VIC-T was characterised by the same dose sensitivity (0.176 ± 0.003 Gy-1 s-1 for VIC-T and 0.171 ± 0.002 Gy-1 s-1 for VIC), dose threshold (0.5 Gy) and dynamic dose range (0.5‒50 Gy) as VIC, and a lower linear dose range (20 Gy for VIC-T, 30 Gy for VIC) (0.47 T NMR measurements). VIC-T was stable for at least 10 days after irradiation, and 3D dose distribution was stable for over 4 months after irradiation. The dose response of VIC-T was independent of the radiation dose rate, type and energy of radiation for 6 and 15 MV photons and 12 MeV electrons. This is an improvement with respect to VIC which showed a different dose response for 6 MV photons than for 12 MeV electrons and 15 MV photons. Raman spectroscopy showed similarity in the rate of radiation-induced conversion of monomers in VIC and VIC-T, indicating interaction of THPC with gelatine in VIC-T, and showed ageing of gelatine in both dosimeters. Differential scanning calorimetry showed VIC-T stability at 0 °C-80 °C (VIC: 0 °C‒29.5 °C). The chemical polymerisation and crosslinking of gelatine with THPC is reported, the mechanism of which was analysed in detail. A comparison of N-vinylpyrrolidone-containing dosimeters is presented in this work.