Novel study of using chitosan in gamma dose monitoring applications

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohamad Bekhit ◽  
Essam Fahim ◽  
Asmaa Sobhy
Keyword(s):  
Color Change ◽  
Dose Range ◽  
Chitosan Film ◽  
Gamma Dose ◽  
High Dose ◽  
Ftir Analysis ◽  
Content Type ◽  
Pale Yellow ◽  
Dose Monitoring ◽  
Absorbed Doses

Purpose The purpose of this paper is to fall light on the possibility of using the biopolymer chitosan in gamma dose monitoring. Design/methodology/approach The chitosan films were irradiated to gamma rays in the range starting from 10 to 120 kGy at a dose rate of 1.4 kGy/h using 60Co gamma source. The ultra violet and visible (UV/Vis) spectrophotometry were used to examine the optical properties of chitosan film. Also, Fourier transform infrared (FTIR) analysis was used to detect and trace any change in structural bands that may take place upon irradiation. Findings Increase in optical density of the chitosan film was recorded at 298 nm that correlated with increasing in the absorbed doses. Change in color of the film from pale yellow to denser yellow was detected upon increasing the absorbed doses. The close investigation for UV/Vis and FTIR analysis nominates the chitosan film to be used as a label-dosimeter in the range of 10–120 kGy depending on chitosan concentrations. The chitosan film has an excellent stability in different environmental conditions with ±3.7% uncertainty in measurements (2σ, approximately equal to a 95% confidence level). Research limitations/implications Chitosan film may be used as a medium and high-dose monitor with an acceptable overall uncertainty in routine radiation processing Originality/value The useful dose range from 10 to 80 kGy was detected for different concentrations of chitosan (0.5, 1, 1.5 Wt%) that correlated with increasing the absorbed dose, which is assigned to the linear parts in the target response curves. For the dose range 10–120 kGy, the film may be used as label dosimeter with detected color change from pale yellow to dense yellow.

scholarly journals Dose–Response of TLD-100 in the Dose Range Useful for Hypofractionated Radiotherapy

Dose-Response ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 155932581989408 ◽  
Author(s):  
Raffaele Liuzzi ◽  
Consiglia Piccolo ◽  
Vittoria D’Avino ◽  
Stefania Clemente ◽  
Caterina Oliviero ◽  
...  
Keyword(s):  
Dose Response ◽  
Radiation Treatment ◽  
Dose Range ◽  
Information Criterion ◽  
High Dose ◽  
Thermoluminescent Dosimeters ◽  
Dose Monitoring ◽  
Coefficients Of Variation ◽  
Best Fitting ◽  
Quadratic Models

Purpose: The aim of the study was to exploit the feasibility of thermoluminescent dosimeters (TLDs) in radiation therapy techniques in which high dose per fraction is involved. Methods: Dose–response of TLD-100 (LiF: Mg, Ti) was investigated in both 6-MV photon and 6-MeV electron beams. The element correction factor (ECF) generation method was applied to check the variability of the TLDs response. Two batches of 50 TLDs were divided into groups and exposed in the dose range 0 to 30 Gy. Regression analysis was performed with both linear and quadratic models. For each irradiation beam, the calibration curves were obtained in 3 dose range 0 to 8 Gy, 0 to 10 Gy, and 0 to 30 Gy. The best-fitting model was assessed by the Akaike Information Criterion test. Results: The ECF process resulted a useful tool to reduce the coefficients of variation from original values higher than 5% to about 3.5%, for all the batches exposed. The results confirm the linearity of dose–response curve below the dose level of 10 Gy for photon and electron beam and the supralinear trend above. Conclusion: The TLDs are suitable dosimeters for dose monitoring and verification in radiation treatment involving dose up to 30 Gy in a single fraction.

Dosimetric evaluation of methyl red radiochromic film for radiation processing

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Awad AL Zahrany ◽  
Khalid Rabaeh ◽  
Molham Eyadeh ◽  
Ahmed Basfar
Keyword(s):  
Gamma Ray ◽  
Dose Range ◽  
Absorbed Dose ◽  
Radiochromic Film ◽  
High Dose ◽  
Methyl Red ◽  
Radiation Processing ◽  
Content Type ◽  
The Stability ◽  
The Impact

Purpose The purpose of this paper is to present a radiochromic film dosimeter containing polyvinyl alcohol (PVA) matrix and various concentrations of methyl red (MR) dye for high dose measurements. Design/methodology/approach The MR-PVA films were exposed to irradiation up to 60 kGy using 60Co source of gamma ray. The ultraviolet and visible regions (UV/VIS) spectrophotometry were used to examine the optical density of pre-and post-irradiated dosimeters at 424 nm. Findings The dose sensitivity of MR-PVA films increases significantly with increasing MR dye concentrations in the dose range of 5 to 60 kGy. The impact of relative humidity, irradiation temperature, dose rate and the stability of the films has been analyzed. The overall uncertainty of the MR-PVA film dosimeter is 6.12% (Double Standard-deviation, 95% confidence level). Practical implications It was found that the MR-PVA films may be used as high dose dosimeter with an acceptable overall uncertainty in routine industrial radiation processing. Originality/value The color bleaching of irradiated MR-PVA films in terms of specific absorbance curves increases significantly with increasing absorbed dose up to 60 kGy.

scholarly journals Clozapine antipsychotic polypharmacy: audit of use and patient monitoring

2013 ◽  
Vol 37 (10) ◽  
pp. 322-325 ◽  
Author(s):  
Sam Wilson ◽  
Ross Hamilton ◽  
John Callender ◽  
Angela MacManus ◽  
Sheila Howitt ◽  
...  
Keyword(s):  
Antipsychotic Medication ◽  
Patient Monitoring ◽  
Dose Range ◽  
Clinical Implications ◽  
High Dose ◽  
Antipsychotic Medications ◽  
Dose Monitoring ◽  
Wide Range

Aims and methodWe audited prescribing within our area to ascertain how widespread the practice of antipsychotic polypharmacy using clozapine was, and whether it was being carried out within existing standards, including those of high-dose monitoring when required.ResultsData on 169 patients were reviewed in year one, rising to 193 in year three. Around 30% of patients on clozapine received additional antipsychotic medication. A disturbingly low proportion of patients on clozapine whose antipsychotic polypharmacy brought them into the high-dose range were being monitored appropriately after three audit cycles (the proportion rose from 10% in cycle 1 to 28% in cycle 3). A wide range of additional antipsychotic medications was used.Clinical implicationsClozapine antipsychotic polypharmacy was prevalent at just below a third of all patients in this review. Prescribers should be alert to the fact that clozapine antipsychotic polypharmacy can push patients into the high-dose range and ensure appropriate monitoring.

High-dose glucocorticoid treatment improves neurological recovery in head-injured mice

1985 ◽  
Vol 62 (6) ◽  
pp. 882-887 ◽  
Author(s):  
Edward D. Hall
Keyword(s):  
Head Injury ◽  
Sodium Succinate ◽  
Dose Range ◽  
Neurological Status ◽  
Neurological Recovery ◽  
High Dose ◽  
Glucocorticoid Treatment ◽  
Content Type ◽  
Head Injured ◽  
Righting Reflex

✓ The ability of a single large intravenous dose of the sodium succinate esters of the glucocorticoids methylprednisolone, prednisolone, or hydrocortisone to enhance early neurological recovery after moderate to severe blunt head injury was examined in male CF-1 mice. Unanesthetized mice were restrained and subjected to a 900 gm-cm head injury produced by a 50-gm weight dropped 18 cm. This injury resulted in immediate loss of consciousness (loss of the righting reflex) in all animals, and death in approximately 30%. Survivors received a 0.1-ml tail vein injection of either vehicle or 15, 30, 60, or 120 mg/kg of methylprednisolone, prednisolone, or hydrocortisone within 5 minutes. Their neurological status was evaluated at 1 hour after injury. A 30-mg/kg dose of methylprednisolone was found to improve recovery significantly in comparison to that seen in vehicle–treated mice. A 15-mg/kg dose was less effective, and a 60- or 120-mg/kg dose was essentially ineffective. Prednisolone was also observed to improve neurological scores at 1 hour postinjury. A 60-mg/kg dose of prednisolone was optimal, while lower and higher doses had no effect. Hydrocortisone was unable to improve recovery over the wide dose range tested. The implications of these findings for the clinical management of head injury with glucocorticoid steroids are discussed.

scholarly journals Thermoluminescence Properties of Bioglass for Radiation Dosimetry

2021 ◽  
Author(s):  
Huda A. Alazab ◽  
N.Y. Abdou ◽  
H. A. Saudi ◽  
wesam Abd-Allah
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Radiation Dosimetry ◽  
Dose Range ◽  
Glow Peak ◽  
Gamma Dose ◽  
High Dose ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Gamma

Abstract The thermoluminescence technique was employed to study bioglass matrices prepared using the traditional technique of glass making. The synthesized bioglass matrices were investigated using X-ray diffraction (XRD), and differential thermal analysis (DTA) has been studied. The highest thermoluminescent intensity was found for the bioglass matric of 26.91% CaO, 46.134% SiO2, 2.60% P2O5, 24.34%Na2O (mol%), with only one glow peak at 460 k. The TL response illustrations linearity in high gamma dose range from 25 to 1000 Gy. This new bioglass matric might become useful in high-dose fields for dosimetry.

Dual-isotope single-photon emission computerized tomography scanning in patients with glioblastoma multiforme: association with patient survival and histopathological characteristics of tumor after high-dose radiotherapy

1998 ◽  
Vol 89 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Richard B. Schwartz ◽  
B. Leonard Holman ◽  
Joseph F. Polak ◽  
Basem M. Garada ◽  
Marc S. Schwartz ◽  
...  
Keyword(s):  
Survival Rate ◽  
Glioblastoma Multiforme ◽  
Single Photon ◽  
Photon Emission ◽  
High Dose ◽  
Term Survival ◽  
Content Type ◽  
Dual Isotope ◽  
Fine Print

Object. The study was conducted to determine the association between dual-isotope single-photon emission computerized tomography (SPECT) scanning and histopathological findings of tumor recurrence and survival in patients treated with high-dose radiotherapy for glioblastoma multiforme. Methods. Studies in which SPECT with 201Tl and 99mTc-hexamethypropyleneamine oxime (HMPAO) were used were performed 1 day before reoperation in 47 patients with glioblastoma multiforme who had previously been treated by surgery and high-dose radiotherapy. Maximum uptake of 201Tl in the lesion was expressed as a ratio to that in the contralateral scalp, and uptake of 99mTc-HMPAO was expressed as a ratio to that in the cerebellar cortex. Patients were stratified into groups based on the maximum radioisotope uptake values in their tumor beds. The significance of differences in patient gender, histological characteristics of tissue at reoperation, and SPECT uptake group with respect to 1-year survival was elucidated by using the chi-square statistic. Comparisons of patient ages and time to tumor recurrence as functions of 1-year survival were made using the t-test. Survival data at 1 year were presented according to the Kaplan—Meier method, and the significance of potential differences was evaluated using the log-rank method. The effects of different variables (tumor type, time to recurrence, and SPECT grouping) on long-term survival were evaluated using Cox proportional models that controlled for age and gender. All patients in Group I (201Tl ratio < 2 and 99mTc-HMPAO ratio < 0.5) showed radiation changes in their biopsy specimens: they had an 83.3% 1-year survival rate. Group II patients (201T1 ratio < 2 and 99mTc-HMPAO ratio of ≥ 0.5 or 201Tl ratio between 2 and 3.5 regardless of 99mTc-HMPAO ratio) had predominantly infiltrating tumor (66.6%); they had a 29.2% 1-year survival rate. Almost all of the patients in Group III (201Tl ratio > 3.5 and 99mTc-HMPAO ratio ≥ 0.5) had solid tumor (88.2%) and they had a 6.7% 1-year survival rate. Histological data were associated with 1-year survival (p < 0.01); however, SPECT grouping was more closely associated with 1-year survival (p < 0.001) and was the only variable significantly associated with long-term survival (p < 0.005). Conclusions. Dual-isotope SPECT data correlate with histopathological findings made at reoperation and with survival in patients with malignant gliomas after surgical and high-dose radiation therapy.

Gamma knife radiosurgery in patients with advanced breast cancer undergoing bone marrow transplant

2002 ◽  
Vol 97 ◽  
pp. 663-665 ◽  
Author(s):  
Kenneth J. Levin ◽  
Emad F. Youssef ◽  
Andrew E. Sloan ◽  
Rajiv Patel ◽  
Rana K. Zabad ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Advanced Breast Cancer ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
High Dose Chemotherapy ◽  
Advanced Breast ◽  
High Dose ◽  
Initial Management ◽  
Content Type ◽  
Fine Print

Object. Recent studies have suggested a high incidence of cognitive deficits in patients undergoing high-dose chemotherapy, which appears to be dose related. Whole-brain radiotherapy (WBRT) has previously been associated with cognitive impairment. The authors attempted to use gamma knife radiosurgery (GKS) to delay or avoid WBRT in patients with advanced breast cancer treated with high-dose chemotherapy and autologous bone marrow transplantation (HDC/ABMT) in whom brain metastases were diagnosed. Methods. A retrospective review of our experience from 1996 to 2001 was performed to identify patients who underwent HDC/ABMT for advanced breast cancer and brain metastasis. They were able to conduct GKS as initial management to avoid or delay WBRT in 12 patients following HDC/ABMT. All patients were women. The median age was 48 years (range 30–58 years). The Karnofsky Performance Scale score was 70 (range 60–90). All lesions were treated with a median prescription dose of 17 Gy (range 15–18 Gy) prescribed to the 50% isodose. Median survival was 11.5 months. Five patients (42%) had no evidence of central nervous system disease progression and no further treatment was given. Four patients were retreated with GKS and three of them eventually received WBRT as well. Two patients were treated with WBRT as the primary salvage therapy. The median time to retreatment with WBRT was 8 months after the initial GKS. Conclusions. Gamma knife radiosurgery can be effectively used for the initial management of brain metastases to avoid or delay WBRT in patients treated previously with HDC, with acceptable survival and preserved cognitive function.

scholarly journals In VitroAnalyses of the Effects of Heparin and Parabens on Candida albicans Biofilms and Planktonic Cells

2011 ◽  
Vol 56 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Marisa H. Miceli ◽  
Stella M. Bernardo ◽  
T. S. Neil Ku ◽  
Carla Walraven ◽  
Samuel A. Lee
Keyword(s):  
Candida Albicans ◽  
Metabolic Activity ◽  
Biofilm Formation ◽  
High Dose ◽  
Dependent Manner ◽  
Planktonic Cells ◽  
Content Type ◽  
Heparin Sodium ◽  
The Individual

ABSTRACTInfections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin onCandida albicansbiofilms and planktonic cells have not been previously studied. Therefore, we sought to determine thein vitroeffect of a heparin sodium preparation (HP) on biofilms and planktonic cells ofC. albicans. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformedC. albicansbiofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (P< 0.0001). Pure-H, MP, and PP each inhibitedC. albicansbiofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H havein vitroantifungal activity againstC. albicansmature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention ofC. albicansbiofilms is warranted.

scholarly journals Skin regeneration is accelerated by a lower dose of multipotent mesenchymal stromal/stem cells—a paradigm change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gertraud Eylert ◽  
Reinhard Dolp ◽  
Alexandra Parousis ◽  
Richard Cheng ◽  
Christopher Auger ◽  
...  
Keyword(s):  
Stem Cells ◽  
Wound Healing ◽  
Low Dose ◽  
Dose Range ◽  
High Dose ◽  
Full Thickness ◽  
Burn Wound ◽  
Dermal Regeneration Template ◽  
Yorkshire Pigs ◽  
Stromal Stem Cells

Abstract Background Multipotent mesenchymal stromal/stem cell (MSC) therapy is under investigation in promising (pre-)clinical trials for wound healing, which is crucial for survival; however, the optimal cell dosage remains unknown. The aim was to investigate the efficacy of different low-to-high MSC dosages incorporated in a biodegradable collagen-based dermal regeneration template (DRT) Integra®. Methods We conducted a porcine study (N = 8 Yorkshire pigs) and seeded between 200 and 2,000,000 cells/cm2 of umbilical cord mesenchymal stromal/stem cells on the DRT and grafted it onto full-thickness burn excised wounds. On day 28, comparisons were made between the different low-to-high cell dose groups, the acellular control, a burn wound, and healthy skin. Result We found that the low dose range between 200 and 40,000 cells/cm2 regenerates the full-thickness burn excised wounds most efficaciously, followed by the middle dose range of 200,000–400,000 cells/cm2 and a high dose of 2,000,000 cells/cm2. The low dose of 40,000 cells/cm2 accelerated reepithelialization, reduced scarring, regenerated epidermal thickness superiorly, enhanced neovascularization, reduced fibrosis, and reduced type 1 and type 2 macrophages compared to other cell dosages and the acellular control. Conclusion This regenerative cell therapy study using MSCs shows efficacy toward a low dose, which changes the paradigm that more cells lead to better wound healing outcome.

scholarly journals Characterization of Food Packaging Films with Blackcurrant Fruit Waste as a Source of Antioxidant and Color Sensing Intelligent Material

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2569
Author(s):  
Mia Kurek ◽  
Nasreddine Benbettaieb ◽  
Mario Ščetar ◽  
Eliot Chaudy ◽  
Maja Repajić ◽  
...  
Keyword(s):  
Food Packaging ◽  
Water Solubility ◽  
Color Change ◽  
Chitosan Film ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Color Changes ◽  
Insoluble Particles ◽  
Polymer Stability ◽  
Food Packaging Films

Chitosan and pectin films were enriched with blackcurrant pomace powder (10 and 20% (w/w)), as bio-based material, to minimize food production losses and to increase the functional properties of produced films aimed at food coatings and wrappers. Water vapor permeability of active films increased up to 25%, moisture content for 27% in pectin-based ones, but water solubility was not significantly modified. Mechanical properties (tensile strength, elongation at break and Young’s modulus) were mainly decreased due to the residual insoluble particles present in blackcurrant waste. FTIR analysis showed no significant changes between the film samples. The degradation temperatures, determined by DSC, were reduced by 18 °C for chitosan-based samples and of 32 °C lower for the pectin-based samples with blackcurrant powder, indicating a disturbance in polymer stability. The antioxidant activity of active films was increased up to 30-fold. Lightness and redness of dry films significantly changed depending on the polymer type. Significant color changes, especially in chitosan film formulations, were observed after exposure to different pH buffers. This effect is further explored in formulations that were used as color change indicators for intelligent biopackaging.

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