scholarly journals Influence of Gamma Irradiation on Electric Cables Models: Study of Additive Effects by Mid-Infrared Spectroscopy

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1451
Author(s):  
Astrid Maléchaux ◽  
Juliette Colombani ◽  
Sandrine Amat ◽  
Sylvain R. A. Marque ◽  
Nathalie Dupuy
Keyword(s):  
Gamma Irradiation ◽  
Dose Rate ◽  
Nuclear Power ◽  
Degradation Products ◽  
Principal Component ◽  
High Dose Rate ◽  
Normal Operation ◽  
High Dose ◽  
Electric Cables ◽  
The Impact

Cables, especially their insulation and jacket materials made of polymers, are vulnerable to ageing degradation during normal operation. However, they must remain functional for the entire life of a nuclear power plant, or even in the event of an accident for cables with a safety requirement. This study focuses on models of crosslinked polyethylene (XLPE)-based insulation of cables and deals with the structure modification and the behavior of XLPE for nuclear applications due to the effect of additives. Various additives are added to the polymer formulation to evaluate their impact on ageing. The samples are irradiated at room temperature by several gamma doses, up to 374 kGy, with two dose rates (40 Gy/h and 300 Gy/h) and compared with a non-irradiated sample used as reference. To understand the impact of gamma irradiation on the materials, the principal component analysis (PCA) method is applied on spectra recorded through attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy. The results highlight the effects of ageing depending on the dose rate and on the formulation of the materials, with the identification of different degradation products. A curve resolution study compares the effects of different additives on polymer oxidation and shows that the low dose rate leads to a higher degradation than the high dose rate.

Cholangiocarcinoma: The impact of endobiliary high-dose-rate (HDR) brachytherapy dose response on survival

Brachytherapy ◽  
2006 ◽  
Vol 5 (2) ◽  
pp. 91
Author(s):  
Matthew Biagioli ◽  
B-Chen Wen ◽  
Brandon Patton ◽  
Caroline Hoffman ◽  
Mark Harvey
Keyword(s):  
Dose Rate ◽  
Dose Response ◽  
High Dose Rate ◽  
High Dose ◽  
Hdr Brachytherapy ◽  
The Impact

scholarly journals Impact of discrete source step size on the 3D dosimetry of interstitial implants with high dose rate brachytherapy

2018 ◽  
Vol 6 (3) ◽  
pp. 990 ◽  
Author(s):  
Anil Kumar Maurya ◽  
Rajesh Kumar Maurya ◽  
Surendrakumar Dayashankar Maurya ◽  
Radha Kesarwani ◽  
Virendra Singh
Keyword(s):  
Dose Rate ◽  
High Dose Rate ◽  
Planning System ◽  
High Dose ◽  
Quality Indices ◽  
Step Size ◽  
Mean Values ◽  
Dose Homogeneity ◽  
Dose Volumes ◽  
The Impact

ABSTRACTBackground: High dose rate remote after loading brachytherapy machines have seen tremendous advancement both technologically and their clinical applications during the last 25 years. With the introduction of computerized remote after loading machines and computerized planning system, stepping source dosimetry system (SSDS) has become the system of choice making almost all traditional dosimetry systems obsolete. In this study we evaluated the impact of source step size on dosimetry of interstitial implant using parameters of ICRU-58 and various quality indices (QI).Material & Methods: For this study, 10 implant cases which have 3-D CT image based planning were selected. Contouring of clinical target volume and various organs were done following standard guidelines for the same. Plans were optimized to achieve the desired clinical outcome using different source step sizes of 2.5, 5 and 10 mm respectively. Cumulative DVH’s were calculated for the estimation of various ICRU-58 parameters and quality indices.Results and Conclusion: The mean values of the target volumes, minimum target doses, treated volumes, low dose volumes; high dose volumes, overdose volumes, reference volumes, coverage, external volume, relative dose homogeneity, overdose volume and COIN indices have been presented for the source step sizes of 2.5 mm, 5 mm and 10 mm respectively. Among source step sizes used in this study, most favorable clinically acceptable dose distributions & dose homogeneity occurs around step size of 5 mm as predicted by the various parameters of ICRU-58 and dose quality indices. Keywords: Brachytherapy, interstitial implant, source step-size, remote after loading, optimization, quality indices.

High dose rate post-operative brachytherapy and external beam radiotherapy for uterine sarcomas

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 15027-15027
Author(s):  
M. A. Maia ◽  
P. Novaes ◽  
A. C. Pellizzon ◽  
R. Ferrigno
Keyword(s):  
Radiation Therapy ◽  
Dose Rate ◽  
High Dose Rate ◽  
External Beam Radiation ◽  
High Dose ◽  
External Beam ◽  
Beam Radiation ◽  
Aggressive Approach ◽  
The Impact ◽  
Disease Free

15027 Background: Uteine sarcoma (US) generally needs an aggressive approach with surgical cytoreduction at the time of initial diagnosis with maximum debulking of tumor. This offers the possibility of prolonged survival or cure. The need for adjuvant radiotherapy is not well established for US. Methods: 25 patients presenting completely ressected US were treated from November, 1992 to June, 2003. All the patients had a multidisciplinary approach with surgery, external beam radiation therapy (EBRT) given in a four- fields “box” technique, and high dose rate brachytherapy (HDRB), using either colpostats or vaginal cylinders with diameters ranging from 2.5 to 4 cm. The entire vaginal length treated with HDRB was 2 cm in all cases. Results: The median age of patients was 62 years (range 39–84). The EBRT dose prescription ranged from 40 Gy to 50,4 Gy (median 48 Gy). HDRB was given concurrent to EBRT in 14 patients (56%). The HDRB for the remaining patients started in median interval of 34 days (range 5–99 days) after the completion of EBRT. The median BED for hole treatment was 91.5 Gy10 (range 85.6 Gy10–97.9 Gy10), with a standard deviation of 3.7. The 10- year actuarial disease free and overall survivals were and 42.2% and 63.4%, respectively. On univariate analysis predictive factors for disease free survival (DFS) were age at initial presentation (p = 0.0268), parity (p = 0.0441), tumor grade (p = 0.0095), cervical or vaginal invasion (p = 0.0014) and node dissection at time of surgery (p = 0.0471). On multivariate analysis the only predictive factor was cervical or vaginal invasion (p = 0.048), hazard ratio of 4.7. Conclusion: Our small and heterogeneous group of patients analyzed precludes any definitive conclusions regarding the impact of HDRB combined to EBRT on recurrence or survival of the patients. As US are aggressive tumors, it is quite likely that neither radiotherapy nor chemotherapy alone will appreciably improve survival. If we assume that adjuvant radiation therapy provides better locoregional tumor control, hematogenous metastases probably will assume an even greater proportion of treatment failures. No significant financial relationships to disclose.

The impact of body mass index on rectal dose in locally advanced cervical cancer treated with high-dose-rate brachytherapy

Brachytherapy ◽  
2013 ◽  
Vol 12 (6) ◽  
pp. 550-554 ◽  
Author(s):  
Jihoon Lim ◽  
Blythe Durbin-Johnson ◽  
Richard Valicenti ◽  
Matthew Mathai ◽  
Robin L. Stern ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Cervical Cancer ◽  
Dose Rate ◽  
Locally Advanced ◽  
High Dose Rate ◽  
High Dose ◽  
Advanced Cervical Cancer ◽  
Locally Advanced Cervical Cancer ◽  
Rectal Dose ◽  
The Impact

scholarly journals Influence of catheters on predicted tumour control probability and severity of acute genitourinary toxicity during high-dose-rate brachytherapy prostate boost

2010 ◽  
Vol 10 (3) ◽  
pp. 173-180
Author(s):  
Mutahir Tunio ◽  
Altaf Hashmi ◽  
Mansoor Rafi ◽  
Rehan Mohsin ◽  
Asad Zameer
Keyword(s):  
Prostate Cancer ◽  
Dose Rate ◽  
High Dose Rate ◽  
Planning System ◽  
High Dose ◽  
High Dose Rate Brachytherapy ◽  
Tumour Control ◽  
Tumour Control Probability ◽  
Gu Toxicity ◽  
The Impact

AbstractPurpose: High-dose-rate brachytherapy (HDR) boost is an effective method for dose escalation when treating prostate cancer. Optimal number and location of catheters play key role in radiation dose delivery. We studied the impact of catheters and associated trauma on the dose uncertainties and urethral toxicity.Methods and Materials: Between July 2008 to August 2009, 50 patients with prostate cancer were treated with 46 Gy of external irradiation of whole pelvis (2 Gy per fraction) and two HDR brachytherapy fractions (each 14 Gy) at the end of 10 fractions of external beam. All brachytherapy implants were planned using real-time, ultrasound-based planning system. Variables were prostate and urethral volumes, number of catheters and their mean distance from base of bladder and dose volume histogram parameters. All data were collected during first implant only. The toxicities were graded according to Radiation Therapy Oncology Group Toxicity Criteria. Statistical analysis was done on SPSS version 17.0.Results: The mean number of catheters implanted was 12.38 (8–19), and number of attempts per needle to achieve desired position was 1.6 (range = 0–5). Mean distance between the catheters tips to contrast filled bladder was 3.2 mm (1–8 mm) after the adjustment. Distances >5 mm showed lower doses to prostate and lower predicted tumour control probability (TCP) (p < 0.01). No correlation was found between numbers of catheters implanted, attempts per catheter and severity of acute genitourinary (GU) toxicity. Significant correlation was found between severity of acute GU toxicity and urethral V130, V150 (p < 0.001).Conclusion: Dose decline and subsequently lower TCP were seen for the greater distances between the needles and bladder. Acute GU toxicity increased with higher urethral, but severity of acute GU toxicity does not increase with increase in prostate/urethral volumes, number of catheters needles and attempts.

scholarly journals A Performance Evaluation of a Notebook PC under a High Dose-Rate Gamma Ray Irradiation Test

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Jai Wan Cho ◽  
Kyung Min Jeong
Keyword(s):  
Performance Evaluation ◽  
Dose Rate ◽  
Nuclear Power ◽  
Gamma Ray ◽  
Control Unit ◽  
High Dose Rate ◽  
High Dose ◽  
Robot System ◽  
Irradiation Test ◽  
Gamma Ray Irradiation

We describe the performance of a notebook PC under a high dose-rate gamma ray irradiation test. A notebook PC, which is small and light weight, is generally used as the control unit of a robot system and loaded onto the robot body. Using TEPCO’s CAMS (containment atmospheric monitoring system) data, the gamma ray dose rate before and after a hydrogen explosion in reactor units 1–3 of the Fukushima nuclear power plant was more than 150 Gy/h. To use a notebook PC as the control unit of a robot system entering a reactor building to mitigate the severe accident situation of a nuclear power plant, the performance of the notebook PC under such intense gamma-irradiation fields should be evaluated. Under a similar dose-rate (150 Gy/h) gamma ray environment, the performances of different notebook PCs were evaluated. In addition, a simple method for a performance evaluation of a notebook PC under a high dose-rate gamma ray irradiation test is proposed. Three notebook PCs were tested to verify the method proposed in this paper.

On the impact of improved dosimetric accuracy on head and neck high dose rate brachytherapy

2016 ◽  
Vol 120 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Vasiliki Peppa ◽  
Eleftherios Pappas ◽  
Tibor Major ◽  
Zoltán Takácsi-Nagy ◽  
Evaggelos Pantelis ◽  
...  
Keyword(s):  
Head And Neck ◽  
Dose Rate ◽  
High Dose Rate ◽  
High Dose ◽  
High Dose Rate Brachytherapy ◽  
Dosimetric Accuracy ◽  
The Impact
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