Location of radiosensitive organs inside pediatric anthropomorphic phantoms: Data required for dosimetry

2015 ◽  
Vol 31 (8) ◽  
pp. 882-888 ◽  
Author(s):  
Stephen Inkoom ◽  
Maria Raissaki ◽  
Kostas Perisinakis ◽  
Thomas G. Maris ◽  
John Damilakis
Keyword(s):  
Anthropomorphic Phantoms ◽  
Radiosensitive Organs

scholarly journals Quantitative, Multi-institutional Evaluation of MR Thermometry Accuracy for Deep-Pelvic MR-Hyperthermia Systems Operating in Multi-vendor MR-systems Using a New Anthropomorphic Phantom

Cancers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1709 ◽  
Author(s):  
Curto ◽  
Aklan ◽  
Mulder ◽  
Mils ◽  
Schmidt ◽  
...  
Keyword(s):  
Hybrid Systems ◽  
Dose Effect ◽  
Institutional Evaluation ◽  
Anthropomorphic Phantoms ◽  
Contrast Magnetic Resonance ◽  
Scatter Plots ◽  
Conformal Heating ◽  
Probe Measurements ◽  
Eccentric Target ◽  
Good Agreement

Clinical outcome of hyperthermia depends on the achieved target temperature, therefore target conformal heating is essential. Currently, invasive temperature probe measurements are the gold standard for temperature monitoring, however, they only provide limited sparse data. In contrast, magnetic resonance thermometry (MRT) provides unique capabilities to non-invasively measure the 3D-temperature. This study investigates MRT accuracy for MR-hyperthermia hybrid systems located at five European institutions while heating a centric or eccentric target in anthropomorphic phantoms with pelvic and spine structures. Scatter plots, root mean square error (RMSE) and Bland–Altman analysis were used to quantify accuracy of MRT compared to high resistance thermistor probe measurements. For all institutions, a linear relation between MRT and thermistor probes measurements was found with R2 (mean ± standard deviation) of 0.97 ± 0.03 and 0.97 ± 0.02, respectively for centric and eccentric heating targets. The RMSE was found to be 0.52 ± 0.31 °C and 0.30 ± 0.20 °C, respectively. The Bland-Altman evaluation showed a mean difference of 0.46 ± 0.20 °C and 0.13 ± 0.08 °C, respectively. This first multi-institutional evaluation of MR-hyperthermia hybrid systems indicates comparable device performance and good agreement between MRT and thermistor probes measurements. This forms the basis to standardize treatments in multi-institution studies of MR-guided hyperthermia and to elucidate thermal dose-effect relations.

scholarly journals USE OF ANTHROPOMORPHIC HETEROGENEOUS PHYSICAL PHANTOMS FOR VALIDATION OF COMPUTATIONAL DOSIMETRY OF MEDICAL PERSONNEL AND PATIENTS

2020 ◽  
Vol 25 ◽  
pp. 148-176
Author(s):  
V. Chumak ◽  
◽  
N. Petrenko ◽  
O. Bakhanova ◽  
V. Voloskyi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Ionizing Radiation ◽  
Human Body ◽  
Ct Scanning ◽  
Medical Personnel ◽  
Radiation Doses ◽  
Physical Measurements ◽  
Simple Geometry ◽  
Anthropomorphic Phantoms ◽  
Validation Of Models

In the dosimetry of ionizing radiation, the phantoms of the human body, which are used as a replacement for the human body in physical measurements and calculations, play an important, but sometimes underestimated, role. There are physical phantoms used directly for measurements, and mathematical phantoms for computational dosimetry. Their complexity varies from simple geometry applied for calibration purposes up to very complex, which simulates in detail the shapes of organs and tissues of the human body. The use of physical anthropomorphic phantoms makes it possible to effectively optimize radiation doses by adjusting the parameters of CT-scanning (computed tomography) in accordance with the characteristics of the patient without compromising image quality. The use of phantoms is an indispensable approach to estimate the actual doses to the organs or to determine the effective dose of workers – values that are regulated, but cannot be directly measured. The article contains an overview of types, designs and the fields of application of anthropomorphic heterogeneous physical phantoms of a human with special emphasis on their use for validation of models and methods of computational dosimetry. Key words: dose, ionizing radiation, physical, mathematical phantoms, computational dosimetry.

scholarly journals Application of Different methods for Reducing Radiation Dose to Breast during MDCT

2018 ◽  
Author(s):  
M Keshtkar ◽  
V Saba ◽  
M A Mosleh-Shirazi
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Low Income ◽  
Low Income Countries ◽  
Radiological Protection ◽  
Reconstruction Algorithms ◽  
Radiation Induced Cancer ◽  
Bismuth Shielding ◽  
Ct Scanners ◽  
Radiosensitive Organs

The increased use of computed tomography (CT) and its high radiation dose have led to great concerns about its potential for radiation induced cancer risks. Breast is a radiosensitive tissue based on tissue weighting factors assigned by the International Commission on Radiological Protection (ICRP). Moreover, the dose is maximal on the surface of the patient. Therefore, strategies should be taken to reduce radiation dose to the breast. The aim of this review is to introduce methods used for reducing radiation dose to breast in thoracic CT and review related performed studies. The literature indicates that bismuth shielding increases image noise and CT numbers as well as introducing streak artifacts. Tube current modulation (TCM) technique and iterative reconstruction algorithms can provide some levels of dose reduction to radiosensitive organs and superior image quality without the disadvantages of bismuth shielding. However, they are not available on all CT scanners, especially in low-income countries. Such centers may have to continue using bismuth shields to reduce the dose until these superior techniques become available at lower costs in all CT scanners. Furthermore, design and manufacture of new shields with the lower impact on image quality are desirable.

scholarly journals Radiation dose evaluation in 64-slice CT examinations with adult and paediatric anthropomorphic phantoms

2009 ◽  
Vol 82 (984) ◽  
pp. 1010-1018 ◽  
Author(s):  
K Fujii ◽  
T Aoyama ◽  
C Yamauchi-Kawaura ◽  
S Koyama ◽  
M Yamauchi ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Dose Evaluation ◽  
Anthropomorphic Phantoms

scholarly journals Radioprotective Role of Peroxiredoxin 6

Antioxidants ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 15 ◽  
Author(s):  
Mars G. Sharapov ◽  
Vladimir I. Novoselov ◽  
Sergey V. Gudkov
Keyword(s):  
Ionizing Radiation ◽  
Mammalian Cells ◽  
Redox Homeostasis ◽  
Phospholipid Metabolism ◽  
Pathological Effect ◽  
Peroxiredoxin 6 ◽  
Leading Role ◽  
Wide Range ◽  
Radiosensitive Organs ◽  
Peroxidase Enzymes

Peroxiredoxin 6 (Prdx6) is a member of an evolutionary ancient family of peroxidase enzymes with diverse functions in the cell. Prdx6 is an important enzymatic antioxidant. It reduces a wide range of peroxide substrates in the cell, thus playing a leading role in the maintenance of the redox homeostasis in mammalian cells. Beside peroxidase activity, Prdx6 has been shown to possess an activity of phospholipase A2, an enzyme playing an important role in membrane phospholipid metabolism. Moreover, Prdx6 takes part in intercellular and intracellular signal transduction due to its peroxidase and phospholipase activity, thus facilitating the initiation of regenerative processes in the cell, suppression of apoptosis, and activation of cell proliferation. Being an effective and important antioxidant enzyme, Prdx6 plays an essential role in neutralizing oxidative stress caused by various factors, including action of ionizing radiation. Endogenous Prdx6 has been shown to possess a significant radioprotective potential in cellular and animal models. Moreover, intravenous infusion of recombinant Prdx6 to animals before irradiation at lethal or sublethal doses has shown its high radioprotective effect. Exogenous Prdx6 effectively alleviates the severeness of radiation lesions, providing normalization of the functional state of radiosensitive organs and tissues, and leads to a significant elevation of the survival rate of animals. Prdx6 can be considered as a potent and promising radioprotective agent for reducing the pathological effect of ionizing radiation on mammalian organisms. The radioprotective properties and mechanisms of radioprotective action of Prdx6 are discussed in the current review.

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