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ESCH1317_Sarabjeet Singh
ESCH1317_Sarabjeet Singh

... and gaps in knowledge between scanning parameters and their effect on image quality. Our proposal will create web based, user-friendly interactive educational modules for protocol based CT radiation dose optimization that will educate the radiology community about the need and ways for clinical indi ...
Evaluation of Diagnostic Reference Levels for CT scan in Isfahan
Evaluation of Diagnostic Reference Levels for CT scan in Isfahan

... the scan from a series of axial scans where the scatter tails are negligible beyond the 100-mm integration limit, CTDIv represents the average absorbed radiation dose over the x, y, and z directions. L is the length of the scanned volume(21). This quantity can be used to evaluate the effective dose ...
Dosimetry of 3 CBCT devices for oral and maxillofacial radiology
Dosimetry of 3 CBCT devices for oral and maxillofacial radiology

... the soft tissue contours of the chin and nose were captured at the margins of the field. Phantom levels 2 – 8 were included in the full FOV examinations produced by each unit. Midsagittal reconstructions resulting from these examinations can be seen in Figure 2. X-ray parameters of kV and mA are aut ...
How to Appropriately Calculate Effective Dose for CT
How to Appropriately Calculate Effective Dose for CT

... mission occupational limits and environmental exposure levels) [2]. However, it should be remembered that effective dose provides a value that takes into account the given exposure conditions, but not the characteristics of a specific individual. The use of effective dose to quantify stochastic risk ...
DoseWatch - GE Healthcare
DoseWatch - GE Healthcare

... rejected series may never be sent at all. These scenarios and others can result in under- or over-counting of dose,5 particularly when that data is retrieved from PACS and there is no other available DICOM source for dose information. DoseWatch takes these issues into consideration by not just offer ...
Three-dimensional Dose Verification Using Normoxic Polymer Gel
Three-dimensional Dose Verification Using Normoxic Polymer Gel

... measurement. Monomer molecules in a polymer gel dosimeter solution change to polymer molecules via polymerization after ionizing radiation irradiated. This polymerization process changes the solution to gum. The amount of such mononer-polymer conversion is proportional to the radiation dose within a ...
Weightbearing CBCT, MDCT, and 2D imaging dosimetry of the foot
Weightbearing CBCT, MDCT, and 2D imaging dosimetry of the foot

... visualization of separate bony structures [4, 5]; however, this examination is expensive, limited in availability to hospitals and large radiology practices, and is associated with significantly increased x-ray dose in relation to plain views. Cone Beam CT (CBCT) represents a less expensive alternat ...
SOMATOM Definition Flash: Impressive Performance
SOMATOM Definition Flash: Impressive Performance

... even higher pitch values, the effect of shielding on dose is greater. The same ...
Diagnostic reference levels as a quality assurance tool
Diagnostic reference levels as a quality assurance tool

... Stochastic refers to effects whose probability increases with increasing dose and for which there is no threshold dose. Any dose, no matter how small, has the potential to cause harm and this becomes apparent years after the exposure. Examples are leukaemia and hereditary effects. Deterministic effe ...
Assessment and Optimization of Radiation Dosimetry and Image
Assessment and Optimization of Radiation Dosimetry and Image

... range of tube potential for chest imaging. The highest CNR of fat, bone and tumor in the chest phantom can be observed in this range of kVp. Increasing the tube potential will increase the radiation dose. The radiation dose gradually increases when the tube potential increases. Thus, it is not neces ...
News Letter - Association of Medical Physicists of India
News Letter - Association of Medical Physicists of India

... Dose Response: The EPID was found to respond linearly (linear regression coefficient r2=1) with increasing MUs as shown in figure 1. But as illustrated in figure 2 under- response has been observed (CU/MU ratio should be constant) for both the energies below 20 MU. Maximum deviation was around 25% & ...
Effective dose range for dental cone beam computed tomography
Effective dose range for dental cone beam computed tomography

... In this formula, wR is the radiation weighting factor (being 1 for X-rays), fi the fraction of tissue T in slice i, and DTi the average absorbed dose of tissue T in slice i, the summation being over all slices. For the brain, salivary glands, thyroid gland, oral mucosa and extrathoracic airways, cal ...
01 physical, technological and organizational bases of radiation
01 physical, technological and organizational bases of radiation

... • 1 sievert (Sv) = 100 rem. • One rem of alpha radiation would be expected to pose the same risk of harm as 1 rem of gamma rays or as 1 rem of combined exposure to neutrons and gamma rays. • The rem and Sv were developed to account for different efficiencies of different types of radiation in produc ...
IAEA Training Material on Radiation Protection in - RPOP
IAEA Training Material on Radiation Protection in - RPOP

... Other ...
Evolution of CT scanners
Evolution of CT scanners

... • Organs selected to allow for effective dose measurement – ICRP 60 ...
Health Effects of Radiation
Health Effects of Radiation

... required to stop energetic gamma rays. X-Rays essentially have the same properties as Gamma rays but differ in origin; are generally lower in energy, therefore less penetrating than Gamma rays; and a few mm of lead can stop penetration of medical x-rays. How can alpha particles affect people’s heal ...
Digital chest radiography
Digital chest radiography

... and optimal collimation was calculated. The experimental research was performed in December 2014 on a Siemens Axiom Aristos digital radiography system DR using 150 kV, 1,25 -3,3 mAs and SID of 180 centimeters using an anthropomorphic phantom (Alderson Radiation Therapy Phantom) and Thermoluminescent ...
Considerations Regarding Radiation Exposure in
Considerations Regarding Radiation Exposure in

... Careful selection of patients to be imaged should be a priority of the radiologist/nuclear medicine physician and the referring physician in order to avoid unnecessary repeated exposure. Risk-benefit ratios of whole body PETCT must be carefully evaluated before each study is ordered. This is especia ...
EPSM 2013 Student Abstracts
EPSM 2013 Student Abstracts

... data. Numerous values were calculated including; the error in each individual MLC leaf position, the speed and acceleration of each leaf, dose segment errors per field and the gravity effect. A large number of Dynalog files were analysed. RESULTS: The developed code is found to take 117.398 ± 8.550s ...
Frequently Asked Questions About Clinical Dose Optimization
Frequently Asked Questions About Clinical Dose Optimization

... patient’s record the radiation dose index (CTDIvol, DLP, or size-specific dose estimate [SSDE]) on every study produced during a diagnostic computed tomography (CT) examination. The radiation dose index must be exam specific, summarized by series or anatomic area, and documented in a retrievable for ...
Introducing Radiology Select: Radiation Dose and Dose Reduction
Introducing Radiology Select: Radiation Dose and Dose Reduction

... of future cancers from low doses of ionizing radiation (16,17) and one arguing quite the opposite—that these increases in cancer risk are not hypothetical and have begun to be measured (18). Because this debate is unlikely to be settled anytime soon, Thrall (19) proposes that the most promising appr ...
Has Transit Dosimetry Come Of Age
Has Transit Dosimetry Come Of Age

... ...during the last few years rather intensive efforts have led to the development of techniques that produce images using high-energy high X- rays directly. As a result, electronic portal imaging devices (EPIDs) are becoming available to cancer radiotherapy. In some systems, a small fraction of the ...
Radiation Safety in the Cath Lab
Radiation Safety in the Cath Lab

... the product of air kerma and x-ray field area. P KA estimates potential stochastic effects (radiation induced cancer). Peak Skin Dose (PSD, Gy) is the maximum dose received by any local area of patient skin. No current method to measure PSD, it can be estimated if air kerma and x-ray geometry detail ...
Clinical Dose Optimization Service™
Clinical Dose Optimization Service™

... patient’s record the radiation dose index (CTDIvol, DLP, or size-specific dose estimate [SSDE]) on every study produced during a diagnostic computed tomography (CT) examination. The radiation dose index must be exam specific, summarized by series or anatomic area, and documented in a retrievable for ...
Good Afternoon I am Bulent Aydogan and I will be Good Afternoon I
Good Afternoon I am Bulent Aydogan and I will be Good Afternoon I

... The failure of localization radiographs to show the surfaces of the colpostats made implementation of this process difficult, so in 1953, Tod and Meredith changed the procedure to begin at the most inferior point of the sources in the tandem (79). By the construction of the Manchester applicator, t ...
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Sievert

The sievert (symbol: Sv) is a derived unit of ionizing radiation dose in the International System of Units (SI). It is a measure of the health effect of low levels of ionizing radiation on the human body.Quantities that are measured in sieverts are intended to represent the stochastic health risk, which for radiation dose assessment is defined as the probability of cancer induction and genetic damage.The sievert is used for radiation dose quantities such as equivalent dose, effective dose, and committed dose. It is used both to represent the risk of the effect of external radiation from sources outside the body, and the effect of internal irradiation due to inhaled or ingested radioactive substances.Conventionally the sievert is not used for high dose rates of radiation which produce deterministic effects, which is the severity of acute tissue damage which is certain to happen. These effects are compared to the physical quantity absorbed dose measured by the unit gray (Gy).To enable consideration of stochastic health risk, calculations are performed to convert the physical quantity absorbed dose into equivalent and effective doses, the details of which depend on the radiation type and biological context. For applications in radiation protection and dosimetry assessment the International Commission on Radiological Protection (ICRP) and International Commission on Radiation Units and Measurements (ICRU) have published recommendations and data which are used to calculate these.The sievert is of fundamental importance in dosimetry and radiation protection, and is named after Rolf Maximilian Sievert, a Swedish medical physicist renowned for work on radiation dosage measurement and research into the biological effects of radiation. One sievert carries with it a 5.5% chance of eventually developing cancer.One sievert equals 100 rem. The rem is an older, non-SI unit of measurement.To enable a comprehensive view of the sievert this article deals with the definition of the sievert as an SI unit, summarises the recommendations of the ICRU and ICRP on how the sievert is calculated, includes a guide to the effects of ionizing radiation as measured in sieverts, and gives examples of approximate figures of dose uptake in certain situations.
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