Percutaneous cryoablation of renal masses under CT fluoroscopy: radiation doses to the patient and interventionalist.

Purpose: Computed tomographic (CT) fluoroscopy-guided percutaneous cryoablation is an effective therapeutic method used to treat focal renal masses. The purpose of this study is to quantify the radiation dose to the patient and interventional radiologist during percutaneous cryoablation of renal masses using CT fluoroscopic guidance.

Methods: Over a 1-year period, the CT fluoroscopy time during percutaneous cryoablation of renal masses was recorded in 41 patients.

Comparison of radiation dose estimates and scan performance in pediatric high-resolution thoracic CT for volumetric 320-detector row, helical 64-detector row, and noncontiguous axial scan acquisitions.

Rationale And Objectives: Efforts to decrease radiation exposure during pediatric high-resolution thoracic computed tomography (HRCT), while maintaining diagnostic image quality, are imperative. The objective of this investigation was to compare organ doses and scan performance for pediatric HRCT using volume, helical, and noncontiguous axial acquisitions.

Materials And Methods: Thoracic organ doses were measured using 20 metal oxide semiconductor field-effect transistor dosimeters.

Comparison of radiation dose estimates, image noise, and scan duration in pediatric body imaging for volumetric and helical modes on 320-detector CT and helical mode on 64-detector CT.

Background: Advanced multidetector CT systems facilitate volumetric image acquisition, which offers theoretic dose savings over helical acquisition with shorter scan times.

Objective: Compare effective dose (ED), scan duration and image noise using 320- and 64-detector CT scanners in various acquisition modes for clinical chest, abdomen and pelvis protocols.

Materials And Methods: ED and scan durations were determined for 64-detector helical, 160-detector helical and volume modes under chest, abdomen and pelvis protocols on 320-detector CT with adaptive collimation and 64-detector helical mode on 64-detector CT without adaptive collimation in a phantom representing a 5-year-old child.

Radiation dose estimation for prospective and retrospective ECG-gated cardiac CT angiography in infants and small children using a 320-MDCT volume scanner.

Objective: The purpose of this study is to determine patient dose estimates for clinical pediatric cardiac-gated CT angiography (CTA) protocols on a 320-MDCT volume scanner.

Materials And Methods: Organ doses were measured using 20 metal oxide semiconductor field effect transistor (MOSFET) dosimeters. Radiation dose was estimated for volumetrically acquired clinical pediatric prospectively and retrospectively ECG-gated cardiac CTA protocols in 5-year-old and 1-year-old anthropomorphic phantoms on a 320-MDCT scanner.

Radiation dose estimations to the thorax using organ-based dose modulation.

Objective: The purpose of this study was to assess the radiation dose distribution and image quality for organ-based dose modulation during adult thoracic MDCT.

Materials And Methods: Organ doses were measured using an anthropomorphic adult female phantom containing 30 metal oxide semiconductor field-effect transistor detectors on a dual-source MDCT scanner with two protocols: standard tube current modulation thoracic CT and organ-based dose modulation using a 120° radial arc. Radiochromic film measured the relative axial dose.

Isodose curve mappings measured while undergoing rotation for quality assurance testing of a 137Cs irradiator.

To enable accurate and reproducible dosimetry for biological sample irradiation in a 137Cs irradiator, routine quality assurance of the dose rate and isodose distributions should be considered. Our previous work demonstrated a means for accurate dose rate quality assurance and for quality assurance of isodose distributions of non-rotational samples. This work presents a means to accurately and cost effectively measure dose distributions within a 137Cs irradiator using rotational geometry, which geometry represent a more typical use of these irradiators.

Organ-specific radiation dose rates and effective dose rates during percutaneous nephrolithotomy.

Background And Purpose: Radiation exposure during medical procedures continues to be an increasing concern for physicians and patients. We determined organ-specific dose rates and calculated effective dose rates during right and left percutaneous nephrolithotomy (PCNL) using a validated phantom model.

Materials And Methods: A validated anthropomorphic adult male phantom was placed prone on an operating room table.

An ear punch model for studying the effect of radiation on wound healing.

Purpose: Radiation and wound combined injury represents a major clinical challenge because of the synergistic interactions that lead to higher morbidity and mortality than either insult would produce singly. The purpose of this study was to develop a mouse ear punch model to study the physiological mechanisms underlying radiation effects on healing wounds.

Materials And Methods: Surgical wounds were induced by a 2 mm surgical punch in the ear pinnae of MRL/MpJ mice.

Radiation dose for body CT protocols: variability of scanners at one institution.

Objective: The objective of our study was to determine, using an anthropomorphic phantom, whether patients are subject to variable radiation doses based on scanner assignment for common body CT studies.

Materials And Methods: Twenty metal oxide semiconductor field effect transistor dosimeters were placed in a medium-sized anthropomorphic phantom of a man. Pulmonary embolism and chest, abdomen, and pelvis protocols were used to scan the phantom three times with GE Healthcare scanners in four configurations and one 64-MDCT Siemens Healthcare scanner.

Early first trimester fetal dose estimation method in a multivendor study of 16- and 64-MDCT scanners and low-dose imaging protocols.

Objective: The purpose of this study was to corroborate the relation between the estimated absorbed fetal dose derived from directly measured uterine doses early in the first trimester and the volume CT dose index (CTDI(vol)) for 16- and 64-MDCT of the maternal chest, abdomen, and pelvis.

Materials And Methods: Estimated absorbed fetal dose was measured with a metal oxide semiconductor field effect transistor (MOSFET) dosimeter placed in the expected uterine location in an anthropomorphic phantom of a woman and scanned with 16- and 64-MDCT units of one vendor and a 64-MDCT unit of another vendor. A trauma chest, abdomen, and pelvis protocol and an abdomen and pelvis protocol were used.

Kerma area product method for effective dose estimation during lumbar epidural steroid injection procedures: phantom study.

Objective: The purpose of this study was to derive from the kerma area product the dose conversion coefficient for estimating the effective dose for lumbar epidural steroid injection procedures.

Materials And Methods: A mobile fluoroscopy system was used for fluoroscopic imaging guidance of lumbar epidural steroid injection procedures. For acquisition of organ dose measurements, 20 diagnostic metal oxide semiconductor field effect transistor detectors were placed at each organ in an anthropomorphic phantom of a man, and these detectors were attached to four mobile metal oxide semiconductor field effect transistor wireless bias supplies to obtain the organ dose readings.

Dosimetric characterisation of bismuth shields in CT: measurements and Monte Carlo simulations.

Although bismuth shields are frequently used in radiology to reduce radiation dose, its mechanism has not been fully investigated. Dosimetric characteristics of bismuth shields in computed tomography (CT) were assessed with ion chamber and Monte Carlo (MC) simulations. Primary attenuation and backscatter effects of paediatric (2-ply) and adult (4-ply) bismuth shields were measured.

Radiation dose savings for adult pulmonary embolus 64-MDCT using bismuth breast shields, lower peak kilovoltage, and automatic tube current modulation.

Objective: The purpose of this study was to assess whether radiation dose savings using a lower peak kilovoltage (kVp) setting, bismuth breast shields, and automatic tube current modulation could be achieved while preserving the image quality of MDCT scans obtained to assess for pulmonary embolus (PE).

Materials And Methods: CT angiography (CTA) examinations were performed to assess for the presence or absence of pulmonary artery emboli using a 64-MDCT scanner with automatic tube current modulation (noise level=10 HU), two kVp settings (120 and 140 kVp), and bismuth breast shields. Absorbed organ doses were measured using anthropomorphic phantoms and metal oxide semiconductor field effect transistor (MOSFET) detectors.

Application of MOSFET detectors for dosimetry in small animal radiography using short exposure times.

Digital subtraction angiography (DSA) X-ray imaging for small animals can be used for functional phenotyping given its ability to capture rapid physiological changes at high spatial and temporal resolution. The higher temporal and spatial requirements for small-animal imaging drive the need for short, high-flux X-ray pulses. However, high doses of ionizing radiation can affect the physiology.