Measurement Of Radiation Exposure Research Articles

Calibration and features of air-kerma length product meters

Pencil-type air-kerma length product meters are generally used for quality control and radiation exposure measurements in computed tomography. To ensure reliable results, these meters should be calibrated so that measurements are traceable to international standards. Suitable calibration procedures, together with the properties of these meters, were examined and compared with the international standards and recommendations. The calibration procedure and setup used in this study were slightly modified compared with international recommendations. The special collimator system was found to cause less scatter than similar setups in earlier studies. The energy dependence of the meter response was investigated for several types of meters with standard radiation qualities. With most tested meter types, the total variation due to energy dependence was <4 %, but some had strong energy dependence and the variation was up to 15 % or higher. This highlights the importance of a proper calibration. The response of one semiconductor meter type varied up to 8 % when rotating the meter around its axis; this should be taken into account when making calibrations with a static setup.

Mo1356 Safety of ERCP in Pregnancy: Fluoroscopy Time and Fetal Exposure, Does It Matter?

Pancreaticobiliary disease in pregnancy is common and can lead to significant maternal and fetal morbidity. Several studies have found ERCP to be safe in pregnancy, but the measurement of fetal radiation exposure is still questioned. Our aim was to analyze the relationship between the fluoroscopy time and the estimated fetal radiation exposure as well as the outcome of the ERCP in the pregnant women.

A Computed Tomography (CT) wish list, from a medical physicist’s perspective

Significant advances in computed tomography (CT) technology have been made since the first clinical images were published in 1973. The initial clinical applications were brain scans where the patient’s head was immobilised by a water bag that compensated for the large changes in flux adjacent to the head. Body imaging became feasible as improvements led to better image quality and reduced scan times. Improved computing technology has allowed for image reconstruction, including rendering and 3D reconstruction, to all occur in real time. Perfusion studies, cardiac imaging and CT angiography are now common and interventional procedures can be performed using CT fluoroscopy guidance. Some of the major scanner developments that have contributed to this progress are slip-ring technology, which facilitated helical scanning, and multidetector CT systems with capabilities for volume scanning. In addition, increasingly complex X-ray tube designs and novel CT detector materials and configurations have also contributed to changes in CT imaging. Dose reporting began to address concerns raised regarding the risks from radiation exposure and other practical dose reduction measures such as the adaptation of parameters to the patient size were implemented. This included modulating the tube current throughout the scan. More recent CT developments include dual-energy imaging and iterative reconstruction techniques, which are used instead of or in combination with traditional filtered back-projection image formation. All of these improvements in technologies combined have resulted in dose reductions for some CT procedures in the order of 90 %! The changes to image quality, dose and the way in which CT scans are performed have been extensive. However, there are always further enhancements that can be made, especially as user requirements or objectives change. For diagnostic medical physicists, there will always be a wish list of what we would like on a CT scanner. This is largely driven by the work that we undertake and the needs of our colleagues, who request, perform or interpret CT scans. Inevitably, achieving the best health outcome for the patient is the primary concern. The wish list is also influenced by current opinions and attitudes towards CT imaging. Hence, the desirable features for a CT scanner are discussed below, with the rationale for these first explored. A small straw poll of radiologists and radiographers from a variety of workplaces was also undertaken to gauge opinions. Z. Brady (&) Radiology Department, The Alfred, P.O. Box 315, Prahran, VIC 3181, Australia e-mail: z.brady@alfred.org.au

Prospective Measurement of Patient Exposure to Radiation During Pediatric Ureteroscopy

Few data have been reported regarding radiation exposure during pediatric endourological procedures, including ureteroscopy. We measured radiation exposure during pediatric ureteroscopy and identify opportunities for exposure reduction. We prospectively observed ureteroscopy procedures as part of a quality improvement initiative. Preoperative patient characteristics, operative factors, fluoroscopy settings and radiation exposure were recorded. Our outcomes were entrance skin dose and midline dose (both mGy). Specific modifiable factors were identified as targets for potential quality improvement. Direct observation was performed in 54 consecutive ureteroscopy procedures. Mean±SD patient age was 14.8±3.8 years (range 7.4 to 19.2), with 9 children being younger than 12 years. Mean±SD entrance skin dose was 46.4±48 mGy. Mean±SD midline dose was 6.2±5.0 mGy. The most important major determinant of radiation dose was total fluoroscopy time (mean±SD 2.68±1.8 minutes) followed by dose rate setting, child anteroposterior diameter and source to skin distance (all p<0.01). Analysis of factors affecting exposure levels revealed that use of ureteral access sheaths (p=0.01) and retrograde pyelography (p=0.04) were significantly associated with fluoroscopy time. We also found that dose rate settings were higher than recommended in up to 43% of cases and ideal C-arm positioning could have reduced exposure by 14% (up to 49% in some cases). Children receive biologically significant radiation doses during ureteroscopy procedures. Several modifiable factors contribute to dose and could be targeted in efforts to implement dose reduction strategies.

The coronary CT angiography vision protocol: a prospective observational imaging cohort study in patients undergoing non-cardiac surgery

IntroductionAt present, physicians have a limited ability to predict major cardiovascular complications after non-cardiac surgery and little is known about the anatomy of coronary arteries associated with perioperative myocardial infarction....

Columnist advocates measuring radiation exposure in banana units

Columnist advocates measuring radiation exposure in banana units

Measurements of long-term external and internal radiation exposure of inhabitants of some villages of the Bryansk region of Russia after the Chernobyl accident

A Nordic–Soviet programme was initiated in 1990 to evaluate the external and internal radiation exposure of the inhabitants of several villages in the Bryansk region of Russia. This area was one of the number of areas particularly affected by the nuclear accident at the Chernobyl Nuclear Power Plant in 1986. Measurements were carried out yearly until 1998 and after that more irregularly; in 2000, 2006 and 2008 respectively. The effective dose estimates were based on individual thermoluminescent dosemeters and on in vivo measurements of the whole body content of 137Cs (and 134Cs during the first years of the programme). The decrease in total effective dose during the almost 2 decade follow-up was due to a continuous decrease in the dominating external exposure and a less decreasing but highly variable exposure from internal irradiation. In 2008, the observed average effective dose (i.e. the sum of external and internal exposure) from Chernobyl 137Cs to the residents was estimated to be 0.3 mSv y −1. This corresponds to 8% of the estimated annual dose in 1990 and to 1% of the estimated annual dose in 1986. As a mean for the population group and for the period of the present study (2006–2008), the average yearly effective dose from Chernobyl cesium was comparable to the absorbed dose obtained annually from external exposure to cosmic radiation plus internal exposure to naturally occurring radionuclides in the human body. Our data indicate that the effective dose from internal exposure is becoming increasingly important as the body burdens of Chernobyl 137Cs are decreasing more slowly than the external exposure. However, over the years there have been large individual variations in both the external and internal effective doses, as well as differences between the villages investigated. These variations and differences are presented and discussed in this paper.

방사선 작업종사자의 피폭선량 비교 평가

최근의 방사선 피폭 선량을 조사하여 그 경각심을 일깨워주기 위함이다. 그 분석결과, K병원의 2008년도 평균피폭 선량은 <TEX>$0.75{\pm}0.26mSv$</TEX>, 2009년은 <TEX>$0.67{\pm}0.30mSv$</TEX>, 2010년은 <TEX>$0.92{\pm}0.33mSv$</TEX>였다. P병원은 2008년이 <TEX>$0.43{\pm}0.13mSv$</TEX>, 2009년 <TEX>$0.43{\pm}0.20mSv$</TEX>, 2010년이 <TEX>$0.33{\pm}0.85mSv$</TEX>로 나타났으며, 연령별 평균 피폭선량은 K병원의 20대가 13.39mSv, 30대 8.37mSv, 40대 1.19mSv, 50대 0.28mSv, 60대 0.32mSv로 나타났고 P병원은 20대 0.33mSv, 30대 1.41mSv, 40대 0.83mSv, 50대 1.66mSv, 60대 1.12mSv 였다. 또한 3년간 피폭선량의 평균을 성별로 나누어서 나타냈는데 K병원에서 남자의 피폭선량은 <TEX>$2.92{\pm}1.03mSv$</TEX>, 여자의 피폭선량은 <TEX>$0.94{\pm}0.93mSv$</TEX>였다. P병원에서의 남자의 피폭 선량은 <TEX>$0.66{\pm}0.18mSv$</TEX>이고 여자는 <TEX>$1.80{\pm}0.60mSv$</TEX>로 나타났다. 방사선을 취급하는 과별로 받는 년간 평균 피폭 선량은 영상의학과 <TEX>$1.65{\pm}1.54mSv$</TEX>, 방사선종양학과 <TEX>$1.17{\pm}0.82mSv$</TEX>, 핵의학과 <TEX>$1.79{\pm}1.42mSv$</TEX>, 기타 <TEX>$0.99{\pm}0.51mSv$</TEX>였으며 상대적으로 저선량율 에너지를 사용하는 핵의학과에서 다른 과와 비교해서 방사선 피폭이 높게 나타났으며(p<0.05), 핵의학과내에서는 특히 동위원소 조작실과 주입실의 년간 평균 피폭량이 <TEX>$3.69{\pm}1.81mSv$</TEX>으로 많은 피폭을 받고 있었다(p<0.01). 직종별 연평균 피폭선량은 의사 <TEX>$1.75{\pm}1.17mSv$</TEX>, 방사선사 <TEX>$1.60{\pm}1.39mSv$</TEX>, 간호사 <TEX>$0.93{\pm}0.35mSv$</TEX>, 기타 <TEX>$1.00{\pm}0.3mSv$</TEX>로 의사와 방사선사가 다른 직종에 비해 높게 나타났다(p<0.05). 방사선 작업 종사자에 대한 피폭측정 및 평가가 철저히 이루어져 피폭 가능성을 줄이는데 관심과 주의가 필요하며 누적 선량을 최소화하여 방사선 작업 종사자의 건강을 유지하고 증진 시켜야 할 것이다. The purpose of this study is to investigate the dose of radiation exposure to radiation-related workers in a hospital setting, thus increasing awareness of the health risk to the radiation-related workers. The result of the analysis showed the average dose of radiation exposure to radiation-related workers in hospital K was <TEX>$0.75{\pm}0.26mSv$</TEX> in 2008, <TEX>$0.67{\pm}0.30mSv$</TEX> in 2009, and <TEX>$0.92{\pm}0.33mSv$</TEX> in 2010. The average dose of radiation exposure in hospital P was <TEX>$0.43{\pm}0.13mSv$</TEX> in 2008, <TEX>$0.43{\pm}0.20mSv$</TEX> in 2009, and <TEX>$0.33{\pm}0.85mSv$</TEX> in 2010. The average dose of radiation exposure in hospital K by age group was 13.39mSv for age 20 to 29, 8.37mSv for age 30 to 39, 1.19mSv for age 40 to 49, 0.28mSv for age 50 to 59, and 0.32mSv for age 60 to 69 The average dose of radiation exposure in hospital P by age group was 0.33mSv for age 20 to 29, 1.41mSv for age 30 to 39, 0.83mSv for age 40 to 49, 1.66mSv for age 50 to 59, and 1.12mSv for age 60 to 69. Moreover, the average radiation exposure to radiation-related workers over 3 year period by gender group in hospital K was <TEX>$2.92{\pm}1.03mSv$</TEX> for male group and <TEX>$0.94{\pm}0.93mSv$</TEX> for female group. The average radiation exposure over 3 year period by gender group in hospital P was <TEX>$0.66{\pm}0.18mSv$</TEX> for male group and <TEX>$1.80{\pm}0.60mSv$</TEX> for female group. Persons working in diagnostic radiology department received mean of <TEX>$1.65{\pm}1.54mSv/year$</TEX>, mean <TEX>$1.17{\pm}0.82mSv/year$</TEX> in radiation oncology, mean <TEX>$1.79{\pm}1.42mSv/year$</TEX> at nuclear medicine department and mean <TEX>$0.99{\pm}0.51mSv/year$</TEX> at other departments. Radiation exposure was higher than that of other departments(p<0.05). Doctors and technologists received higher radiation exposure (mean <TEX>$1.75{\pm}1.17mSv/year$</TEX>, <TEX>$1.60{\pm}1.39mSv/year$</TEX> each) than other workers(p<0.05). Measurement and evaluation of radiation exposure in radiation-related workers should be widely conducted accurately and consistently in the radiation-related occupational setting so that people in these occupational settings are more aware of the risk from radiation exposure, and thus give more attention and caution to decrease radiation exposure. It would be essential to minimize accumulated radiation dose in the radiation-related occupational setting in order to maintain and improve the health of radiation-related workers.

Pediatric digital radiography education for radiologic technologists: current state

Digital radiography (DR) is one of several new products that have changed our work processes from hard copy to digital formats. The transition from analog screen-film radiography to DR requires thorough user education because of differences in image production, processing, storage and evaluation between the forms of radiography. Without adequate education, radiologic technologists could unknowingly expose children to higher radiation doses than necessary for adequate radiograph quality. To evaluate knowledge about image quality and dose management in pediatric DR among radiologic technologists in the U.S. This communication describes a survey of 493 radiologic technologists who are members of the American Society of Radiologic Technologists (ASRT) and who evaluated the current state of radiological technologist education in image quality and dose management in pediatric DR. The survey included 23 survey questions regarding image acquisition issues, quality assurance, radiation exposure and education in DR of infants and children. Radiologic technologists express many needs in areas of training and education in pediatric DR. Suggested improvements include better tools for immediate feedback about image quality and exposure, more information about appropriate technique settings for pediatric patients, more user-friendly vendor manuals and educational materials, more reliable measures of radiation exposure to patients, and more regular and frequent follow-up by equipment vendors. There is a clear and widespread need for comprehensive and practical education in digital image technology for radiologic technologists, especially those engaged in pediatric radiography. The creation of better educational materials and training programs, and the continuation of educational opportunities will require a broad commitment from equipment manufacturers and vendors, educational institutions, pediatric radiology specialty organizations, and individual imaging specialists.

565 ASSESMENT OF PEDIATRIC RADIATION EXPOSURE DURING URETEROSCOPY

You have accessJournal of UrologyPediatrics: Imaging/Infections & Vesicoureteral Reflux1 Apr 2011565 ASSESMENT OF PEDIATRIC RADIATION EXPOSURE DURING URETEROSCOPY Paul Kokorowski, Jeanne Chow, Keith Strauss, Melanie Pennison, and Caleb Nelson Paul KokorowskiPaul Kokorowski Boston, MA More articles by this author , Jeanne ChowJeanne Chow Boston, MA More articles by this author , Keith StraussKeith Strauss Boston, MA More articles by this author , Melanie PennisonMelanie Pennison Boston, MA More articles by this author , and Caleb NelsonCaleb Nelson Boston, MA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.1375AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Pediatric patients are more sensitive to ionizing radiation than adults. The ′as low as reasonably achievable′ (ALARA) principle requires efforts to minimize exposure to the patient, but little is known about radiation exposure during urologic procedures in children, including ureteroscopy (URS) for urolithiasis. The aim of this study was to measure radiation exposure during pediatric URS and identify opportunities for quality improvement. METHODS We performed a prospective direct observation of URS procedures as part of a quality improvement initiative. Information regarding pre-operative patient characteristics, operative factors, fluoroscopy unit settings and radiation exposure were recorded. Primary outcomes were total fluoroscopy time (min) and patient skin entrance dose (SED, in mGy). Specific modifiable factors were identified from observations as targets for potential quality improvement. Univariate tests of association were used to identify specific patient and operative factors associated with primary outcomes. RESULTS Direct observation was performed on 48 consecutive ureteroscopic procedures at a single institution. 34 procedures were included in our analysis after excluding two procedures for arterio-venous malformations, one terminated procedure, and 11 non-pediatric patients (≥21 years of age). Median patient age was 16.5 years old (range 7.4 to 19.2). 21% (7/34) procedures resulted in failure to treat a stone due to spontaneous passage or difficult access. Median total fluoroscopy time was 2.85 min (range 0.4–6.7) and median SED was 42.7mGy (range 2.23–223.4).For reference purposes, SED for chest x-ray in a 15 year old is ∼0.16 mGy. There was considerable variability across multiple examined factors and thus no single factor was significantly associated with fluoroscopy time and only source to skin distance (SSD) was associated with skin entrance dose (p=0.02). However, several other modifiable factors including fluoroscopic image rate and field of view demonstrated opportunities for dose reduction. CONCLUSIONS Pediatric patients receive considerable radiation exposure during ureteroscopic procedures. No specific modifiable factors were consistently predictive of total fluoroscopy time and only SSD was associated with skin entry dose. Large variations limited the power to detect differences. Multiple potential methods for potential radiation reduction were identified and future efforts will focus on implementing dose reduction strategies consistent with the ALARA principle. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e228 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Paul Kokorowski Boston, MA More articles by this author Jeanne Chow Boston, MA More articles by this author Keith Strauss Boston, MA More articles by this author Melanie Pennison Boston, MA More articles by this author Caleb Nelson Boston, MA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Hand and Body Radiation Exposure With the Use of Mini C-Arm Fluoroscopy

To determine whole body and hand radiation exposure to the hand surgeon wearing a lead apron during routine intraoperative use of the mini C-arm fluoroscope. Four surgeons (3 hand attending surgeons and 1 hand fellow) monitored their radiation exposure for a total of 200 consecutive cases (50 cases per surgeon) requiring mini C-arm fluoroscopy. Each surgeon measured radiation exposure with a badge dosimeter placed on the outside breast pocket of the lead apron (external whole body exposure), a second badge dosimeter under the lead apron (shielded whole body exposure), and a ring dosimeter (hand exposure). Completed records were noted in 198 cases, with an average fluoroscopy time of 133.52 seconds and average cumulative dose of 19,260 rem-cm(2) per case. The total measured radiation exposures for the (1) external whole body exposure dosimeters were 16 mrem (for shallow depth), 7 mrem (for eye depth), and less than 1 mrem (for deep depth); (2) shielded whole body badge dosimeters recorded less than 1 mrem; and (3) ring dosimeters totaled 170 mrem. The total radial exposure for 4 ring dosimeters that had registered a threshold of 30 mrem or more of radiation exposure was 170 mrem at the skin level, for an average of 42.5 mrem per dosimeter ring or 6.3 mrem per case. This study of whole body and hand radiation exposure from the mini C-arm includes the largest number of surgical cases in the published literature. The measured whole body and hand radiation exposure received by the hand surgeon from the mini C-arm represents a minimal risk of radiation, based on the current National Council on Radiation Protection and Management standards of annual dose limits (5,000 mrem per year for whole body and 50,000 mrem per year to the extremities).

Fluoroscopic Radiation Exposure during Percutaneous Kyphoplasty

The author measured levels of fluoroscopic radiation exposure to the surgeon's body based on the different beam directions during kyphoplasty. This is an observational study. A series of 84 patients (96 vertebral bodies) were treated with kyphoplasty over one year. The patients were divided into four groups based on the horizontal and vertical directions of the X-Ray beams. We measured radiation exposure with the seven dosimetry badges which were worn by the surgeon in each group (total of 28 badges). Twenty-four procedures were measured in each group. Cumulative dose and dose rates were compared between groups. Fluoroscopic radiation is received by the operator in real-time for approximately 50% (half) of the operation time. Thyroid protectors and lead aprons can block radiation almost completely. The largest dose was received in the chest irrespective of beam directions. The lowest level of radiation were received when X-ray tube was away from the surgeon and beneath the bed (dose rate of head, neck, chest, abdomen and knee : 0.2986, 0.2828, 0.9711, 0.8977, 0.8168 mSv, respectively). The radiation differences between each group were approximately 2.7-10 folds. When fluoroscopic guided-KP is performed, the X-Ray tube should be positioned on the opposite side of the operator and below the table, otherwise the received radiation to the surgeon's body would be 2.7-10 times higher than such condition.

The risk of radiation exposure to the eyes of the interventional pain physician.

It is widely accepted that the use of medical imaging continues to grow across the globe as does the concern for radiation safety. The danger of lens opacities and cataract formation related to radiation exposure is well documented in the medical literature. However, there continues to be controversy regarding actual dose thresholds of radiation exposure and whether these thresholds are still relevant to cataract formation. Eye safety and the risk involved for the interventional pain physician is not entirely clear. Given the available literature on measured radiation exposure to the interventionist, and the controversy regarding dose thresholds, it is our current recommendation that the interventional pain physician use shielded eyewear. As the breadth of interventional procedures continues to grow, so does the radiation risk to the interventional pain physician. In this paper, we attempt to outline the risk of cataract formation in the scope of practice of an interventional pain physician and describe techniques that may help reduce them.

Study of Radiation Safety Concerns in Departments of Diagnostic Radiology of various Hospitals of Kashmir valley

BACKGROUND: A primary consideration in any radiographic procedure is to reduce the dose to the patient and the operator while still achieving the diagnostic goals.&#x0D; OBJECTIVE: To study the radiation exposure and protective measures in different units of various hospitals in Kashmir valley in compliance to recommendations from regulatory authorities.&#x0D; METHODS: Twenty-eight stationary X-ray units of various major hospitals of the Kashmir Valley were surveyed by the radiation safety group of SKIMS. Panoramic survey meter, Thyac-V survey meter-470A, Prima-7 digital survey meters were used for radiation exposure estimations. The radiation level measurements were carried out at different critical locations like control console, door and the corridor adjacent to the Diagnostic equipment and were compared with the standards of AERB and IAEA.&#x0D; RESULTS: Of the 28 stationary X-Ray units identified 21 were functional and surveyed. Seventy seven Radiation workers (Technicians) operating these units perform about 1335 diagnostic procedures daily on these units. Out of 21 X-ray units surveyed, 9 (42.86%) had dose rate at the control panel within the permissible limits and 12(57.14%) had exposure levels higher than permissible limits. The dose levels at the door and corridor were exceeding the permissible limits in all the units. Most of the radiation workers had no concept of radiation protective measures and did not use any personal radiation monitoring device like TLD (Thermo-luminescent dosimeter).&#x0D; CONCLUSIONS: To avoid radiation exposure, the radiation safety measures ought to be strictly followed which is possible by making the concerned authorities answerable and accountable. Also the radiation workers need to be made aware of hazards of radiation exposure, importance of using personnel monitoring devices and providing knowledge about the safety measures. (JMS 2010;13(2):51-55)

Measurement and calculation of cosmic radiation exposure during a pole-to-pole flight sequence

Cosmic ray dosimetry measurements were carried out on board a Global Express business jet operated by TAG Aviation (UK) during a pole-to-pole flight sequence that took place in November 2008. One Hawk TEPC and two EPDN2s were flown, and the TEPC measurements compared to calculated values from the route dose codes AVIDOS, CARI 6M, EPCARD versions 3.2 and 3.34, QARM and SIEVERT (online version). The largest difference between measured and calculated doses for the total flight sequence was found to be 13%. Agreement between the readings of the TEPC and the EPDN2s (once a calibration factor from the CERN High Energy Reference Field had been applied) was reasonably good given the relatively large uncertainties associated with the EPDN2 measurements.

Risk of radiation exposure during PCNL.

Fluoroscopic guidance is a routine practice in endourology; both the physician and the assistants are exposed to some radiation via radiation scatter. Measurement of radiation doses in staff is important, but often these data are not reported. We measured radiation exposure during 100 cases of percutaneous nephrolithotomy using lithium fluoride thermoluminescent dosimeters placed at the head, eye glasses, the fingers, and the legs of the operating surgeon, the assistant, and the circulating nurse. The mean screening time was 4.5 minutes (range, 1 to 8 minutes) with mean fluoroscopy tube potential of 73 kVp, and mean tube current of 2.8 mA. The estimated scatter exposure rate at 40 cm from the x-ray beam was 0.47, 0.04, 0.21, and 4.1 microGy to the head, eye glasses, the fingers, and the legs of the operating surgeon, respectively. The estimated scatter exposure rate at different points from the x-ray beam was 0.05, 0.01, 0.025, and 0.1 microGy to the head, eye glasses, the fingers, and the legs of the assistant, respectively and the estimated scatter exposure rate at all different points from the x-ray beam for circulating nurse was 0 microGy. Fluoroscopic screening results in radiation exposure of the medical staff. The surgeon received the maximum radiation exposure, mostly to the legs and very least to the eyes. The assistant received less radiation exposure than the surgeon and the nurse did not receive significant amount of radiation.

SU-GG-I-81: Partial Volume Characteristics of Ionization Chambers in Kilovoltage X-Ray Exposure Measurements

Purpose: The study is designed to evaluate partial volume response of ionization chambers used for measuring radiation exposure in quality control in radiology. Materials and Methods: A diagnostic x-ray unit(Philip Super 80 CP) was used to measure partial volume response of 15cm3, 150cm3 and 600cm3 chambers for 81kVp, 400mA, and 0.25s. The beam output was measured using a monitor chamber (Radcal 6.0cm3) placed close to the collimator. A slit of 2.0mm wide made in a lead sheet of 3.2mm thick and size of 30×30cm2 was placed on the ionization chamber and moved in an increment of 2.0mm over the entire length of the chamber. For the measurements of the ionization chamber of 10 cm3(CT chamber), the beams of 120kVp, 200mA and 0.2s were generated, and a slit of 5mm wide was made in a similar lead sheet that was moved in an increment of 5.0mm. All measurements were made at source to chamber distance of 1.0meter. Results: Keithley 15cm3 Model 96035 B ion chamber exhibits a narrow region (30–50mm) from the edge of the chamber of increased sensitivity. Beyond the region the exposure measurement decreases relative to the chamber position exhibiting a partial volume effect. Keithley 150cm3 Model 96020C, the center of the chamber 55mm to 90mm shows an area of increased sensitivity with sensitivity decreases at the edges. Keithley 600cm3 Model96050, and Keithley Computed Tomography Chamber(10cm3) Model 500-200: the response of the chambers is uniform along its axis. However, the sensitivity decreases at the edges (1cm from either side) of the ion chambers. Conclusion: The spatial dependence of ion chambers sensitivity varies from chamber to chamber. It is therefore, important that ion chamber behavior and the manufacturer's specification should be strictly adhered such as dose and dose rate changes, operating voltage, x-ray energy and/or spectral characteristics.

Anesthetic Considerations for Electrophysiologic Studies and Catheter Ablations

OPEN ACCESSMay 14, 2010Anesthetic Considerations for Electrophysiologic Studies and Catheter Ablations Mary Arthur, MD, Nadine Odo, Adam Berman, MD Mary Arthur, MD Medical College of Georgia at Georgia Regents University Google Scholar More articles by this author , Nadine Odo Medical College of Georgia Google Scholar More articles by this author , Adam Berman, MD Medical College of Georgia Google Scholar More articles by this author https://doi.org/10.15766/mep_2374-8265.7985 SectionsAbout ToolsDownload Citations ShareFacebookTwitterEmail AbstractWith increasingly complex electrophysiologic procedures, particularly in patients with complex cardiovascular disease, the presence of an anesthesiologist in the electrophysiology lab has become more important. Anesthesiologists currently in training are likely to be involved in such procedures. This resource is intended to give anesthesia providers, including residents, medical students, and faculty, a better understanding of the basics of electrophysiologic procedures, the varied responses of both normal and abnormal myocardial tissue to volatile and intravenous anesthetic agents, and the anesthetic equipment required for the electrophysiology lab. This resource can be presented in 20 to 45 minutes, depending on the experience of the students. We have been able to successfully implement this program by using it as a training resource for faculty, residents, and medical students. For residents, training shortly before their scheduled time in the electrophysiologic lab will help to ensure retention of the information learned. Educational Objectives By the end of this resource, participants will be able to: Describe the interaction between anesthetic agents and the normal conduction system of the heart.Become familiar with which drugs to avoid.Identify the various “phases” of any catheter ablation procedure.Become familiar with the various techniques/maneuvers used by the electrophysiologist to modulate autonomic tone to induce arrhythmias in the electrophysiologic laboratory.Become familiar with the risks of radiation exposure and precautionary measures to limit these risks. Sign up for the latest publications from MedEdPORTAL Add your email below FILES INCLUDEDReferencesRelatedDetails FILES INCLUDED Included in this publication: Instructor's Guide.pdf Slides.pdf Guide.pdf To view all publication components, extract (i.e., unzip) them from the downloaded .zip file. Download editor’s noteThis publication may contain technology or a display format that is no longer in use. CitationArthur M, Odo N, Berman A. Anesthetic Considerations for Electrophysiologic Studies and Catheter Ablations. MedEdPORTAL. 2010;6:7985. https://doi.org/10.15766/mep_2374-8265.7985 Copyright & Permissions© 2010 Arthur et al. This is an open-access publication distributed under the terms of the Creative Commons Attribution-NonCommercial-Share Alike license.KeywordsRadiationElectrophysiologyCatheter AblationCardiac ArrythmiaConduction AnesthesiaLocal Anesthesia Disclosures None to report. Funding/Support None to report. Loading ...

Radiation Exposure in Percutaneous Spinal Cord Stimulation Mapping: A Preliminary Report

Background: The utilization of spinal cord stimulation (SCS) to treat intractable pain has increased substantially in recent years. Integral to this therapy, the fluoroscope assists with requisite mapping protocols during trialing procedures to identify topographical dermatomal representations of spinal segments, and its use demands measurements of radiation exposure. However, such data is not found in the literature. Purpose: The aim of this study was to report on radiation exposure during percutaneous SCS trialing procedures. Design: An observational study. Setting: A non-university out-patient Interventional Pain Management practice in the United States. Methods: Fluoroscopy time from 110 SCS trialing procedures performed in a non-university, outpatient setting was studied retrospectively. Summary statistics were reported for all procedures collectively, as well as for lead arrangement and location. The interventional spine team carried out all procedural cases with the same mobile C-arm fluoroscopy system. Incident air kerma was evaluated by simplistic modeling. Results: Mean total fluoroscopy time was 133.4 s with a standard deviation of 84.8 s, and the mean percentage of time allocated to pulsed fluoroscopy was 31.9%. Fluoroscopy time for the most common lead arrangement/location, neural canal dual leads/low-thoracic (n=87), ranged from 28.5 s to 387.4 s. Incident air kerma was 1.8–43.7 mGy. Limitations: A preliminary report with a sample size of 110. Conclusion: Various lead placement options are available to the spinal interventionalist to treat pain with SCS. Our data set provides first steps to obtain benchmark reference estimates on fluoroscopy times and radiation exposure during SCS trialing procedures/spinal segment mapping. Fluoroscopy times for such interventions may be considerable when compared to more commonly performed pain medicine procedures; however, skin injury is improbable. Key words: Neuromodulation, radiation safety, fluoroscopy, dosimetry, dose reduction, health physics

049 Marked reduction of operator radiation exposure by using a patient lead cover during coronary angiography or percutaneous intervention

Operators and patient radiation exposure during interventional cardiology procedures may induce radiation injury and may increase risk of cancer. To determine the effectiveness of a lead cover placed over the patient abdomen and groins in reducing operator radiation exposure during coronary intervention. Radiation exposure measurements were performed over an 8 weeks period, in patients undergoing diagnostic and/or interventional coronary procedures. Usual protection of the operator was ensured using a lead apron, low leaded flaps, and leaded glass. Each of three procedures was realized using a lead cover placed on the patient abdomen. Operator irradiation was assessed by using 3 electronic dosimeters placed over the apron on the chest and in the back (no 1, 2) on the left arm (no 3). Patient radiation exposure (using the diamentor system), ambiental irradiation (using an electronic dosimeter placed in the room opposite to the Xray tube) and fluoroscopy times were recorded. Results are presented in mean ± SEM and comparisons assessed by student t test. Operator exposure was assessed during 189 procedures (136 coronary angiograms and 53 percutaneous coronary interventions) in 71 cases (37%) with the lead cover over the patient (group 1) and in 118 cases (63%) without it (group 2). Fluoroscopy times, dose area products and ambient irradiation were similar with and without the lead cover (4 ± 2 vs 4.1 ± 0.6 min, 55,7 ± 5,8 vs 57,6 ± 4,2 Gy cm 2 and 0.7 ± 0.2 vs 0.8 ± 0.1 μSv respectively – p > 0.05). However, operator irradiation was markedly decreased by using the lead cover: from 19.2 ± 3.1 to 4.9 ± 0.9 μSv at the chest level (p=0,001), from 1.8 ± 0.3 to 0.3 ± 0.1 μSv at the back (p=0.002) and from 25.8 ± 4.7 to 10.2 ± 2.2 μSv at the left arm (p=0,019). Using a lead cover placed over the patient is highly effective in attenuating operator scatter radiation exposure during coronary procedure. Such additional protection device might be useful either in the perspective of long duration procedure or in routine use.