Skin injuries from fluoroscopically guided procedures: part 2, review of 73 cases and recommendations for minimizing dose delivered to patient

Efforts to optimize radiation protection in interventional fluoroscopy

While it has been known for more than a century that radiation presents risks to both the physician and the patient, skin injuries from fluoroscopy became increasingly rare after the 1930s, and radiation risk from fluoroscopy appeared to be adequately controlled. However, beginning in approximately 1975, new technologies and materials for interventional devices were developed. These enabled new procedures, and as these were instituted, skin injuries again occurred in patients. Four central issues were identified: equipment, quality management, operator training, and occupational radiation protection. Recognition that these were areas for improvement provoked changes in technology and practice that continue today.

Reversed C-arm projection for reduction of focal skin radiation exposure: experimental analysis and first clinical experience

Radiodermatitis, predominantly over the right scapula, is a well-known complication of complex percutaneous coronary interventions (PCI). To reduce focal radiation exposure, we analyzed an inversed X-ray beam direction using a reversed C-arm position. On phantom experiment, we found that 130° right anterior oblique projection reduced skin dose over the right scapula by 98.2 % (P < 0.001) compared with conventional 50° left anterior oblique projection. A 73-year-old man with history of bypass surgery, multiple PCI and chronic radiodermatitis over the right scapula presented with recurrent chest pain. After successful PCI using the reversed C-arm projection, no aggravation of radiodermatitis was found.

Radiation-induced noncancer risks in interventional cardiology: optimisation of procedures and staff and patient dose reduction

Concerns about ionizing radiation during interventional cardiology have been increased in recent years as a result of rapid growth in interventional procedure volumes and the high radiation doses associated with some procedures. Noncancer radiation risks to cardiologists and medical staff in terms of radiation-induced cataracts and skin injuries for patients appear clear potential consequences of interventional cardiology procedures, while radiation-induced potential risk of developing cardiovascular effects remains less clear. This paper provides an overview of the evidence-based reviews of concerns about noncancer risks of radiation exposure in interventional cardiology. Strategies commonly undertaken to reduce radiation doses to both medical staff and patients during interventional cardiology procedures are discussed; optimisation of interventional cardiology procedures is highlighted.

[Inspection of dose reduction in patients during percutaneous coronary intervention and catheter ablation procedures]

With an increasing number of interventional radiology (IVR) procedures, it is a critical issue to control and reduce the radiation dose for patients by radiological technologists. In our study, we analyzed the usefulness of a provision for radiation reduction on catheter ablation and percutaneous coronary intervention (PCI) procedures based on the data from radiation information system (RIS). With regard to catheter ablation, 50% reduction was enabled with decreasing fluoroscopic and radiographic conditions regardless of each technique. Radiation reduction enabled a decrease in the fluoroscopic dose during PCI procedure. However, note that excessive radiation reduction does not show positive results of the radiation dose reduction. Moreover it leads to an increase in fluoroscopic time.

Surgeon education decreases radiation dose in complex endovascular procedures and improves patient safety

OBJECTIVE

Complex endovascular procedures such as fenestrated endovascular aneurysm repair (FEVAR) are associated with higher radiation doses compared with other fluoroscopically guided interventions (FGIs). The purpose of this study was to determine whether surgeon education on radiation dose control can lead to lower reference air kerma (RAK) and peak skin dose (PSD) levels in high-dose procedures.

METHODS

Radiation dose and operating factors were recorded for FGI performed in a hybrid room over a 16-month period. Cases exceeding 6 Gy RAK were investigated according to institutional policy. Information obtained from these investigations led to surgeon education focused on reducing patient dose. Points addressed included increasing table height, utilizing collimation and angulation, decreasing magnification modes, and maintaining minimal patient-to-detector distance. Procedural RAK doses and operating factors were compared 8 months pre- (group A) and 8 months post- (group B) educational intervention using analysis of variance with Tukey pairwise comparisons and t-tests. PSD distributions were calculated using custom software employing input data from fluoroscopic machine logs.

RESULTS

Of 447 procedures performed, 300 FGIs had sufficient data to be included in the analysis (54% lower extremity, 11% thoracic endovascular aneurysm repair, 10% cerebral, 8% FEVAR, 7% endovascular aneurysm repair, 5% visceral, and 5% embolization). Twenty-one cases were investigated for exceeding 6 Gy RAK. FEVAR comprised 70% of the investigated cases and had a significantly higher median RAK dose compared with all other FGIs (P < .0001). There was no difference in body mass index between groups A and B; however, increasing body mass index was an indicator for increased RAK. PSD calculations were performed for the 122 procedures that focused on the thorax and abdomen (group A, 80 patients; group B, 42 patients). Surgeon education most strongly affected table height, with an average table height elevation of 10 cm per case after education (P < .0001). The dose index (PSD/RAK ratio) was used to track changes in operating practices, and it decreased from 1.14 to 0.79 after education (P < .0001). These changes resulted in an estimated 16% reduction in PSD. There was a trend toward a decrease in patient to detector distance, and the use of collimation increased from 25% to 40% (P < .001) for all cases; however, these did not result in a decrease in PSD. The number of cases that exceeded 6 Gy RAK did not change after education; however, the proportion of non-FEVAR cases that exceeded 6 Gy decreased from 40% to 20%.

CONCLUSIONS

Surgeon education on the appropriate use of technical factors during FGIs improved operating practice, reduced patient radiation dose, and decreased the number of non-FEVAR cases that exceeded 6 Gy. It is essential that vascular surgeons be educated in best operating practices to lower PSD; nonetheless, FEVAR remains a high-dose procedure.

Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging

X-ray fluoroscopy-guided endovascular procedures have several significant limitations, including difficult catheter navigation and use of ionizing radiation, which can potentially be overcome using a magnetically steerable catheter under MR guidance. The main goal of this work is to develop a microcatheter whose tip can be remotely controlled using the magnetic field of the MR scanner. This protocol aims to describe the procedures for applying current to the microcoil-tipped microcatheter to produce consistent and controllable deflections. A microcoil was fabricated using laser lathe lithography onto a polyimide-tipped endovascular catheter. In vitro testing was performed in a waterbath and vessel phantom under the guidance of a 1.5-T MR system using steady-state free precession (SSFP) sequencing. Various amounts of current were applied to the coils of the microcatheter to produce measureable tip deflections and navigate in vascular phantoms. The development of this device provides a platform for future testing and opportunity to revolutionize the endovascular interventional MRI environment.

Updates in the real-time Dose Tracking System (DTS) to improve the accuracy in calculating the radiation dose to the patients skin during fluoroscopic procedures

We have developed a dose-tracking system (DTS) to manage the risk of deterministic skin effects to the patient during fluoroscopic image-guided interventional cardiac procedures. The DTS calculates the radiation dose to the patient's skin in real-time by acquiring exposure parameters and imaging-system geometry from the digital bus on a Toshiba C-arm unit and displays the cumulative dose values as a color map on a 3D graphic of the patient for immediate feedback to the interventionalist. Several recent updates have been made to the software to improve its function and performance. Whereas the older system needed manual input of pulse rate for dose-rate calculation and used the CPU clock with its potential latency to monitor exposure duration, each x-ray pulse is now individually processed to determine the skin-dose increment and to automatically measure the pulse rate. We also added a correction for the table pad which was found to reduce the beam intensity to the patient for under-table projections by an additional 5-12% over that of the table alone at 80 kVp for the x-ray filters on the Toshiba system. Furthermore, mismatch between the DTS graphic and the patient skin can result in inaccuracies in dose calculation because of inaccurate inverse-square-distance calculation. Therefore, a means for quantitative adjustment of the patient-graphic-model position and a parameterized patient-graphic library have been developed to allow the graphic to more closely match the patient. These changes provide more accurate estimation of the skin-dose which is critical for managing patient radiation risk.

Occupational dose in interventional radiology procedures

OBJECTIVE

Interventional radiology tends to involve long procedures (i.e., long fluoroscopic times). Therefore, radiation protection for interventional radiology staff is an important issue. This study describes the occupational radiation dose for interventional radiology staff, especially nurses, to clarify the present annual dose level for interventional radiology nurses.

MATERIALS AND METHODS

We compared the annual occupational dose (effective dose and dose equivalent) among interventional radiology staff in a hospital where 6606 catheterization procedures are performed annually. The annual occupational doses of 18 physicians, seven nurses, and eight radiologic technologists were recorded using two monitoring badges, one worn over and one under their lead aprons.

RESULTS

The annual mean ± SD effective dose (range) to the physicians, nurses, and radiologic technologists using two badges was 3.00 ± 1.50 (0.84-6.17), 1.34 ± 0.55 (0.70-2.20), and 0.60 ± 0.48 (0.02-1.43) mSv/y, respectively. Similarly, the annual mean ± SD dose equivalent range was 19.84 ± 12.45 (7.0-48.5), 4.73 ± 0.72 (3.9-6.2), and 1.30 ± 1.00 (0.2-2.7) mSv/y, respectively. The mean ± SD effective dose for the physicians was 1.02 ± 0.74 and 3.00 ± 1.50 mSv/y for the one- and two-badge methods, respectively (p < 0.001). Similarly, the mean ± SD effective dose for the nurses (p = 0.186) and radiologic technologists (p = 0.726) tended to be lower using the one-badge method.

CONCLUSION

The annual occupational dose for interventional radiology staff was in the order physicians > nurses > radiologic technologists. The occupational dose determined using one badge under the apron was far lower than the dose obtained with two badges in both physicians and nonphysicians. To evaluate the occupational dose correctly, we recommend use of two monitoring badges to evaluate interventional radiology nurses as well as physicians.

Patient radiation dose management in the follow-up of potential skin injuries in neuroradiology

BACKGROUND AND PURPOSE

Radiation exposure from neurointerventional procedures can be substantial, with risk of radiation injuries. We present the results of a follow-up program applied to potential skin injuries in interventional neuroradiology based on North American and European guidelines.

MATERIALS AND METHODS

The following guidelines approved in 2009 by SIR and CIRSE have been used over the last 2 years to identify patients with potential skin injuries requiring clinical follow-up: peak skin dose >3 Gy, air kerma at the patient entrance reference point >5 Gy, kerma area product >500 Gy · cm(2), or fluoroscopy time >60 minutes.

RESULTS

A total of 708 procedures (325 in 2009 and 383 in 2010) were included in the study. After analyzing each dose report, 19 patients (5.9%) were included in a follow-up program for potential skin injuries in 2009, while in 2010, after introducing several optimizing actions and refining the selection criteria, only 4 patients (1.0%) needed follow-up. Over the last 2 years, only 3 patients required referral to a dermatology service.

CONCLUSIONS

The application of the guidelines to patient radiation dose management helped standardize the selection criteria for including patients in the clinical follow-up program of potential skin radiation injuries. The peak skin dose resulted in the most relevant parameter. The refinement of selection criteria and the introduction of a low-dose protocol in the x-ray system, combined with a training program focused on radiation protection, reduced the number of patients requiring clinical follow-up.

ICRP PUBLICATION 120: Radiological protection in cardiology

Cardiac nuclear medicine, cardiac computed tomography (CT), interventional cardiology procedures, and electrophysiology procedures are increasing in number and account for an important share of patient radiation exposure in medicine. Complex percutaneous coronary interventions and cardiac electrophysiology procedures are associated with high radiation doses. These procedures can result in patient skin doses that are high enough to cause radiation injury and an increased risk of cancer. Treatment of congenital heart disease in children is of particular concern. Additionally, staff(1) in cardiac catheterisation laboratories may receive high doses of radiation if radiological protection tools are not used properly. The Commission provided recommendations for radiological protection during fluoroscopically guided interventions in Publication 85, for radiological protection in CT in Publications 87 and 102, and for training in radiological protection in Publication 113 (ICRP, 2000b,c, 2007a, 2009). This report is focused specifically on cardiology, and brings together information relevant to cardiology from the Commission's published documents. There is emphasis on those imaging procedures and interventions specific to cardiology. The material and recommendations in the current document have been updated to reflect the most recent recommendations of the Commission. This report provides guidance to assist the cardiologist with justification procedures and optimisation of protection in cardiac CT studies, cardiac nuclear medicine studies, and fluoroscopically guided cardiac interventions. It includes discussions of the biological effects of radiation, principles of radiological protection, protection of staff during fluoroscopically guided interventions, radiological protection training, and establishment of a quality assurance programme for cardiac imaging and intervention. As tissue injury, principally skin injury, is a risk for fluoroscopically guided interventions, particular attention is devoted to clinical examples of radiation-related skin injuries from cardiac interventions, methods to reduce patient radiation dose, training recommendations, and quality assurance programmes for interventional fluoroscopy.

Fluoroscopy-induced chronic radiation dermatitis

A 62-year-old man with a history of 2 previous cardiac catheterizations presented with an itchy, nontender skin lesion over his right scapula. The skin lesion had been present for >5 years. Review of the medical records found evidence of a prolonged and complicated cardiac catheterization 8 years previously. Physical examination revealed an 8 × 6 cm, well-demarcated, erythematous reticulated atrophic plaque with telangiectasias and ulceration. Biopsy confirmed histologic changes consistent with radiation dermatitis. In conclusion, the characteristic histologic findings of radiation dermatitis, along with the location over the right scapula and the history of prolonged fluoroscopic exposure during cardiac catheterization, led to the clinical diagnosis of fluoroscopy-induced chronic radiation dermatitis.

The necessity of follow-up for radiation skin injuries in patients after percutaneous coronary interventions: radiation skin injuries will often be overlooked clinically

BACKGROUND

Percutaneous coronary intervention (PCI) offers great benefit that could improve a patient's quality of life. However, numerous case reports of patient radiation injury resulting from PCI are being published, these reports likely represent a small fraction of the actual cases.

PURPOSE

To demonstrate the appropriate duration of patient follow-up after PCI to identify radiation effects.

MATERIAL AND METHODS

We evaluated 400 consecutive PCIs. The radiation dose (dose-area product, cumulative dose, maximum skin dose), number of cine runs, and fluoroscopic time were recorded for all patients. The skin on the patients' backs was reviewed periodically after PCI.

RESULTS

Radiation skin effects occurred in six patients from PCI of the right coronary artery in chronic total occlusion (CTO) patients (mild erythema; occurrence rate 1.5%). Skin injury in two patients appeared in cycles. In most cases, erythema was vividly seen at 4 weeks after PCI.

CONCLUSION

Careful observation for skin injury is needed. At a few days following PCI, early erythema can be detected through careful observation by well-trained staff. At 7-10 days after PCI, most erythematous pigmentation can be detected. At 4 weeks after PCI, most skin erythema appears clearly, however, some cases of skin erythema occur without back pain. After that, follow-up every 6 months is needed to detect the reappearance of erythema.

Use of GAFCHROMIC XR type R films for skin-dose measurements in interventional radiology: Validation of a dosimetric procedure on a sample of patients undergone interventional cardiology

The Gafchromic XR type R film is a suitable dosimeter to determine the map of the skin dose in patients undergone complex interventional radiological procedures, such as cardiology ones. The need of preventing or locating possible skin injuries due to high doses administered to patients-as recommended by international organizations-wants the introduction in patient dosimetry of a dosimeter easy to handle, with low dependence of the response on energy in the typical radiological range, and extended measurable dose range. XR type R films fulfil all these requirements and moreover may be quickly analyzed by cheap commercial scanners. In order to determine skin-dose values by XR-R, a film calibration curve is required. In this work, validation of the XR-R dosimetry has been performed for the determination of the skin dose: maximum skin-dose values in 14 patients undergone radiofrequency ablation and pacemaker implant procedures have been determined by XR-R calibrated films. A comparison between skin-dose values determined by XR-R films and retrospective ionometric measurements has pointed out some discrepancies in the results, due to difficulties in retrospectively reproducing the real procedure settings, where XR-R film dosimetry is related to the specific patient procedure, even, in very complex interventional settings.

Occupational radiation doses to operators performing fluoroscopically-guided procedures

In the past 30 y, the numbers and types of fluoroscopically-guided (FG) procedures have increased dramatically. The objective of the present study is to provide estimated radiation doses to physician specialists, other than cardiologists, who perform FG procedures. The authors searched Medline to identify English-language journal articles reporting radiation exposures to these physicians. They then identified several primarily therapeutic FG procedures that met specific criteria: well-defined procedures for which there were at least five published reports of estimated radiation doses to the operator, procedures performed frequently in current medical practice, and inclusion of physicians from multiple medical specialties. These procedures were percutaneous nephrolithotomy (PCNL), vertebroplasty, orthopedic extremity nailing for treatment of fractures, biliary tract procedures, transjugular intrahepatic portosystemic shunt creation (TIPS), head/neck endovascular therapeutic procedures, and endoscopic retrograde cholangiopancreatography (ERCP). Radiation doses and other associated data were abstracted, and effective dose to operators was estimated. Operators received estimated doses per patient procedure equivalent to doses received by interventional cardiologists. The estimated effective dose per case ranged from 1.7-56 μSv for PCNL, 0.1-101 μSv for vertebroplasty, 2.5-88 μSv for orthopedic extremity nailing, 2.0-46 μSv for biliary tract procedures, 2.5-74 μSv for TIPS, 1.8-53 μSv for head/neck endovascular therapeutic procedures, and 0.2-49 μSv for ERCP. Overall, mean operator radiation dose per case measured over personal protective devices at different anatomic sites on the head and body ranged from 19-800 (median = 113) μSv at eye level, 6-1,180 (median = 75) μSv at the neck, and 2-1,600 (median = 302) μSv at the trunk. Operators' hands often received greater doses than the eyes, neck, or trunk. Large variations in operator doses suggest that optimizing procedure protocols and proper use of protective devices and shields might reduce occupational radiation dose substantially.

Radiofrequency ablation of cardiac arrhythmias: past, present and future

The treatment of cardiac arrhythmias has been revolutionized by the ability to definitively treat many patients with radiofrequency catheter ablation, rather than requiring lifelong medication. This review covers the history of how this has developed and the methods used currently and explores what the future holds for this rapidly evolving branch of Cardiology.

[The comparison between dose rates at the interventional reference point of the angiography systems in many facilities]

The management of the radiation dose is very important in interventional radiology (IVR), especially in percutaneous coronary intervention (PCI). Therefore, we measured entrance surface doses at the interventional reference point of 27 cardiac intervention procedures in 22 cardiac catheterization laboratories around Hiroshima, and compared these doses. Recently, for cardiac interventional radiology, the X-ray machines using flat-panel detectors (FPD) instead of image intensifiers (I.I.) is increasing; 13 systems used FPD and 14 systems used I.I. For fluoroscopy rate, the difference between laboratories was 9 times. For cineangiography rate, the difference between laboratories was 7 times. In addition, between both devices, the I.I. group is bigger than the FPD group. When comparing by the same condition, for the dose at the interventional reference point, no significant difference was detected between the FPD group and the I.I. group. This study shows that FPD is not available for reducing the radiation dose simply. Therefore, it is necessary that we think of the balance with image quality and radiation dose. The optimization of the devices and cardiac intervention procedures becomes very important.

Occult radiation injury following angiographic procedures: recognition and treatment of an evolving complication

As the indications for fluoroscopically guided procedures increase, so do the potential complications from radiation. Radiation-induced wounds can have an insidious onset and time course that the plastic surgeon and wound specialist must be able to identify early. We review 3 cases of radiation-induced wounds following fluoroscopic procedures, which presented at various stages of diagnosis and healing. The pathophysiology of these wounds is discussed to aid in their diagnosis by providing an understanding of the resultant time course of injury and characteristics of the wounds. In addition, a familiarity of the concepts of interventional procedures and an increased element of caution in those patients most susceptible to injury is critical for prevention. Finally, an appropriate treatment protocol is proposed including early diagnosis, local wound care, hyperbaric oxygen, en bloc resection of the affected tissue, and reconstruction with tissue outside the zone of injury for recalcitrant or late stage wounds.

Clarifying and visualizing sources of staff-received scattered radiation in interventional procedures

OBJECTIVE

Interventional radiology tends to involve long procedures (i.e., long fluoroscopic times). Therefore, radiation protection for interventional radiology physicians and staff is an important issue. We examine and identify sources of staff-received scattered radiation in an interventional radiology system using a pinhole camera method.

CONCLUSION

Physicians and staff are exposed primarily to two sources of scattered radiation: radiation scattered from the patient and radiation from the cover of the x-ray beam collimating device. Those who stand close to the patient and the x-ray beam collimating device, where scattered radiation is higher, have higher radiation doses. Thus, radiation protection during interventional radiology procedures is an important problem.

Patients' radiation doses during thoracic stent-graft implantation: the problem of long-lasting procedures

BACKGROUND

This article investigates patient radiation doses during implantation of thoracic stent-graft. Aortic stengraft implantation can be disturbed by many factors, which, in turn, lead to prolongation of the procedure time and, as a consequence, increase the radiation dose.

METHODS

Measurements of radiation length (fluoroscopy and exposure), air kerma (AK) in grays, and dose-area product in grays·square centimeters were conducted simultaneously in 100 patients. The patients were analyzed retrospectively, regarding their body mass index (BMI), type of aneurysms, number of stent-graft parts, angulation of aorta, and coverage of the left subclavian artery.

RESULTS

Mean total dose-area product value for this kind of treatment was 361 Gy·cm2. This was caused by the fact that total mean AK was high for the cohort analyzed and reached 797 mGy. For 23 patients total AK was between 1 and 2 Gy, and for 3 it exceeded 2 Gy. In the remaining group, the maximal radiation dose was very high and exceeded 3 Gy. The total AK of patients with BMI within the range of 25 to 29.9 kg/m2 and with BMI greater than 30 kg/m2 significantly increased in comparison with the group of patients with BMI between 18 and 24.9 kg/m2 (p=0.00005 and 0.000001, respectively). During the study, a good correlation between AK and fluoroscopy time (r=0.6) and for AK (or dose-area product) and exposure time (r=0.66 or 0.81, respectively) was observed.

CONCLUSIONS

The main factors contributing to a high radiation dose being acquired by patients during thoracic stent-graft were BMI greater than 25 kg/m2, number of parts of the stent-graft, and angulation of the neck of aneurysm exceeding 60 degrees.

[Efficacy of patient skin dose reduction by a compensating filter through of irradiation field overlaps on the area during percutaneous coronary intervention]

Our study was involved with entrance surface dose reduction and irradiation field by the filter use of PCI, and insertion in place of an effective compensating filter to maximize entrance surface dose reduction, which we verified. The radiation dosimetry put a 6cc ion chamber on the back side of the thorax phantom, and changed the filter of the four corners (a: upper left, b: upper right, c: lower right, d: lower left) of the monitor confirmed with fluoroscopy [(0) no filter, (1) one filter, (2) two filters]. The angle of C arm was assumed to be eight directions and 0 degrees adopted by this hospital. It was compared with a corrective rate of which one was no filter. Next, the presence of filter and irradiation field overlaps on the area in monitor in the angle of C arm was verified by this hospital's classic example. As for corrective rate, (1) becomes 0.41 and (2) become 0.25 at fluoroscopy, (1) becomes 0.26 and (2) become 0.16 at exposure. Irradiation field overlaps on the area (+) compensating filter (-) was many with d of RAO/CAU, a of RAO and c of CAU at left CAG, c of LAO at right CAG, b of LAO/CRA (left CAG), b of CRA (right CAG) and a and d of RAO (right CAG) at both CAG. Irradiation field overlaps on the area (+) compensating filter (+) was many with b of CRA at left CAG, a of LAO/CRA at right CAG, b of CRA (left CAG) and b of RAO (right CAG) at both CAG. When the compensating filter is used the entrance surface dose reduction effect was great. If automatic exposure control protects the part of irradiation field overlaps on the area in the range without operating excessively, the radiological risk can be reduced, and it is conceivable as useful clinical setting.

Quality initiatives: Establishing an interventional radiology patient radiation safety program

The Interventional Radiology Patient Radiation Safety Program was created to better educate patients who are scheduled to undergo high-dose interventional radiologic procedures about the risks of radiation, better monitor the delivered doses, and reduce the risk for deterministic effects. The program combines preprocedure evaluation and counseling, intraprocedure monitoring, and postprocedure documentation and counseling with the guidelines of the National Cancer Institute and the Society of Interventional Radiology. Between July 2009, when the program was implemented, and September 2010, over 3500 interventional radiologic procedures were monitored and documented, and 63 procedures with an adjusted cumulative dose of more than 3 Gy were identified and further analyzed; four procedures were found to be outside the control limits. Additional review of these four procedures resulted in practice modifications. Anecdotal feedback from physician assistants and attending physicians indicated that the program had another positive effect: Patients who required postprocedure counseling about the potential for radiation-induced skin injuries were no longer surprised by this information. Implementation of this program is straightforward, requires little infrastructure and few resources, and may be applied in most interventional radiology practices. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.321115002/-/DC1.

Toward a holistic approach in the presentation of benefits and risks of medical radiation

Frequently messages are conveyed about benefit and risk in medical imaging or in imaging-guided medical intervention that are quite different from the intended communication. This is because communication is not merely the words used to express an idea. The message involves many personal factors on the part of the communicator and on the part of the audience. The intent of this article is to disclose some of the underlying factors that disproportionately bias communication of benefit and risk. Suggestions on how to develop a holistic communication of benefits and risks are presented. It is recommended that communication about the application of radiation to patients be disassociated from standard radiation protection concepts. The medical profession should develop unique communication tools to deliver a message that focuses on benefit/risk as a holistic entity, not benefit or risk as separate entities.

Increases in patient doses need to be avoided when upgrading interventional cardiology systems to flat detectors

The aim of this study was to evaluate patient doses in two interventional cardiology laboratories over a period of 1 y in which the imaging devices were changed from image intensifier (II) to flat detector (FD). Dosimetric data from a total of 1040 coronary angiography (CA) procedures and 1087 percutaneous transluminal coronary angioplasty (PTCA) procedures were gathered. During the period studied with II imaging, median values of dose area product were 28 Gy cm(2) for CA and 57 Gy cm(2) for PTCA. In the first half of the year with FD imaging, median values were 37 Gy cm(2) for CA and 89 Gy cm(2) for PTCA. A significant increase in patient doses was noticed in the early stages of use of FD technology for imaging IC procedures, while fluoroscopy time and number of images remained similar. A careful setting of the X-ray systems, after upgrading the imaging system, is essential to avoid unjustified increases in patient doses.

Skin injuries in interventional procedures

Radiation-induced skin injuries to patients in interventional procedures have been reported since the early 1990s, but the number reported is far less than what might be occurring around the world. There is a gross lack of awareness resulting in patients suffering. A case of severe injury observed in multiple percutaneous coronary interventions for chronic total occlusion is reported in this paper. Further, the paper summarises the existing knowledge on radiation dosimetry in interventional procedures, factors involved in skin injury, guidance on detection, and avoidance and management of injury when it occurs. Information on a recently launched international anonymous reporting system of the International Atomic Energy Agency is also included.

Automatic management system for dose parameters in interventional radiology and cardiology

The purpose of this work was to develop an automatic management system to archive and analyse the major study parameters and patient doses for fluoroscopy guided procedures performed in cardiology and interventional radiology systems. The X-ray systems used for this trial have the capability to export at the end of the procedure and via e-mail the technical parameters of the study and the patient dose values. An application was developed to query and retrieve from a mail server, all study reports sent by the imaging modality and store them on a Microsoft SQL Server data base. The results from 3538 interventional study reports generated by 7 interventional systems were processed. In the case of some technical parameters and patient doses, alarms were added to receive malfunction alerts so as to immediately take appropriate corrective actions.

[X-ray in trauma and orthopedic surgery. Physical and biological impact, reasonable use, and radiation protection in the operating room]

Orthopedic and especially trauma surgeons' use of x-rays during operations vary extensively, especially in minimally invasive osteosynthesis procedures. Radiation hazards often are neglected. In this paper, a short overview of physical and biological effects of radiation are given. In addition, practical information about how to lower radiation exposure in the daily work in the operating room (OR) is given. The operating team is exposed mainly to scattered radiation. The radiation exposure is 10 times higher on the tube side than on the amplifier side. The distance between tube and surgeon must be as great as possible. The tube should be positioned under the OR table, and the distance between tube and patient should be as short as possible. The positioning of the C-arm device without radiation is important. The use of patient landmarks is used to position the C-arm over the region of interest, but the preoperative training of surgeons and team with virtual learning tools, e.g., virtX, is very effective in reducing radiation hazards.

[Development of software for estimating exposure dose and radiation exposure region in cardiac catheterization inspection]

We developed software for estimating exposure doses and radiation exposure regions in cardiac catheterization inspection. In the software, the back of a thoracic phantom were divided into a total of 21 square blocks with a width of 30 degrees. Furthermore, we developed a system with which reference air kerma is distributed to each of the above blocks in accordance with the distribution ratio calculated from the data obtained by the system, and the calculation results are displayed. Coronary angiography was performed using thoracic phantoms, and actual measurements were obtained using a fluoroglass dosimeter. The calculated results obtained using the software were compared to the measured results. An almost identical tendency was seen, and the radiation regions of the top three estimated exposure doses were successfully estimated. Radiation region estimation using this software is affected by exposure time as one of its properties. This software enables estimating radiation exposure regions and exposure doses.

Calibration of GafChromic XR-RV3 radiochromic film for skin dose measurement using standardized x-ray spectra and a commercial flatbed scanner

PURPOSE

In this study, newly formulated XR-RV3 GafChromic film was calibrated with National Institute of Standards and Technology (NIST) traceability for measurement of patient skin dose during fluoroscopically guided interventional procedures.

METHODS

The film was calibrated free-in-air to air kerma levels between 15 and 1100 cGy using four moderately filtered x-ray beam qualities (60, 80, 100, and 120 kVp). The calibration films were scanned with a commercial flatbed document scanner. Film reflective density-to-air kerma calibration curves were constructed for each beam quality, with both the orange and white sides facing the x-ray source. A method to correct for nonuniformity in scanner response (up to 25% depending on position) was developed to enable dose measurement with large films. The response of XR-RV3 film under patient backscattering conditions was examined using on-phantom film exposures and Monte Carlo simulations.

RESULTS

The response of XR-RV3 film to a given air kerma depended on kVp and film orientation. For a 200 cGy air kerma exposure with the orange side of the film facing the source, the film response increased by 20% from 60 to 120 kVp. At 500 cGy, the increase was 12%. When 500 cGy exposures were performed with the white side facing the x-ray source, the film response increased by 4.0% (60 kVp) to 9.9% (120 kVp) compared to the orange-facing orientation. On-phantom film measurements and Monte Carlo simulations show that using a NIST-traceable free-in-air calibration curve to determine air kerma in the presence of backscatter results in an error from 2% up to 8% depending on beam quality. The combined uncertainty in the air kerma measurement from the calibration curves and scanner nonuniformity correction was +/- 7.1% (95% C.I.). The film showed notable stability. Calibrations of film and scanner separated by 1 yr differed by 1.0%.

CONCLUSIONS

XR-RV3 radiochromic film response to a given air kerma shows dependence on beam quality and film orientation. The presence of backscatter slightly modifies the x-ray energy spectrum; however, the increase in film response can be attributed primarily to the increase in total photon fluence at the sensitive layer. Film calibration curves created under free-in-air conditions may be used to measure dose from fluoroscopic quality x-ray beams, including patient backscatter with an error less than the uncertainty of the calibration in most cases.

Verification of the performance accuracy of a real-time skin-dose tracking system for interventional fluoroscopic procedures

A tracking system has been developed to provide real-time feedback of skin dose and dose rate during interventional fluoroscopic procedures. The dose tracking system (DTS) calculates the radiation dose rate to the patient's skin using the exposure technique parameters and exposure geometry obtained from the x-ray imaging system digital network (Toshiba Infinix) and presents the cumulative results in a color mapping on a 3D graphic of the patient. We performed a number of tests to verify the accuracy of the dose representation of this system. These tests included comparison of system-calculated dose-rate values with ionization-chamber (6 cc PTW) measured values with change in kVp, beam filter, field size, source-to-skin distance and beam angulation. To simulate a cardiac catheterization procedure, the ionization chamber was also placed at various positions on an Alderson Rando torso phantom and the dose agreement compared for a range of projection angles with the heart at isocenter. To assess the accuracy of the dose distribution representation, Gafchromic film (XR-RV3, ISP) was exposed with the beam at different locations. The DTS and film distributions were compared and excellent visual agreement was obtained within the cm-sized surface elements used for the patient graphic. The dose (rate) values agreed within about 10% for the range of variables tested. Correction factors could be applied to obtain even closer agreement since the variable values are known in real-time. The DTS provides skin-dose values and dose mapping with sufficient accuracy for use in monitoring diagnostic and interventional x-ray procedures.

Evaluating the maximum patient radiation dose in cardiac interventional procedures

Many of the X-ray systems that are used for cardiac interventional radiology provide no way to evaluate the patient maximum skin dose (MSD). The authors report a new method for evaluating the MSD by using the cumulative patient entrance skin dose (ESD), which includes a back-scatter factor and the number of cineangiography frames during percutaneous coronary intervention (PCI). Four hundred consecutive PCI patients (315 men and 85 women) were studied. The correlation between the cumulative ESD and number of cineangiography frames was investigated. The irradiation and overlapping fields were verified using dose-mapping software. A good correlation was found between the cumulative ESD and the number of cineangiography frames. The MSD could be estimated using the proportion of cineangiography frames used for the main angle of view relative to the total number of cineangiography frames and multiplying this by the cumulative ESD. The average MSD (3.0 ± 1.9 Gy) was lower than the average cumulative ESD (4.6 ± 2.6 Gy). This method is an easy way to estimate the MSD during PCI.

Managing radiation use in medical imaging: a multifaceted challenge

This special report aims to inform the medical community about the many challenges involved in managing radiation exposure in a way that maximizes the benefit-risk ratio. The report discusses the state of current knowledge and key questions in regard to sources of medical imaging radiation exposure, radiation risk estimation, dose reduction strategies, and regulatory options.

Clinical radiation management for fluoroscopically guided interventional procedures

The primary goal of radiation management in interventional radiology is to minimize the unnecessary use of radiation. Clinical radiation management minimizes radiation risk to the patient without increasing other risks, such as procedural risks. A number of factors are considered when estimating the likelihood and severity of patient radiation effects. These include demographic factors, medical history factors, and procedure factors. Important aspects of the patient's medical history include coexisting diseases and genetic factors, medication use, radiation history, and pregnancy. As appropriate, these are evaluated as part of the preprocedure patient evaluation; radiation risk to the patient is considered along with other procedural risks. Dose optimization is possible through appropriate use of the basic features of interventional fluoroscopic equipment and intelligent use of dose-reducing technology. For all fluoroscopically guided interventional procedures, it is good practice to monitor radiation dose throughout the procedure and record it in the patient's medical record. Patients who have received a clinically significant radiation dose should be followed up after the procedure for possible deterministic effects. The authors recommend including radiation management as part of the departmental quality assurance program.

Radiation dose to the pediatric cardiac catheterization and intervention patient

OBJECTIVE

The radiation dose from cardiac catheterization is particularly relevant when treating children because of their greater radiosensitivity compared with adults. Moreover, cardiac catheterization is being used increasingly for interventional radiology procedures, possibly resulting in higher patient radiation doses. This article reports the radiation doses and related factors, such as fluoroscopy time, for children who underwent cardiac catheterization and children who underwent other interventional radiology procedures.

MATERIALS AND METHODS

We evaluated 239 consecutive patients who underwent cardiac catheterization (n = 205) or another interventional radiology procedure (n = 34) for which the dose-area product (DAP) was measured. The number of cine runs and fluoroscopic time for each procedure and the body mass index and body weight of each patient were recorded. We also used the double product combined with body weight, which is the weight- fluoroscopic time product.

RESULTS

The average DAP ± SD of cardiac catheterization and of an interventional radiology procedure was 1,702.6 ± 2,110.1 cGy × cm² and 2,242.2 ± 2,509.4 cGy × cm², respectively. The average fluoroscopic time ± SD of cardiac catheterization and of an interventional radiology procedure was 24.1 ± 16.8 minutes and 37.2 ± 20.0 minutes. For children who underwent cardiac catheterization and those who underwent an interventional radiology procedure, a strong correlation was seen between the DAP and weight-fluoroscopic time product (cardiac catheterization, r = 0.906; interventional radiology procedure, r = 0.885) and a good correlation was detected between the DAP and weight (r = 0.819 and 0.895, respectively).

CONCLUSION

There was a good correlation between the DAP and weight and between DAP and weight-fluoroscopic time product for children who underwent cardiac catheterization or an interventional radiology procedure. Therefore, body weight is important for determining radiation dose to children undergoing cardiac catheterization or an interventional radiology procedure. The normalized DAP (i.e., DAP divided by body weight), fluoroscopy time, and number of cine runs were greater in children who underwent an interventional radiology procedure than in those who underwent cardiac catheterization. Therefore, the radiation dose to children from interventional radiology procedures is a more critical issue.

A study of the relationship between peak skin dose and cumulative air kerma in interventional neuroradiology and cardiology

A study of peak skin doses (PSDs) during neuroradiology and cardiology interventional procedures has been carried out using Gafchromic XR-RV2 film. Use of mosaics made from squares held in cling film has allowed doses to the head to be mapped successfully. The displayed cumulative air kerma (CAK) has been calibrated in terms of cumulative entrance surface dose (CESD) and results indicate that this can provide a reliable indicator of the PSD in neuroradiology. Results linking PSD to CESD for interventional cardiology were variable, but CAK is still considered to provide the best option for use as an indicator of potential radiation-induced effects. A CESD exceeding 3 Gy is considered a suitable action level for triggering follow-up of patients in neuroradiology and cardiology for possible skin effects. Application of dose action levels defined in this way would affect 8% of neurological embolisation procedures and 5% of cardiology ablation and multiple stent procedures at the hospitals where the investigations were carried out. A close relationship was observed between CESD and dose-area product (DAP) for particular types of procedure, and DAPs of 200-300  Gy cm(2) could be used as trigger levels where CAK readings were not available. The DAP value would depend on the mean field size and would need to be determined for each application.

Risk of deterministic effects during endovascular aortic stent graft implantation

Since the 1990s, stent graft implantation for aortic pathology has become an alternative to extensive surgical procedures in some patients. Indeed, many patients with such pathology are now treated endovascularly. Only limited data concerning the risk of a deterministic effect during aortic stent graft implantation are available Accordingly, 179 consecutive patients treated in our institute between October 2002 and July 2008 with endovascular aortic stent grafts were included in this study. Dosimetric data (kerma area product (KAP) and cumulative dose at the interventional reference point (CD(irp))) from radiograph reports were analysed for 172 patients. On a group of 19 patients, GAFCHROMIC XR type dosimetric films were also used to verify the automatic measurements. Readings from the integrated KAP meter were found to be too high and were therefore corrected - KAP to dose area product (DAP) and CD(irp) to entrance skin dose (ESD). Median DAP was 153 Gy cm² (35-700 Gy cm²) and median ESD was 0.44 Gy (0.12-2.73 Gy). Recorded dosimetric quantities were found to be good predictors of the skin dose and highlighted 4 patients (2.3%) who received skin doses that might cause possible deterministic effects. Endovascular stent graft implantation is less invasive than a surgical procedure and is widely used; mid-term results are encouraging. In a small number of patients, deterministic effects can occur even in departments with well-trained staff. Operators should inform the patients of possible skin injury after receiving high doses of ionising radiation and proper support must be available should that occur.