Medical Interventional Procedures Research Articles

Shaping photomechanical effects in tissue ablation using 355 nm laser pulses.

We investigate the influence of the cladding diameter of an optical delivery fiber on the ablation dynamics of porcine aorta immersed in tetracycline antibiotic solution using 355 nm nanosecond pulses. We manipulate the pressure transients by enforcing a rear rigid interface (applied by an enlargement of the cladding diameter) to the ablated area, which leads to enhanced ablation efficiency along with a reduction in tissue disruption effects. Numerical simulations, based on the finite elements method, are used to study the propagation of the pressure transients within the suggested scheme. Ultrasonic transducers are used for measuring the increased pressure in front of the fiber's facet and the reduced pressure at the fiber's circumference in the presence of large diameter cladding. The increase and decrease are both found to be by a factor of ˜1.8. The width of the cavitation bubble is measured by high-speed photography. An enlargement of 13.8% is demonstrated, at the expense of backward expansion along the fiber's axis. A histopathological in vitro study demonstrates an average enhancement of 12.27% in the diameter of the ablated crater, as well as significant reduction in the disruption effects. Our study sheds light on the potential to improve the ablation efficiency without additional energy cost, along with attaining improved safety for interventional medical procedures.

Ferromagnetic particles as magnetic resonance imaging temperature sensors.

Magnetic resonance imaging is an important technique for identifying different types of tissues in a body or spatial information about composite materials. Because temperature is a fundamental parameter reflecting the biological status of the body and individual tissues, it would be helpful to have temperature maps superimposed on spatial maps. Here we show that small ferromagnetic particles with a strong temperature-dependent magnetization, can be used to produce temperature-dependent images in magnetic resonance imaging with an accuracy of about 1 °C. This technique, when further developed, could be used to identify inflammation or tumours, or to obtain spatial maps of temperature in various medical interventional procedures such as hyperthermia and thermal ablation. This method could also be used to determine temperature profiles inside nonmetallic composite materials.

SU‐F‐J‐10: Sliding Mode Control of a SMA Actuated Active Flexible Needle for Medical Procedures

Purpose:In medical interventional procedures such as brachytherapy, ablative therapies and biopsy precise steering and accurate placement of needles are very important for anatomical obstacle avoidance and accurate targeting. This study presents the efficacy of a sliding mode controller for Shape Memory Alloy (SMA) actuated flexible needle for medical procedures.Methods:Second order system dynamics of the SMA actuated active flexible needle was used for deriving the sliding mode control equations. Both proportional‐integral‐derivative (PID) and adaptive PID sliding mode control (APIDSMC) algorithms were developed and implemented. The flexible needle was attached at the end of a 6 DOF robotic system. Through LabView programming environment, the control commands were generated using the PID and APIDSMC algorithms. Experiments with artificial tissue mimicking phantom were performed to evaluate the performance of the controller. The actual needle tip position was obtained using an electromagnetic (EM) tracking sensor (Aurora, NDI, waterloo, Canada) at a sampling period of 1ms. During experiment, external disturbances were created applying force and thermal shock to investigate the robustness of the controllers.Results:The root mean square error (RMSE) values for APIDSMC and PID controllers were 0.75 mm and 0.92 mm, respectively, for sinusoidal reference input. In the presence of external disturbances, the APIDSMC controller showed much smoother and less overshooting response compared to that of the PID controller.Conclusion:Performance of the APIDSMC was superior to the PID controller. The APIDSMC was proved to be more effective controller in compensating the SMA uncertainties and external disturbances with clinically acceptable thresholds.

Anesthetic Management for Radiofrequency Ablation in Patients with Hepatocellular Carcinoma in a Developing Country

Radiofrequency ablation (RFA) is a novel minimally invasive technique of tumor destruction by heat in hepatic malignancies. It is one of the most common interventional medical procedures performed throughout the world. The study is aimed to report and evaluate the choices and techniques, drugs used and complications of anesthesia for percutaneous RFA in patients with hepatocellular carcinoma during the period of January, 2010 to December, 2012 in Siriraj Hospital in Thailand. The patients’ characteristics, pre-anesthetic problems, anesthetic techniques, drugs, duration of anesthesia, and anesthesia-related complications were assessed and summarized by using descriptive statistics. During the study period there were 400 RFA procedures. Mean age 63.0±11.4 years. The majority of them was male (69.0%) and classified in ASA physical status II (68.3%). Most common pre-anesthetic problems were liver disease (57.5%), hypertension (46.8%), hematologic disease (37.3%) and diabetes mellitus (35.3%). Intravenous sedation (99.3%) was the main anesthetic technique. The mainly used anesthetic agents were propofol, fentanyl and midazolam. The duration of anesthesia ranged from 15 to 270 minutes. The overall anesthesia-related complication rate was 23.8%. Hypotension (16.5%) was the most frequent anesthetic complication. Almost all of the RFA procedures, intravenous sedation technique can be used effectively. However, clinical signs should be carefully observed and the anesthetic personnel had to optimize the patient’s condition for safety and beware of

Development of Self-Actuating Flexible Needle System for Surgical Procedures1

Numerous medical interventional procedures, such as brachytherapy, biopsy, radio frequency based thermal ablation, and anesthetic drug delivery, require precise placement of needles. Most of these interventions are performed percutaneously. However, precise placement of the needle to a specific target inside human body is a difficult task. Furthermore, the involved needles are usually rigid and straight, and real-time sensory feedback of the needle is rarely available. Medical imaging and interventional delivery systems have undergone significant growth in the recent years, but the development of needles for percutaneous interventions for clinical amiability is undergoing a slow progress. Also, most of the clinically used needles are several decades old in design. Controlling the needle to reach the target precisely through a desired trajectory by the guidance of quantitative sensory feedbacks could benefit various medical procedures. Accurate and safe navigation of the needle to the desired target is the major challenge in needle based interventional techniques. Needle geometry and lack of proper actuation of the needle contribute to this major challenge.The overall system integration and control of the needling device involve three loops as shown in Fig. 1. The inner loop comprising the flexible active needle actuated by the shape memory alloy (SMA); the next outer loop of the 5 degrees of freedom robotic system guiding the needle to reach the target with high accuracy and precision; and finally, the outer most human-in-the-loop involving the physician for detecting the target and optimally planning the trajectory to reach the target.To avoid the physiological obstacle, a self-actuating flexible needle has been developed [1,2]. The developed self-actuating flexible needle deployed in our experimental work of trajectory tracking task is shown in Fig. 2. It is a 17 gage needle of length 200 mm. The SMA wire is of dimension 0.24 mm in diameter and 70 mm in length.During the movement of the needle in the soft phantom, the needle tip is detected in real-time using the gray scale value pyramid pattern matching algorithm in labview (NI, Dublin, Ireland) using the noisy ultrasound (U.S.) images (Fig. 3).The U.S. transrectal transducer (BK Medical, Peabody, MA) is utilized to detect the needle tip using a DVI2USB 2.0 frame grabber (Epiphan, Palo Alto, CA). The sampling time in obtaining the U.S. imaging feedback is 5 ms.The flexible needle and the guiding robot are controlled by discrete-time proportional integral derivative (PID)-P3 and PID control algorithms with the U.S. imaging feedback.The equation of the discrete-time PID-P3 controller is given by(1)u(k)=u(k-1)+KP[e(k)-e(k-1)] ×KPhTIe(k)+KPTD[ef(k)-2ef(k-1) +ef(k-2)]+KT[e(k)-e(k-1)]3where h is the time step, e(k) = xd(k) – x(k) is the error at kth instant; ef(k) is the low pass filtered error given by ef(k)=[τf/(τf+TS)]ef(k-1)+[TS/(τf+TS)]e(k); u(k) is the controller output at kth instant; KP, KPh/TI, and KPTD are the proportional, integral, and derivative gains, respectively.Similarly, the discrete-time PID controller is given by(2)u(k)=u(k-1)+KP[e(k)-e(k-1)] ×KPhTIe(k)+KPTD[ef(k)-2ef(k-1)+ef(k-2)]The discrete controller output u(k) is hard limited to the range 0–10 V.The curvilinear trajectory tracked by the coordinated movement of the flexible needle and the robot with U.S. imaging feedback is shown in Fig. 4(a). The corresponding error norm plot is shown in Fig. 4(b). Similarly, Fig. 5 shows the tracking results with electromagnetic (EM) sensor feedback.The coordinated control performance in trajectory tracking with U.S. imaging feedback is comparable with the EM sensory feedback based performance. The root mean square error (RMSE) values in the curvilinear trajectory tracking task with these different feedback modalities are given in Table 1. The difference in accuracy between these feedback modalities is clinically acceptable (about 0.12 mm versus 0.1 mm). The results reveal that U.S. imaging feedback based coordinated robot-needle control can be performed with in vivo tissues in real-time. The near future work involves the inclusion of the human-in-the-loop to supervise the coordinated control task.This study is fully supported by the U.S. Department of Defense (Grant Nos. W81XWH-11-1-0397/98/99).

Depth of anaesthesia monitoring during procedural sedation and analgesia: a systematic review protocol.

BackgroundProcedural sedation and analgesia (PSA) is used to attenuate the pain and distress that may otherwise be experienced during diagnostic and interventional medical or dental procedures. As the risk of adverse events increases with the depth of sedation induced, frequent monitoring of level of consciousness is recommended. Level of consciousness is usually monitored during PSA with clinical observation. Processed electroencephalogram-based depth of anaesthesia (DoA) monitoring devices provide an alternative method to monitor level of consciousness that can be used in addition to clinical observation. However, there is uncertainty as to whether their routine use in PSA would be justified. Rigorous evaluation of the clinical benefits of DoA monitors during PSA, including comprehensive syntheses of the available evidence, is therefore required. One potential clinical benefit of using DoA monitoring during PSA is that the technology could improve patient safety by reducing sedation-related adverse events, such as death or permanent neurological disability. We hypothesise that earlier identification of lapses into deeper than intended levels of sedation using DoA monitoring leads to more effective titration of sedative and analgesic medications, and results in a reduction in the risk of adverse events caused by the consequences of over-sedation, such as hypoxaemia. The primary objective of this review is to determine whether using DoA monitoring during PSA in the hospital setting improves patient safety by reducing the risk of hypoxaemia (defined as an arterial partial pressure of oxygen below 60 mmHg or percentage of haemoglobin that is saturated with oxygen [SpO2] less than 90 %). Other potential clinical benefits of using DoA monitoring devices during sedation will be assessed as secondary outcomes.Methods/designElectronic databases will be systematically searched for randomized controlled trials comparing the use of depth of anaesthesia monitoring devices with clinical observation of level of consciousness during PSA. Language restrictions will not be imposed. Screening, study selection and data extraction will be performed by two independent reviewers. Disagreements will be resolved by discussion. Meta-analyses will be performed if suitable.DiscussionThis review will synthesise the evidence on an important potential clinical benefit of DoA monitoring during PSA within hospital settings.Systematic review registrationPROSPERO CRD42015017251Electronic supplementary materialThe online version of this article (doi:10.1186/s13643-015-0061-z) contains supplementary material, which is available to authorized users.

Active ultrasound pattern injection system (AUSPIS) for interventional tool guidance.

Accurate tool tracking is a crucial task that directly affects the safety and effectiveness of many interventional medical procedures. Compared to CT and MRI, ultrasound-based tool tracking has many advantages, including low cost, safety, mobility and ease of use. However, surgical tools are poorly visualized in conventional ultrasound images, thus preventing effective tool tracking and guidance. Existing tracking methods have not yet provided a solution that effectively solves the tool visualization and mid-plane localization accuracy problem and fully meets the clinical requirements. In this paper, we present an active ultrasound tracking and guiding system for interventional tools. The main principle of this system is to establish a bi-directional ultrasound communication between the interventional tool and US imaging machine within the tissue. This method enables the interventional tool to generate an active ultrasound field over the original imaging ultrasound signals. By controlling the timing and amplitude of the active ultrasound field, a virtual pattern can be directly injected into the US machine B mode display. In this work, we introduce the time and frequency modulation, mid-plane detection, and arbitrary pattern injection methods. The implementation of these methods further improves the target visualization and guiding accuracy, and expands the system application beyond simple tool tracking. We performed ex vitro and in vivo experiments, showing significant improvements of tool visualization and accurate localization using different US imaging platforms. An ultrasound image mid-plane detection accuracy of ±0.3 mm and a detectable tissue depth over 8.5 cm was achieved in the experiment. The system performance is tested under different configurations and system parameters. We also report the first experiment of arbitrary pattern injection to the B mode image and its application in accurate tool tracking.

Radiation Impacts on Human Health

The atomic bomb and other studies have established with certainty that moderate-to-high doses of radiation cause many types of solid cancer and leukemia. Moving down the dose range to the vicinity of 100-200 mSv, the risks become fuzzy and then unknown at low doses on the order of 10-20 mSv. Nor have low-dose experimental studies provided definitive answers: some have suggested there may be adverse biological effects in the range of 5-50 mSv, while others support a "no risk" interpretation. Epidemiologic data contain intrinsic "noise" (variation by known and unknown factors related to genetics, lifestyle, other environmental exposures, sociodemographics, diagnostic accuracy, etc.) so are generally too insensitive to provide compelling answers in the low-dose range. However, there have been recent provocative reports regarding risk from relatively low-dose occupational and medical radiation exposures that warrant careful consideration. Summaries of the largest studies with low-dose or low dose-rate radiation exposure provide suggestive evidence of risk for solid cancer and stronger evidence for leukemia risk. Recently, interest in health endpoints other than cancer also has risen sharply, in particular the degree of cardiovascular and cataract risk following doses under 1 Sv. Data regarding cardiovascular disease are limited and fuzzy, with suggestions of inconsistencies, and the risk at low doses is essentially unknown. The evidence of cataract risk after low dose-rate exposures among those conducting interventional medical radiological procedures is becoming strong. The magnitude of radiation impacts on human health requires fuller documentation, especially for low-dose or low dose-rate exposures. From the epidemiologic vantage point, this will require longer observation of existing irradiated cohorts and development of new informative cohorts, improved accuracy in dose assessments, more attention to confounding variables, and more biosamples from irradiated groups to enable translational radiobiological studies. Introduction of Radiation Impacts on Human Health (Video 2:02, http://links.lww.com/HP/A35).

Microrobotics in the vascular network: present status and next challenges

The field of microrobotics dedicated to medical interventions although relatively new, is progressing at a very fast pace. Among the various accesses inside the body being investigated, the vascular network with close to 100,000 km of potential routes in each human and offering a large range of interventional opportunities has been of special interest in recent years. Although significant progresses and milestones have been achieved in this particular field of research, some important challenges remain to be solved before microrobotics in the human vasculature becomes a reality. Nonetheless, despite these challenges, some applications are already on the horizon. This paper aims at providing a quick overview of the present status of the field of microrobotics for interventions in the vascular network and to describe the main critical challenges that must be met in the short term to enable new or enhanced medical interventional procedures that may bring potential great outcomes for the patients.

Radiological protection in medicine: work of ommittee 3

Committee 3 of the International Commission on Radiological Protection (ICRP) is concerned with protection in medicine, and develops recommendations and guidance on the protection of patients, staff, and the public against radiation exposure in medicine. This paper presents an overview of the work of Committee 3 over recent years, and the work in progress agreed at the last annual meeting in Bethesda, MD in October 2011. The reports published by ICRP dealing with radiological protection in medicine in the last 10years cover topics on: education and training in radiological protection; preventing accidental exposures in radiation therapy; dose to patients from radiopharmaceuticals; radiation safety aspects of brachytherapy; release of patients after therapy with unsealed radionuclides; managing patient dose in digital radiology and computed tomography; avoidance of radiation injuries from medical interventional procedures; pregnancy and medical radiation; and diagnostic reference levels in medical imaging. Three new reports will be published in the coming months dealing with aspects of radiological protection in fluoroscopically guided procedures outside imaging departments; cardiology; and paediatric radiology. The work in progress agreed by Committee 3 is also described.

Radiation Dose Management for Fluoroscopically Guided Interventional Medical Procedures

This report released by the National Council of Radiation Protection and Measurements (NCRP) discusses how to manage radiation doses during fluoroscopically guided interventional medical procedures. It provides recommendations and supporting information with a compendium of references on radiation dose management for patients and medical personnel during interventional medical procedures. This report was prepared by the members of the NCRP Scientific Committee 2-3 on Radiation Safety Issues for Image-Guided Interventional Medical Procedures which includes well-known scientific experts on the subject. The report is a welcome addition as it contains a wealth of information on the types of interventional fluoroscopy procedures, fluoroscopy equipment, radiation dose measurements, assessment of risks, how to manage radiation dose, and so forth. Recent surveys have shown an increasing number of fluoroscopically guided interventional procedures performed in the United States and worldwide. The procedures are often less invasive and less costly with significant benefits to patients. They are performed by radiologists, cardiologists, and other medical specialists with assistance from medical support staff. However, according to another NCRP report (160), interventional procedures now account for nearly 14% of the collective dose to the US population from among the various medical x-ray procedures and therefore warrants ways to optimize and manage radiation doses. The main purpose of the report is to provide valuable information about interventional fluoroscopy procedures and how to manage the radiation dose to both patient and staff. As aptly described in the report's preface, this report will benefit radiologists, cardiologists and other medical specialists performing fluoroscopy procedures. Those who perform fluoroscopically guided interventional procedures, but do not have sufficient training in the practical aspects of radiation protection, will find this report very useful. Medical physicists, health physicists, and radiation safety officers will find this report especially helpful in assisting their physician colleagues in developing optimal methods for managing radiation dose during interventional fluoroscopy. This report is also intended to benefit policy makers who plan to establish radiation dose management requirements for those who conduct fluoroscopically guided interventional procedures with regard to optimizing imaging protocols, managing, tracking, and trending radiation doses to patients and medical staff and credentialing and privileging physicians to use the fluoroscopic equipment for such procedures. The report follows the standard NCRP report format with an executive summary providing more than 30 recommendations with references to the sections that discuss each recommendation in detail. The report is further divided into sections organized in the following way: general information (Sec. II) that includes a list of fluoroscopically guided interventional procedures, justification, benefit-risk, physics, dosimetry and radiation biology; Sec. III on fluoroscopy equipment and facilities that includes discussion on room design and structural radiation protection and protection of patients; Sec. IV is the longest section providing details on patient dose reviews, a patient dose management program with a sample dose-management process including how to monitor patient radiation dose. This section contains a number of tables of patient radiation doses for various interventional procedures, including table (4.7) that suggests values for first and subsequent notifications for the various dose metrics available during interventional procedures. Section V deals with the protection of staff while Sec. VI covers the administrative and regulatory considerations that includes discussion on education and training, purchase, configuration and quality control followed by summary and conclusions (Sec. VII). In addition, the report consists of 13 appendices that include topics such as benefit-cost and benefit-risk analyses, physics and dosimetry, radiation injuries, equipment operations, an example for informed consent for radiation risk plus an extensive bibliography. In addition to providing thorough treatment of each of the subject areas, the report offers unique methods to implement and assess radiation protection programs in general. Overall this report is very timely and will benefit the reader in understanding various aspects of radiation protection during interventional fluoroscopy procedures. This report can serve as a valuable resource guide to anyone exploring ways to optimize fluoroscopy procedures, to establish guidelines on patient dose, dose tracking and trending, and establish education and training to those performing fluoroscopically guided interventional procedures. Medical physicists will find this report very helpful and can use this as a reference guide to assist their physician colleagues to optimize interventional procedures. I highly recommend this report to medical physicists and health physicists who are active in the area of interventional fluoroscopy and also participating in maintenance of certification (MOC) related activities. Mahadevappa Mahesh is Associate Professor of Radiology and Cardiology at the Johns Hopkins University School of Medicine and is the Chief Physicist at the Johns Hopkins Hospital, Baltimore, MD. His research interests are in medical imaging, particularly in areas of multiple-row detector computed tomography (MDCT), interventional fluoroscopy and digital mammography. He teaches medical physics related topics to medical residents, and undergraduate and graduate students.

Procedimentos intervencionistas para o manejo da dor no câncer

To describe types of interventional medical procedures its rationale use and benefits for a population with cancer assisted at a private hospital in São Paulo. Quantitative and descriptive cross-sectional study using data from patients submitted to interventional procedures between 2007 and 2008. We used descriptive and inferential statistics (frequency, mean, and t-test) to analyze data. A total of 137 patients were submitted to interventional procedures for pain and, out of this total, 14 mentioned cancer-related pain. The mean pain intensity was 7.1 before the procedure and 1.3 after it. Reduction in pain intensity was statistically significant in this population (t=9.09; p=0.001). In almost 70% of patients (n=10) a reduction of 50% of the consumption of opioid a month after the procedure was realized. These results are in accordance with the literature and support the efficacy of interventional procedures for several types of cancer pain.

Radiation Exposure—Do Urologists Take it Seriously in Turkey?

A questionnaire was administered to urologists to evaluate attitudes and behaviors about protection from radiation exposure during fluoroscopy guided endourological procedures. The questionnaire was e-mailed to 1,482 urologists, including urology residents, specialists and urologists holding all levels of academic degrees, between May and June 2011. The questionnaire administered to study participants was composed of demographic questions, and questions on radiation exposure frequency, and the use of dosimeters and flexible protective clothes. If a respondent reported not using dosimeters or protective clothes, additional questions asked for the reason. Of the 1,482 questionnaires 394 (26.58%) were returned, of which 363 had completed answers. A total of 307 physicians (84.58%) were exposed to ionizing radiation, of whom 79.61% stated that they perform percutaneous nephrolithotomy at the clinic. Fluoroscopy guidance was the initial choice of 96.19% of urologists during percutaneous nephrolithotomy. Despite the common use of lead aprons (75.24%) most urologists did not use dosimeters (73.94%), eyeglasses (76.95%) or gloves (66.67%) while 46.44% always used thyroid shields during fluoroscopy. When asked why they did not use protective clothing, the most common answers were that protective clothes are not ergonomic and not practical. Results clearly highlight the lack of use of ionizing radiation protection devices and dosimeters during commonly performed fluoroscopy guided endourological procedures among urologists in Turkey.

MO‐D‐110‐01: Benefit Risk Assessment: Identifying the at Risk Patient; SYMPOSIUM‐Estimating Patient‐Specific Radiation Dose from Fluorosocpy

Radiation dose management for fluoroscopically‐ guided interventional medical procedures requires a combined effort from physicians, physicists and government regulators. Paramount to this process is an understanding of the benefits and risk for these procedures. For cardiovascular disease, despite the increasing prevalence in a setting of escalating risk factors, mortality has steadily decreased. Diagnostic and therapeutic fluoroscopic imaging has undoubtedly attributed to this as seen specifically in the areas of acute myocardial infarction, sudden cardiac arrest, and heart failure therapy. All facilities should have a radiation safety program as part of the institutional quality assurance umbrella with specific focuses on dose management as it applies to the equipment, physician, and patient. The regular interactions between the physicist and physician/staff assure proper equipment purchase and maintenance, initial and annual training, and patient dose assessment. The current challenges of the high risk patient require specific attention. As techniques and equipment advance, application of procedures expands and previously “untreatable” patients are approached. Patient factors such as morbid obesity, diabetes and repeat procedures are seen more as the norm rather than the exception. Complex anatomy in elderly, critically ill patients dictate challenging clinical decisions before, during, and after the procedure. This presentation will present a best practice approach to the challenges of benefit risk assessment in patients undergoing fluoroscopically‐guided interventional procedures.

Chronic low-dose radiation exposure from interventional cardiology procedures induces chromosomal abnormalities in originally genetically identical twins

Current radiation protection standards are based on the premise that even low dose of ionizing radiation may result in detrimental health effects, such as long-term development of cancer and hereditary disease [ [1] Committee on the Biological Effects of Ionizing Radiation Health effects from exposure to low levels of ionizing radiation. National Research Council, 2005 Google Scholar ]. Cardiovascular testing accounts for at least one-third of all ionising testing and invasive cardiologists working in a busy catheterization laboratory are the most exposed among professionally exposed physicians. Interventional cardiologists have an exposure per-head per year two to three times higher than that of radiologists [ 2 Cordella J, Faulkner K, Hopewell J, et al. Avoidance of radiation injuries from medical interventional procedures extracted from International Commission on Radiaton Protection.ICRP Publication 85. Ann. ICRP 30:2 (2000). Google Scholar , 3 Hirshfeld Jr., J.W. Balter S. Brinker J.A. et al. American College of Cardiology Foundation; American Heart Association; HRS; SCAI; American College of Physicians Task Force on Clinical Competence and Training. ACCF/AHA/HRS/SCAI clinical competence statement on physician knowledge to optimize patient safety and image quality in fluoroscopically guided invasive cardiovascular procedures: a report of the American College of Cardiology Foundation/American Heart Association/American College. Circulation. 2005; 111: 511-532 Crossref PubMed Scopus (208) Google Scholar ]. Chromosome aberration (CA)-based assays are considered the gold standard of biological dosimeter of radiation exposure and intermediate endpoints of cancer risk [ [4] International Atomic Energy Agency (IAEA) Cytogenetic analysis for radiation dose assessment. Technical Report. vol. 405. 2001 Google Scholar ]. We and others have recently reported that cardiologists working in a high-volume catheterization laboratory chronically exposed to low-dose radiation well within allowed limits show increased chromosomal damage versus non-exposed controls [ 5 Zakeri F. Assaei R.G. Cytogenetic monitoring of personnel working in angiocardiography laboratories in Iran hospitals. Mutat Res. 2004; 562: 1-9 Crossref PubMed Scopus (45) Google Scholar , 6 Andreassi M.G. Cioppa A. Botto N. et al. Somatic DNA damage in interventional cardiologists: a case-control study. FASEB J. 2005; 19: 998-999 Crossref PubMed Scopus (89) Google Scholar ]. However, from a case-control study, it is not completely possible to determine the role of other potentially confounding factors that appear to have great influence on the frequency of CA, such as age, smoking or individual genetic susceptibility.

Symptoms of immediate chlorhexidine hypersensitivity in patients with a positive prick test

There are numerous reports of anaphylaxis from chlorhexidine in surgical operations and other medical procedures, usually due to its application to wounds or mucous membranes. We wanted to analyse the clinical data of patients with a positive chlorhexidine prick test and perform some additional testing. We studied the case records of the patients with a positive chlorhexidine prick test and performed an open application test and tests for specific IgE. We found 33 patients with a positive prick test. 10 of them had had severe symptoms from chlorhexidine, and 11 had had only mild local symptoms. The size of the prick test reaction was mainly in line with the strength of the severest symptoms. Small 3- to 4-mm reactions were usually without obvious clinical relevance. Specific IgE could be demonstrated in 6 patients out of 14 tested by the ImmunoCAP method. Besides severe attacks, patients with a positive prick test often have milder local symptoms, such as exacerbation of dermatitis. Local symptoms from chlorhexidine-containing products may precede severe attacks. We recommend a prick test to be performed routinely when symptoms during medical interventional procedures, e.g. local and general anaesthesia, are investigated.

Why Do Some Patients Die Following Therapeutic ERCP?: Results of the United Kingdom National Confidential Enquiry Into Patient Outcome and Death

Introduction: Studies of ERCP complications have concentrated on procedure related morbidity and mortality. There have been no studies evaluating the reasons for death with 30 days of a therapeutic ERCP. NCEPOD is an independent organisation intended to improve clinical outcomes from interventional medical procedures. The study aim is to critically appraise the clinical process of those who have died during or following ERCP. Methods: All deaths in hospital within 30 days of ERCP were recorded between 1st April 2002 and 31st March 2003 from 252 NHS hospitals.

Abstract: Avoidance of radiation injuries from medical interventional procedures, ICRP Publication 85

Interventional radiology (fluoroscopically-guided) techniques are being used by an increasing number of clinicians not adequately trained in radiation safety or radiobiology. Many of these interventionists are not aware of the potential for injury from these procedures or the simple methods for decreasing their incidence. Many patients are not being counselled on the radiation risks, nor followed up when radiation doses from difficult procedures may lead to injury. Some patients are suffering radiation-induced skin injuries and younger patients may face an increased risk of future cancer. Interventionists are having their practice limited or suffering injury, and are exposing their staff to high doses. In some interventional procedures, skin doses to patients approach those experienced in some cancer radiotherapy fractions. Radiation-induced skin injuries are occurring in patients due to the use of inappropriate equipment and, more often, poor operational technique. Injuries to physicians and staff performing interventional procedures have also been observed. Acute radiation doses (to patients) may cause erythema at 2 Gy, cataract at 2 Gy, permanent epilation at 7 Gy, and delayed skin necrosis at 12 Gy. Protracted (occupational) exposures to the eye may cause cataract at 4 Gy if the dose is received in less than 3 months, at 5.5 Gy if received over a period exceeding 3 months. Practical actions to control dose to the patient and to the staff are listed. The absorbed dose to the patient in the area of skin that receives the maximum dose is of priority concern. Each local clinical protocol should include, for each type of interventional procedure, a statement on the cumulative skin doses and skin sites associated with the various parts of the procedure. Interventionists should be trained to use information on skin dose and on practical techniques to control dose. Maximum cumulative absorbed doses that appear to approach or exceed 1 Gy (for procedures that may be repeated) or 3 Gy (for any procedure) should be recorded in the patient record, and there should be a patient follow-up procedure for such cases. Patients should be counselled if there is a significant risk of radiation-induced injury, and the patient's personal physician should be informed of the possibility of radiation effects. Training in radiological protection for patients and staff should be an integral part of the education for those using interventional techniques. All interventionists should audit and review the outcomes of their procedures for radiation injury. Risks and benefits, including radiation risks, should be taken into account when new interventional techniques are introduced. A concluding list of recommendations is given. Annexes list procedures, patient and staff doses, a sample local clinical protocol, dose quantities used, and a procurement checklist.