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

Can computer-assisted surgery reduce the effective dose for spinal fusion and sacroiliac screw insertion?

BACKGROUND

The increasing use of fluoroscopy-based surgical procedures and the associated exposure to radiation raise questions regarding potential risks for patients and operating room personnel. Computer-assisted technologies can help to reduce the emission of radiation; the effect on the patient's dose for the three-dimensional (3-D)-based technologies has not yet been evaluated.

QUESTIONS/PURPOSES

We determined the effective and organ dose in dorsal spinal fusion and percutaneous transsacral screw stabilization during conventional fluoroscopy-assisted and computer-navigated procedures.

PATIENTS AND METHODS

We recorded the dose and duration of radiation from fluoroscopy in 20 patients, with single vertebra fractures of the lumbar spine, who underwent posterior stabilization with and without the use of a navigation system and 20 patients with navigated percutaneous transsacral screw stabilization for sacroiliac joint injuries. For the conventional iliosacral joint operations, the duration of radiation was estimated retrospectively in two cases and further determined from the literature. Dose measurements were performed with a male phantom; the phantom was equipped with thermoluminescence dosimeters.

RESULTS

The effective dose in conventional spine surgery using 2-D fluoroscopy was more than 12-fold greater than in navigated operations. For the sacroiliac joint, the effective dose was nearly fivefold greater for nonnavigated operations.

CONCLUSION

Compared with conventional fluoroscopy, the patient's effective dose can be reduced by 3-D computer-assisted spinal and pelvic surgery.

LEVEL OF EVIDENCE

Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Direct measurement of patient's entrance skin dose during neurointerventional procedure to avoid further radiation-induced skin injuries

Although several cases of radiation-induced skin injury (RSI) have been reported in association with neurointerventional procedures such as endovascular embolization for cerebral aneurysm, cerebral arteriovenous malformation, and dural arteriovenous fistula, in most cases the absorbed doses are not measured directly; therefore, we built the first direct measurement system that enables the ideal dosimetry for entrance skin dose (ESD) during neurointerventional procedures to be easily determined. This system was then applied to a 55-year-old man who underwent two transvenous embolizations with a 2-month interval, for a right cavernous sinus dural arteriovenous fistula, to establish the efficacy of precise mapping of ESDs. Throughout the procedures, the patient wore a fitted dosimetry cap that contained 60 radiophotoluminescence glass dosimeter (RPLGD) chips. After the first procedure, temporary epilation occurred in the occipital region. Precise mapping of ESDs revealed that this region was exposed to 4.2Gy. In the first procedure, the X-ray tube was generally positioned straight for an optimal posterior-anterior view; however, in the second procedure we intermittently used the second-best position to prevent further RSI. In this position, the maximum ESD was 1.0Gy in the right posterior-temporal region and the epilation site was exposed to </=0.7Gy. Thus, the patient did not develop any further epilation. We conclude that direct dosimetry using multiple RPLGDs can accurately reveal the maximum ESD and that precise information regarding ESD can prevent further RSIs from subsequent procedures.

Health effects of medical radiation on cardiologists who perform cardiac catheterization

BACKGROUND

We investigated the health effects of low-dose radiation on cardiologists exposed to scattered radiation while performing cardiac catheterization (CC) in a hospital setting from 2003 to 2006.

METHODS

We performed a 4-year retrospective study on 2, 292 medical doctors, using claims data from all contracted hospitals of the Bureau of National Health Insurance, Taiwan. We gathered statistical data regarding radiation-related diseases using the International Classification of Diseases, 9(th) Revision, Clinical Modification record numbers of each doctor.

RESULTS

Of the 2,292 doctors evaluated, 1,721 were aged 35-50 years and the remaining 571 were aged 51-65 years. There were 892 cardiologists who performed CC (experimental group), and the majority of these (733/892, 82.17%) were aged 35-50 years. There were 1,400 medical doctors who performed no CC from 2003 to 2006 (control group). A total of 988 of these belonged to the 35-50 years age group and 412 to the 51-65 years group. In the 35-50 years group, the controls had significantly more medical visits for hematological and thyroid cancer (p <0.05), skin disease (p <0.001), and acute upper respiratory tract infection (p <0.001) compared with the experimental group. In contrast, cardiologists who performed catheterization had more cataracts compared with the control group, but this difference was not significant.

CONCLUSION

Doctors who did not perform CC had more visits for radiation-related diseases than those who performed catheterization. In the experimental group, cardiologists aged 35-50 years who were exposed to radiation during CC had more visits for cataracts than the control group. We recommend that radiation protection concepts be emphasized to cardiologists, and that hospital managers be obligated to upgrade angiography equipment because the newer models have less scattered radiation.

Patient peak skin doses from cardiac interventional procedures

Interventional cardiac procedures not only lead to significant effective doses for the patient but also can potentially cause deterministic effects on the patient's skin. Information about the peak (maximal) skin doses (PSD) received by patients during percutaneous transluminal coronary angioplasty procedures were collected from three cardiac catheter rooms. Cumulative dose at the interventional reference point (CD(IRP)) was collected for 161 patients and for 16 patients PSD was determined using Gafchromic dosimetry films. The comparison showed that CD(IRP) readings give a useful but conservative estimation of patient peak skin dose as it can lead to a significant overestimation. The median and third quartile values of CD(IRP) were 0.64 and 0.92 Gy, respectively. The 2 Gy threshold for deterministic effects was exceeded in nine patients. A good correlation was found between CD(IRP) and kerma area product measurements while the correlation with fluorography time was very weak.

Patient doses in interventional cardiology in Bosnia and Herzegovina: first results

Cardiologists at the Cardiac Centre of the Clinical Centre of Sarajevo University performed invasive cardiology procedures in one room equipped with a Siemens Coroskop (Siemens Healthcare, Erlangen, Germany) unit with the possibility of digital cine imaging. The number of procedures performed with this unit is 1126 per year. The number of adults performing only diagnostic procedures is 816, therapeutic procedures 62 and both diagnostic and therapeutic 228. Twenty diagnostic examinations but no therapeutic procedure are performed on children per year. The workload is increasing year by year, with an average increase of 26 % per year. The X-ray system does not have a kerma area product (KAP) meter installed; therefore an external KAP meter was mounted on the X-ray tube. Gafchromic dosimetry films (International Specialty Products, Wayne, USA) were placed under the patient to record the skin dose distribution. The peak skin dose (PSD) was calculated from the maximum optical density of the dosimetry films. Dose measurements were performed on 51 patients undergoing therapeutic procedures (percutaneous transluminal coronary angioplasty and stent placement). Two patients received doses (KAP) larger than 100 Gycm(2). The PSD was higher than 1 Gy in 3 out of 16 evaluations, and one of these patients received a skin dose >2 Gy. No deterministic skin effects were recorded. The dosimetry results are similar to results reported in other countries. Invasive cardiac procedures deliver high doses to the skin that could cause deterministic effects (erythema). Physicians performing these procedures should be aware of these risks. More efforts should be put into the training of cardiologists in radiation protection.

Fluoroscopically guided interventional procedures: a review of radiation effects on patients' skin and hair

Most advice currently available with regard to fluoroscopic skin reactions is based on a table published in 1994. Many caveats in that report were not included in later reproductions, and subsequent research has yielded additional insights. This review is a consensus report of current scientific data. Expected skin reactions for an average patient are presented in tabular form as a function of peak skin dose and time after irradiation. The text and table indicate the variability of reactions in different patients. Images of injuries to skin and underlying tissues in patients and animals are provided and are categorized according to the National Cancer Institute skin toxicity scale, offering a basis for describing cutaneous radiation reactions in interventional fluoroscopy and quantifying their clinical severity. For a single procedure performed in most individuals, noticeable skin changes are observed approximately 1 month after a peak skin dose exceeding several grays. The degree of injury to skin and subcutaneous tissue increases with dose. Specialized wound care may be needed when irradiation exceeds 10 Gy. Residual effects from radiation therapy and from previous procedures influence the response of skin and subcutaneous tissues to subsequent procedures. Skin irradiated to a dose higher than 3-5 Gy often looks normal but reacts abnormally when irradiation is repeated. If the same area of skin is likely to be exposed to levels higher than a few grays, the effects of previous irradiation should be included when estimating the expected tissue reaction from the additional procedure.

Patient radiation doses in the most common interventional cardiology procedures in Croatia: first results

Apart from its benefits, the interventional cardiology (IC) is known to generate high radiation doses to patients and medical staff involved. The European Union Medical Exposures Directive 97/43/Euroatom strongly recommend patient dosimetry in interventional radiology, including IC. IC patient radiation doses in four representative IC rooms in Croatia were investigated. Setting reference levels for these procedures have difficulties due to the large difference in procedure complexity. Nevertheless, it is important that some guideline values are available as a benchmark to guide the operators during these potentially high-dose procedures. Local and national diagnostic reference levels (DRLs) were proposed as a guidance. A total of 138 diagnostic (coronary angiography, CA) and 151 therapeutic (PTCA, stenting) procedures were included. Patient irradiation was measured in terms of kerma-area product (KAP), fluoroscopy time (FT) and number of cine-frames (F). KAP was recorded using calibrated KAP-meters. DRLs of KAP, FT and F were calculated as third quartile values rounded up to the integer. Skin doses were assessed on a selected sample of high skin dose procedures, using radiochromic films, and peak skin doses (PSD) were presented. A relative large range of doses in IC was detected. National DRLs were proposed as follows: 32 Gy cm(2), 6.6 min and 610 frames for CA and 72 Gy cm(2), 19 min and 1270 frames for PTCA. PSD <1 Gy were measured in 72 % and PSD >2 Gy in 8 % of selected patients. Measuring the patient doses in radiological procedures is required by law, but rarely implemented in Croatia. The doses recorded in the study are acceptable when compared with the literature, but optimisation is possible. The preliminary DRL values proposed may be used as a guideline for local departments, and should be a basis for radiation reduction measures and quality assurance programmes in IC in Croatia.

Radiation dose and radiation protection for patients and physicians during interventional procedure

Although the wide acceptance of interventional radiology (IVR) procedures has led to increasing numbers of interventions being performed, the radiation doses from IVR are higher. Increasing numbers of case reports of patient radiation injury resulting from IVR are being published. Therefore, radiation protection during IVR poses a very important problem. To protect against radiation injury, the evaluation of radiation dose is essential. The radiation dose must be evaluated for each IVR x-ray machine and each laboratory, because it varies greatly. To obtain this information easily, and to ensure practical use of the radiation information, good relationships between interventionists and medical physicists are essential.

Impact of biplane versus single-plane imaging on radiation dose, contrast load and procedural time in coronary angioplasty

Coronary angioplasties can be performed with either single-plane or biplane imaging techniques. The aim of this study was to determine whether biplane imaging, in comparison to single-plane imaging, reduces radiation dose and contrast load and shortens procedural time during (i) primary and elective coronary angioplasty procedures, (ii) angioplasty to the main vascular territories and (iii) procedures performed by operators with various levels of experience. This prospective observational study included a total of 504 primary and elective single-vessel coronary angioplasty procedures utilising either biplane or single-plane imaging. Radiographic and clinical parameters were collected from clinical reports and examination protocols. Radiation dose was measured by a dose-area-product (DAP) meter intrinsic to the angiography system. Our results showed that biplane imaging delivered a significantly greater radiation dose (181.4+/-121.0 Gycm(2)) than single-plane imaging (133.6+/-92.8 Gycm(2), p<0.0001). The difference was independent of case type (primary or elective) (p = 0.862), vascular territory (p = 0.519) and operator experience (p = 0.903). No significant difference was found in contrast load between biplane (166.8+/-62.9 ml) and single-plane imaging (176.8+/-66.0 ml) (p = 0.302). This non-significant difference was independent of case type (p = 0.551), vascular territory (p = 0.308) and operator experience (p = 0.304). Procedures performed with biplane imaging were significantly longer (55.3+/-27.8 min) than those with single-plane (48.9+/-24.2 min, p = 0.010) and, similarly, were not dependent on case type (p = 0.226), vascular territory (p = 0.642) or operator experience (p = 0.094). Biplane imaging resulted in a greater radiation dose and a longer procedural time and delivered a non-significant reduction in contrast load than single-plane imaging. These findings did not support the commonly perceived advantages of using biplane imaging in single-vessel coronary interventional procedures.

Radiation exposure to patients during interventional procedures in 20 countries: initial IAEA project results

OBJECTIVE

The purpose of our study was to investigate the level of radiation protection of patients and staff during interventional procedures in 20 countries of Africa, Asia, and Europe.

SUBJECTS AND METHODS

In a multinational prospective study, information on radiation protection tools, peak skin dose (PSD), and kerma-area product (KAP) was provided by 55 hospitals in 20 mainly developing countries (nine mostly in Eastern Europe, five in Africa, and six in Asia).

RESULTS

Nearly 40% of the interventional rooms had an annual workload of more than 2,000 patients. It is remarkable that the workload of pediatric interventional procedures can reach the levels of adult procedures even in developing countries. About 30% of participating countries have shown a 100% increase in workload in 3 years. Lead aprons are used in all participating rooms. Even though KAP was available in almost half of the facilities, none had experience in its use. One hundred of 505 patients monitored for PSD (20%) were above the 2-Gy threshold for deterministic effects.

CONCLUSION

Interventional procedures are increasing in developing countries, not only for adults but also for pediatric patients. The situation with respect to staff protection is considered generally acceptable, but this is not the case for patient protection. Many patients exceeded the dose threshold for erythema. A substantial number (62%) of percutaneous transluminal coronary angioplasty procedures performed in developing countries in this study are above the currently known dose reference level and thus could be optimized. Therefore, this study has significance in introducing the concept of patient dose estimation and dose management.

[Occupational exposure to radiation]

Since the discovery of X-rays, over exposures and radiation in juries have been reported in both patients and persons exposed in the course of their professional duties. Each year, more than 2,500 million diagnostic radiological examinations, 32 million nuclear medicine examinations or treatment procedures and 5.5 million radiotherapy sessions are performed world wide. Despite all precautions, avoidable incidents and accidents occur through out the world every year, albeit with low frequency. Where as diagnostic radiology is generally safe for patients and staff, intervention al procedures (e.g. coronary artery dilatations) involve the risks of occupational over exposure and of skin injuries to patients. In nuclear medicine, radiation protection is focused on the introduction of new procedures with beta-emitters, for example. The increasing frequency of positron emission tomography (PET) requires a special focus on shielding measures. In radiotherapy, occupational over exposure caused by mal functions and accidents is relatively rare.

[A study of operator's hand and finger exposure dose reduction during angiographic procedures]

The number of examinations using interventional radiology (IVR) has increased recently. Because of the more advanced and more complex procedures for IVR, longer treatment time is required. Therefore, it is important to determine exposure doses. We measured operator exposure dose during IVR using a thermoluminescence dosimeter. The results revealed the dose equivalent to the operator's hands and fingers to be higher than that of other parts, although the effective dose for the operator was low. Moreover, we looked into the factors that affected exposure dose to the operator's fingers, and examined ways to reduce the dose. In regard to the exposed dose to the operator's fingers, dose reduction was possible as a result of a geometric arrangement of the fluoroscopic unit, the radiation field size, using a radiation protective device and deliberation to exposure dose reduction of the operator. It is possible to carry out IVR more safely using the method of exposure dose reduction to the operator's fingers.

Direct and indirect measurement of patient radiation exposure during endovascular aortic aneurysm repair

With the increasing complexity of endovascular procedures, concern has grown regarding patient radiation exposure. Abdominal aortic aneurysm (AAA) repair represents the most common complex endovascular procedure currently performed by vascular specialists. Our study evaluates the patient radiation dose received during endovascular AAA repair. Over a 3-month period we prospectively monitored the radiation dose in a series of consecutive patients undergoing endovascular AAA repair. All patients underwent standard endovascular AAA repair with one of two commercially available grafts using the GE OEC 9800 unit. Direct measurement of maximum radiation dose at skin level (peak skin dose, PSD) was recorded using GAFCHROMIC radiographic dosimetry film. Indirect measurements of radiation dose (fluoroscopy time and dose-area-product [DAP]) were recorded with the C-arm dosimeter. A total of 12 consecutive patients undergoing standard endovascular AAA repair were evaluated. Mean PSD was 0.75 Gy (range 0.27-1.25). Mean total fluoroscopy time was 20.6 min (range 12.6-34.2) with an average of 92% spent in standard fluoroscopy and 8% spent in cinefluoroscopy. Regarding total fluoroscopy time, 49% was spent in normal field of view and 51% in magnified view. Mean DAP was 15,166 cGy x cm(2) (range 5,207-24,536). PSD correlated with DAP (r = 0.9, p < 0.05) but not total fluoroscopy time (r = 0.18, p > 0.05). PSD also correlated with body mass index (BMI; r = 0.82, p < 0.05). Obese patients had a mean PSD of 1.1 Gy compared to 0.5 Gy in nonobese patients. PSD of all patients was well below the accepted 2.0 Gy threshold for skin injury. PSD correlated with DAP but not total fluoroscopy time. PSD also correlated with BMI, and the mean PSD was significantly increased in obese compared to nonobese patients. Despite the complexity and duration of endovascular AAA repair, the procedure can be performed safely without excessive radiation exposure.

A large-scale multicentre study of patient skin doses in interventional cardiology: dose-area product action levels and dose reference levels

For 318 patients in 8 different Belgian hospitals, the entire skin-dose distribution was mapped using a grid of 70 thermoluminescence dosimeters per patient, allowing an accurate determination of the maximum skin dose (MSD). Dose-area product (DAP) values, exposure parameters and geometry, together with procedure, patient and cardiologist characteristics, were also registered. Procedures were divided into two groups: diagnostic procedures (coronary angiography) and therapeutic procedures (dilatation, stent, combined procedures (e.g. coronary angiography + dilatation + stent)). The mean value of the MSD was 0.310 Gy for diagnostic and 0.699 Gy for therapeutic procedures. The most critical projection for receiving the MSD is the LAO90 (left anterior oblique) geometry. In 3% of cases, the MSD exceeded the 2 Gy dose threshold for deterministic effects. Action levels in terms of DAP values as the basis for a strategy for follow-up of patients for deterministic radiation skin effects were derived from measured MSD and cumulative DAP values. Two DAP action levels are proposed. A first DAP action level of 125 Gy cm(2) corresponding to the dose threshold of 2 Gy would imply an optional radiopathological follow-up depending on the cardiologist's decision. A second DAP action level of 250 Gy cm(2) corresponding to the 3 Gy skin dose would imply a systematic follow-up. Dose reference levels - 71.3 Gy cm(2) for diagnostic and 106.0 Gy cm(2) for therapeutic procedures - were derived from the 75 percentile of the DAP distributions. As a conclusion, we propose that total DAP is registered in patient's record file, as it can serve to improve the follow-up of patients for radiation-induced skin injuries.

Radiation dose descriptors: BERT, COD, DAP, and other strange creatures

Over the years, a number of terms have been used to describe radiation dose. Eight common radiation dose descriptors include background equivalent radiation time (BERT), critical organ dose (COD), surface absorbed dose (SAD), dose area product (DAP), diagnostic acceptable reference level (DARLing), effective dose (ED), fetal absorbed dose (FAD), and total imparted energy (TIE). BERT is compared to the annual natural background radiation (about 3 mSv per year) and is easily understandable for the general public. COD refers to the radiation dose delivered to an individual critical organ. SAD is the radiation dose delivered at the skin surface. DAP is a product of the irradiated surface area multiplied by the radiation dose at the surface. DARLing is usually the radiation level that encompasses 75% (the third quartile) of the data derived from a nationwide or regional survey. DARLings are meant for voluntary guidance. Consistently higher patient doses should be investigated for possible equipment deficiencies or suboptimal protocols. ED is obtained by multiplying the radiation dose delivered to each organ by its weighting factor and then by adding those values to get the sum. It can be used to assess the risk of radiation-induced cancers and serious hereditary effects to future generations, regardless of the procedure being performed, and is the most useful radiation dose descriptor. FAD is the radiation dose delivered to the fetus, and TIE is the sum of the energy imparted to all irradiated tissue. Each of these descriptors is intended to relate radiation dose ultimately to potential biologic effects. To avoid confusion, the key is to avoid using the terms interchangeably. It is important to understand each of the radiation dose descriptors and their derivation in order to correctly evaluate radiation dose and to consult with patients concerned about the risks of radiation.

Radiation dose to the brain and subsequent risk of developing brain tumors in pediatric patients undergoing interventional neuroradiology procedures

Radiation dose to the brain and subsequent lifetime risk of diagnosis of radiation-related brain tumors were estimated for pediatric patients undergoing intracranial embolization. Average dose to the whole brain was calculated using dosimetric data from the Radiation Doses in Interventional Radiology Study for 49 pediatric patients who underwent neuroradiological procedures, and lifetime risk of developing radiation-related brain tumors was estimated using published algorithms based on A-bomb survivor data. The distribution of absorbed dose within the brain can vary significantly depending on field size and movement during procedures. Depending on the exposure conditions and age of the patient, organ-averaged brain dose was estimated to vary from 6 to 1600 mGy. The lifetime risk of brain tumor diagnosis was estimated to be increased over the normal background rates (57 cases per 10,000) by 3 to 40% depending on the dose received, age at exposure, and gender. While significant uncertainties are associated with these estimates, we have quantified the range of possible dose and propagated the uncertainty to derive a credible range of estimated lifetime risk for each subject. Collimation and limiting fluoroscopy time and dose rate are the most effective means to minimize dose and risk of future induction of radiation-related tumors.

Radiation injury is potentially a severe consequence of fluoroscopically guided complex interventions

Fluoroscopically guided interventions and radiation injury: Is physician training in radiation management adequate? Radiation injury from fluoroscopically guided complex medical interventions is relatively rare but sometimes seriously debilitating. This manuscript provides a summary of their occurrence. The question is raised as to whether or not the seriousness of these radiation effects and their underlying causes are sufficient justification to warrant new proposals on how to credential physicians before they are declared qualified to perform complex interventional procedures.

X-ray burns--painful, protracted, and preventable

Very high doses of x-ray may produce deep burns in the backs of patients having fluoroscopically guided cardiac interventional procedures. While these incidents are uncommon they can be prevented by judicious limitation of fluoroscopy and timely repositioning of the x-ray tube. Better education and improved methods for dose mapping should make these distressing complications a thing of the past.

Technical developments in radiology in Australasia dating from 1977

This article outlines the enormous technological advances that have taken place in the practice of radiology in Australasia in the 30 years since approximately 1977. These developments have led to significant improvements in image quality across all modalities, including even general radiography, which had as its genesis Roentgen's ground-breaking discovery of X-rays in 1895. However, nowhere has the development been more dramatic than in magnetic resonance imaging (MRI). This may be brought into stark reality by noting that the first MRI image of a human finger was produced in 1976 followed one year later by that of a human chest and the first MRI units were not installed in Australia and New Zealand until 1986 and 1991, respectively. The quality of these early images would be judged as laughable by today's standards where the impressive isotropic imaging that can be achieved at sub-millimetre level by both MRI and CT could not have been dreamed of 30 years ago. The review also highlights some challenges for the future of the medical physics profession.

Total Entrance Skin Dose: An Effective Indicator of Maximum Radiation Dose to the Skin During Percutaneous Coronary Intervention

OBJECTIVE

A number of cases of radiation-associated patient skin injury during percutaneous coronary intervention (PCI) have been reported. To protect against this complication, maximum skin dose to the patient should be monitored in real time. Unfortunately, in most cardiac intervention procedures, real-time monitoring of maximum skin dose is not possible. Angiographic X-ray units, however, display the patient's total entrance skin dose in real time. We therefore investigated the relation between maximum skin dose and total entrance skin dose to determine whether total entrance skin dose can be used to estimate maximum skin dose during PCI.

MATERIALS AND METHODS

The dose-area product was measured, and maximum skin dose and total entrance skin dose were calculated with a skin-dose-mapping software program. The target vessels of 194 PCI procedures were divided into four groups according to the American Heart Association (AHA) segment system.

RESULTS

The maximum skin dose constituted 48%, 52%, 50%, and 52% of the total entrance skin dose during PCI on AHA segments 1-3, 4, 5-10, and 11-15, respectively. There were significant correlations between maximum skin dose and total entrance skin dose during PCI (r = 0.894, 0.935, 0.859, and 0.898 for segments 1-3, 4, 5-10, and 11-15, respectively; p < 0.001).

CONCLUSION

Maximum skin dose during PCI is approximately 50% of the total entrance skin dose for each target vessel. Correlation between the two doses was very good. Total entrance skin dose is an effective predictor of maximum skin dose during PCI when the formula used is maximum skin dose = 0.5 x total entrance skin dose. Our results provide useful information for avoiding deterministic radiation skin injury to patients undergoing PCI.

Radiation injury is a potentially serious complication to fluoroscopically-guided complex interventions

Radiation-induced injury to skin is an infrequent but potentially serious complication to complex fluoroscopically-guided interventional procedures. Due to a lack of experience with such injuries, the medical community has found fluoroscopically-induced injuries difficult to diagnose. Injuries have occurred globally in many countries. Serious injuries most frequently occur on the back but have also occurred on the neck, buttocks and anterior of the chest. Severities of injuries range from skin rashes and epilation to necrosis of the skin and its underlying structures. This article reviews the characteristics of these injuries and some actions that can be taken to reduce their likelihood or seriousness.

Severe radiation-induced injury after cardiac catheter ablation: a case requiring free anterolateral thigh flap and vastus lateralis muscle flap reconstruction on the upper arm

Although cases of radiation-induced skin injury after fluoroscopically-guided procedures have been reported since 1996, diagnosis and treatment of such injury remain difficult. We present the case of a patient who complained of two ulcers, one on his right arm and one on his back, and limited motion of the right elbow joint after repeated cardiac radiofrequency catheter ablations. After resection of the skin ulcer on the patient's arm and of degenerated tissue in the distal part of the triceps brachii muscle, a combined free flap incorporating an anterolateral thigh flap and vastus lateralis muscle flap was transplanted. In the present case, this combined flap was very useful for simultaneous reconstruction of the muscle and skin defects under and over the tendon because the muscle flap and skin flap could be arranged separately.

Minimizing radiation injury and neoplastic effects during pediatric fluoroscopy: what should we know?

Radiation-induced injuries from fluoroscopic procedures in pediatric patients have occurred, and young patients are at greatest risk of many radiation-induced neoplasms. Some fluoroscopists have been injured from their use of fluoroscopy, and they are known to be at risk of radiation-induced neoplasm when radiation is not well-controlled. This article reviews the circumstances that lead to radiation injury and delineates some procedural methods to avoid injury and limit radiation exposure to both the patient and the fluoroscopist.

Angiographic guidewire with measuring markers: design and clinical experience

PURPOSE

We have developed an angiographic guidewire with measuring markers to determine accurately how far a guidewire is inserted within a catheter. We investigated whether use of this guidewire reduces the risk of vascular injury and the fluoroscopic time during guidewire manipulations.

METHODS

Four markers were put on the surface of the guidewire at 80, 100, 110, and 120 cm from the tip. The actual lengths of 54 catheters from seven manufacturers were measured and compared with the nominal lengths. Sixty consecutive patients who underwent angiography were randomized into two groups: in one group guidewires with surface markers were used (marker group) and in the other group, conventional guidewires (control group). For each guidewire insertion, the fluoroscopic time before the guidewire was pushed forward into the vessel lumen was recorded. The number of occasions on which unintentionally the guidewire had already been pushed out of the catheter at the start of fluoroscopy was also evaluated.

RESULTS

The actual lengths of all catheters were greater than the nominal lengths by 1.0-11.0 cm. Mean fluoroscopic time for each guidewire insertion was 3.3 sec in the marker group and 5.7 sec in the control group (p < 0.05). Guidewires were unintentionally pushed out of the catheters without fluoroscopy three times (3.6%), in each case in the control group.

CONCLUSION

The guidewire with measuring markers is effective for enhancing safety and in reducing fluoroscopic radiation during angiographic procedures. It is recommended that operators be aware that actual lengths of catheters may vary significantly from the nominal lengths listed; they should be aware of this with any guidewire, but particularly with the angiographic measuring guidewire.

Endovascular and interventional procedures in obese patients: a review of procedural technique modifications and radiation management

As the prevalence of obesity in the United States continues to increase, the volume of endovascular and fluoroscopically guided procedures is also increasing. With obese patients, it often seems the only consideration is whether the table weight tolerance can accommodate the patient. This is a naive approach to performing procedures in obese patients, as there are multiple considerations involved in providing state-of-the-art endovascular and interventional care to obese patients. A growing collection of literature is beginning to surface regarding the appropriate modifications in the interventional care of these patients. This article reviews the relevant literature on this important subject.

Six years experience in intracoronary brachytherapy procedures: patient doses from fluoroscopy

Typical patient dose levels during intracoronary brachytherapy (ICB) procedures using beta sources were determined across a sample of 221 treatments. Dose-area product values, fluoroscopy time and number of frames per procedure, with median values of 62 Gy cm2, 17.0 min and 1493 images, respectively, resulted in a 20% to 50% increase in the values measured for percutaneous transluminal coronary angioplasty procedures in the same medical centre (median values 41 Gy cm2, 14.3 min and 1078 images). Likely reasons for this increase include the additional complexity of ICB, the need for recording and reporting every step of the treatment, getting the essential parameters for the volume determination of the lesion and therapeutic radiation dose calculation and, finally, the learning curve for this kind of procedure. A high concentration skin dose distribution during ICB procedures was measured and in 12% of the patients peak skin doses higher than 1.5 Gy were confirmed. 10 patients were submitted to clinical follow-up and skin injuries were not identified.

Incidence des radiodermites secondaires à un geste de radiologie interventionnelle

INTRODUCTION

Radiodermatitis due to fluoroscopically guided interventional radiology procedures was reported, mostly by dermatologists, several times between 1992 and 2000, but less frequently since 2000. TYPE OF STUDY AND OBJECTIVE: This feasibility study sought to determine whether radiodermatitis secondary to interventional radiology was still occurring recently (2003-2004).

METHODS

During summer 2004, we sent a questionnaire to the 1450 dermatologists belonging to the French Dermatology Society (société française de dermatologie), asking them to report any cases of radiodermatitis related to fluoroscopically guided interventional radiology between 1 September 2003 and 31 August 2004.

RESULTS

Responses from 218 dermatologists reported ten cases of radiodermatitis. Median age at diagnosis was 56 years. The procedures involved interventional neuroradiology (n=1), interventional cholangiography (n=1), pacemaker insertion (n=1), and interventional cardiology (n=7). Median time from the fluoroscopic procedure to first symptoms was 2 months and from procedure to radiodermatitis diagnosis 7.5 months. Plastic surgery was necessary for two patients.

CONCLUSION

Radiodermatitis related to interventional radiology still occurs. We recommend the development of a reporting system for this adverse effect as part of the optimization of interventional radiology practices, including dose reduction.

Radiation exposure of computed tomography and direct intracoronary angiography: risk has its reward

A hallmark of noninvasive testing has been the identification of patients with coronary artery disease. Now, with multislice computed tomography (MSCT), information about coronary anatomy can be obtained without the need for catheterization. A major concern with the application of MSCT coronary angiography is the radiation exposure to the patient. Both MSCT and selective coronary angiography share the risks of procedure-related complications, such as allergic contrast reactions, and stochastic risks (i.e., cancer induction) of low-level radiation. There is a substantially higher radiation dose for MSCT angiography (effective dose [ED] 14 mSv) than for CCA (ED 6 mSv). These exposures yield lifetimes risks of 0.07% and 0.02%, respectively, of inducing a fatal cancer in the general (i.e., age- and gender-averaged) population. However, CCA poses additional serious risks associated with cardiac catheterization, yielding a non-radiogenic risk of mortality--excluding contrast reactions--of 0.11%. Combining the radiogenic and non-radiogenic risks (0.02% and 0.11%, respectively) yields a 0.13% overall risk of mortality from CCA--nearly two-fold higher than that for MSCT angiography (0.07%). If one were to use the lower, more age-appropriate risk factors for the older patient population in question, the radiogenic risks of both CCA and MSCT would be reduced by about one-half, further widening the overall safety ratio of MSCT relative to CCA. When weighing the relative risks of alternative medical procedures, therefore, it is imperative that one consider the overall risk of the respective procedures.

Relationship Between Fluoroscopic Time, Dose–Area Product, Body Weight, and Maximum Radiation Skin Dose in Cardiac Interventional Procedures

OBJECTIVE

Real-time maximum dose monitoring of the skin is unavailable on many of the X-ray machines that are used for cardiac intervention procedures. Therefore, some reports have recommended that physicians record the fluoroscopic time for patients undergoing fluoroscopically guided intervention procedures. However, the relationship between the fluoroscopic time and the maximum radiation skin dose is not clear. This article describes the correlation between the maximum radiation skin dose and fluoroscopic time for patients undergoing cardiac intervention procedures. In addition, we examined whether the correlations between maximum radiation skin dose and body weight, fluoroscopic time, and dose-area product (DAP) were useful for estimating the maximum skin dose during cardiac intervention procedures.

MATERIALS AND METHODS

Two hundred consecutive cardiac intervention procedures were studied: 172 percutaneous coronary interventions and 28 cardiac radiofrequency catheter ablation (RFCA) procedures. The patient skin dose and DAP were measured using Caregraph with skin-dose-mapping software.

RESULTS

For the RFCA procedures, we found a good correlation between the maximum radiation skin dose and fluoroscopic time (r = 0.801, p < 0.0001), whereas we found a poor correlation between the maximum radiation skin dose and fluoroscopic time for the percutaneous coronary intervention procedures (r = 0.628, p < 0.0001). There was a strong correlation between the maximum radiation skin dose and DAP in RFCA procedures (r = 0.942, p < 0.0001). There was also a significant correlation between the maximum radiation skin dose and DAP (r = 0.724, p < 0.0001) and weight-fluoroscopic time product (WFP) (r = 0.709, p < 0.0001) in percutaneous coronary intervention procedures.

CONCLUSION

The correlation between the maximum radiation skin dose with DAP is more striking than that with fluoroscopic time in both RFCA and percutaneous coronary intervention procedures. We recommend that physicians record the DAP when it can be monitored and that physicians record the fluoroscopic time when DAP cannot be monitored for estimating the maximum patient skin dose in RFCA procedures. For estimating the maximum patient skin dose in percutaneous coronary intervention procedures, we also recommend that physicians record DAP when it can be monitored and that physicians record WFP when DAP cannot be monitored.

[Measurement of patient skin dose in interventional radiology using passive integrating dosimeter]

To avoid radiation injury from interventional radiology (IVR), quality assurance (QA) of IVR equipment based on dosimetry is important. In this study, we investigated the usefulness of measuring patient skin dose with a passive integrating dosimeter and water phantom. The optically stimulated luminescence dosimeter (OSLD) was chosen from among various passive integrating dosimeters. The characteristics of the OSLD were compared with a reference ionization dosimeter. The effective energy obtained from the OSLD was compared with that found by the aluminum attenuation method for using the reference ionization dosimeter. Doses and effective energies measured by OSLD correlated well with those of the reference ionization dosimeter. (dose: y=0.971x, r=0.999, effective energy: y=0.990x, r=0.994). It was suggested that OSLD could simultaneously and correctly measure both patient skin dose and effective energy. Patient skin dose rate and effective energy for 15 IVR units of 10 hospitals were investigated using OSLD and a water phantom for automatic brightness control fluoroscopy. The measurement was performed at the surface of a water phantom that was located on the interventional reference point, and source image intensifier distance was fixed to 100 cm. When the 9-inch field size was selected, the average patient skin dose rate was 16.3+/-8.1 mGy/min (3.6-32.0 mGy/min), the average effective energy was 34.6+/-4.1 keV (30.5-42.5 keV). As a result, it was suggested that QA should be performed not only for patient dose but also for effective energy. QA of equipment is integral to maintaining consistently appropriate doses. Consequently, the dosimetry of each IVR unit should be regularly executed to estimate the outline of patient skin dose. It was useful to investigate patient skin dose/effective energy with the passive integrating dosimeter for IVR equipment.

Radiation doses from venous access procedures

PURPOSE

To retrospectively analyze radiation dose data for six common venous access procedures.

MATERIALS AND METHODS

Institutional review board approval was obtained for this HIPAA-compliant study; informed consent was not required. Data review was limited to a quality assurance database. Patient medical records were not reviewed. We retrospectively analyzed radiation dose data from a prospective quality assurance program. Dose data were analyzed for 1010 instances of six different venous access placement procedures performed between February 1998 and July 2004. Radiation dose measurements were generated automatically by the interventional fluoroscopy units and were recorded at the conclusion of each procedure. Descriptive and summary statistical analyses were performed to determine median, minimum, and maximum values of radiation dose for each procedure. A P value of less than .05 indicated a significant difference. Because the data distribution was highly skewed, logarithmic transformation was performed. Dose data for four different venous access procedures (excluding chest port placement and peripherally inserted central catheter placement) were compared with a one-way analysis of variance. Pairwise comparisons with the Tukey honestly significant difference test were subsequently performed for each analogue where analysis of variance demonstrated a significant result.

RESULTS

No procedure yielded a cumulative dose of more than 950 mGy or a peak skin dose of more than 760 mGy. The highest mean cumulative dose (ie, 88 mGy), mean dose-area product (ie, 873 cGy . cm(2)), and mean peak skin dose (ie, 43 mGy) were observed for tunneled dialysis catheter placements. Significant differences in dose were observed for tunneled catheter placement versus nontunneled catheter placement (<.001 to .027). No significant differences in dose were observed for larger-diameter versus smaller-diameter catheters.

CONCLUSION

Radiation doses from venous access procedures are low. Even extreme outlier cases are unlikely to produce doses high enough to cause skin effects, especially when knowledgeable operators using well-calibrated equipment perform the procedures.

Patient skin dose in cardiac interventional procedures: Conventional fluoroscopy versus pulsed fluoroscopy

OBJECTIVES

To investigate whether pulsed fluoroscopy reduces a patient's exposure compared with the exposure owing to conventional (continuous) fluoroscopy, we simulated the skin radiation doses of patients at cardiac catheterization facilities with various X-ray systems used in fluoroscopically guided intervention procedures.

BACKGROUND

Although many reports have noted that "pulsed fluoroscopy" provides important further reductions in radiation exposure, it has been determined that when comparing dose rates between different vendor systems, "pulsed fluoroscopy" does not reduce patients' exposure as compared with "conventional fluoroscopy".

METHODS

We examined 13 X-ray systems; 10 used pulsed fluoroscopy and three used conventional fluoroscopy. The entrance surface doses with fluoroscopy were compared for the 13 X-ray systems by using acrylic plates (20-cm thick) and a skin dose monitor. The X-ray conditions used in the measurements were those normally used in the facilities performing percutaneous coronary intervention.

RESULTS

The average surface dose for systems from three different vendors producing conventional fluoroscopy systems was 23.93+/-2.77 mGy/min vs. an average surface dose of 22.52+/-4.50 mGy/min from five vendors of pulsed fluoroscopy systems (25, 30, and 50 pulses/sec) (P=0.646). The average entrance surface dose was significantly (P<0.0001) higher with conventional fluoroscopy and pulsed fluoroscopy at 25, 30, and 50 pulses/sec (23.05+/-3.78 mGy/min) than with pulsed fluoroscopy at 15 pulses/sec (13.86+/-3.22 mGy/min).

CONCLUSIONS

Pulsed fluoroscopy did not in itself reduce radiation exposure. In general, the use of pulsed fluoroscopy at a pulse rate lower than 25 pulses/sec should reduce the skin dose in fluoroscopically guided intervention procedures. Nevertheless, some X-ray systems are not designed to reduce the dose rate as the number of pulses per second is decreased. Physicians should be aware of the entrance surface dose of the X-ray system that they use for cardiac IVR.

Indicators of the maximum radiation dose to the skin during percutaneous coronary intervention in different target vessels

OBJECTIVES

To evaluate whether the maximum radiation dose to the patient's skin (MSD) can be estimated during percutaneous coronary intervention (PCI) procedures, we investigated the relationship between the MSD and fluoroscopic time, dose-area product (DAP), and body weight, separately analyzing the relationships for different target vessels.

BACKGROUND

Many cases of skin injury caused by excessive radiation exposure during cardiac intervention procedures have been reported. However, real-time maximum-dose monitoring of the skin is unavailable for many cardiac intervention procedures.

METHODS

We studied 197 consecutive PCI procedures that involved a single target vessel and were conducted. The DAP was measured, and the MSD was calculated by a skin-dose mapping software program (Caregraph). The target vessels of the PCI procedures were divided into four groups based on the AHA classification system: AHA 5-10, left anterior descending artery domain (LAD), AHA 11-15, left circumflex artery domain (LCx), AHA 1-3 = R 1-3, and AHA 4 = R 4.

RESULTS

The correlation coefficient (r) between the MSD and fluoroscopic time was higher for the right coronary artery (RCA) vessels (R 1-3, 0.852; R 4, 0.715) than for the left coronary artery (LCA) vessels (LAD, 0.527; LCx, 0.646), and the r value between the MSD and DAP was higher for the RCA vessels (R 1-3, 0.871; R 4, 0.898) than for the LCA vessels (LAD, 0.628; LCx, 0.694). Similarly, the correlation coefficient between the MSD and weight x fluoroscopic time (WFP) was higher for the RCA vessels (R 1-3, 0.874; R 4, 0.807) than for the LCA vessels (LAD, 0.551; LCx, 0.735).

CONCLUSIONS

The DAP and WFP can be used to estimate the MSD during PCI in the RCA but not in the LCA, especially the LAD.

New automated fluoroscopic systems for pediatric applications

Pediatric patients are at higher risk to the adverse effects from exposure to ionizing radiation than adults. The smaller sizes of the anatomy and the reduced X-ray attenuation of the tissues provide special challenges. The goal of this effort is to investigate strategies for pediatric fluoroscopy in order to minimize the radiation exposure to these individuals, while maintaining effective diagnostic image quality. Modern fluoroscopy systems are often entirely automated and computer controlled. In this paper, various selectable and automated modes are examined to determine the influence of the fluoroscopy parameters upon the patient radiation exposures and image quality. These parameters include variable X-ray beam filters, automatic brightness control programs, starting kilovolt peak levels, fluoroscopic pulse rates, and other factors. Typical values of radiation exposure rates have been measured for a range of phantom thicknesses from 5 cm to 20 cm of acrylic. Other factors that have been assessed include spatial resolution, low contrast discrimination, and temporal resolution. The selection menu for various procedures is based upon the examination type, anatomical region, and patient size. For pediatric patients, the automated system can employ additional filtration, special automatic brightness control curves, pulsed fluoroscopy, and other features to reduce the patient radiation exposures without significantly compromising the image quality. The benefits gained from an optimal selection of automated programs and settings for fluoroscopy include ease of operation, better image quality, and lower patient radiation exposures.