Heavy metal pad shielding during fluoroscopic interventions

Significant direct and scatter radiation doses to patient and physician may result from routine interventional radiology practice. A lead-free disposable tungsten antimony shielding pad was tested in phantom patients during simulated diagnostic angiography procedures. Although the exact risk of low doses of ionizing radiation is unknown, dramatic dose reductions can be seen with routine use of this simple, sterile pad made from lightweight tungsten antimony material.     

Optimizing Staff Dose in Fluoroscopy-Guided Interventions by Comparing Clinical Data with Phantom Experiments

PurposeTo evaluate conditions for minimizing staff dose in interventional radiology, and to provide an achievable level for radiation exposure reduction.Materials and MethodsComprehensive phantom experiments were performed in an angiography suite to evaluate the effects of several parameters on operator dose, such as patient body part, radiation shielding, x-ray tube angulation, and acquisition type. Phantom data were compared with operator dose data from clinical procedures (n = 281), which were prospectively acquired with the use of electronic real-time personal dosimeters (PDMs) combined with an automatic dose-tracking system (DoseWise Portal; Philips, Best, The Netherlands). A reference PDM was installed on the C-arm to measure scattered radiation. Operator exposure was calculated relative to this scatter dose.ResultsIn phantom experiments and clinical procedures, median operator dose relative to the dose-area product (DAP) was reduced by 81% and 79% in cerebral procedures and abdominal procedures, respectively. The use of radiation shielding decreased operator exposure up to 97% in phantom experiments; however, operator dose data show that this reduction was not fully achieved in clinical practice. Both phantom experiments and clinical procedures showed that the largest contribution to relative operator dose originated from left-anterior-oblique C-arm angulations (59%–75% of clinical operator exposure). Of the various x-ray acquisition types used, fluoroscopy was the main contributor to procedural DAP (49%) and operator dose in clinical procedures (82%).ConclusionsAchievable levels for radiation exposure reduction were determined and compared with real-life clinical practice. This generated evidence-based advice on the conditions required for optimal radiation safety.     

CT fluoroscopy-guided abdominal interventions: techniques, results, and radiation exposure.

PURPOSE: To evaluate the benefits of computed tomographic (CT) fluoroscopy-guided interventions and assess radiation exposures incurred with CT fluoroscopy. MATERIALS AND METHODS: A 6-month period of use of CT fluoroscopy to guide abdominal biopsy procedures and catheter drainage was analyzed. Efficacy measures and needle placement and procedure room times were compared with those of the preceding 6 months during which conventional CT was used. CT fluoroscopic times and estimated radiation exposures were compared for two CT fluoroscopic methods. RESULTS: The sensitivity and negative predictive values for biopsy procedures and the success rate for needle aspiration or catheter drainages for CT fluoroscopy--98%, 86%, and 100%, respectively--were not significantly different from those for conventional CT--95%, 80%, and 97%, respectively. Room time was not reduced significantly, but mean needle placement time for CT fluoroscopy (29 minutes; n = 95) was significantly lower than that for conventional CT (36 minutes; n = 93; P < .005). The mean patient dose index was 74 cGy. Limiting CT fluoroscopy to scanning the needle tip rather than scanning the entire needle pass significantly reduced the dose to the patient and the operator. CONCLUSION: Although CT fluoroscopy is a useful targeting technique, significant radiation exposures may result. Therefore, radiologists need to be aware of different methods of CT fluoroscopic guidance and the factors that contribute to radiation exposure.     

Evaluation of thyroid radiation dose during abdominal Computed Tomography procedures and dose reduction effectiveness of thyroid shielding

IntroductionDuring abdominal Computed Tomography (CT) studies, vicinity organs receive a dose from scatter radiation. The thyroid is considered an organ at greater risk due to high radiosensitivity.MethodsThe primary objective of this study was to determine the entrances surface dose (ESD) to the thyroid during abdominal CT studies and to evaluate the efficiency of dose reduction by lead shielding. The calibrated thermoluminescence dosimeter (TLD) chips were used to measure the ESD during 180 contrast-enhanced (CE) and non-contrast-enhanced (NC) abdominal CT studies in the presence and absence of lead shielding.ResultsThyroid shielding reduces the ESD by 72.3% (0.55 mGy), 86.5% (2.95 mGy) and 64.0% (2.24 mGy) during NC, 3–phase and 4–phase abdominal CT scans. Also, the patient height was identified as a parameter that inversely influenced the thyroid dose, proving that the taller patients receive less dose to the thyroid. Regardless, the scan parameters such as time and display field of view (DFOV) positively impact the thyroid dose.ConclusionLead shielding can prevent the external scatter reaching the thyroid region by 64%–87% during the non-vicinity scans such as abdomen CT. However, the actual dose saving lies between 0.2% and 0.4%, compared to the total effective dose of the whole CT procedure.Implications for practiceThe thyroid shield can effectively reduce external scatter radiation during abdominal CT procedures. However, the dose saving is insignificant compared to the total effective dose from the whole examination. Therefore, the use of thyroid shielding should be carefully evaluated during CT abdomen procedures.     

Percutaneous abdominal and pelvic interventional procedures using CT fluoroscopy guidance.

OBJECTIVE: The purpose of our study was to assess the use of low-milliamperage CT fluoroscopy guidance for percutaneous abdominopelvic biopsy and therapeutic procedures. MATERIALS AND METHODS: We reviewed the clinical records and relevant imaging studies of 97 patients who underwent 119 percutaneous CT fluoroscopy-guided abdominal or pelvic procedures: fluid collection aspiration or drainage catheter insertion (n = 59), biopsy (n = 49), hepatocellular carcinoma ethanol ablation (n = 6), chemoneurolysis (n = 4), and brachytherapy catheter insertion (n = 1). These procedures were guided using a helical CT scanner providing real-time fluoroscopy reconstruction at six frames per second. A control panel and video monitor beside the gantry allowed direct operator control during all interventional procedures. RESULTS: One hundred twelve (94.1%) procedures were successfully performed using either a stand-off needle holder and continuous real-time CT fluoroscopy guidance or incremental manual insertion and intermittent CT fluoroscopy to confirm position. Image quality using low milliamperage was adequate for needle or drainage tube placement in all but two low-contrast liver lesions. Two hematomas were accessed but yielded no fluid on aspiration; one drainage procedure was abandoned after the patient developed endotoxic shock. Imaging of ethanol distribution during injection facilitated tumor ablation and neurolytic procedures. CT fluoroscopy allowed rapid assessment of needle, guidewire, dilator, and catheter placement, especially in nonaxial planes. Average CT fluoroscopy time for biopsy and therapeutic procedures was 133 sec (range, 35-336 sec) and 186 sec (range, 20-660 sec), respectively. CONCLUSION: CT fluoroscopy is a practical clinical tool that facilitates effective performance of percutaneous abdominal and pelvic interventional procedures.     

Benefits and safety of CT fluoroscopy in interventional radiologic procedures

PURPOSE: To determine the benefits and safety of computed tomographic (CT) fluoroscopy when compared with conventional CT for the guidance of interventional radiologic procedures. MATERIALS AND METHODS: Data on 203 consecutive percutaneous interventional procedures performed with use of CT fluoroscopic guidance and 99 consecutive procedures with conventional CT guidance were obtained from a questionnaire completed by the radiologists and CT technologists who performed the procedures. The questionnaire specifically addressed radiation dose measurements to patients and personnel, total procedure time, total CT fluoroscopy time, mode of CT fluoroscopic guidance (continuous versus intermittent), success of procedure, major complications, type of procedure (biopsy, aspiration, or drainage), site of procedure, and level of operator experience. RESULTS: The median calculated patient absorbed dose per procedure and the median procedure time with CT fluoroscopy were 94% less and 32% less, respectively, than those measurements with conventional CT scanning (P <.05). An intermittent mode of image acquisition was used in 97% of the 203 cases. This resulted in personnel radiation dosimetric readings below measurable levels in all cases. CONCLUSION: As implemented at the authors' institution, use of CT fluoroscopy for the guidance of interventional radiologic procedures markedly decreased patient radiation dose and total procedure time compared with use of conventional CT guidance.     

CT fluoroscopy--guided interventional procedures: techniques and radiation dose to radiologists.

PURPOSE: To determine the radiation dose to radiologists who perform computed tomographic (CT) fluoroscopic interventional procedures by using a quick-check method and a low-milliampere technique. MATERIALS AND METHODS: Two hundred twenty CT fluoroscopy--guided interventional procedures were performed in 189 patients. Procedures included 57 spinal injections, 17 spinal biopsies, 24 chest biopsies, 20 abdominal aspirations, 44 abdominal biopsies, and 58 abdominal drainages. Procedure details were prospectively recorded and included site, depth, target diameter, milliampere value, kilovolt peak, fluoroscopic time, and CT technique (continuous CT fluoroscopy, quick-check method, or a combination of these techniques). An individual collar and finger radiation detector were worn by each radiologist during each procedure to determine the dose per procedure. RESULTS: The quick-check technique was performed in 191 (87%) of 220 procedures. Four procedures were performed with continuous CT fluoroscopy, and a combination technique was used for 25 (11%) procedures. The overall mean CT fluoroscopic time was 17.9 seconds (range, 1.2--101.5 seconds). The mean milliampere value was 13.2 mA (range, 10--50 mA). The overall mean radiologist radiation dose per procedure was 2.5 mrem (0.025 mSv) (whole body). Individual procedure doses ranged from 0.66 to 4.75 mrem (0.007--0.048 mSv). The finger radiation dose was negligible. CONCLUSION: By using a low-milliampere technique and the quick-check method, CT fluoroscopic time and radiation exposure can be minimized.     

Radiation Dose to the Radiologist’s Hand During Continuous CT Fluoroscopy-Guided Interventions

Computed tomography fluoroscopy (CT fluoroscopy) enables real-time image control over the entire body with high geometric accuracy and, for the most part, without significant interfering artifacts, resulting in increased target accuracy, reduced intervention times, and improved biopsy specimens [1–4]. Depending on the procedure being used, higher radiation doses than in conventional CT-supported interventions might occur. Because the radiologist is present in the CT room during the intervention, he is exposed to additional radiation, which is an important aspect. Initial experience with CT fluoroscopically guided interventions is from the work of Katada et al. in 1994 [5] and only relatively few reports on radiation aspects in CT fluoroscopy are found in the literature [1, 2, 6–11]. To date, there are no reported injuries to patients and radiologists occurring with CT fluoroscopy. The time interval since the wide use of CT fluoroscopy is too short to have data on late effects to the operator using CT fluoroscopy on a daily basis. In addition, the spectrum of CT fluoroscopically guided interventional procedures will expand and more sophisticated procedures requiring longer fluoroscopy times will be performed. Thus, effective exposure reduction is very important. The purpose of our study was to assess the radiation dose to the operator’s hand by using data from phantom measurements. In addition, we investigated the effect of a lead drape on the phantom surface adjacent to the scanning plane, the use of thin radiation protective gloves, and the use of different needle holders.     

Multislice CT fluoroscopy: technical principles, clinical applications and dosimetry

PURPOSE: The aim of this study is describing fluoroscopic techniques with multislice CT during interventional procedures. We emphasize the technical principles of the multislice CT fluoroscopy and the relative advantages in clinical application, in comparison to single slice fluoroCT and conventional CT guided procedures. Other topics are dosimetry and patient's and operator's radioprotection. MATERIALS AND METHODS: We describe our experience in 60 cases of interventional procedures performed with CT fluoroscopy array for the TOSHIBA AQUILION-MULTI TSX-101A scanner that allows a real-time 3 slices simultaneous representation of the target: middle target slice, superior and inferior slices. Thirty nine biopsies, 5 abscess drainage, 12 shoulder arthrocentesis previous to arthro-MR and 4 hepatic neoplasm ablations have been performed during the last 9 months. For each procedure questionnaires have been used to evaluate: target organs, scan parameters, fluoroscopy techniques (continuous or spot) and total time of fluoroCT. Basing on these data and on the measurements made on a body phantom we calculated patient's and operator's radiation dose rate. RESULTS AND DISCUSSION: The real-time simultaneous representation of the middle target slice and the adjacent superior and inferior slices has always allowed an immediate identification of the needle tip and direction. The use of a needle holder has been determined by the needle type, the fluoroscopy technique (continuous or spot), the type of interventional procedure and the target. In our experience freehand spot fluoroscopy approach was easier, faster and with less radiation dose rate. 24 seconds were the mean fluoroscopy time for all different CT fluoroscopy modalities and procedures. The mean absorbed equivalent dose rate to patient's skin was 5300 microSv/s while the dose to operator's body and hand was respectively 0.3 microSv/s and 30 microSv/s. CONCLUSIONS: Multislice CT fluoroscopy, specially if performed by spot technique, leads to an acceptable radiation dose rate to patient and operator, is user friendly and guides interventional procedures with rapidity.     

Personnel exposure rates during simulated biopsies with a real-time CT scanner

RATIONALE AND OBJECTIVES: Real-time computed tomography (CT) has the potential to expedite and improve CT-guided needle biopsies by allowing cross-sectional images to be viewed in real time as a needle is advanced toward the target lesion. A major concern about this procedure is the scattered and leaked radiation to which the operator is exposed. This study was undertaken to determine the exposure rates around a CT scanner during CT-guided needle biopsies and to identify the areas of greatest personnel exposure. MATERIALS AND METHODS: Pig and human cadavers were used to simulate patients undergoing a CT-guided needle biopsy. Various anatomic biopsy sites were used. The radiologist's exposure was assessed by timing the procedure and measuring the exposure rates around the CT scanner with an ionization-chamber survey meter. Ion-chamber measurements multiplied by the time the radiologist spent performing several mock biopsies were compared with film dosimeter results. Doses to the hands, wrists, and whole body were measured with ring, wrist, body, and collar film dosimeters. RESULTS: The average time required to perform a single biopsy was about 1 minute. The dose to the radiologist performing the simulated biopsies was calculated to be 123 mR, 68 mR, 14 mR, and less than 0.5 mR to the fingers, wrist, collar, and body, respectively, as calculated from ionization-chamber and time measurements. These exposure rates correlate well with the film dosimeter readings accumulated during the mock procedures. CONCLUSION: The dose received by the radiologist performing a CT-guided biopsy was comparable to that of other interventional procedures. In addition, operating from the head of the machine (ie, distal to the bed) appeared to markedly reduce personnel exposure, due to the shielding in the gantry of the CT scanner used in the study.     

Dose reduction in computed tomography: the effect of eye and testicle shielding on radiation dose measured in patients with beryllium oxide-based optically stimulated luminescence dosimetry

The aim of this study was to assess the effect of eye and testicle shielding on radiation dose to the lens and the testes of patients undergoing CT examinations. Fifty-one male patients underwent CT twice with identical protocols initially without, the second time with protective garments. Doses to the testes and the lenses were recorded with beryllium oxide-based dosimeters. The dose to the testes and lenses from CT exposure was reduced by 96.2% ± 1.7% and 28.2% ± 18.5%, when testicle and eye shielding was used, respectively. The effect of the eye shielding on the eye lens dose was found to depend on the x-ray tube position when the eye is primarily exposed during the scan. The maximum eye lens dose reduction achieved was found to be 43.2% ± 6.5% corresponding to the anterior position of the tube. A significant correlation between the patient’s body mass index and dose exposure could not be found. Eye and testicle shields, apart from being inexpensive and easy to use, were proven to be effective in reducing eye lens and testicle radiation dose burden from CT exposures.     

Evaluation of additional lead shielding in protecting the physician from radiation during cardiac interventional procedures

Since cardiac interventional procedures deliver high doses of radiation to the physician, radiation protection for the physician in cardiac catheterization laboratories is very important. One of the most important means of protecting the physician from scatter radiation is to use additional lead shielding devices, such as tableside lead drapes and ceiling-mounted lead acrylic protection. During cardiac interventional procedures (cardiac IVR), however, it is not clear how much lead shielding reduces the physician dose. This study compared the physician dose [effective dose equivalent (EDE) and dose equivalent (DE)] with and without additional shielding during cardiac IVR. Fluoroscopy scatter radiation was measured using a human phantom, with an ionization chamber survey meter, with and without additional shielding. With the additional shielding, fluoroscopy scatter radiation measured with the human phantom was reduced by up to 98%, as compared with that without. The mean EDE (whole body, mean+/-SD) dose to the operator, determined using a Luxel badge, was 2.55+/-1.65 and 4.65+/-1.21 mSv/year with and without the additional shielding, respectively (p=0.086). Similarly, the mean DE (lens of the eye) to the operator was 15.0+/-9.3 and 25.73+/-5.28 mSv/year, respectively (p=0.092). In conclusion, although tableside drapes and lead acrylic shields suspended from the ceiling provided extra protection to the physician during cardiac IVR, the reduction in the estimated physician dose (EDE and DE) during cardiac catheterization with additional shielding was lower than we expected. Therefore, there is a need to develop more ergonomically useful protection devices for cardiac IVR.     

PET/CT-guided Interventions: Personnel Radiation Dose

Purpose

To quantify radiation exposure to the primary operator and staff during PET/CT-guided interventional procedures.

Methods

In this prospective study, 12 patients underwent PET/CT-guided interventions over a 6 month period. Radiation exposure was measured for the primary operator, the radiology technologist, and the nurse anesthetist by means of optically stimulated luminescence dosimeters. Radiation exposure was correlated with the procedure time and the use of in-room image guidance (CT fluoroscopy or ultrasound).

Results

The median effective dose was 0.02 (range 0–0.13) mSv for the primary operator, 0.01 (range 0–0.05) mSv for the nurse anesthetist, and 0.02 (range 0–0.05) mSv for the radiology technologist. The median extremity dose equivalent for the operator was 0.05 (range 0–0.62) mSv. Radiation exposure correlated with procedure duration and with the use of in-room image guidance. The median operator effective dose for the procedure was 0.015 mSv when conventional biopsy mode CT was used, compared to 0.06 mSv for in-room image guidance, although this did not achieve statistical significance as a result of the small sample size (p = 0.06).

Conclusion

The operator dose from PET/CT-guided procedures is not significantly different than typical doses from fluoroscopically guided procedures. The major determinant of radiation exposure to the operator from PET/CT-guided interventional procedures is time spent in close proximity to the patient.     

Fluoroscopy: patient radiation exposure issues.

Fluoroscopic procedures (particularly prolonged interventional procedures) may involve high patient radiation doses. The radiation dose depends on the type of examination, the patient size, the equipment, the technique, and many other factors. The performance of the fluoroscopy system with respect to radiation dose is best characterized by the receptor entrance exposure and skin entrance exposure rates, which should be assessed at regular intervals. Management of patient exposure involves not only measurement of these rates but also clinical monitoring of patient doses. Direct monitoring of patient skin doses during procedures is highly desirable, but current methods still have serious limitations. Skin doses may be reduced by using intermittent exposures, grid removal, last image hold, dose spreading, beam filtration, pulsed fluoroscopy, and other dose reduction techniques. Proper training of fluoroscopic operators, understanding the factors that influence radiation dose, and use of various dose reduction techniques may allow effective management of patient dose.     

Patient and occupational dose in neurointerventional procedures

Neurointerventional procedures can involve very high doses of radiation to the patient. Our purpose was to quantify the exposure of patients and workers during such procedures, and to use the data for optimisation. We monitored the coiling of 27 aneurysms, and embolisation of four arteriovenous malformations. We measured entrance doses at the skull of the patient using thermoluminescent dosemeters. An observer logged the dose-area product (DAP), fluoroscopy time and characteristics of the digital angiographic and fluoroscopic projections. We also measured entrance doses to the workers at the glabella, neck, arms, hands and legs. The highest patient entrance dose was 2.3 Gy, the average maximum entrance dose 0.9+/-0.5 Gy. The effective dose to the patient was estimated as 14.0+/-8.1 mSv. Other average values were: DAP 228+/-131 Gy cm(2), fluoroscopy time 34.8+/-12.6 min, number of angiographic series 19.3+/-9.4 and number of frames 267+/-143. The highest operator entrance dose was observed on the left leg (235+/-174 microGy). The effective dose to the operator, wearing a 0.35 mm lead equivalent apron, was 6.7+/-4.6 microSv. Thus, even the highest patient entrance dose was in the lower part of the range in which nonstochastic effects might arise. Nevertheless, we are trying to reduce patient exposure by optimising machine settings and clinical protocols, and by informing the operator when the total DAP reaches a defined threshold. The contribution of neurointerventional procedures to occupational dose was very small.     

Evolution of radiation exposure to operator in diagnostic and interventional radiology procedures and reduction of radiation exposure to operator with protective device

A study was performed to evaluate operator dose during diagnostic and interventional radiology procedures (IVR) and to establish methods of operator dose reduction with a radiation protective device. Operator dose was measured by glass dosimeters worn on the neck and on the abdomen outside the lead apron. In addition, the dose of the primary beam at the collimator surface was measured, which made it possible to define the correlation between the entrance air kerma, measured with Skin Dose Monitor, and operator dose exposed during the monitored procedure. IVR protectors were developed to decrease the amount of scatter radiation received by operators performing the procedures, and their effects were evaluated in abdominal and cardiac angiography procedures. The average effective dose and doses of the neck and abdomen outside the lead apron, estimated for individual procedures, were as follows: abdominal angiography procedures: effective dose, 0.07 mSv; neck area, 0.18 mSv; abdominal area, 0.51 mSv; cardiac angiography procedures: effective dose, 0.07 mSv; neck area, 0.13 mSv; abdominal area, 0.68 mSv. Operator doses were well correlated with exposure dose in abdominal angiography procedures (diagnostic procedure r=0.84, IVR r=0.77). It was found that 68.0% of the effective dose in abdominal angiography procedures and 43.0% of the effective dose in cardiac angiography procedures could be reduced by the use of IVR protectors. Operator and patient doses in interventional radiology were interdependent. The minimization of operator doses is particularly important during interventional radiology, and it is necessary to be aware of practical radiation protection procedures. Measures that reduce patient dose will also reduce occupational exposure. Moreover, operator dose could be substantially reduced by the use of IVR protectors in addition to wearing a protective lead apron during IVR. It was suggested that IVR protectors are effective radiation protective devices in interventional radiology procedures.     

Effect of Real-Time Radiation Dose Feedback on Pediatric Interventional Radiology Staff Radiation Exposure

PurposeTo measure and compare individual staff radiation dose levels during interventional radiologic (IR) procedures with and without real-time feedback to evaluate whether it has any impact on staff radiation dose.Materials and MethodsA prospective trial was performed in which individuals filling five different staff roles wore radiation dosimeters during all IR procedures during two phases: a 12-week “closed” phase (measurements recorded but display was off, so no feedback was provided) and a 17-week “open” phase (display was on and provided real-time feedback). Radiation dose rates were recorded and compared by Mann–Whitney U test.ResultsThere was no significant difference in median procedure time, fluoroscopy time, or patient dose (dose–area product normalized to fluoroscopy time) between the two phases. Overall, the median staff dose was lower in the open phase (0.56 µSv/min of fluoroscopy time) than in the closed phase (3.01 µSv/min; P < .05). The IR attending physician dose decreased significantly for procedures for which the physicians were close to the patient, but not for ones for which they were far away.ConclusionsA radiation dose monitoring system that provides real-time feedback to the interventional staff can significantly reduce radiation exposure to the primary operator, most likely by increasing staff compliance with use of radiation protection equipment and dose reduction techniques.     

Patient and operator exposure during percutaneous vertebroplasty

Purpose

The purpose of this study was to compare exposure of patient and operator to ionising radiation during percutaneous vertebroplasty performed under combined computed tomography (CT) and fluoroscopic guidance or fluoroscopic guidance alone.

Materials and methods

With the collaboration of our physics department, we measured exposure on ten patients undergoing vertebroplasty with combined CT and fluoroscopic guidance and on ten undergoing vertebroplasty with fluoroscopic guidance alone.

Results

Mean operator dose was approximately 0.8 microSv during vertebroplasty done with combined CT and fluoroscopic guidance and 5.8 microSv in procedures with fluoroscopic guidance alone. Mean patient dose was approximately 6 mSv for combined guidance and 8 mSv for fluoroscopic guidance, a difference that was not found to be statistically significant.

Conclusions

Although combined CT and fluoroscopic guidance is normally preferred for difficult areas such as the cervical and upper thoracic vertebrae, to ensure operator radiation protection, the technique should also be considered for areas normally treated under fluoroscopic guidance alone. However, a larger patient series is needed to correctly evaluate the real contribution of low-dose CT to patient exposure.     

Percutaneous CT-Guided Abdominal and Pelvic Biopsies: Comparison of an Electromagnetic Navigation System and CT Fluoroscopy

PurposeTo compare electromagnetic navigation (EMN) with computed tomography (CT) fluoroscopy for guiding percutaneous biopsies in the abdomen and pelvis.Materials and MethodsA retrospective matched-cohort design was used to compare biopsies in the abdomen and pelvis performed with EMN (consecutive cases, n = 50; CT-Navigation; Imactis, Saint-Martin-d’Hères, France) with those performed with CT fluoroscopy (n = 100). Cases were matched 1:2 (EMN:CT fluoroscopy) for target organ and lesion size (±10 mm).ResultsThe population was well-matched (age, 65 vs 65 years; target size, 2.0 vs 2.1 cm; skin-to-target distance, 11.4 vs 10.7 cm; P > .05, EMN vs CT fluoroscopy, respectively). Technical success (98% vs 100%), diagnostic yield (98% vs 95%), adverse events (2% vs 5%), and procedure time (33 minutes vs 31 minutes) were not statistically different (P > .05). Operator radiation dose was less with EMN than with CT fluoroscopy (0.04 vs 1.2 μGy; P < .001), but patient dose was greater (30.1 vs 9.6 mSv; P < .001) owing to more helical scans during EMN guidance (3.9 vs 2.1; P < .001). CT fluoroscopy was performed with a mean of 29.7 tap scans per case. In 3 (3%) cases, CT fluoroscopy was performed with gantry tilt, and the mean angle out of plane for EMN cases was 13.4°.ConclusionsPercutaneous biopsies guided by EMN and CT fluoroscopy were closely matched for technical success, diagnostic yield, procedure time, and adverse events in a matched cohort of patients. EMN cases were more likely to be performed outside of the gantry plane. Radiation dose to the operator was higher with CT fluoroscopy, and patient radiation dose was higher with EMN. Further study with a wider array of procedures and anatomic locations is warranted.     

Radiation exposure to interventional radiologists during manual-injection digital subtraction angiography

Purpose: We investigated the relationship between the amount of radiation exposure to the operator during table-side manual-injection angiographic procedures including digital subtraction angiography (DSA) and the operator’s position, as well as a simple means to decrease radiation exposure. Methods: Measurement of radiation exposure was carried out with thermoluminescent dosimeters (TLDs) in nine abdominal angiographies. In the first study, radiation exposure during DSA or during fluoroscopy was measured using TLDs placed near the angiographic table. In the second study, radiation exposure to the interventional radiologist was measured during manual-injection DSA at a near and a far operator position. Results: Radiation exposure to the operator received during manual-injection DSA accounted for more than 90% of the total procedural exposure. The exposure to the operator markedly decreased at the far position compared with that at the near position when performing DSA. Conclusion: Manual-injection DSA is the largest contributor to radiation exposure received by the interventional radiologist, therefore, the use of a power injector is always recommended when performing DSA. When manual-injection DSA is necessary, radiologists should position themselves as far away from the patient as possible.