Occupational radiation exposure from fluoroscopically guided percutaneous transhepatic biliary procedures

PURPOSE: The aim of this study was to determine occupational dose levels for projections commonly used in fluoroscopically guided percutaneous transhepatic biliary (PTB) drainage and stent placement procedures. METHODS: Exposure data from 71 consecutive PTB examinations were analyzed to determine average examination parameters for biliary drainage and stent placement procedures. An anthropomorphic phantom was exposed at three projections common in PTB interventions according to the actual geometric parameters recorded in the patient study. Scattered air-kerma dose rates were measured for neck, waist, and gonad levels at various sites in the interventional radiology laboratory. To produce technique- and instrumentation-independent data, dose rate values were converted to dose-area product (DAP)-normalized air-kerma values. In addition, sets of thermoluminescent dosimetry crystals were placed in both hands of the interventional radiologist to monitor doses during all PTB procedures. RESULTS: Isodose maps of DAP-normalized air-kerma doses in the interventional laboratory for projections commonly used in PTB procedures are presented. To facilitate effective dose estimation, normalized dosimetric data at the interventional radiologist's position are presented for left and right access drainage procedures, metallic stent placement only, and drainage and metallic stent placement in one-session procedures with and without under-couch shielding. Doses to the hands of interventional radiologists are presented for left and right transhepatic biliary access and metallic stent placement. CONCLUSIONS: Body level-specific normalized air-kerma distributions from commonly used projections in PTB procedures may be useful to accurately quantify dose, maximum workloads, and possible radiogenic risks delivered to medical personnel working in the interventional radiology laboratory. Normalized dose data presented will enable occupational exposure estimation from other institutions.     

Significantly reduced radiation exposure to operators during kyphoplasty and vertebroplasty procedures: methods and techniques

BACKGROUND AND PURPOSE: Vertebroplasty and kyphoplasty can be associated with significant radiation exposure to the operator. We compared the exposure levels to an operator performing vertebral fracture augmentation with vertebroplasty and kyphoplasty, to assess a cement injection and a monitoring technique designed to reduce this exposure. METHODS: A neuroradiologist performed 189 consecutive vertebral augmentation procedures in 135 patients with osteoporotic compression fractures by using a bilateral approach with biplane pulse fluoroscopy at 7.5 pulses/second. Cement delivery was performed with intermittent fluoroscopy with kyphoplasty and vertebroplasty by using syringes or continuous fluoroscopic monitoring with a cement delivery system (CDS). Data collection included time and operator exposure parameters. RESULTS: A total of 87 kyphoplasty procedures, 82 vertebroplasty procedures with a CDS (VP-CDS), and 20 vertebroplasty procedures with syringes (VP-S) were safely performed. Mean fluoroscopy time for device positioning was 4.3 minutes for each procedure type. Mean fluoroscopy time (minutes) for cement delivery was significantly different for the 3 procedure types; 2.1 for kyphoplasty, 3.7 for VP-CDS, and 1.5 for VP-S (P < .0001). Comparable mean radiation exposure rates (microsieverts/minute) were 0.8 for kyphoplasty, 1.1 for VP-CDS, and 0.3 for VP-S during device-positioning and 1.7 for kyphoplasty, 2.9 for VP-CDS, and 0.2 for VP-S during cement injection (P < .002). CONCLUSION: Use of the modified cement injection technique and intermittent fluoroscopy with kyphoplasty and vertebroplasty with syringes results in a significantly lower operator exposure rate compared with vertebroplasty with a CDS.     

Clinical radiation management for fluoroscopically guided interventional procedures

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

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.     

Galactic cosmic radiation exposure and associated health risks for air carrier crewmembers

The dose equivalent to air carrier crewmembers from galactic cosmic radiation was estimated for each of 32 nonstop flights on a variety of routes to and from, or within, the contiguous United States. Flying times were from 0.4 to 13 hours. The annual dose equivalents received on the flights ranged from 0.2 to 9.1 mSv (20 to 910 mrem), or 0.4 to 18% of the recommended annual limit for occupational exposure of an adult. We reviewed some of the characteristics of galactic and solar cosmic radiation and provided example calculations for estimating radiation-induced risks of fatal cancer, genetic defects and harm to an embryo or fetus. The estimated increased risk of dying from cancer because of galactic radiation exposure received during 20 years of flying ranged from 0.1 to 5 in 1,000. For the adult U.S. population the risk of dying from cancer is about 220 in 1,000.     

Comparative review of vertebroplasty and kyphoplasty

The aim of this review is to compare the effectiveness of percutaneous vertebroplasty and kyphoplasty to treat pain and improve functional outcome from vertebral fractures secondary to osteoporosis and tumor conditions. In 2009, two open randomized controlled trials published in the New England Journal of Medicine questioned the value of vertebroplasty in treating vertebral compression fractures. Nevertheless, the practice of physicians treating these conditions has barely changed. The objective of this review is to try to clarify the most important issues, based on our own experience and the reported evidence about both techniques, and to guide towards the most appropriate choice of treatment of vertebral fractures, although many questions still remain unanswered.     

CT and fluoroscopically guided percutaneous embolization treatment of a pseudoaneurysm associated with pancreatitis

A novel approach to embolization treatment with a cyanoacrylate solution for a bleeding pseudoaneurysm associated with pancreatitis is described in the setting of a critically ill patient. Computed tomography and a C-arm fluoroscopic unit were used to guide percutaneous placement of a needle and injection of the embolic material. This technique represents an alternative form of embolization when traditional angiographic techniques are not possible.     

Patient radiation exposure during coronary angiography and intervention

Purpose: To prospectively register fluoroscopic and cine times in a random fashion, and to measure patient radiation exposure from routine coronary angiography and coronary balloon angioplasty. We also evaluated an optional dose reduction system used during interventions.Material and Methods: The incident radiation to the patient was measured as kerma area product (KAP) in Gycm², obtained from an ionisation chamber mounted on the undercouch tube during 65 coronary angiography procedures and another 53 percutaneous transluminal coronary angioplasties (including 29 stent procedures), mostly directly following complete coronary angiography.Results and Conclusion: The values from coronary angiography were comparable to other reports with a mean fluoroscopic time of 4.4 min and a mean KAP value of 62.6 Gycm². The corresponding figures from coronary balloon angioplasty without stenting were lower than otherwise reported, with 8.2 min and 47.9 Gycm², respectively. The use of coronary stents did prolong the mean fluoroscopic time (10.5 min) but did not significantly enhance the patient mean radiation dose (51.4 Gycm²). The dose reduction technique resulted in a significant KAP value reduction of 57%. In conclusion, with regard to radiation exposure, coronary angiography and balloon angioplasty are considered safe procedures.     

Patient radiation exposure during pediatric cardiac catheterization

Exposure area product (EAP) and center field entrance exposure (free-in-air) were measured in seventeen pediatric patients undergoing cardiac catheterization. Exposures were recorded separately for biplane fluoroscopy and cine angiocardiography using flat-plate ionization chambers. In the posterior-anterior (PA) projections, median EAP was 425 Roentgen-square centimeter (R-cm2), with a range of 90.5-3,882 R-cm2;29-35% of this exposure occurred during cine filming. In the lateral projection, median EAP was 276 R-cm2 (range 117-1,173); 52-59% of this exposure was due to cine filming. Median center field entrance exposure in the PA view was 7.86 Roentgens (R) with a range 2.16-73.9 of and in the lateral projection 7.39 R (range 2.64-24.6). As much as 25% of the exposure from the entire examination was contributed by manual "test" exposures to set cine radiographic kVp. We recommend use of testing circuits, which determine cine radiographic factors automatically and thus should lower levels of exposure.     

Percutaneous vertebral augmentation: vertebroplasty, kyphoplasty and skyphoplasty

vertebroplasty is a safe, inexpensive, and effective interventional vertebral augmentation technique that provides pain relief and stabilization in carefully selected patients with severe back pain due to vertebral compression. Complications from percutaneous vertebroplasty can be devastating, but are rare and avoidable with application of a meticulous technique. Percutaneous vertebroplasty has a role in the management pathway of patients presenting with painful vertebral compression fractures. Kyphoplasty uses a balloon tamp with the aim of restoring vertebral body height, improving kyphotic deformity, and creating a cavity into which bone cement is injected. Kyphoplasty is as effective and safe as vertebroplasty in treatment of painful vertebral compression fractures. Skyphoplasty, a modification of kyphoplasty, is a promising new technique.     

Feasibility and safety of infracolic fluoroscopically guided percutaneous radiologic gastrostomy

We study the feasibility and safety of infracolic fluoroscopically guided percutaneous gastrostomy when patient anatomy prevents conventional supracolic puncture. From September 2004 to April 2007, 508 gastrostomy and gastrojejunostomy catheters were inserted in a single institution, and in six patients, the position of the transverse colon prevented conventional supracolic puncture. All were male, with a mean age of 57 years. Four patients had head and neck cancer and two had neurologic conditions. With fluoroscopic guidance, a 14-F gastrostomy tube was inserted with T-fastener gastropexy caudal to the colon. The medical records of patients treated with this technique were reviewed for demographics, indication, technique, complications, function of gastrostomy, timing of removal of the gastrostomy, and subsequent hospital admissions. All procedures were technically successful and there was no procedure-related morbidity or mortality. The mean follow-up was 16 months (range, 7-25 months) and the mean duration of therapy was 7 months. Five patients had their gastrostomy removed after clinical improvement and one of these patients had a gastrostomy reinserted cephalic to the colon after recurrence of head and neck cancer. Two patients died of disease progression and one still had the gastrostomy in position. No patient was subsequently admitted for a complication of the technique or catheter malfunction. In conclusion, infracolic percutaneous radiologic gastrostomy with gastropexy is feasible in patients without an access route cephalic to the transverse colon.     

Pulmonary embolism of polymethyl methacrylate during percutaneous vertebroplasty and kyphoplasty

OBJECTIVE: The purpose of this study was to determine the frequency, radiographic findings, and clinical significance of a pulmonary embolism of cement occurring during percutaneous vertebroplasty or kyphoplasty as detected on conventional chest radiography. MATERIALS AND METHODS: Chest radiographs were obtained after 69 percutaneous vertebroplasty procedures in 64 patients. Chest radiographs were reviewed retrospectively for the presence of pulmonary emboli of cement, and findings were assessed. The frequency was calculated from the cases treated. Medical records were reviewed for procedure-related complications. RESULTS: The emboli of cement were noted radiographically in three (4.6%) of 65 procedures performed in our institution. All patients with cement emboli had multiple myeloma. The chest radiographic findings were multiple radiographically dense opacities with a tubular and branching shape that were scattered sporadically or distributed diffusely throughout the lungs. All patients with cement pulmonary embolism remained asymptomatic. A correlation of embolism of cement to lungs was found with paravertebral venous cement leak (p < 0.001) but not with the number of vertebral bodies treated (p = 0.185) or with the type of procedure performed-kyphoplasty versus vertebroplasty (p = 0.98). CONCLUSION: Pulmonary embolism of cement is seen in 4.6% of patients after percutaneous vertebroplasty or kyphoplasty. The characteristic radiographic findings should be recognized by radiologists.