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PubMed2001

[Comparative study of the quality of C-arm based 3D imaging of the talus].

Malposition of extraosseous or intra-articular screws, e.g., in osteosyntheses of joint fractures or in the vicinity of joints, frequently remains undiscovered in intraoperative fluoroscopy and is only recognized on postoperative computed tomography (CT) scans. The aim of the study, therefore, was to assess the value of a new mobile C-arm three-dimensional imaging device in comparison with fluoroscopy, conventional radiographs, and CT scans using an extremity model. Screws were inserted ventrally in four anatomic lower leg specimens without talus fractures parallel to the longitudinal axis to simulate surgical management of fractures of the talus. The specimens supplied were examined with fluorscopy, conventional radiography, spiral CT, and the new three-dimensional imaging with the SIREMOBIL Iso-C3D. These four modalities were evaluated by ten radiologists and ten trauma surgeons and were compared regarding subjective image quality and position of the screws. The quality of information acquired with the SIREMOBIL Iso-C3D was equal to that of the CT examinations, although image quality was considered inferior to fluoroscopy, conventional radiography, and CT (p < 0.001). In contrast to the previous procedure with intraoperative fluoroscopy and subsequent postoperative X-ray control, the results obtained with the SIREMOBIL IsoC3D were superior. The SIREMOBIL Iso-C3D is useful for the intraoperative diagnosis of small joints with few artifacts producing osteosynthesis material, i.e., for recognizing the position of screws in the region of glenoid surfaces.

Bone Screws↗
PubMed2004

Is the 10th and 11th intercostal space a safe approach for percutaneous nephrostomy and nephrolithotomy?

The aim of this study was to determine the rate of complications in percutaneous nephrostomy (PCN) and nephrolithotomy (PCNL) performed through the 11th and 10th intercostal spaces using our monitoring technique and to discuss the safety of the procedure. Out of 398 PCNs and PCNLs carried out during a 3-year period, 56 patients had 57 such procedures performed using an intercostal approach. The 11th intercostal route was used in 42 and the 10th in 15 cases. One patient had two separate nephrostomies performed through the 10th and 11th intercostal spaces. The technique utilizes bi-planar fluoroscopy with a combination of a conventional angiographic machine to provide anterior-posterior fluoroscopy and a C-arm mobile fluoroscopy machine to give a lateral view, displayed on two separate monitors. None of the patients had clinically significant thoracic or abdominal complications. Two patients had minor chest complications. Only one developed changes (plate atelectasis, elevation of the hemi-diaphragm) directly related to the nephrostomy (2%). The second patient had bilateral plate atelectasis and unilateral congestive lung changes after PCNL. These changes were not necessarily related to the procedure but rather to general anesthesia during nephrolithotomy. The authors consider PCN or PCNL through the intercostal approach a safe procedure with a negligible complication rate, provided that it is performed under bi-planar fluoroscopy, which allows determination of the skin entry point just below the level of pleural reflection and provides three-dimensional monitoring of advancement of the puncturing needle toward the target entry point.

Adult↗
PubMed2006

Accurate localization of tissue layers in the esophagus by using a double-lumen injection catheter: implications for the Enteryx procedure.

BACKGROUND: Enteryx (Boston Scientific Corp, Natick, Mass) is an injectable polymer used for the treatment of GERD. Current use of Enteryx requires fluoroscopy for accurate placement into the deep esophageal wall (ie, the deep submucosa or muscularis propria). In this study, we assessed the use of a new double-lumen, double-needle injection catheter for accurate placement of Enteryx into the deep esophageal wall, without fluoroscopy, in a porcine model. METHODS: All procedures were performed by using a new injection catheter (GZ Medical, LLC, Minnetonka, Minn), which allows for tissue depth assessment via the flow of gas through one lumen and the injection of a therapeutic substance (Enteryx) via a second lumen. Endoscopy was performed on 5 consecutive pigs by using the new catheter alone, without fluoroscopy, and attempting deep injections. Four injections of Enteryx were made at the gastroesophageal junction, 10 cm above the junction, and 15 cm above the junction. A total of 60 sites (12 per animal) were injected. The animals were sacrificed and each esophagus was harvested. The mediastinal cavity was searched for extravasated Enteryx material, and the esophagus was examined grossly for Enteryx adherent to the outside wall. Injection sites then were classified morphologically as superficial (mucosa or submucosa), deep (muscularis propria or deep submucosa contiguous to muscularis), subadventitial (between muscle and adventitia), or transmural. Only deep injections were considered adequate. RESULTS: No extravasated Enteryx was found in the mediastinum in 60 injected sites. One area of transmural injection had Enteryx adherent to the outside esophageal wall (1.7%). Fifty-one injected sites (85%) were adequate deep injections, 4 injections (6.7%) were subadventitial, 1 injection (1.7%) was superficial, and 3 injections (5%) could not be assessed. There were no complications observed in any animal. CONCLUSIONS: By using a new injection device without fluoroscopy, Enteryx can be deposited consistently into the deep esophageal wall with a high degree of accuracy, avoiding mediastinal extravasation. Additional clinical trials are necessary to determine the relative accuracy and role of the new technique compared to standard radiographically guided placement.

Animals↗
PubMed2006

Reproducibility of liver position using active breathing coordinator for liver cancer radiotherapy.

PURPOSE: To measure the intrabreath-hold liver motion and the intrafraction and interfraction reproducibility of liver position relative to vertebral bodies using an active breathing coordinator (ABC) in patients with unresectable liver cancer treated with hypofractionated stereotactic body radiation therapy (SBRT). METHODS: Tolerability of ABC and organ motion during ABC was assessed using kV fluoroscopy in 34 patients. For patients treated with ABC, repeat breath-hold CT scans in the ABC breath-hold position were acquired at simulation to estimate the volumetric intrafraction reproducibility of the liver relative to the vertebral bodies. In addition, preceding each radiation therapy fraction, with the liver immobilized using ABC, repeat anteroposterior (AP) megavoltage verification images were obtained. Off-line alignments were completed to determine intrafraction reproducibility (from repeat images obtained before one treatment) and interfraction reproducibility (from comparisons of the final image for each fraction with the AP) of diaphragm position relative to vertebral bodies. For each image set, the vertebral bodies were aligned, and the resultant craniocaudal (CC) offset in diaphragm position was measured. Liver position during ABC was also evaluated from kV fluoroscopy acquired at the time of simulation, kV fluoroscopy at the time of treatment, and from MV beam's-eye view movie loops acquired during treatment. RESULTS: Twenty-one of 34 patients were screened to be suitable for ABC. The average free breathing range of these patients was 13 mm (range, 5-1 mm). Fluoroscopy revealed that the average maximal diaphragm motion during ABC breath-hold was 1.4 mm (range, 0-3.4 mm). The MV treatment movie loops confirmed diaphragm stability during treatment. For a measure of intrafraction reproducibility, an analysis of 36 repeat ABC computed tomography (CT) scans in 14 patients was conducted. The average mean difference in the liver surface position was -0.9 mm, -0.5 mm, and 0.2 mm in the CC, AP, and medial-lateral (ML) directions, with a standard deviation of 1.5 mm, 1.5 mm, and 1.5 mm, respectively. Ninety-five percent of the liver surface had an absolute differences in position between repeat ABC CT scans of less than 4.1 mm, 3.3 mm, and 3.3 mm in the CC, AP, and ML directions, respectively. Analysis of 257 MV AP images from patients treated using ABC revealed an average intrafraction CC reproducibility (sigma) of diaphragm relative to vertebral bodies of 1.5 mm (range, 0.6-3.9 mm). The average interfraction CC reproducibility (sigma) was 3.4 mm (range, 1.5-7.9 mm), indicating less day-to-day reproducibility of diaphragm position relative to vertebral bodies. The average absolute intra and interfraction CC offset in diaphragm position relative to vertebral bodies was 1.7 and 3.7 mm, respectively, with 86% of intrafraction and 54% of interfraction absolute offsets 3.0 mm or less. CONCLUSIONS: Intrafraction reproducibility of liver position using ABC is good in the majority of screened patients. However, interfraction reproducibility is worse, suggesting a need for image guidance.

Adult↗
PubMed1997

Reconstruction accuracy of a dedicated localiser for filmless planning in intra-operative brachytherapy.

BACKGROUND AND PURPOSE: With the use of HDR and PDR afterloaders containing a single stepping source, brachytherapy dose distributions can be optimised by varying the source dwell time. With the goal of implementing 'conformal brachytherapy', i.e. ensuring that the dose distribution conforms as accurately as possible to the target volume, we evaluated a set-up which enabled on-line implant localisation and dose planning during implantation. MATERIALS AND METHODS: The set-up, designated as an integrated brachytherapy unit (IBU), consists of a shielded operating room equipped with an HDR afterloader and a dedicated brachytherapy localiser connected to a treatment planning computer. The localiser is isocentric and has an extra degree of freedom in comparison to conventional simulators (i.e. an L-arm in combination with a C-arm) and enables viewing of the implant from any direction. A reconstruction algorithm which takes into account both rotation axes, i.e. the L-arm and C-arm angle, was developed for the localiser. The reconstruction procedure was tested by using the IBU localiser to measure the reconstruction accuracy with a phantom (containing 25 markers at well defined positions) and using reconstruction from radiographs. These results were compared to simulations where the accuracy of reconstruction was determined as a function of the reconstruction angle and the accuracy of read-outs of the localiser settings. On-line localisation and dose planning during implantation is based on filmless planning, i.e. fluoroscopy images and the corresponding localiser settings are imported into the treatment planning computer during implantation. The accuracy of filmless planning was determined using fluoroscopy images in the same set-up as for the experiments with the radiographs. The effect of reconstruction inaccuracies on the total irradiation time and the dose in target or normal tissue points was elucidated for clinically relevant implant geometries. The treatment plans of two phantoms based on reconstruction from films as well as fluoroscopy images were compared with plans for implants defined by exact co-ordinates. RESULTS: The average reconstruction error due to the accuracy of the read-out of the localiser settings varied between -0.18 and 0.24 mm, with a standard deviation (arising from digitisation errors) ranging from 0.11 to 0.22 mm. Using filmless reconstruction and the 10 inch field of view of the image intensifier (without applying correction for the geometric distortions) the average reconstruction error ranged from 0.01 to 0.65 mm, and the standard deviation ranged from 0.40 to 0.73 mm. These errors arose as a consequence of the finite pixel size and geometric distortions. These limited errors did not influence the treatment time for clinical implant geometries and had only a minor effect (<1%) on the dose in markers during filmless planning. CONCLUSION: This IBU set-up, with a dedicated brachytherapy localiser, allows for a rapid and accurate filmless planning procedure based on implant localisation from fluoroscopy images.

Brachytherapy↗
PubMedDate not supplied

Emergency percutaneous nephrostomy: technical success based on level of operator experience.

PURPOSE: The outcomes of emergency percutaneous nephrostomy procedures performed by operators with different levels of experience were analyzed. PATIENTS AND METHODS: A prospective study of 160 patients undergoing 169 emergency percutaneous nephrostomies was conducted. Three categories of operator experience were compared based on the number of percutaneous nephrostomies performed each year (level 1 = more than 20, level 2 = 10-20, or level 3 = less than 10). RESULTS: The level 1 operators (mean fluoroscopy time, 2 minutes; mean procedure time, 25 minutes) achieved success in 141 of 142 cases (99%) and failed in one case (1%), which was repeated successfully the next day. The level 2 operators (mean fluoroscopy time, 6 minutes; mean procedure time, 35 minutes) achieved initial success in all of 15 cases (100%), but three cases (20%) were repeated the next day because of catheter migration or malposition. Level 3 operators (mean fluoroscopy time, 10 minutes; mean procedure time, 42 minutes) were successful in 10 of 12 cases (83%), but in four cases (33%) the procedure had to be repeated. CONCLUSION: The experience of the operators played little role in the initial success rate of the procedure after they had performed 10 or more per year. However, the level of experience did influence the number of procedures that needed to be repeated, the prevalence of minor complications, and the mean fluoroscopy and procedure time.

Clinical Competence↗
PubMed1999

Transcatheter closure of atrial septal defects under echocardiographic guidance without X-ray: initial experiences.

BACKGROUND: Transcatheter closure of atrial septal defects is performed under fluoroscopy, but echocardiography has gained an important role in the procedure. With the new Amplatzer Septal Occluder a device has become available which is easy to implant with minimal fluoroscopy time. We developed an interventional procedure with this device under transesophageal echocardiography alone without fluoroscopy. METHODS AND RESULTS: Four patients (3 to 16 years of age, bodyweight 14 to 60 kg) with atrial septal defects centrally located in the oval fossa were elected for transcatheter closure. After sedation with midazolam and propofol a diagnostic and interventional catheterization was performed in all cases without fluoroscopy. Oxymetric shunt was Qp: Qs = 1.7 (1.5 to 2.1). Under transesophageal echocardiography, the defects were sized over the wire with a balloon catheter. Mean balloon stretched diameter was 10 mm (7 to 14 mm). Under transesophageal echocardiography an Amplatzer Septal Occluder was placed into the defect. In two patients this was achieved with a 5 MHz monoplane pediatric transducer, in two patients a 10mm 5 MHz multiplane probe was used. Complete closure was achieved in all patients and no complications were encountered. CONCLUSION: We conclude that in selected cases with an atrial septal defect located in the oval fossa and clear-cut echocardiographic findings, an Amplatzer Septal Occluder can be safely deployed under echocardiographic guidance alone.

Adolescent↗
PubMed2004

[Erroneous X-ray dose measurements in paediatric cardiac investigations].

According to national and international rules the x-ray exposure of cardiac catheter examinations have to be measured. For a Philips Integris angiographic system used for paediatric heart catheterization we found severe errors in the indicated time of fluoroscopy and total dose area product ( DAP) both for fluoroscopy and radiography. Fluoroscopy times shorter than 6 seconds and DAPs smaller than 0.1 Gy cm (2) are ignored and not considered in the indicated total fluoroscopy time and the fluoroscopic and radiographic DAPs. This error leads to a systematic underestimation of the risk of radiation-induced cancer especially with infants and children.

Child↗
PubMed2001

Radiation doses to patients during ERCP.

BACKGROUND: There is a scarcity of data regarding the radiation dose and associated risks to patients during ERCP. Dose area product (DAP) measurements can be used to estimate an effective dose (ED) to patients undergoing ERCP. This measure allows radiation risk associated with such procedures to be quantified. The aim of this study was to evaluate the ED to patients undergoing ERCP. METHODS: A DAP meter was fitted to the x-ray tube before each ERCP. DAP reading (Gy-cm(2)), fluoroscopy time, average screening kVp, number of films, and kVp per film were recorded. Mean ED was estimated by using DAP readings and Monte Carlo computer software to model radiation exposure conditions. RESULTS: Data were recorded on 20 subjects. Average DAP was 13.5 Gy-cm(2) (6.8-23.9) for diagnostic and 66.8 Gy-cm(2) (28.7-108.5) for therapeutic ERCP (p < 0.05). Average fluoroscopy time was 2.3 minutes (1.1-5.3) for diagnostic and 10.5 minutes (5.9-16.6) for therapeutic ERCP (p < 0.05). DAP showed a linear relationship with fluoroscopy time (R(2) = 0.928). Mean number of diagnostic and therapeutic films was 2.8 and 3.7, respectively. Fluoroscopic exposure represented 69% of the DAP for diagnostic ERCP and 90% of the DAP for therapeutic ERCP. Average ED was 3.1 mSv for diagnostic and 12.4 mSv for therapeutic ERCP. CONCLUSIONS: Therapeutic ERCP is associated with significantly higher radiation exposure than diagnostic ERCP. ED in therapeutic ERCP is a result largely of fluoroscopy time as opposed to number of films.

Adult↗
PubMed1992

Sonographic transcervical balloon tuboplasty.

The purpose of this study was to evaluate sonographic guidance for transcervical tubal catheterization and transcervical balloon tuboplasty of patients with bilateral proximal tubal occlusion. Cornual catheterization and transcervical balloon tuboplasty were performed under sonographic guidance. Injection of micro-bubble emulsion confirmed tubal recanalization. Tubal patency demonstrated by sonography was confirmed by injection of contrast material under fluoroscopy. Four women with bilateral proximal tubal occlusion confirmed by previous hysterosalpingogram and laparoscopy underwent sonographically guided transcervical balloon tuboplasty. Patients with distal or peritubal damage were excluded from this study. Bilateral tubal patency confirmed by sonography and subsequent fluoroscopy was achieved in all four patients. One patient conceived spontaneously, a month following the procedure, and delivered at term. Sonographically guided transcervical balloon tuboplasty can be performed successfully on patients with proximal tubal occlusion. Identification of the catheter tip and successful cannulation of the internal tubal ostia were easier to perform under fluoroscopy. Further improvements in sonographic equipment and catheter technology will hopefully eliminate radiation and replace fluoroscopy during the performance of transcervical balloon tuboplasty. Sonographic transcervical tubal catheterization may, therefore, become a simple and cost-effective procedure for the diagnosis and treatment of patients with proximal tubal occlusion.

Evaluation Studies as Topic↗
PubMed2005

First results on patient dose measurements from conventional diagnostic radiology procedures in Serbia and Montenegro.

The objective of this work is to assess patient doses for the most frequent X-ray examinations for the first time in Serbia and Montenegro. A total of 510 procedures for 11 different examination categories in 3 general hospitals were analysed. Mean and median entrance surface air kerma (ESAK) and kerma area product (KAP) values followed by mean effective doses were reported. Using X-ray tube output data, ESAK for each radiographic examination was calculated, as well as the effective dose for each patient. Except for chest PA examination, all estimated doses are less than stated European and International Atomic Energy Agency (IAEA) reference levels for simple radiographic examinations. For complex examinations involving fluoroscopy and radiography total KAP was measured and contributions from fluoroscopy and radiography were assessed. The study of KAP confirms that the dose level for complex fluoroscopy investigations is closely related to the technique and individual patient variation in terms of fluoroscopy time and number of radiography exposures. The obtained values are comparable to those reported in the UK. Survey data are aimed aid development of a national quality control and radiation protection programme for medical exposures.

Body Burden↗
PubMed1997

Use of electrocardiogram to position right atrial catheters during surgery.

OBJECTIVE: This study evaluated the accuracy of placing right atrial catheters using an electrocardiographic (ECG) technique. SUMMARY BACKGROUND DATA: Placement of right atrial catheters for vascular access is a common operative procedure. Accurate placement is essential for proper function. Previous placement techniques have used fluoroscopy, which is both time consuming and hazardous. METHODS: The accuracy of placement of 1236 right atrial catheters using an ECG technique was compared to placement of 586 catheters using fluoroscopy between March 1991 and November 1995. In the ECG technique, the catheter was flushed with sodium bicarbonate. A sterile left-leg ECG lead was attached to the catheter with the other ECG leads applied normally. On advancing the catheter through the superior vena cava, the P-wave amplitude (lead II) increased in negative deflection until greater than the QRS complex. Passing the sinoatrial node, the P-wave developed an initial positive then negative deflection. The catheter was positioned so the P-wave was biphasic, representing a position midway between the sinoatrial and atrioventricular nodes. For the fluoroscopic technique, catheters were positioned under direct observation just within the atrium estimated from cardiac contour. Use of contrast was optional if atrial anatomy was unclear. RESULTS: Postoperative portable chest x-rays showed the ECG method to position the catheter tip within the right atrium just as accurately (average, 1.9 +/- 1.3 cm) as with the use of fluoroscopy (average, 1.1 +/- 1.6 cm). The ECG method eliminated an average of 20 seconds of radiation exposure, an average of 3.0 minutes operating room time (p < 0.04), avoided all risks of contrast dye, and saved $279.10 per case. CONCLUSIONS: The ECG method is a satisfactory alternative to that of fluoroscopy for placement of long-term central venous catheters into the right atrium.

Cardiac Catheterization↗
PubMed2006

Needle biopsy of anatomically unfavorable liver lesions with an electromagnetic navigation assist device in a computed tomography environment.

PURPOSE: Emerging interventional radiology assistance systems that incorporate electromagnetic navigation (EMN) can help the operator guide a needle or other instrument toward a target along preplanned oblique trajectories while avoiding critical structures. A proof-of-concept study was conducted to assess the use of EMN, and EMN was compared with the standard computed tomographic (CT) fluoroscopy guidance technique. MATERIALS AND METHODS: A total of 14 needle passes, seven each with EMN and CT fluoroscopy guidance, were performed into an artificially created liver lesion of a single swine. The accuracy of needle placement for each pass was verified with a confirmatory CT scan. The total radiation dose and time of procedure was compared between the EMN and conventional CT fluoroscopy methods. RESULTS: All needle passes were successful, and all passes conducted with EMN were completed with a single insertion, whereas multiple passes (mean, 2.9) with needle repositioning were required with CT fluoroscopic guidance. Statistically significant reduction in procedure time and overall radiation dose for EMN punctures was shown. Accuracy of needle placement was statistically equivalent for the two methods. CONCLUSIONS: This proof-of-concept study shows that EMN guidance has equivalent accuracy of needle placement to conventional CT fluoroscopy-guided methods in swine. EMN is also associated with favorable radiation-dose and time-of-procedure profiles for biopsy of liver lesions. Clinical studies are needed to evaluate the safety and efficacy of this technology in the biopsy of lesions in anatomically challenging locations that require steep angles of needle insertion.

Animals↗
PubMed2001

Locating a catheter transducer in a three-dimensional ultrasound imaging field.

Cardiac procedures rely on fluoroscopy for catheter guidance and visualization. However, fluoroscopy provides poor contrast of myocardial structures and exposes both the patient and health care providers to ionizing radiation. As an alternative to fluoroscopy, real-time three-dimensional (3-D) ultrasound imaging has the potential to provide a safe means for tracking catheter position in 3-D while simultaneously imaging the heart's anatomy. A method is described for locating a catheter-mounted transducer in the 3-D ultrasound imaging field. The distance from the imaging transducer to the catheter transducer is measured by time of flight, while the angular position is determined by a spatial crosscorrelation of the received signals with stored receive profiles. Results from simulations with 20-dB SNR demonstrated a mean accuracy of 0.22 +/- 0.13 mm at a 70-mm range. In vitro testing showed a resolution of 0.23 +/- 0.11 mm at a range of 75 mm and a resolution of 0.47 +/- 0.47 mm at a range of 97 mm. With combined catheter position and imaging, this tracking method has the potential to replace fluoroscopy and enhance interventional procedures.

Cardiac Catheterization↗
PubMed2005

Use of a new non-fluoroscopic three-dimensional mapping system in type I atrial flutter ablation.

We studied 40 patients who underwent cavo-tricuspid isthmus ablation for typical counterclockwise atrial flutter with cooled tip catheters between 2001 and 2003. Complete bi-directional isthmus block was created in all patients. A new, three-dimensional (3D), non-fluoroscopic mapping system was used in 20 patients (test group), and conventional fluoroscopy in 20 others (conventional group), using anatomic and electrophysiologic criteria in both groups. We measured the total procedure, ablation procedure, and overall fluoroscopy times, and the total number of radiofrequency (RF) applications delivered in the two groups. The overall fluoroscopy time was shorter in the test group (mean 8.8 minutes, range 2-17 minutes) than the conventional group (29.7 minutes, range 12-57 minutes; P < 0.001). Though the overall procedure time was similar in both groups (92.5 +/- 28.6 minutes vs 106.5 +/- 20.9 minutes; P = 0.067) the ablation duration (25.1 +/- 6.6 minutes versus 43.3 +/- 19.6 minutes; P = 0.0051) and the total RF applications (10.6 +/- 9.4 versus 16.4 +/- 9.4; P = 0.044) were smaller in the test group. The use of a new, 3D non-fluoroscopic mapping system markedly reduced the fluoroscopy exposure during typical atrial flutter ablation. It was also associated with a significant reduction in ablation time and in the number of RF applications. Since atrial flutter ablation is one of the most frequently performed procedures, this system may significantly reduce the overall amount of radiation exposure in high-volume laboratories.

Atrial Flutter↗
PubMed1995

X-ray imaging using amorphous selenium: feasibility of a flat panel self-scanned detector for digital radiology.

We investigate a concept for making a large area, flat-panel detector for digital radiology. It employs an x-ray sensitive photoconductor to convert incident x-radiation to a charge image which is then electronically read out with a large area integrated circuit. The large area integrated circuit, also called an active matrix, consists of a two-dimensional array of thin film transistors (TFTs). The potential advantages of the flat-panel detector for digital radiography include: instantaneous digital radiographs without operator intervention; compact size approaching that of a screen-film cassette and thus compatibility with existing x-ray equipment; high quantum efficiency combined with high resolution. Its potential advantages over the x-ray image intensifier (XRII)/video systems for fluoroscopy include: compactness; geometric accuracy; high resolution, and absence of veiling glare. The feasibility of the detector for digital radiology was investigated using the properties of a particular photoconductor (amorphous selenium) and active matrix array (with cadmium selenide TFTs). The results showed that it can potentially satisfy the detector design requirements for radiography (e.g., chest radiography and mammography). For fluoroscopy, the images can be obtained in real-time but the detector is not quantum noise limited below the mean exposure rate typically used in fluoroscopy. Possible improvements in x-ray sensitivity and noise performance for the application in fluoroscopy are discussed.

Cobalt Radioisotopes↗
PubMed1997

Adjunctive intracardiac echocardiography to guide slow pathway ablation in human atrioventricular nodal reentrant tachycardia: anatomic insights.

BACKGROUND: Because of the inability of fluoroscopy to image intracardiac structures, the precise anatomic location of successful slow pathway (SP) ablation is controversial. We hypothesized that adjunctive intracardiac echocardiography (ICE) in concert with conventional fluoroscopy and electrogram guidance could identify the anatomic site of successful SP ablation. METHODS AND RESULTS: In 25 patients, radiofrequency ablation was performed in the triangle of Koch directed by biplane fluoroscopy and a 6.2F, 12.5-MHz ICE catheter positioned adjacent to the triangle of Koch. Persistent SP conduction, number of radiofrequency applications, presence of junctional tachycardia, and fluoroscopy times were evaluated. As demonstrated by ICE, anterograde SP ablation was achieved between 2 and 7 mm from the tricuspid valve in imaging planes containing the AV muscular septum in all cases. Radiofrequency energy applications applied at other sites within the triangle of Koch failed to interrupt SP conduction. A mean of three radiofrequency energy applications (3+/-2; range, 1 to 12) successfully ablated all evidence of anterograde SP conduction in all patients studied. Junctional tachycardia was seen in 96% (71/74) of the radiofrequency energy applications. CONCLUSIONS: Radiofrequency ablation at the tricuspid valve's insertion into the AV muscular septum as identified by ICE reliably terminates anterograde SP conduction, supporting the hypothesis that the SP consistently traverses this anatomic location.

Adult↗
PubMedDate not supplied

Development of a urinary lithiasis localizer mechanism to couple ultrasound and extracorporeal lithotripsy equipment in canine model.

INTRODUCTION: Due to the evolution of extracorporeal lithotripsy equipment (ESWL) and presently, the fact that most part of the equipment does not present ultrasound to localize urinary calculi, a system that allows adapting ultrasound equipment to ESWL equipment was developed, disposing only of fluoroscopy. Thus, this equipment was developed and was tested in urinary stones in canine models, to check its precision in relation to fluoroscopy. METHOD: Seven male dogs were utilized with the introduction, in the bladder through the ureteral route, of chalkstones, with initial localization by fluoroscopy, with a further ultrasound coincidence check localization of the vesical stones, being submitted to ESWL with a 3-hour, 21 days and 60 days follow-up after the procedure. RESULTS: Success of localization in all animals was verified presenting elimination of stones in the first micturitions, after ESWL. No complications were verified in those animals for 60 days. CONCLUSION: We verified that this equipment can lead to an update of the equipment that use only fluoroscopy, increasing in this way, their technical capacity in the treatment of urinary calculi, mainly in cases of non-radiopaque stones.

Animals↗