Level of patient and operator dose in the largest cardiac centre in Greece.

The objective of this study was to investigate the patient and staff doses in the most frequent interventional cardiology (IC) procedures performed in Onassio, the largest Cardiac Centre in Greece. Data were collected from three digital X-ray systems for 212 coronary angiographies, 203 percutaneous transluminal coronary angioplasties (PTCA) and 134 various electrophysiological studies. Patient skin dose was measured using suitably calibrated slow radiotherapy films and cardiologist dose using suitably calibrated thermoluminescent dosemeters placed on left arm, hand and foot.

Commissioning and constancy protocols for digital angiographic units.

During the European Concerted Action SENTINEL 'Safety and Efficacy for New Techniques and Imaging using New Equipment to Support European Legislation', protocols for commissioning and constancy tests for dynamic digital flat detectors angiography units have been developed in order to harmonise practice among the European counties. The commissioning protocol includes measurements on X-ray tube and generator, patient and detector radiation dose and image quality. The constancy protocol is based on the dose and image quality measurements.

Computed tomography versus Acute Physiology and Chronic Health Evaluation II score in predicting severity of acute pancreatitis: a prospective, comparative study with statistical evaluation.

Objective: The aim of the study was to compare Acute Physiology and Chronic Health Evaluation II score and C-reactive protein as a clinical index and computed tomography-based severity index (CTSI) in predicting the course of acute pancreatitis.

Methods: One hundred forty-eight patients with acute pancreatitis were enrolled in the study during a 2-year period. All data concerning etiology, Atlanta classification, CT findings, Acute Physiology and Chronic Health Evaluation score, C-reactive protein levels, stay in the intensive care unit, length of hospital stay, treatment, complications, and deaths were analyzed with Mann-Whitney U, Wilcoxon, Pearson, and Spearman statistical tests.

CT-guided interventional procedures without CT fluoroscopy assistance: patient effective dose and absorbed dose considerations.

Objective: The purpose of this study was to determine patient effective dose (E) and peak absorbed dose to the skin of the patient from various CT-guided interventional procedures performed without CT fluoroscopy assistance.

Materials And Methods: In total, 49 interventions were retrospectively studied: 14 biopsies, 14 radiofrequency ablations, 14 abscess drainages, and seven nephrostomies. CT images were acquired from the department's PACS system and reviewed to record the scan parameters of each slice.

Dose management in CT facility.

Computed Tomography (CT) examinations have rapidly increased in number over the last few years due to recent advances such as the spiral, multidetector-row, CT fluoroscopy and Positron Emission Tomography (PET)-CT technology. This has resulted in a large increase in collective radiation dose as reported by many international organisations. It is also stated that frequently, image quality in CT exceeds the level required for confident diagnosis.

Dose reduction in CT while maintaining diagnostic confidence: diagnostic reference levels at routine head, chest, and abdominal CT--IAEA-coordinated research project.

Purpose: To measure radiation doses for computed tomography (CT) of the head, chest, and abdomen and compare them with the diagnostic reference levels, as part of the International Atomic Energy Agency Research coordination project.

Materials And Methods: The local ethics committees of all participating institutions approved the study protocol. Written informed consent was obtained from all patients.

Factors that influence radiation dose in percutaneous coronary intervention.

Aim: To explore the factors that may influence the radiation dose imparted to the patient in PCI, and investigate whether the use of the latest digital X-ray system based on FP detector technology can have an impact on dose.

Materials And Method: Demographic and clinical data such as number of lesions treated, number of stents placed, grade of tortuosity, and stage of occlusion, as well as use of double wire and double balloon technique, ostial stenting or bifurcation stenting, and presence of major complications were recorded, together with radiation parameters.

Results: The factors that increased patient radiation dose were (1) patient gender, as men exhibited higher doses than women; (2) complex lesion; (3) increasing number of stents; (4) position of stent; (5) grade of tortuosity; and (6) stage of occlusion.

Optical density variations in CT films and their effect on image quality.

It was recently reported that optical density (OD) variations were observed in CT films printed with a laser camera, depending on the printing format and the frame position within the film. The purpose of the present study was to investigate if these variations are common to both laser and dry-film printers and if the different OD settings along with day-to-day and frame-to-frame variations may affect the image quality. Eight laser and five dry-film printers installed at 12 different CT facilities were tested.

Excessive leakage radiation measured on two mobile X-ray units due to the methodology used by the manufacturer to calculate and specify the required tube shielding.

During the quality control (QC) procedure of a new mobile X-ray unit, it was revealed that the leakage radiation was well in excess of the current limit of 1 mSv h(-1). As a result, this unit was returned to the vendor company and it was replaced by a new unit of the same brand and model. Leakage measurements revealed that the second unit presented the same problem.

Correlation of patient and staff doses in interventional cardiology.

The purpose of this study was to measure staff radiation doses in representative institutions of five European countries performing coronary angiographies (CA) and percutaneous transluminal coronary angioplasties (PTCA), as well as to investigate any correlation with patient doses. Patient doses were recorded in terms of dose-area product (DAP). Staff doses were measured by thermoluminescence dosemeters placed on the operator's left shoulder and left foot.

Comparison of a CCD and a flat-panel digital system in an Interventional Cardiology Laboratory.

We evaluated the performances of angiographic units equipped with a flat-panel (FP) detector and image intensifier (II) charge-coupled device (CCD) in the Interventional Cardiology (IC) Department. Entrance dose rate and dose per image, along with the dose at the II level were measured using 2 mm copper sheets to simulate a patient. Image quality (IQ) was evaluated using a phantom.

Radiation doses to patients and cardiologists from permanent cardiac pacemaker implantation procedures.

Background: The purpose of this study was to determine the patient and cardiologist doses during the implantation of permanent cardiac pacemakers under fluoroscopic control.

Methods: For 55 procedures concerning three different types of pacemakers (DDD, VDD, and VVI), the dose-area product (DAP) meter readings and fluoroscopy times were recorded. From these data, the dose to the operating cardiologist was estimated.

Analysis of radiological examination request forms in conjunction with justification of X-ray exposures.

Objectives: To evaluate the adequacy of patient data and clinical information transmitted to the radiological departments by the referring clinicians in view of the justification demands concerning the radiological examinations, as those are described in the Radiation Protection Regulations of the European Union Nations.

Materials And Methods: Request forms for 1708 patients referred to radiology department and 410 referred to the CT department were evaluated concerning the proper completion of the form fields. Furthermore, for CT examinations a more detailed evaluation was carried out, to assess the rationalistic use of CT within the diagnostic algorithm.

Variation of the sensitometric characteristics of seven mammographic films with processing conditions.

The effect of different processing conditions on the sensitometric characteristics of mammographic films was investigated and the implications of this effect on clinical practice are discussed. Three Agfa (MR5-II, HDR and HT), two Kodak (MinR-M, MinR-2000), one Fuji (AD-M) and one Konica (CM-H) single emulsion mammographic films were used. For each film type a 21-step sensitometric strip was developed in seven different processing conditions involving the use of four processors, five developing times and four chemistries.

Radiation dose measurements to the interventional cardiologist using an electronic personal dosemeter.

The aim of this study was to investigate the use of an electronic personal dosemeter (EPD) worn by a senior cardiologist in an Interventional Cardiology (IC) Laboratory of a busy cardiac centre and how the results could help in the evaluation of radiation protection equipment used. Patient samples consist of 28 patients (10 coronary angiographies (CAs) and 18 percutaneous transluminal coronary angioplasties (PTCAs)). Patient dose was measured with a dose-area product (DAP) meter.

Dose performance evaluation of a charge coupled device and a flat-panel digital fluoroscopy system recently installed in an interventional cardiology laboratory.

The purpose of the study was to evaluate the dose performance of a flat-panel (FP) and an image intensifier (II) charge coupled device (CCD) digital fluoroscopy X-ray systems newly installed in an Interventional Cardiology (IC) department. Filter entrance dose rate, detector dose rate (during fluoroscopy) and filter entrance dose per image were measured at 70 cm from the focus using 2 mm copper sheets to mimic normal size patient. Image quality was also evaluated.

Comparison of a conventional and a flat-panel digital system in interventional cardiology procedures.

The purpose of the study was to analyse the technical characteristics of a newly installed flat-panel fluoroscopy (FPF) system in an interventional cardiology (IC) department and compare it with an older conventional system. A patient survey was performed to investigate the radiation doses delivered by the X-ray systems. Finally, methods of technique optimization regarding the new digital system were investigated.

Occupational dose constraints in interventional cardiology procedures: the DIMOND approach.

Radiation fields involved in angiographic suites are most uneven with intensity and gradient varying widely with projection geometry. The European Commission DIMOND III project addressed among others, the issues regarding optimization of staff doses with an attempt to propose preliminary occupational dose constraints. Two thermoluminescent dosemeters (TLD) were used to assess operators' extremity doses (left shoulder and left foot) during 20 coronary angiographies (CAs) and 20 percutaneous transluminal coronary angioplasties (PTCAs) in five European centres.

Quality control of a laser camera with the SMPTE test pattern: optical density variations with printing format and frame position.

The purpose of this study was to investigate the use of the Society of Motion Picture and Television Engineers (SMPTE) test pattern in the quality control of a modern laser camera and the variations in the optical density (OD) of the film when different formats are used. The SMPTE pattern was printed on all the available frames in eight different formats. Furthermore, six films were produced using the same format to check for any reproducibility problems.

Radiation doses to patients from endoscopic retrograde cholangiopancreatography examinations and image quality considerations.

The purpose of this investigation was to measure the dose-area product (DAP) and the other relevant dosimetric quantities in diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP). Furthermore, the dependence of patient dose and image quality on the tube potential was investigated. A DAP meter was used for dose monitoring in seven diagnostic and 21 therapeutic ERCPs.

A model for calculating shielding requirements in diagnostic X-ray facilities.

In this study a new model for calculating shielding requirements in diagnostic X-ray facilities is presented. It is based on the combination and modification of models and concepts originally proposed by other authors in order to calculate barrier requirements in diagnostic X-ray facilities accurately and realistically without unjustified exaggerations. With this model, multiple sources of radiation operating at different potentials, leakage radiation reduction when operating at potentials less than the maximum rated value, secondary radiation use factors reduction for primary barriers, attenuation by image receptor hardware and existing building materials are all taken into account.

A semiempirical method for the description of off-center ratios at depth from linear accelerators.

A semiempirical method for the description of the off-center ratios (OCR) at depth from linear accelerators is presented, which is based on a method originally developed for cobalt-60 (60)Co units. The OCR profile is obtained as the sum of 2 components: the first describes an OCR similar to that from a (60)Co unit, which approximates that resulting from the modification of the original x-ray intensity distribution by the flattening filter; the second takes into account the variable effect of the flattening filter on dose profile for different depths and field sizes, by considering the existence of a block and employing the negative field concept. The above method is formulated in a mathematical expression, where the parameters involved are obtained by fitting to the measured OCRs.

The diagnostic X-ray protection characteristics of Panelcrete, Aquapanel, Betopan and Gypsoplak Superboard.

Panelcrete, Aquapanel and Betopan are cement-based building materials with uses similar to those of gypsum wallboard, whose properties as a diagnostic X-ray shielding material have been extensively studied. The X-ray attenuation characteristics of these cement-based boards as well as those of a gypsum wallboard, Gypsoplak Superboard, are investigated for broad beam geometry conditions and for tube potentials of 50 kVp, 70 kVp, 100 kVp, 125 kVp and 140 kVp. Comparisons between these materials as well as with published data for gypsum wallboard are made.

Dose calculations for asymmetric fields defined by independent collimators using symmetric field data.

Several methods have been developed for the dosimetry of asymmetric radiation fields formed by independently moving collimator jaws. Three of these methods, based on different principles and modified to comply with our set of available data, are utilized for the calculation of asymmetric field dose profiles. All three methods use output factors and per cent depth doses or tissue maximum ratios of symmetric fields.

The diagnostic X-ray protection characteristics of Ytong, an aerated concrete based building material.

Ytong is a widely used building material. The X-ray attenuation properties of Ytong for broad beam geometry conditions and for tube potentials in the 50-140 kVp range are investigated. Comparisons with published data for concrete and other building materials are made.