Accuracy of CT dose monitor values: a multicentric study.

Four hundred and ninety-five adult patients in 16 medical centres participated in this study aiming to investigate the congruence between the volume CT dose index (CTDIvol) monitor values and measured ones during common CT procedures, performed by 20 systems. Tube output CTDIair measurements were carried out on single and multislice scanners for any kV, slice thickness, mA and FOV combination used. The maximum/minimum ratio of measured CTDIvol values found to be 3.

The effect of a combined tube current modulation system on dose delivered to patients undergoing thoracic and abdominal CT with a 128-slice scanner.

Combined tube current modulation techniques (such as Care Dose4D used in this study) during computed tomography (CT) procedures bring together the benefits of the angular and z-axis modulation techniques, measuring X-ray attenuation profile in the z-axis together with the data from the perpendicular x-y direction with a sophisticated algorithm. The purpose of this study was to investigate the radiation dose, in terms of computed tomography dose index (CTDI(vol)), delivered to patients during thoracic and abdominal CT using this technique and compare it with the corresponding CTDI(vol) of the fixed tube current CT technique. The results revealed a 5-32% dose reduction for chest CT and a dose reduction of 7.

Patient dose in cardiac radiology.

Introduction: In diagnostic and interventional cardiology procedures performed with the use of X-ray diagnostic imaging systems, the long fluoroscopy time and the large number of cine projections, as well as the repetition of the procedure due to the recurrence of the lesion--a common event--result in a high locally delivered skin dose, which may even lead to patient skin necrosis. The purpose of this study was to collect information in order to estimate the patient dose during coronary angiography and coronary angioplasty procedures, using the dose-area product measuring system of the X-ray angiographic machine.

Methods: Dose-area product (DAP), fluoroscopy time, number of sequences and frames per sequence were collected for each of 108 coronary angiography and 101 coronary angioplasty procedures, using the dedicated X-ray machine of the hospital's haemodynamic department, where more than 3000 procedures are performed per year.

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.

Iodine 131 treatment for differentiated thyroid carcinoma in patients with end stage renal failure: dosimetric, radiation safety, and practical considerations.

Background: Iodine 131 ablation following total thyroidectomy is considered an indispensable element of successful treatment of differentiated thyroid carcinoma (Dtc). because of the essential role of the kidneys in iodine clearance, (131)I therapy of Dtc in patients with end stage renal disease, particularly those maintained on haemodialysis, present a number of special features: the (131)I activity needs to be modified, the haemodialysis sessions need to be adjusted at the time of (131)I therapy, and there are radiation safety considerations during dialysis. there is considerable controversy over these crucial questions in the reports published so far in the literature, which concern a total of fourteen patients.

Differentiated thyroid cancer: comparison of therapeutic iodine 131 biological elimination after discontinuation of levothyroxine versus administration of recombinant human thyrotropin.

The biological elimination of therapeutic 131I in patients with differentiated thyroid cancer (DTC), post total or near-total thyroidectomy, was compared after withholding levothyroxine suppression against administration of recombinant human thyrotropin without stopping levothyroxine. In 163 patients (group G1) levothyroxine was withheld before 131I therapy: in 138 patients the tumor was limited to the thyroid bed (group G1.1) and in 25 patients metastases were present (group G1.

Quality assurance (QA) procedures for software: evaluation of an ADC quality system.

Image viewing and processing software in computed radiography manipulates image contrast in such a way that all relevant image features are rendered to an appropriate degree of visibility, and improves image quality using enhancement algorithms. The purpose of this study was to investigate procedures for the quality assessment of image processing software for computed radiography with the use of existing test objects and to assess the influence that processing introduces on physical image quality characteristics. Measurements of high-contrast resolution, low-contrast resolution, spatial resolution, greyscale (characteristic curve) and geometric distortion were performed 'subjectively' by three independent observers and 'objectively' by the use of criteria based on pixel intensity values.

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.

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.

A survey of 14 computed tomography scanners in Greece and 32 scanners in Italy. Examination frequencies, dose reference values, effective doses and doses to organs.

A survey of examination frequencies, dose reference values, effective doses and doses to organs involving 14 scanners from Greece and 32 scanners from Italy was carried out for the years 1999 and 2000. Examination frequencies per scanner and per year were found to be 3590 for Greece and 4520 for Italy. For the types of examinations considered, CDTI(W) and DLP measurements were taken.

Personnel doses in haemodynamic units in Greece.

Personnel of haemodynamic and interventional radiology units receive continuously increasing radiation doses due to extended fluoroscopy. Moreover, there is not a parallel increase in the number of cardiology specialists involved. Doses received by 15 cardiologists and 5 nurses, in 5 Athenian hospitals were measured using thermoluminescence dosemeters (TLD) and film badges.

Patient dose, image quality and radiographic techniques for common X ray examinations in two Greek hospitals and comparison with European guidelines.

The radiographic technique factors and the quality of each radiographic image for three common examinations (chest PA, pelvis AP and lumbar spine LAT) were compared with the European criteria and entrance surface dose (ESD) was measured for each radiograph in two Greek hospitals. The measurements were carried out using calibrated LiF thermoluminescence dosemeters. The patients were selected so that their weight was close to 70 +/- 10 kg and their height to 170 +/- 10 cm.