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The objective of the present project was the determination of the dose received by patients during cardiac procedures, such as coronary angiography, percutaneous transluminal coronary angioplasty (PTCA) and stent implantation. Thermoluminescent dosemeters (TLDs), suitably calibrated, were used for the measurement of the dose received at four anatomical locations on the patient's skin. A dose-area product (DAP) meter was also used. The contribution of cinefluorography to the total DAP was higher than that of fluoroscopy. A DAP to effective dose conversion factor equal to 0.183 mSv Gy-1 cm-2 was estimated with the help of a Rando phantom. Thus, the effective dose received by the patients could be assessed. Mean values of effective dose equal to 5.6 mSv, 6.9 mSv, 9.3 mSv, 9.0 mSv and 13.0 mSv were estimated for coronary angiography, PTCA, coronary angiography and ad hoc PTCA, PTCA followed by stent implantation and coronary angiography and ad hoc PTCA followed by stent implantation, respectively.

Purpose:To evaluate the usefulness of a time-efficient MRI method for the quantitative determination of tissue iron in the liver and heart of ␤-thalassemic patients using spinspin relaxation rate, R2, measurements. Materials and Methods:Images were obtained at 1.5 T from aqueous Gd-DTPA solutions (0.106 -8 mM) and from the liver and heart of 46 ␤-thalassemic patients and 10 controls. The imaging sequence used was a respiratorytriggered 16-echo Carr-Purcell-Meiboom-Gill (CPMG) spinecho (SE) pulse sequence (TR ϭ 2000 msec, TE min ϭ 5 msec, echo spacing (ES) ϭ 5 msec, matrix ϭ 192 ϫ 256, slice thickness ϭ 10 mm). Liver iron concentration (LIC) measurements were obtained for 22 patients through biopsy specimens excised from the relevant liver segment. Biopsy specimens were also evaluated regarding iron grade and fibrosis. Serum ferritin (SF) measurements were obtained in all patients.Results: A statistically significant difference was found between patients and healthy controls in mean liver (P Ͻ 0.004) and myocardium (P Ͻ 0.004) R2 values. The R2 values correlated well with Gd DTPA concentration (r ϭ 0.996, P Ͻ 0.0001) and LIC (r ϭ 0.874, P Ͻ 0.0001). A less significant relationship (r ϭ 0.791, P Ͻ 0.0001) was found between LIC measurements and SF levels. R2 measurements appear to be significantly affected (P ϭ 0.04) by different degrees of hepatic fibrosis. The patients' liver R2 values did not correlate with myocardial R2 values (r ϭ 0.038, P Ͻ 0.21). Conclusion:Tissue iron deposition in ␤-thalassemic patients may be adequately quantified using R2 measurements obtained with a 16-echo MRI sequence with short ES (5 msec), even in patients with a relatively increased iron burden.

Purpose:To investigate the correlation between the degree of hepatic, splenic, pancreatic, vertebral bone marrow (VBM), and myocardial siderosis, as expressed by relaxation rate (R2 ϭ 1/T2) values, in patients with thalassemia. Materials and Methods:R2 relaxation rate values of liver, spleen, VBM, pancreas, and myocardium were estimated in 68 consecutive transfusion-dependent patients with ␤-thalassemia major and 10 healthy controls using a respiratory triggered 16-echo Carr-Purcell-Meiboom-Gill (CPMG) spin echo sequence. Results:Hepatic R2 values were significantly increased in all 68 patients; VBM, pancreatic, and myocardial R2 values were increased in 67/68, 35/47, and 47/61 patients, whereas five patients showed decreased pancreatic R2 attributed to fatty degeneration. Of the 39 nonsplenectomized patients, splenic R2 values were decreased in 30 and normal in nine patients. Hepatic R2 values correlated with splenic (r ϭ 0.63, P Ͻ 0.001), VBM (r ϭ 0.52, P Ͻ 0.001), but not with myocardial and pancreatic R2 values. Conclusion:Despite positive correlations between the degree of hepatic, splenic, and VBM siderosis, as expressed by respective R2 values, there was variability of iron distribution patterns in thalassemic patients. Unpredictable patterns of iron distribution may be seen, such as normal signal of the spleen in the presence of siderotic liver, resembling primary hemochromatosis. Fatty degeneration of the pancreas was not uncommon.

Interventional cardiology procedures result in substantial patient radiation doses due to prolonged fluoroscopy time and radiographic exposure. The procedures that are most frequently performed are coronary angiography, percutaneous coronary interventions, diagnostic electrophysiology studies and radiofrequency catheter ablation. Patient radiation dose in these procedures can be assessed either by measurements on a series of patients in real clinical practice or measurements using patient-equivalent phantoms. In this article we review the derived doses at non-pediatric patients from 72 relevant studies published during the last 22 years in international scientific literature. Published results indicate that patient radiation doses vary widely among the different interventional cardiology procedures but also among equivalent studies. Discrepancies of the derived results are patient-, procedure-, physician-, and fluoroscopic equipmentrelated. Nevertheless, interventional cardiology procedures can subject patients to considerable radiation doses. Efforts to minimize patient exposure should always be undertaken.

Objectives: The aim of this study was to determine occupational dose levels in interventional radiology and cardiology procedures. Methods: The study covered a sample of 25 procedures and monitored occupational dose for all laboratory personnel. Each individual wore eight thermoluminescent dosemeters next to the eyes, wrists, fingers and legs during each procedure. Radiation protection shields used in each procedure were recorded. Results: The highest doses per procedure were recorded for interventionists at the left wrist (average 485 mSv, maximum 5239 mSv) and left finger (average 324 mSv, maximum 2877 mSv), whereas lower doses were recorded for the legs (average 124 mSv, maximum 1959 mSv) and the eyes (average 64 mSv, maximum 1129 mSv). Doses to the assisting nurses during the intervention were considerably lower; the highest doses were recorded at the wrists (average 26 mSv, maximum 41 mSv) and legs (average 18 mSv, maximum 22 mSv), whereas doses to the eyes were minimal (average 4 mSv, maximum 16 mSv). Occupational doses normalised to kerma area product (KAP) ranged from 11.9 to 117.3 mSv/1000 cGy cm 2 and KAP was poorly correlated to the interventionists' extremity doses. Conclusion: Calculation of the dose burden for interventionists considering the actual number of procedures performed annually revealed that dose limits for the extremities and the lenses of the eyes were not exceeded. However, there are cases in which high doses have been recorded and this can lead to exceeding the dose limits when bad practices are followed and the radiation protection tools are not properly used.

Measures have to be taken to reduce patient's skin dose, which, in extreme cases, may be close to deterministic effects threshold. The highest dose rates, recorded during the procedure, were found for primary operator's hands and chest when no shielding was used.

Aims To perform a comprehensive analysis of all aspects of patient and in-room personnel radiation dosimetry in interventional electrophysiology. Methods and results Measurements were performed during 19 diagnostic electrophysiology studies and 24 catheter ablations. Kerma-area product and exposure time values were 48.7 (6.4-230) Gy cm 2 and 25.5 (4.4-79.2) min for ablation, and 12.5 (4.5-117.2) Gy cm 2 and 4.5 (1.2-31) min for diagnostic studies, respectively. Patient effective doses were 15.2 (2.1-59.6) mSv for ablation and 3.2 (1.3-23.9) mSv for diagnostic procedures. Radiation risk to the patient was estimated to be up to eight cases of fatal cancer in 10 000 procedures. The risk of development of fatal cancer was less than 3 Â 10 26 per procedure to the primary operator. The risk for the nurse and technician was much lower. The dose per procedure for the primary operator was 7.1 mGy at the eyes, 0.79 mGy at the chest under the lead apron, 13.68 mGy at the chest over the apron, 3.82 mGy at the thyroid, 17.76 mGy at the left hand, and 12.11 mGy at the left knee. Conclusion As far as radiation exposure is concerned, electrophysiology studies followed by radiofrequency ablation are safe procedures for both patient and personnel when performed in catheterization laboratories with modern equipment, experienced operators, and standard safety precautions.