Preliminary background indoor EMF measurements in Greece.

The main purpose of this work was to investigate the fluctuation of Greek indoor electromagnetic field (EMF) intensity values and identify peaks that might occur. The scientific interest is mainly focused on the bands of extremely low-frequency (ELF) magnetic fields and radiofrequency (RF) electric fields which have been suggested to be possibly carcinogenic to humans by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR). Electromagnetic radiation (EMR) measurements were performed in a variety of indoor dwellings, in Attica and in the islands of Zakynthos and Lesvos. A total number of 4540 measurements were taken in a wide frequency range (50 Hz-2100 MHz) of which 3301 in Attica, 963 in Lesvos and 276 in Zakynthos. Statistical analysis of the data revealed specific statistically significant differences between the mean values of the electric (ELF and RF) but not the magnetic (ELF) field strengths measured at different distances from the EMF source, as well as between some of the mean values of the RF electric field at different bands. Some statistically significant differences between mean electric field values at different geographic locations were also identified. As far as the RF electric field is concerned, the maximum values, in most cases, were below 0.5 V/m, however increased values above 1 V/m and up to 5.6 V/m were occasionally observed. The ELF magnetic field values were lower than 1 µT. It may be concluded that overall, the observed indoor EMF intensity values remained well below domestic and European established limits.

Dosimetry modelling of transient radon and progeny concentration peaks: results from in situ measurements in Ikaria spas, Greece.

Radon and progeny ((218)Po, (214)Pb, (214)Bi and (214)Po) are radioactive indoor pollutants recognised for the human radiation burden that they induce. Bathing in thermal spas causes transient concentration peaks of radon and progeny and additional short-term impact in patients and personnel. This paper reports a semi-empirical non-linear first order model for describing radon and progeny variations in treatment rooms of the Ikaria spas. Non-measured physical parameters were estimated from in situ measurements in Ikaria through non-linear numerical solving. Exposure and dose variations were additionally modelled. Attachment rate constants were found to be between 0.44 and 55 h(-1). Deposition rate constants were between 0.28 and 7.3 h(-1) for attached nuclei and 0.42 and 64 h(-1) for unattached nuclei. Unattached progeny peaks were right-shifted compared to those of radon. Modelled effective doses ranged between 0.001 mSv per year and 0.589 mSv per year for patients and between 0.001 mSv per year and 18.9 mSv per year for workers. Apollon spas presented quite high doses. These were the highest reported in Greece and are significant worldwide.

Radiation doses in paediatric interventional cardiology procedures.

The objective was to investigate paediatric doses in coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) in the largest cardiac hospital in Greece. Forty procedures were carried out by two board-certified senior interventional cardiologists. Data collected were: patient weight, height, age, fluoroscopy time (FT), total number of images (N) and kerma-area product (KAP). Median (range) age was 7.5 y (17 d to 17 y). Median FT, N and KAP were 4 min, 655, 2.1 Gy cm2 for CA and 12.1 min, 1296, 14.7 Gy cm2 for PTCA (corresponding adult diagnostic reference levels (DRLs) are: 6.5 min, 700, 45 Gy cm2 for CA and 15.5 min, 1000 and 85 Gy cm2 for PTCA). The highest percentage of cine dose was in newborns (0-1 y) (CA: 92% and PTCA: 100%). As age increased, cine dose percentage decreased, whereas total radiation dose increased. Median paediatric FT and N recorded reached or even exceeded adult DRL and should be optimised. Paediatric DRL should be set.

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. OBJECTIVE: the aim of our study was to present our experience on (131)I treatment of 5 Dtc patients with end stage renal disease. DESIGN: the data of 5 Dtc patients with end stage renal disease, treated with (131)I, were retrospectively analysed; four cases were treated for remnant ablation and one for locoregional progression. In order to allow for prolonged plasma clearance of (131)I, we used a lower activity of radioiodine, reduced to roughly 40-50% of the empirically calculated activity used for normal individuals; dialysis sessions were performed immediately before and at 48 hours after (131)I administration. All patients had (131)I retention measurements performed post dialysis; in two of them some additional measurements such as iodine clearances were also performed. RESULTS: None of the patients experienced any short-term side effects, while they all had undetectable thyroglobulin levels on the first post therapy evaluation off thyroxine. (131)I elimination in the first haemodialysis was about 60%. staff incidental exposure and (131)I contamination were insignificant. CONCLUSIONS: On the basis of our experience, an empiric activity of 40-50% of that used for normal individuals appears to be effective as well as safe. these encouraging findings are discussed in relation with other reports in the literature.

Patient and staff dosimetry in vertebroplasty.

STUDY DESIGN: Eleven vertebroplasty operations were studied in terms of radiation dose. OBJECTIVE: Doses to patients and staff associated with vertebroplasty were measured. Occupational doses were compared with the annual dose limits, and the effectiveness of the used radiation protection means was estimated. Patient dose was estimated by means of both surface and effective dose, and the radiation-induced risk was evaluated. SUMMARY OF BACKGROUND DATA: Vertebroplasty is a recent minimally invasive technique for the restoration of vertebral body fractures. It involves fluoroscopic exposure, and so, it demands dose measurements for both patient and staff exposed to radiation. METHODS: Thermoluminescent dosimeters (TLDs) were placed on the medical personnel and the effective dose was derived. Slow films were placed to patients' skin to measure entrance surface dose. Furthermore, a Rando phantom loaded with TLDs was irradiated under conditions simulating vertebroplasty, in order to estimate effective dose to the patient. RESULTS: Mean fluoroscopy time was 27.7 minutes. Patient's mean skin dose was 688 mGy, while effective dose was calculated to be 34.45 mGy. It was estimated that the primary operator can perform about 150 vertebroplasty operations annually without exceeding the annual dose constraints, whereas occupational dose can be reduced by 76% using mobile shielding. CONCLUSIONS: 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.

Patient and staff radiation dosimetry during cardiac electrophysiology studies and catheter ablation procedures: a comprehensive analysis.

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 cm2 and 25.5 (4.4-79.2) min for ablation, and 12.5 (4.5-117.2) Gy cm2 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 3x10(-6) 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 microGy at the eyes, 0.79 microGy at the chest under the lead apron, 13.68 microGy at the chest over the apron, 3.82 microGy at the thyroid, 17.76 microGy at the left hand, and 12.11 microGy 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.

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 G1.2). A second group of patients (G2; n = 28) received 131I therapy after administration of recombinant human thyrotropin without stopping levothyroxine. Mean retained 131I activity (as a percentage of the administered dose) was 5%-29% (group G1.1), 20%-43% (group G1.2) and 1%-17% (group G2). The effective half-life of 131I was 0.59-0.69 days (group G1.1), 0.87-1.22 days (group G1.2) and 0.38-0.44 days (group G2). In conclusion, the use of recombinant human thyrotropin to prepare patients with thyroid cancer for therapy with 131I shortens its effective half-life and reduces its retained activity compared to preparation with discontinuation of levothyroxine suppression.

Patient dosimetry during coronary interventions: a comprehensive analysis.

BACKGROUND: We performed a detailed analysis of patient radiation during coronary interventions, comparing dose measurements to established dose reference levels, assessing coronary artery doses, and estimating total radiation risk of fatal cancer. METHODS: We prospectively examined 281 patients who were subjected to 307 percutaneous coronary interventions. RESULTS: The mean kerma area product (KAP) per procedure was 82.1 +/- 47.9 Gy x cm2. Corresponding values for fluoroscopy and digital cineangiography were 28.3 +/- 25.5 Gy x cm2 and 53.8 +/- 35.5 Gy x cm2, respectively, and exposure times were 13.1 +/- 6.8 minutes (87%) and 2.0 +/- 1.5 minutes (13%), respectively. The right anterior oblique caudal and left anterior oblique cranial projections accounted for the highest amount of KAP (24.0% and 23.1%, respectively) compared with other projections. The maximum recorded skin-dose was 182 mGy. Performing a representative procedure on a phantom, the effective dose was 14.9 mSv. The mean coronary dose was 61.7 +/- 38.2 mGy, with a highest calculated dose of 220.1 mGy. The third quartile of KAP measurements was 105 Gy x cm2, the 95th percentile was 175 Gy x cm2, and the mean value of KAP measurements was 82 Gy x cm2. The total risk for the development of fatal cancer was calculated as 83 cases for every 100,000 patients subjected to coronary intervention. CONCLUSIONS: A detailed analysis of patient radiation during coronary interventions is presented. Coronary doses and total radiation risk of fatal cancer are also calculated, and a method for establishing dose reference level values is proposed.

Medical personnel and patient dosimetry during coronary angiography and intervention.

Percutaneous coronary interventions are associated with increased radiation exposure compared to most radiological examinations. This prospective study aimed at (1) measuring entrance doses for all in-room personnel, (2) performing an assessment of patient effective dose and intracoronary doses, (3) investigating the contribution of each projection to kerma-area product (KAP) and irradiation time, (4) comparing results with established DRL values in this clinical setting and (5) estimating the risk for fatal cancer to patients and operators. Measurements were performed during 40 consecutive procedures of coronary angiography (CA), half of which were followed by ad hoc coronary angioplasty (PTCA). KAP measurements were used for patients and thermoluminescent dosimetry for the in-room personnel. The mean KAP value per procedure for CA was 29 +/- 9 Gy cm2. Thirty four per cent of KAP was due to fluoroscopy, whereas the remainder (66%) was due to digital cine. Accordingly, the mean KAP value per PTCA procedure was 75 +/- 30 Gy cm2, and contribution of fluoroscopy is 57%. Effective dose per year was estimated to be 0.04-0.05 mSv y(-1) for the primary operator, and 0.03-0.04 mSv y(-1) for those assisting. Corresponding measurements for radiographer and nurse were below detectable level, implying minimal radiation hazards for them. Regarding radiation exposure, coronary intervention is considered a quite safe procedure for both patients and personnel in laboratories with modern equipment and experienced operators as long as standard safety precautions are considered. Exposure optimization though should be constantly sought through continuous review of procedures.