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 3.1, 3.5, 7.4, 7.5, 4.2, 11.3 and 5.5 for head base, head cerebrum, thorax, abdomen, pelvis, cervical spine and lumbar spine protocols, respectively. The mean divergence between the measured and displayed CTDIvol values was 4.2, 3.5, -1.0, 2.7, 4.9, -3.9 and -2.8 % for protocols as mentioned above, respectively. From the perspective of the number of detector rows of the scanners, the mean divergence was -6.7, -6.0, 0.8, -1.1, -0.4, -1.9, -5.3, 5.2 and 10.1 % for single, dual, 4, 6, 16, 24, 64, 128 and dual source 256-slice systems, respectively.

Investigation of breast dose in five screening mammography centres in Greece.

The objectives of this study were to investigate the techniques currently used for screening mammography in Greece, to estimate the mean glandular dose (MGD) for establishing a baseline radiation dose database, to analyse the effects of various factors on MGD, and to compare the results with others in the literature. Five mammographic facilities and 250 women having as a routine screening mammogram one craniocaudal (CC) and one mediolateral oblique (MLO) projection in each breast were included in the study. The parameters recorded were age, weight, compressed breast thickness (CBT), tube potential (kV), tube loading (mA s) and MLO projection angle. Large differences were observed among the different mammography facilities, mainly in terms of the tube potential setting and the MLO angle used. The average MGD per exposure was 1.4 +/- 0.6 mGy while the respective averages separately for the CC and MLO projections were 1.2 +/- 0.5 and 1.5 +/- 0.7 mGy, respectively. The average MGD values recorded in this study were below the limit of 2 mGy established for the reference medium-sized breast of 4.5 cm CBT. However, the variety of techniques observed revealed the need for a nationwide survey concerning screening mammography in Greece.

Radon exposure in the thermal spas of Lesvos Island--Greece.

The aim of this work is to study the exposure due to radon to bathers and personnel in the spas of Lesvos Island under a specific use pattern. 222Rn concentrations in the supplying water were measured during a long time period. Variations in indoor 222Rn, attached and unattached progenies, and influence of the ambient atmosphere were thoroughly analysed during bath treatment for the purpose of investigating a consequent probable short-term health impact. Concentration peaks both for 222Rn and PAEC were found to appear during bathtubs filling. These peaks considered imposing an additional short-term radiation burden for spa users. The additional doses delivered to bathers during bath treatment were found to be very low and for personnel did not exceed the value of 5 mSv per year.

Study of a Greek area with enhanced indoor radon concentrations.

In this paper the focus is on Arnea Chalkidikis, an area in Greece with granitic geological background and indications of possible elevated radon concentration indoors. Data are reported of indoor radon measurements with etched track detectors and those are used for dosimetric estimations. Moreover, data are reported on soil gas and soil radon concentrations in Arnea, as well as radon and uranium concentrations in water samples. From the measured radon concentrations in water samples the contribution to the overall dose has been calculated. For a period of 1 month, indoor radon and progeny activity has also been monitored in the dwelling that has the maximum indoor radon concentration in Greece. This dwelling is in Arnea and the dose delivered to the inhabitants has been calculated. The mean annual effective dose due to indoor radon was 4.5 mSv and about 11% of this was due to the use of water. Mean soil gas concentration and soil radon concentration were (90 +/- 30) kBq m(-3) (p<0.05) and (30 +/- 5) kBq m(-3) (p<0.05) respectively. Mean uranium concentration of the water samples was (98 +/- 13) mBq l(-1) (p<0.05).

Estimation of body composition in competitive swimmers by means of three different techniques.

Up to now controversial reports have been published in regard to the beneficial effects of swimming, a non-weight-bearing activity, on bone mass (BM). Therefore, the aim of this study was to investigate the effects of competitive swimming practice on the bone mineral density (BMD) and bone mineral content (BMC) as well as on the different factors of body composition. For this purpose, competitive swimmers (16 males and 16 females) were selected as subjects in order to investigate the influence of swimming on the three main factors of body composition (BMC, lean body mass [LBM] and body fat [BF]) of the human body. The latter were estimated using three different approaches: the skinfold, the dual energy x-ray absorptiometry (DEXA) and the whole body potassium (K-40) methods. Since BM and LBM are also related, the possible correlations between shoulder strength (extensions and flexion movements) and performance with BMD, BMC, LBM and BF were also investigated. Our results showed that BMD was not affected by swimming exercise since z (%) values were similar between swimmers and their respective age-matched controls. Swimmers also showed lower BF and increased LBM in the region of upper extremities (arms and trunk) as compared to their lower extremities (legs), a finding which is typical for the sport they are trained for. Also, comparison between sexes showed that males had a more central distribution of fat when compared to females, in which BF was built up in the region of legs. Furthermore, shoulder strength and performance were significantly related (p < 0.05) to age, BMC, and LBM while performance was also significantly related (p < 0.05) to all the other BM indices. So, mineralization of the bone is important for shoulder muscular strength which is subsequently related to performance. We used the DEXA because it enabled the direct estimation of the three factors of body composition (BM, BF and LBM).

Trends and geographical distribution of childhood leukemia in Greece in relation to the Chernobyl accident.

Parts of Greece have been exposed to fallout radiation from the Chernobyl accident as much as any of the countries boardering with the former Soviet Union, because of the direction of the prevailing winds after the accident. Although fallout radiation did not reach levels expected to be associated with measurable effects, there is widespread concern in Greece that the incidence of childhood leukemia may be rising in the more heavily affected parts of Greece. Patient discharge data from all Greek hospitals treating childhood leukemia were used to calculate the annual incidence of the disease from January 1980 to June 1986 (preaccident period), from July 1986 to June 1988 (immediate postaccident period) and from July 1988 to June 1991 ("relevant" post-accident period, that accommodates the presumed latent period of the disease). Fallout radiation measurements (in Bq/kg Cs-137) were used to create 17 regions of similar (within regions) but highly variable (between regions) levels of fallout deposition. Background radiation (in Bq/kg Ra-226) and annual incidence of childhood leukemia by region were also estimated. There was no evidence of increased incidence of childhood leukemia during the immediate or the "relevant" post-Chernobyl period in any part of the country. Furthermore, regression analyses did not show any significant or suggestive association of childhood leukemia by region with either background or fallout radiation. These results indicate that the Chernobyl accident did not affect noticeably the incidence of childhood leukemia in Greece during the five-year post accident period.

Effect of dietary intake on the 137Cs retention model.

Whole-body counting measurements were conducted to monitor the 137Cs biological half-life of 14 individuals in Athens during the period June 1988 to June 1989. The results and the solution of a 137Cs retention model showed that the individuals examined were receiving 0-3.7 Bq d-1 of 137Cs through the food chain during the period investigated.