Measurement of solar ultraviolet radiation in Yazd, Iran

Ultraviolet [UV] radiation is divided into three regions: UVA, UV[B], and UVC. Both the quality and quantity of solar UV radiation vary with various factors including the elevation of the sun above the horizon, as well as absorption and scattering of UV photons by molecules in the atmosphere, notably ozone and clouds. It is clear that whereas a moderate amount of UV exposure is beneficial, too much is detrimental, so there is a need to quantify variations of solar UV on the earth surface, at different time intervals. The measurement of solar UV radiation in Yazd city was achieved by two radiometers: 1] a special UVA light meter with maximum sensitivity to 365nm in the range of 320- 390nm and 2] a radiometer with a probe for 280-320 nm in UV[B] radiation. Measurement duration was from 1rst January to the end of December 2008 and from sunrise to sunset, every one hour. Daily integral UVA radiation in December with the lowest [0.38×10[5]Jm[-2]] and July with the highest intensity [5.26×10[5]Jm[-2]] were found. The minimum and maximum monthly UVA radiation on the ground level of Yazd city were 25.8×10[5]Jm[-2] in December and 128.7×10[5]Jm[-2] in July, respectively. Based on UV[B] /UV[A] ratio the UV[B] intensity at 12 o'clock is 25 times lower than the UV[A]. Therefore, the integrated hourly UV[B] in this time is equal to 3.13 kjm-2and almost the effective UV[B] is 1.56 kJm[-2] so the minimum required exposure time of UV[B] radiation for one SDD and MED by hands and head are about 22 and 110 minutes respectively

Evaluation of cancer risk of the patients undergoing coronary angiography in Yazd, Iran

Coronary angiography is a commonly performed diagnostic procedure with life saving benefits for the patient. However, this procedure involves relatively high radiation dose. The purpose of this study was to determine the average effective dose of patients undergoing coronary angiography and to estimate the associated radiation risk in terms of fatal malignancy. Radiation doses received by 103 patients who underwent coronary angiography [CA] at one hospital of Yazd province in Iran were measured in terms of Kerma Area Product [KAP]. KAP values were then used to determine the effective dose and the organ doses using the NRPB-S262 conversion factors and to estimate the radiation cancer risk based on the population averaged probability coefficients given in ICRP-60 and BEIR-VII report. A mean KAP value was found to be 29.15 +/- 16.97Gy. Cm[2] and the estimated mean values of effective dose was 5.0 +/- 3.18mSv. The dose of lung, esophagus, bone marrow, skin, stomach and female breast were 24.99 +/- 14.93 mSv, 14.01 +/- 9.47 mSv, 3.72 +/- 2.61 mSv, 2.9 +/- 1.8 mSv, 2.17 +/- 1.62 mSv and 1.46 +/- 0.32 mSv, respectively. The estimated total annual collective dose and caput dose were 17.52 man-Sv and 0.018mSv respectively. The frequency of examinations per 1000 population in Yazd was 3.5 which is lower than UK and the health care level I countries. Taking into account the ICRP risk factors, radiation dose arising from CA examinations could lead to 239 fatal cancers per million cases. Although the mean values of effective dose found in this study was lower than most of the published results, however CA examinations should be justified

Patient dose values during interventional cardiology examinations in Yazd hospital, Iran

The number of interventional cardiology [IC[procedures has increased rapidly, coronary angiography [CA] and percutaneous transluminal coronary angioplasty [PTCA] are now widely performed as a matter of routine, and they are considered safe procedures for experienced cardiologists. However, it is also known that these procedures are associated with high radiation doses due to long fluoroscopy time [T], and large number of cineradiography frames [F]. These levels of radiation may even lead to radiation skin injuries under certain conditions. A detailed study of radiation doses received by 168 patients who underwent coronary angiography [CA], and 84 patients who underwent percutaneous transluminal coronary angioplasty [PTCA] using 3 angiography X-ray systems in two hospitals of Yazd-Iran is presented. An air kerma-area product [KAP] meter was used for patient dosimetry. KAP, fluoroscopy time and total number cine frames for CA and PTCA prodecures were recorded for each patient. Mean +/- SD of KAP in CA and PTCA were 33 Gy.cm[2] +/- 18.8 Gy.cm[2] and 80.3 Gy.cm[2] +/- 65.6 Gy.cm[2] respectively. The comparison showed that CA KAP [33Gy.cm[2]], fluoroscopy time [2.7 +/- 2.4 min], and cine frames number [571 +/- 149] except of on case, were lower than [P<0.001] the results of other studies an mean KAP due to PTCA procedures, except for three cases, were not significantly different from the other references' results. The high level expert cardiologists couldn't have a significant effect on the decrease of patient dose since they should also teach angiography examinations to medicine students. With increasing patient BMI the value of KAP increased, but the fluoroscopy time and cineframes number did not change significantly. In addition, the results showed that the use of flat detector was not sufficient for decreasing patient dose, and system's adjustment was more important