Influence of lead apron shielding on absorbed doses from panoramic radiography

Objectives:

This study investigated the absorbed doses in a full anthropomorphic body phantom from two different panoramic radiography devices, performing protocols with and without applying a lead apron.

Methods:

A RANDO^® full body phantom (Alderson Research Laboratories Inc., Stamford, CT) was equipped with 110 thermoluminescent dosemeters at 55 different sites and set up in two different panoramic radiography devices [SCANORA^® three-dimensional (3D) (SOREDEX, Tuusula, Finland) and ProMax^® 3D (Planmeca, Helsinki, Finland)] and exposed. Two different protocols were performed in the two devices. The first protocol was performed without any lead shielding, whereas the phantom was equipped with a standard adult lead apron for the second protocol.

Results:

A two-tailed paired samples t-test for the SCANORA 3D revealed that there is no difference between the protocol using lead apron shielding (m = 87.99, s = 102.98) and the protocol without shielding (m = 87.34, s = 107.49), t(54) = −0.313, p > 0.05. The same test for the ProMax 3D showed that there is also no difference between the protocol using shielding (m = 106.48, s = 117.38) and the protocol without shielding (m = 107.75, s = 114,36), t(54) = 0.938, p > 0.05.

Conclusions:

In conclusion, the results of this study showed no statistically significant differences between a panoramic radiography with or without the use of lead apron shielding.     

Gonad protective effect of radiation protective apron in chest radiography

Depending on the facility, a radiation protective apron (protector) is used to protect the gonad from radiation exposure in chest radiography. To determine the necessity of using a protector during chest radiography, we measured the effect of the protector on the gonad in this study. First, using a human body phantom, we measured the absorbed dose of the female gonad with and without the protector, using a thermoluminescence dosimeter (TLD), and confirmed its protective effect. Using the protector, the absorbed dose was reduced to 28+/-2% and 39+/-4% for field sizes of 14 x 17 inch and 14 x 14 inch, respectively. Next, we used Monte Carlo simulation and confirmed, not only the validity of the actual measurement values, but also the fact that the influence of radiation on the absorbed dose of the gonad was mostly from scattered radiation from inside the body for the 14 x 17 inch field size, and also from the X-ray tube for the 14 x 14 inch field size. Although a certain protective effect is achieved by using the protector, the radiation dose to the gonad is only a few microGy even without a protector. Thus, the risk of a genetic effect would be as small as 10(-8). Given that acceptable risk is below 10(-6), we conclude the use of a radiation protective apron is not necessary for diagnostic chest radiography.     

辅助125I粒子植入器械包联合腹部125I粒子植入防护铅褂在恶性梗阻性黄疸125I粒子支架植入患者中的应用及效果

【摘要】 目的 探讨自制辅助125I粒子植入器械包联合腹部125I粒子植入防护铅褂在恶性梗阻性黄疸125I粒子支架植入患者中的应用及效果。方法 选择行胆道125I粒子支架植入术的恶性梗阻性黄疸患者80例,随机分成实验组和对照组各40例。实验组患者术中医师使用自主创新的辅助125I粒子植入器械包（专利号:ZL201620728909.3）,术后患者穿自主创新的腹部125I粒子植入防护铅褂（专利号:ZL201620839740.9）;对照组患者术中医师采用传统粒子植入手术器械,术后患者穿常规防护铅衣。比较两组患者术中医师精确植入1颗粒子所用的时间,术后两种铅衣的辐射屏蔽效果、患者主动防护的持续时间及患者舒适度。采用SPSS23.0软件包对数据进行统计学分析。结果 两组患者术中医师精确植入1颗粒子所用的时间差异有显著统计学意义（t=-6.974,P＜0.001）,两组患者穿戴不同铅衣进行放射性防护后间隔0 m距离、0.5 m距离时的辐射携带量差异均无统计学意义（t0m=1.449,t0.5m=0.08633,P均＞0.05）、两组患者主动穿防护铅衣的持续时间差异有统计学意义（t=7.866,P＜0.05）,两组患者舒适度差异有统计学意义（Z值=-2.193 , P＜0.05 ）。结论 辅助125I粒子植入器械包联合腹部125I粒子植入防护铅褂应用于恶性梗阻性黄疸125I粒子支架植入患者中,可提高医师手术工作效率,减少受粒子辐射的照射时间,可提高患者主动防护辐射的依从性及舒适度,具有临床应用价值及推广意义。     

Experimental and theoretical studies on radiation protective effect of a lighter non-lead protective apron

Non-lead aprons using composite materials are often used for radiation protective aprons instead of heavy lead aprons. However, the protective effect of the lighter, non-lead aprons has not been well evaluated, and it is not yet clear how they compare with lead aprons. Therefore, we investigated the protective performance of non-lead aprons theoretically and experimentally by comparing them with lead aprons under clinical conditions. We measured the energy spectra for direct and scattered X-rays passing through protective aprons or not, and measured doses with glass dosimeters for validation of theoretical calculations based on the energy spectra. We found that the protective effect of non-lead aprons was higher than that of lead aprons at X-ray of tube voltages of 70-100 kV, which are often used for radiography and fluorography. This demonstrated that the non-lead aprons are more useful in many situations than heavy lead aprons.     

Assessing doses to interventional radiologists using a personal dosimeter worn over a protective apron

Backround: Interventional radiologists receive significant radiation doses, and it is important to have simple methods for routine monitoring of their exposure.

Purpose: To evaluate the usefulness of a dosimeter worn outside the protective apron for assessments of dose to interventional radiologists.

Material and Methods: Assessments of effective dose versus dose to dosimeters worn outside the protective apron were achieved by phantom measurements. Doses outside and under the apron were assessed by phantom measurements and measurements on eight radiologists wearing two routine dosimeters for a 2-month period during ordinary working conditions. Finger doses for the same radiologists were recorded using thermoluminescent dosimeters (TLD; DXT-RAD Extremity dosimeters).

Results: Typical values for the ratio between effective dose and dosimeter dose were found to be about 0.02 when the radiologist used a thyroid shield and about 0.03 without. The ratio between the dose to the dosimeter under and outside a protective apron was found to be less than 0.04. There was very good correlation between finger dose and dosimeter dose.

Conclusion: A personal dosimeter worn outside a protective apron is a good screening device for dose to the eyes and fingers as well as for effective dose, even though the effective dose is grossly overestimated. Relatively high dose to the fingers and eyes remains undetected by a dosimeter worn under the apron.     

Maternity exclusion with a very high autosomal STRs kinship index

This paper reports a maternity testing case to assess the biological relationship between a woman and the boy she was adopting. For all 46 tested autosomal STR loci, the adopting woman and the boy shared at least one allele at each locus, which supported that the woman could be the biological mother of the boy. The pairwise kinship indices (KIs) were calculated for various identity-by-descent distributions. Motherson was the most likely relationship with a very high KI (i.e., 6.91E+08) based on 35 independent autosomal STR loci, but KIs of other pairwise relationships (e.g., aunt-nephew, full sib, etc.) were also high. Further testing of X-STRs and mtDNA excluded the maternity relationship between woman and boy, in which 13 out of 20 X-STR loci were inconsistent and 18 nucleotide mismatches were observed at hypervariable regions I and II of the mtDNA. However, a more distant relationship (e.g., aunt-nephew) cannot be excluded. This case reinforces that possible false identifications can occur in kinship analysis cases yielding very high KIs.     

Blood lead levels in patients with lead shot retained in the appendix

Seven patients with one or two lead shots retained in the appendix were identified by radiography. For each case, two sex- and age-matched control patients without lead shot in the appendix were found. None of the 7 patients with lead shot in the appendix had blood lead levels (median 0.55 mumol/l) approaching the toxic levels, but they averaged almost twice the levels of the controls (median 0.29 mumol/l). Thus, lead shots may add to individual lead exposures, and blood lead analysis should be performed, at least when more than a few lead shots are present.     

Investigation of lead radioactivity

Surface alpha radioactivity of lead after surface rescraping increases with time approximately exponentially, with a relaxation time of a few days. Increment of the alpha radioactivity is comparable with initial radioactivity after rescraping. Hypothesis of the atomic mechanism of this effect is presented.     

High risk factors and preventive strategies of Abortion or prematurity in multiple pregnancy Maternity

目的:分析多胎妊娠流产、早产的高危因素,探讨宫颈环扎术预防高危人群流产、早产的临床效果.方法:选择2011-01～2012-05收治的多胎妊娠患者97例,经阴道宫颈彩超测量宫颈长度≤ 2cm,宫颈内口宽度＞1cm的47例作为高危组,其余50例为低危组,选择高危组47例中自愿行宫颈环扎术的26例作为高危环扎组,其余21例作为高危未环扎组.结果:高危环扎组流产1例(3.85%),高危未环扎组流产7例(33.3%),两者比较差异显著,高危环扎组早产9例(34.6%),高危未环扎组早产8例(38.1%),两者比较差异不明显.结论:利用经阴道宫颈彩超检查宫颈形态可筛查出多胎妊娠自然流产的高危人群,宫颈环扎术可显著降低多胎妊娠高危人群的流产率.     

多胎妊娠流产、早产高危因素及预防对策

目的：分析多胎妊娠流产、早产的高危因素,探讨宫颈环扎术预防高危人群流产、早产的临床效果.方法：选择2011-01～2012-05收治的多胎妊娠患者97例,经阴道宫颈彩超测量宫颈长度≤ 2cm,宫颈内口宽度＞1cm的47例作为高危组,其余50例为低危组,选择高危组47例中自愿行宫颈环扎术的26例作为高危环扎组,其余21例作为高危未环扎组.结果：高危环扎组流产1例（3.85%）,高危未环扎组流产7例（33.3%）,两者比较差异显著,高危环扎组早产9例（34.6%）,高危未环扎组早产8例（38.1%）,两者比较差异不明显.结论：利用经阴道宫颈彩超检查宫颈形态可筛查出多胎妊娠自然流产的高危人群,宫颈环扎术可显著降低多胎妊娠高危人群的流产率.     

How to calculate lead concentration and concentration uncertainty in XRF in vivo bone lead analysis

The authors provide a substantial correction for calculating estimates of lead concentration and uncertainty for in vivo X-ray fluorescent bone analysis with Cd-109 source. Based on general principles, they provide mathematical techniques for propagation of uncertainties in XRF analysis. They give additional considerations for lowering the detection limit and improving spectral data quality.