Eye lens and thyroid gland radiation exposure for patients undergoing brain computed tomography examination

This study aims to estimate the effective radiation dose and organ dose from head CT procedures. It was conducted in three main private hospitals in Khartoum State-Sudan, using Toshiba machines with 64 slices. The total number of patients included in this study was 142 patients (82 males and 60 females). The effective dose and organ dose were calculated by CT Expo software. The effective dose slightly varied among patients according to gender and age. The effective dose for female patients (5.99 mSv) was higher than that for male patients (5.84 mSv), and the pediatric dose (5.46 mSv) was lower than the adults’ dose (5.94 mSv).The dose for eye lens was found lower for male patients (89.117 mSv) than the dose for female patients (94.62) mSv). According to patients’ age: the dose received by the lens of the eye was much lower in pediatric (79.93 mSv) than the adults (92.41 mSv). The dose for thyroid in female patients (33.52 mSv) was higher than the male patients (28 mSv). The pediatric dose (28.34 mSv) was lower than the adults’ dose (30.64 mSv).Departmental imaging protocol and lack of training among hospital staff are expected to be responsible for these variations. Therefore, this study recommends that the CT technologists be trained on suitable strategies to achieve dose optimization. Moreover, patients’ doses must be monitored regularly.     

Validation of multi‐detector computed tomography as a non‐invasive method for measuring ovarian volume in macaques (Macaca fascicularis)

The purpose of this study was to validate low radiation dose, contrast‐enhanced, multi‐detector computed tomography (MDCT) as a non‐invasive method for measuring ovarian volume in macaques. Computed tomography scans of four known‐volume phantoms and nine mature female cynomolgus macaques were acquired using a previously described, low radiation dose scanning protocol, intravenous contrast enhancement, and a 32‐slice MDCT scanner. Immediately following MDCT, ovaries were surgically removed and the ovarian weights were measured. The ovarian volumes were determined using water displacement. A veterinary radiologist who was unaware of actual volumes measured ovarian CT volumes three times, using a laptop computer, pen display tablet, hand‐traced regions of interest, and free image analysis software. A statistician selected and performed all tests comparing the actual and CT data. Ovaries were successfully located in all MDCT scans. The iliac arteries and veins, uterus, fallopian tubes, cervix, ureters, urinary bladder, rectum, and colon were also consistently visualized. Large antral follicles were detected in six ovaries. Phantom mean CT volume was 0.702±SD 0.504 cc and the mean actual volume was 0.743±SD 0.526 cc. Ovary mean CT volume was 0.258±SD 0.159 cc and mean water displacement volume was 0.257±SD 0.145 cc. For phantoms, the mean coefficient of variation for CT volumes was 2.5%. For ovaries, the least squares mean coefficient of variation for CT volumes was 5.4%. The ovarian CT volume was significantly associated with actual ovarian volume (ICC coefficient 0.79, regression coefficient 0.5, P=0.0006) and the actual ovarian weight (ICC coefficient 0.62, regression coefficient 0.6, P=0.015). There was no association between the CT volume accuracy and mean ovarian CT density (degree of intravenous contrast enhancement), and there was no proportional or fixed bias in the CT volume measurements. Findings from this study indicate that MDCT is a valid non‐invasive technique for measuring the ovarian volume in macaques. Am. J. Primatol. 72:530–538, 2010. © 2010 Wiley‐Liss, Inc.     

Immunosuppressants inhibit hormone-stimulated Mg2+ uptake in mouse distal convoluted tubule cells

Immunosuppressants such as cyclosporinA and FK506 (tacrolimus) are widely prescribed to treat numerous disorders and to treat organ transplant recipients. However, cyclosporine A and FK506 are both known to produce hypomagnesaemia. The mechanism of this effect is still unclear. The present study determined the effects of immunosuppressant treatment on the parathyroid hormone (PTH) mediated Mg(2+) uptake and the mitogen-activated protein kinase (MAPK) activation in mouse distal convoluted tubule (MDCT) cells. The intracellular Ca(2+) and Mg(2+) concentrations in a single MDCT cell were measured by using the fluorescentdye Fura-2 AM and Mag-fura-2 AM, respectively. Cyclosporine A and FK506 illicited a transient increase of intracellular Ca(2+) from a basal level of 99 +/- 16 nM to 685 +/- 105 and 608 +/- 96 nM, respectively. In order to determine the Mg(2+) transport, the MDCT cells were Mg(2+)-depleted by culturing them in Mg(2+)-free media for 16 h, and the Mg(2+) uptake was measured by microfluorescence after placing the depleted cells in 1.5mM MgCl(2). The mean rate of Mg(2+) uptake, d([Mg(2+)](i))/dt, was 140 +/- 16 nM/s in the control MDCT cells. PTH increased the Mg(2+) uptake more than 2 times in this cell. Cyclosporine A (10 microM) and FK506 (0.1 microM) did not affect the basal Mg(2+)uptake (140 +/- 16 and 142 +/- 14 nM/s, respectively), but they inhibited the PTH-stimulated Mg(2+) entry, decreasing it from 248+/-12 to 147 +/- 7 and 148 +/- 14 nM/s, respectively. These effects were inhibited by L685818, which is a potent competitive antagonist of FK506. PTH stimulated the extracellular signal-regulated kinase1/2 (ERK1/2) protein synthesis. This PTH-stimulated ERK1/2 activation was inhibited by cyclosporine A and FK506. In the present study, the role of ERK1/2 activation on the PTH-dependent magnesium uptake was examined in MDCT cells, and we showed that immunosuppressants inhibit the hormone-stimulated Mg(2+) uptake into the MDCT cells by inhibiting the MAPK pathway.     

多层螺旋CT测定肺容积指标对慢性阻塞性肺疾病的诊断价值探讨

目的：分析多层螺旋CT检测慢性阻塞性肺疾病患者肺容积指数的准确性,探讨多层螺旋CT的诊断价值,为慢性阻塞性肺病的临床诊断提供可借鉴的方法。方法：选取2010年10月-2012年8月我院收治的慢性阻塞性肺疾病患者98例为观察组,另选取同期接受体检的健康志愿者70例为对照组。采用多层螺旋CT测定两组不同肺区的肺容积指标并与临床PFT指标进行相关性分析。结果：对照组与观察组的肺功能指标存在显著差异（P〈0.05）;观察组患者在不同肺区测定的Vin及上肺区Vin-Vex值无统计学意义（P〉0.05）;最大呼气末容积（Vex）、容积比（Vex/Vin）和肺容积变化比率[（Vin-Vex）/Vin]均呈显著差异,具有统计学意义（P〈0.05）;肺容积差（Vin-Vex）与各项PFT指标无相关性（P〉0.05）。结论：64层螺旋CT肺容积成像对诊断COPD有预测意义,值得临床上进一步研究和推广。     

不同病理类型囊腔样肺癌的多排螺旋CT诊断

目的:分析不同病理类型囊腔样肺癌的多排螺旋CT(Multi-Detector Computed Tomography,MDCT)影像表现,以提高对该病的认识及早期诊断水平。方法:回顾性分析28例经病理证实的囊腔样肺癌的一般资料和MDCT表现,并分析不同病理类型的影像特征包括病灶大小、部位、形态分型、磨玻璃征、形态和边缘、瘤-肺界面、与支气管关系、囊腔内残留血管分隔、胸膜凹陷征、合并肺大泡等及其相关性。结果:28例囊腔样肺癌包括18例腺癌,3例微浸润腺癌,6例鳞癌,1例腺鳞癌。患者的平均发病年龄腺癌(60.56±8.03)和鳞癌(66.00±7.93岁)高于微浸润腺癌组(49.33±16.17岁)(F=3.449,P=0.048)。平均病灶大小腺癌(1.99±0.69 cm)和鳞癌(2.45±0.87 cm)大于微浸润腺癌(0.73±0.23 cm)(F=5.980,P=0.008)。磨玻璃征主要见于腺癌(14例,77.8%)或微浸润腺癌(3例,100.0%),与鳞癌(1例,16.7%)之间比较有统计学差异(P=0.012)。鳞癌(5例)与腺癌(2例)相比更容易显示支气管截断(P=0.003)。对不同病理类型囊腔样肺癌的其他影像特征之间比较无统计学差异(P0.05)。结论:不同病理类型囊腔样肺癌具有一定的典型CT影像特征,如磨玻璃征可高度提示腺癌或微浸润腺癌,鳞癌更容易出现支气管截断征象或肺门侧软组织影。对于不典型病灶,影像动态随访对确诊很重要。     

Two examples of indication specific radiation dose calculations in dental CBCT and Multidetector CT scanners

PurposeTo calculate organ doses and estimate the effective dose for justification purposes in patients undergoing orthognathic treatment planning purposes and temporal bone imaging in dental cone beam CT (CBCT) and Multidetector CT (MDCT) scanners.MethodsThe radiation dose to the ICRP reference male voxel phantom was calculated for dedicated orthognathic treatment planning acquisitions via Monte Carlo simulations in two dental CBCT scanners, Promax 3D Max (Planmeca, FI) and NewTom VGi evo (QR s.r.l, IT) and in Somatom Definition Flash (Siemens, DE) MDCT scanner. For temporal bone imaging, radiation doses were calculated via MC simulations for a CBCT protocol in NewTom 5G (QR s.r.l, IT) and with the use of a software tool (CT-expo) for Somatom Force (Siemens, DE). All procedures had been optimized at the acceptance tests of the devices.ResultsFor orthognathic protocols, dental CBCT scanners deliver lower doses compared to MDCT scanners. The estimated effective dose (ED) was 0.32 mSv for a normal resolution operation mode in Promax 3D Max, 0.27 mSv in VGi-evo and 1.18 mSv in the Somatom Definition Flash. For temporal bone protocols, the Somatom Force resulted in an estimated ED of 0.28 mSv while for NewTom 5G the ED was 0.31 and 0.22 mSv for monolateral and bilateral imaging respectively.ConclusionsTwo clinical exams which are carried out with both a CBCT or a MDCT scanner were compared in terms of radiation dose. Dental CBCT scanners deliver lower doses for orthognathic patients whereas for temporal bone procedures the doses were similar.     

多层螺旋CT 测定肺容积指标对慢性阻塞性肺疾病的诊断价值探讨

目的：分析多层螺旋CT检测慢性阻塞性肺疾病患者肺容积指数的准确性,探讨多层螺旋CT 的诊断价值,为慢性阻塞性肺 病的临床诊断提供可借鉴的方法。方法：选取2010 年10 月-2012 年8月我院收治的慢性阻塞性肺疾病患者98例为观察组,另选 取同期接受体检的健康志愿者70 例为对照组。采用多层螺旋CT 测定两组不同肺区的肺容积指标并与临床PFT 指标进行相关 性分析。结果：对照组与观察组的肺功能指标存在显著差异(P<0.05);观察组患者在不同肺区测定的Vin 及上肺区Vin-Vex 值无 统计学意义(P>0.05);最大呼气末容积(Vex)、容积比(Vex/Vin)和肺容积变化比率[(Vin-Vex)/Vin]均呈显著差异,具有统计学意义 (P<0.05);肺容积差(Vin-Vex)与各项PFT 指标无相关性(P>0.05)。结论：64层螺旋CT 肺容积成像对诊断COPD有预测意义,值得 临床上进一步研究和推广。     

Does gantry rotation time influence accuracy of volume computed tomography dose index (CTDIvol) in modern CT?

PurposeThe purpose of this study was to develop a gantry overrun corrected CTDI_vol (cCTDI_vol) dosimetry and evaluate the differences between the displayed CTDI_vol (dCTDI_vol), measured CTDI_vol (mCTDI_vol), and the cCTDI_vol.Methods and materialsThe each 8 rotation times between 275 and 1000 ms of two CT scanners were investigated. Rotation time (T_rot) and the beam-on time (T_beam) in axial scanning were measured accurately to determine the gantry overrun time (T_over) as T_beam − T_rot. Subsequently, mCTDI_vol was measured by using a 100 mm ionization chamber and CTDI phantoms. Furthermore, we introduced a gantry overrun correction factor (C_o = T_rot/T_beam) to obtain cCTDI_vol. Upon completion of the data acquisition, the dCTDI_vol and mCTDI_vol were compared with the cCTDI_vol.ResultsThe discrepancies of T_rot were 0.2 ± 0.2 ms as compared to the preset rotation times, and T_over was machine-specific and almost constant (22.4 ± 0.5 ms or 45.1 ± 0.3 ms) irrespective of the preset rotation time. Both dCTDI_vol and mCTDI_vol were increasingly overestimated compared to cCTDI_vol as the faster the preset rotation time was selected (1.7–23.5%).ConclusionThe rotation time influences the accuracy of CTDI_vol in modern CT, and should be taken into consideration when assessing the radiation output in modern CT.     

Influence of atorvastatin on coronary calcifications and myocardial perfusion defects in systemic lupus erythematosus patients: a prospective,randomized, double-masked,placebo-controlled study

Introduction  

Mortality in systemic lupus erythematosus (SLE) patients is influenced by an increased occurrence of severe cardiovascular complications. Statins have been proven to protect a wide spectrum of SLE patients from these complications. This study was conducted to determine the possible efficacy of atorvastatin in SLE patients as assessed by multi-detector computed tomography (MDCT)-based coronary calcium scoring and single photon emission computed tomography (SPECT) of the myocardium.