共查询到20条相似文献，搜索用时 11 毫秒
1.
PurposeThe feasibility of setting-up generic, hospital-independent dose alert levels to initiate vigilance on possible skin injuries in interventional procedures was studied for three high-dose procedures (chemoembolization (TACE) of the liver, neuro-embolization (NE) and percutaneous coronary intervention (PCI)) in 9 European countries.MethodsGafchromic® films and thermoluminescent dosimeters (TLD) were used to determine the Maximum Skin Dose (MSD). Correlation of the online dose indicators (fluoroscopy time, kerma- or dose-area product (KAP or DAP) and cumulative air kerma at interventional reference point (Ka,r)) with MSD was evaluated and used to establish the alert levels corresponding to a MSD of 2 Gy and 5 Gy. The uncertainties of alert levels in terms of DAP and Ka,r, and uncertainty of MSD were calculated.ResultsAbout 20–30% of all MSD values exceeded 2 Gy while only 2–6% exceeded 5 Gy. The correlations suggest that both DAP and Ka,r can be used as a dose indicator for alert levels (Pearson correlation coefficient p mostly >0.8), while fluoroscopy time is not suitable (p mostly <0.6). Generic alert levels based on DAP (Gy cm2) were suggested for MSD of both 2 Gy and 5 Gy (for 5 Gy: TACE 750, PCI 250 and NE 400). The suggested levels are close to the lowest values published in several other studies. The uncertainty of the MSD was estimated to be around 10–15% and of hospital-specific skin dose alert levels about 20–30% (with coverage factor k = 1).ConclusionsThe generic alert levels are feasible for some cases but should be used with caution, only as the first approximation, while hospital-specific alert levels are preferred as the final approach. 相似文献
2.
《Reports of Practical Oncology and Radiotherapy》2020,25(1):35-40
AimThis study retrospectively analysed the results of using optically stimulated radiation dosimeters (OSLDs) for in vivo dose measurements during total skin electron therapy (TSET, also known as TSEI, TSEB, TSEBT, TSI or TBE) treatments of patients with mycosis fungoides.BackgroundTSET treatments are generally delivered to standing patients, using treatment plans that are devised using manual dose calculations that require verification via in vivo dosimetry. Despite the increasing use of OSLDs for radiation dosimetry, there is minimal published guidance on the use of OSLDs for TSET verification.Materials and methodsThis study retrospectively reviewed in vivo dose measurements made during treatments of nine consecutive TSET patients, treated between 2013 and 2018. Landauer nanoDot OSLDs were used to measure the skin dose at reference locations on each patient, as well as at locations of clinical interest such as the head, hands, feet, axilla and groin.Results1301 OSLD measurements were aggregated and analysed, producing results that were in broad agreement with previous TLD studies, while providing additional information about the variation of dose across concave surfaces and potentially guiding future refinement of treatment setup. In many cases these in vivo measurements were used to identify deviations from the planned dose in reference locations and to identify anatomical regions where additional shielding or boost treatments were required.ConclusionsOSLDs can be used to obtain measurements of TSET dose that can inform monitor unit adjustments and identify regions of under and over dosage, while potentially informing continuous quality improvement in TSET treatment delivery. 相似文献
3.
PurposeValidate the skin dose software within the radiation dose index monitoring system NEXO[DOSE]® (Bracco Injeneering S.A., Lausanne, Switzerland). It provides the skin dose distribution in interventional radiology (IR) procedures.MethodsTo determine the skin dose distribution and the Peak Skin Dose (PSD) in IR procedures, the software uses exposure and geometrical parameters taken from the radiation dose structured report and additional information specific to each angiographic system. To test the accuracy of the software, GafChromic® XR-RV3 films, wrapped under a cylindrical PMMA phantom, were irradiated with different setups. Calculations and films results are compared in terms of absolute dose and geometric accuracy, using two angiographic systems (Philips Integris Allura FD20, Siemens AXIOM-ArtisZeego).ResultsCalculated and film measured PSD values agree with an average difference of 7% ± 5%. The discrepancies in dose evaluation increase up to 33% in lower dose regions, because the algorithm does not consider the out-of-field scatter contribution of the neighboring fields, which is more significant in these areas. Regarding the geometric accuracy, the differences between the simulated dose spatial distributions and the measured ones are<3 mm (4%) in simple tests and 5 mm (5%) in setups closer to clinical practice. Moreover, similar results are obtained for the two studied angiographic system vendors.ConclusionsNEXO[DOSE]® provides an accurate skin dose distribution and PSD estimate. It will allow faster and more accurate monitoring of patient follow-up in the future. 相似文献
4.
目的:了解哈尔滨市某三级医院介入人员外照射个人剂量现况和本院辐射防护情况,以期为本院介入防护策略提供一定的科学依据。方法:按照《中华人民共和国国家职业卫生标准》(GBZ128-2016)版本要求,在2016年7月8号～2017年7月8号期间,采用双剂量计监测目标人群年外照射个人剂量,x2检验和logistic回归分析介入人员外照射个人剂量的影响因素。结果:年外照射最小个人剂量为0.08mSv,最大个人剂量为3.60mSv,平均个人剂量为0.23mSv,x2检验表明科室(x~2=50.420,P0.001)、职业类别(x~2=32.992,P0.001)、职称(x~2=33.806,P0.001)和学历(x2=9.289,P0.05)有统计学意义;logistic回归分析均表明,职称、工作年限、职业类别进入方程,但只有职称(Wals=4.896,P0.05)和职业类别(Wals=8.424,P0.05)有统计学意义,医务人员职称和职业类别(Wals=8.424,P0.05)是影响个人外照射剂量的因素。结论:本院总体外照射防护措施得当,本院从事介入工作的相关医务人员中,高级职称医务人员外照射个人剂量低于中、低级职称医务人员;技师外照射个人剂量高于护士和医生。根据本研究结果,在医院的外照射防护中应采取一些措施,比如合理分配工作,避免同一工种医务人员长时间暴露于介入相关外照射,避免中低级职称医生长时间接触介入相关外照射,加强医务人员防护意识,适当调整工作岗位,适时进行防护培训。 相似文献
5.
PurposeInstitutional (local) Diagnostic Reference Levels for Cerebral Angiography (CA), Percutaneous Transhepatic Cholangiography (PTC), Transarterial Chemoembolization (TACE) and Percutaneous Transhepatic Biliary Drainage (PTBD) are reported in this study.Materials and methodsData for air kerma-area product (PKA), air kerma at the patient entrance reference point (Ka,r), fluoroscopy time (FT) and number of images (NI) as well as estimates of Peak Skin Dose (PSD) were collected for 142 patients. Therapeutic procedure complexity was also evaluated, in an attempt to incorporate it into the DRL analysis.ResultsLocal PKA DRL values were 70, 34, 189 and 54 Gy.cm2 for CA, PTC, TACE and PTBD respectively. The corresponding DRL values for Ka,r were 494, 194, 1186 and 400 mGy, for FT they were 9.2, 14.2, 27.5 and 22.9 min, for the NI they were 844, 32, 602 and 13 and for PSD they were 254, 256, 1598 and 540 mGy respectively. PKA for medium complexity PTBD procedures was 2.5 times higher than for simple procedures. For TACE, the corresponding ratio was 1.6. PSD was estimated to be roughly 50% of recorded Ka,r for procedures in the head/neck region and 10% higher than recorded Ka,r for procedures in the body region. In only 5 cases the 2 Gy dose alarm threshold for skin deterministic effects was exceeded.ConclusionProcedure complexity can differentiate DRLs in Interventional Radiology procedures. PSD could be deduced with reasonable accuracy from values of Ka,r that are reported in every angiography system. 相似文献
6.
PurposeOnline and offline software products can estimate the maximum skin dose (MSD) delivered to the patient during interventional cardiology procedures. The capabilities and accuracy of several skin dose mapping (SDM) software products were assessed on X-ray systems from the main manufacturers following a common protocol.MethodsSkin dose was measured on four X-ray systems following a protocol composed of nine fundamental irradiation set-ups and three set-ups simulating short, clinical procedures. Dosimeters/multimeters with semiconductor-based detectors, radiochromic films and thermoluminescent dosimeters were used. Results were compared with up to eight of 10 SDM products, depending on their compatibility.ResultsThe MSD estimates generally agreed with the measurements within ± 40% for fundamental irradiation set-ups and simulated procedures. Only three SDM products provided estimates within ± 40% for all tested configurations on at least one compatible X-ray system. No SDM product provided estimates within ± 40% for all combinations of configurations and compatible systems. The accuracy of the MSD estimate for lateral irradiations was variable and could be poor (up to 66% underestimation). Most SDM products produced maps which qualitatively represented the dimensions, the shape and the relative position of the MSD region. Some products, however, missed the MSD region when situated at the intersection of multiple fields, which is of radiation protection concern.ConclusionsIt is very challenging to establish a common protocol for quality control (QC) and acceptance testing because not all information necessary for accurate MSD calculation is available or standardised in the radiation dose structured reports (RDSRs). 相似文献
7.
PurposeThe aim of this study was to assess patient exposure data and operator dose in coronary interventional procedures, when considering patient body-mass index and procedure complexity.MethodsTotal air kerma area product (PKA), Air-Kerma (AK), Fluoroscopy time (FT), operator dose and patient body-mass index (BMI) from 97 patients’ procedures (62 coronary angiography (CA) and 35 Percutaneous Coronary Intervention (PCI) were collected for one year. For PCI procedures, also the complexity index-CI was collected. Continuous variables for each of the 2 groups procedures (CA and PCI) were compared as medians with interquartile range and using Mann-Whitney U test. Multiple group data were compared using Kruskal-Wallis test (significance: p < 0.05).ResultsMedian PKA was 63 and 125 Gy cm2 for CA and PCI respectively (p < 0.001); FT was 3 and 14 min, respectively (p < 0.001). PKA and FT significantly increased (p < 0.05) with BMI class for CA procedures. PKA and FT also increased in function of CI class for PCI, thought significantly only for FT (p < 0.001), possibly because of the low number of PCI procedures included; cine mode contributed most to PKA. Significant dose variability was observed among cardiologists for CA procedures (p < 0.001).ConclusionsDose references levels for PKA and FT in interventional cardiology should be defined - on a sufficient number of procedures- in function of CI and BMI classes. These could provide an additional tool for refining a facility’s quality assurance and optimization processes. Dose variability associated with cardiologists underlines the importance of continuous training. 相似文献
8.
后生元因为具有益生菌的某些功效,但又无活菌体,更易被商品化,且分子更小,更易被皮肤吸收,一直受到美容护肤领域的关注。影响皮肤老化的因素很多,皮肤微生态平衡是维持皮肤健康的必要因素。皮肤在病理状态会出现微生态失衡,皮肤微生物组在老化过程中也会不断发生变化。本文介绍了皮肤微生物群和后生元制剂的制备,综述了后生元在皮肤稳态的维持和美容护肤领域的开发与应用,探讨了后生元发挥作用的可能机制,为后生元在皮肤美容与健康领域的进一步开发与应用提供一定的依据。 相似文献
9.
《Saudi Journal of Biological Sciences》2017,24(3):514-518
In order to quantitatively evaluate the improvement of the skin condition after using skin care products and beauty, a quantitative evaluation method for skin surface state and texture is presented, which is convenient, fast and non-destructive. Human skin images were collected by image sensors. Firstly, the median filter of the 3 × 3 window is used and then the location of the hairy pixels on the skin is accurately detected according to the gray mean value and color information. The bilinear interpolation is used to modify the gray value of the hairy pixels in order to eliminate the negative effect of noise and tiny hairs on the texture. After the above pretreatment, the gray level co-occurrence matrix (GLCM) is calculated. On the basis of this, the four characteristic parameters, including the second moment, contrast, entropy and correlation, and their mean value are calculated at 45 ° intervals. The quantitative evaluation model of skin texture based on GLCM is established, which can calculate the comprehensive parameters of skin condition. Experiments show that using this method evaluates the skin condition, both based on biochemical indicators of skin evaluation methods in line, but also fully consistent with the human visual experience. This method overcomes the shortcomings of the biochemical evaluation method of skin damage and long waiting time, also the subjectivity and fuzziness of the visual evaluation, which achieves the non-destructive, rapid and quantitative evaluation of skin condition. It can be used for health assessment or classification of the skin condition, also can quantitatively evaluate the subtle improvement of skin condition after using skin care products or stage beauty. 相似文献
10.
《Reports of Practical Oncology and Radiotherapy》2014,19(6):428-432
AimTo investigate incidence of toxicity and related hospitalization among patients treated at our institute by a short course of palliative cranial radiotherapy against a longer, widely established schedule.BackgroundShorter schedule palliative cranial radiotherapy is more convenient for patients and reduce waiting times. Although many studies have established safety of short schedules, the need for hospitalization due to acute treatment toxicity remains under-explored. Hospital admissions are an economic burden both for the patient and healthcare system in a limited resource setting. Delivery of treatment on an outpatient basis and within shorter times is preferred by patients, caregivers and healthcare staff.Materials and methodsThis was a prospective study on 68 patients treated with palliative whole brain radiotherapy between November 2010 and October 2012. One group received 20 Gy in 5 fractions over 1 week and the other group, 30 Gy in 10 fractions over 2 weeks. Treatment toxicity due to cranial radiotherapy was assessed as per RTOG acute and late toxicity criteria. Need for hospitalization owing to acute toxicity was also noted. Significant differences in the study parameters between the two groups were calculated by Fisher's t-test.ResultsRequirement for hospital stay due to acute toxicity was not significantly different between the two groups. Patients in both groups experienced similar toxicity both during and after treatment.ConclusionsThe shorter course entailed no significant increase in toxicity related admissions, suitable for limited resource settings where patient transport is difficult, there are financial constraints, and the healthcare system is overburdened. 相似文献
11.
《Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB)》2016,32(11):1475-1478
There is currently no effective real-time patient dosimeter available for use in interventional radiology (IR). We conducted a feasibility study in a clinical setting to investigate the use of the new dosimeter using photoluminescence sensors during procedures. Reference dosimeters were set at almost the same position of the prototype dosimeter sensors.We found excellent correlations between the reference measurements and those of the prototype dosimeter (r2 = 0.950). The sensor of the new dosimeter does not interfere with the IR procedure. The new dosimeter will be an effective tool for the real-time measurement of patient skin doses during IR. 相似文献
12.
PurposeTo determine how the skin dose varies in patients receiving radiation treatment for breast cancer in the prone and supine positions.MethodsFifty patients were scanned in the prone and supine positions. A radiation treatment plan was created for the left breast using a 6-MV beam for a prescribed dose of 42.66 Gy in 16 fractions. The dose was calculated using 1- and 2.5-mm calculation grid sizes and the surface dose was compared in both techniques.ResultsThe median gantry angles relative to the skin surface at the central axis were 8 and 52 degrees for treatment in the prone and supine positions, respectively. The mean dose difference between the prone and supine techniques was statistically significant from 3- to 5-mm depth for both grid sizes. For the 1-mm calculation grid size, the doses at 3-, 4-, and 5-mm depths in the prone and supine techniques were 87.80% and 89.10% (P < 0.003), 91.92% and 94.50% (P < 0.00), and 95.30% and 98.20% (P < 0.00), respectively; for the 2.5-mm grid size, the respective doses were 87.10% and 88.59% (P < 0.00), 91.60% and 94.63% (P < 0.00), and 95.10% and 97.80% (P < 0.00), respectively.ConclusionsThis study demonstrates that the prone technique facilitates a relatively lower skin dose than the supine technique. This observation is probably due to the beam angle. The beam is more perpendicular to the skin surface in the prone technique, whereas it is more tangential in the supine technique, which may deliver a higher skin dose. Thus, the dose to the skin should be evaluated in the prone technique, and if desired, the skin dose could be carefully augmented via a bolus or beam spoiler. 相似文献
13.
摘要 目的：探究医用护肤品对湿疹患者皮肤屏障损伤、免疫指标和血清因子的影响。方法：选取2020年12月~2021年3月来我院皮肤科就诊治疗的115例慢性湿疹的患者,按照其治疗不同分为单药组（n=66）与联合组（n=49）,其中单药组外涂糠酸莫米松乳膏,联合组外涂糠酸莫米松乳膏加用护肤品（保湿霜）。观察并记录治疗前后两组患者血清白细胞介素（IL）-2、IL-4、IL-5、Th细胞群、IgE水平及嗜酸性粒细胞（EOS）数目变化。对比两组患者湿疹病情严重程度评分差异。分析两组患者皮肤屏障功能[经表皮水分流失（TEWL）、皮肤油脂（SC）和角质层含水量（WCSC）]差异,并对比两组患者的临床疗效。结果：治疗后,联合组总有效率显著高于单药组（P<0.05）。两组患者血清IL-2水平与治疗前相比明显升高,而IL-4、IL-5水平显著降低,且联合组较单药组变化更为明显（P<0.05）。两组患者Th1、Th2与治疗前相比均显著下降,但联合组Th1/Th2比值较单药组显著升高（P<0.05）。两组患者外周血IgE、EOS与治疗前相比明显降低,且联合组更为明显（P<0.05）。两组患者瘙痒、皮损面积评分及EASI评分与治疗前相比下降明显,且联合组优于单药组（P<0.05）。两组患者TEWL指标与治疗前相比明显降低,而WCSC和SC指标显著升高,且联合组较单药组变化更为明显（P<0.05）。治疗后,两组患者皮损处TLR4,MyD88及NF-κB mRNA表达量与治疗前相比明显降低,且联合组更为明显,差异均有统计学意义（P<0.05）。结论：糠酸莫米松乳膏联合医用护肤品能够修复湿疹患者皮肤屏障损伤,调节免疫指标和血清因子的变化,改善湿疹患者临床症状。其机制可能与抑制TLR4/MyD88/NF-κB信号通路有关。 相似文献
14.
The aim of this work was to create a model of a wide-bore Siemens Somatom Sensation Open CT scanner for use with GMCTdospp, which is an EGSnrc-based software tool dedicated for Monte Carlo calculations of dose in CT examinations.The method was based on matching spectrum and filtration to half value layer and dose profile, and thus was similar to the method of Turner et al. (Med. Phys. 36, pp. 2154–2164). Input data on unfiltered beam spectra were taken from two sources: the TASMIP model and IPEM Report 78. Two sources of HVL data were also used, namely measurements and documentation. Dose profile along the fan-beam was measured with Gafchromic RTQA-1010 (QA+) film. Two-component model of filtration was assumed: bow-tie filter made of aluminum with 0.5 mm thickness on central axis, and flat filter made of one of four materials: aluminum, graphite, lead, or titanium.Good agreement between calculations and measurements was obtained for models based on the measured values of HVL. Doses calculated with GMCTdospp differed from the doses measured with pencil ion chamber placed in PMMA phantom by less than 5%, and root mean square difference for four tube potentials and three positions in the phantom did not exceed 2.5%. The differences for models based on HVL values from documentation exceeded 10%. Models based on TASMIP spectra and IPEM78 spectra performed equally well. 相似文献
15.
The appearance of a malignant disease during pregnancy is relatively rare. The use of external-beam radiation therapy is limited to non-pelvic tumors which are usually located above the diaphragm. However, supradiaphragmatic radiotherapy unavoidably exposes the fetus to secondary radiation due to head leakage, scatter from the machine and scatter produced inside the patient. This fetal exposure may be associated with an elevated risk for the development of deterministic harmful effects and/or carcinogenesis. The decision about the administration of radiotherapy in a pregnant patient is influenced by the fetal dose which must always be estimated before the patient’s treatment course. The methods employed for fetal dosimetry in external-beam radiotherapy are described in this review study. Direct dose measurements using thermoluminescent dosemeters or large ionization chambers placed on physical phantoms may be used. Monte Carlo simulations on computational phantoms may also provide accurate fetal dose calculations. The physical and/or computational phantoms need to simulate the full-scatter geometry of the pregnant patient. Typical fetal dose values attributable to radiation therapy for brain tumors, head and neck cancer, breast carcinoma and Hodgkin lymphoma at the first, second and third trimesters of gestation are presented. The effectiveness of different shielding devices for fetal dose reduction in radiotherapy is discussed. The effect of the dimensions and setup of the shielding material on the radiation dose received by the fetus is described. Moreover, practical methods for reducing the fetal dose by selecting the appropriate irradiation parameters are presented. 相似文献
16.
This work provides an improvement of the approach using Monte Carlo simulation for the Amersham Model 6711 125I brachytherapy seed source, which is well known by many theoretical and experimental studies. The source which has simple geometry was researched with respect to criteria of AAPM Tg-43 Report. The approach offered by this study involves determination of differential dose contributions that come from virtual partitions of a massive radioactive element of the studied source to a total dose at analytical calculation point. Some brachytherapy seeds contain multi-radioactive elements so the dose at any point is a total of separate doses from each element. It is momentous to know well the angular and radial dose distributions around the source that is located in cancerous tissue for clinical treatments. Interior geometry of a source is effective on dose characteristics of a distribution. Dose information of inner geometrical structure of a brachytherapy source cannot be acquired by experimental methods because of limits of physical material and geometry in the healthy tissue, so Monte Carlo simulation is a required approach of the study. EGSnrc Monte Carlo simulation software was used. In the design of a simulation, the radioactive source was divided into 10 rings, partitioned but not separate from each other. All differential sources were simulated for dose calculation, and the shape of dose distribution was determined comparatively distribution of a single-complete source. In this work anisotropy function was examined also mathematically. 相似文献
17.
目的:研究甘油三酯代谢过程对紫外线照射后HaCaT细胞的影响及机制研究。方法:HaCaT细胞分为4组,分别为对照组、紫外线照射组、紫外线照射并予甘油三酯组、紫外线照射并予甘油三酯合成酶抑制剂TOFA组,查看MMP-1、COX-2和IL-1β在mRNA及蛋白水平上的变化,并查看其上游转录因子NF-κB/IκB的表达情况。结果:1)甘油三酯可以抑制紫外线照射后细胞外基质溶解蛋白MMP-1的表达(P0.05)。2)甘油三酯可以抑制紫外线照射后炎症相关蛋白COX-2和IL-1β的表达(P0.05)。3)甘油三酯合成酶抑制剂TOFA可以增强外线照射后细胞外基质溶解蛋白MMP-1以及炎症相关蛋白COX-2和IL-1β的表达(P0.05)。4)其调节过程可能通过NF-κB/IκB信号传导通路实现(P0.05)。结论:甘油三酯对紫外线的照射后的HaCaT细胞有保护作用,若抑制其代谢将减弱其保护作用。 相似文献
18.
IntroductionThe International Atomic Energy Agency (IAEA) organized the 3rd international conference on radiation protection (RP) of patients in December 2017. This paper presents the conclusions on the interventional procedures (IP) session.Material and methodsThe IAEA conference was conducted as a series of plenary sessions followed by various thematic sessions. “Radiation protection of patients and staff in interventional procedures” session keynote speakers presented information on: 1) Risk management of skin injuries, 2) Occupational radiation risks and 3) RP for paediatric patients. Then, a summary of the session-related papers was presented by a rapporteur, followed by an open question-and-answer discussion.ResultsSixty-seven percent (67%) of papers came from Europe. Forty-four percent (44%) were patient studies, 44% were occupational and 12% were combined studies. Occupational studies were mostly on eye lens dosimetry. The rest were on scattered radiation measurements and dose tracking. The majority of patient studies related to patient exposure with only one study on paediatric patients. Automatic patient dose reporting is considered as a first step for dose optimization. Despite efforts, paediatric IP radiation dose data are still scarce. The keynote speakers outlined recent achievements but also challenges in the field. Forecasting technology, task-specific targeted education from educators familiar with the clinical situation, more accurate estimation of lens doses and improved identification of high-risk professional groups are some of the areas they focused on.ConclusionsManufacturers play an important role in making patients safer. Low dose technologies are still expensive and manufacturers should make these affordable in less resourced countries. Automatic patient dose reporting and real-time skin dose map are important for dose optimization. Clinical audit and better QA processes together with more studies on the impact of lens opacities in clinical practice and on paediatric patients are needed. 相似文献
19.
PurposeOptimization of CT scan practices can help achieve and maintain optimal radiation protection. The aim was to assess centering, scan length, and positioning of patients undergoing chest CT for suspected or known COVID-19 pneumonia and to investigate their effect on associated radiation doses.MethodsWith respective approvals from institutional review boards, we compiled CT imaging and radiation dose data from four hospitals belonging to four countries (Brazil, Iran, Italy, and USA) on 400 adult patients who underwent chest CT for suspected or known COVID-19 pneumonia between April 2020 and August 2020. We recorded patient demographics and volume CT dose index (CTDIvol) and dose length product (DLP). From thin-section CT images of each patient, we estimated the scan length and recorded the first and last vertebral bodies at the scan start and end locations. Patient mis-centering and arm position were recorded. Data were analyzed with analysis of variance (ANOVA).ResultsThe extent and frequency of patient mis-centering did not differ across the four CT facilities (>0.09). The frequency of patients scanned with arms by their side (11–40% relative to those with arms up) had greater mis-centering and higher CTDIvol and DLP at 2/4 facilities (p = 0.027–0.05). Despite lack of variations in effective diameters (p = 0.14), there were significantly variations in scan lengths, CTDIvol and DLP across the four facilities (p < 0.001).ConclusionsMis-centering, over-scanning, and arms by the side are frequent issues with use of chest CT in COVID-19 pneumonia and are associated with higher radiation doses. 相似文献
20.
To derive effective dose (E), organ dose (HT) and conversion factors with the air kerma area product (KAP) in coronary angiography (CA) and percutaneous coronary intervention (PCI) by the radial route, using the ICRP 103 tissue weighting factors.The study included 34 patients referred for CA and 31 for PCI. E and HT were derived from in-the-field KAP measurements using Montecarlo methods.Median KAP of 23.2 and 56.8 Gy cm2 and E of 6.9 and 20.0 mSv were found for CA and PCI, respectively. Mean KAP and E were significantly higher in males than in females (52.4 ± 40.0 vs 32.3 ± 16.6 Gy cm2; p = 0.02) and (16.8 ± 13.6 vs 10.7 ± 5.8 mSv; p = 0.04). KAP (r = 0.39; p = 0.001) and E (r = 0.34; p = 0.005) showed a significant correlation with the patient’s weight.Conversion factors between KAP and E (E/KAP) were 0.30 ± 0.04 mSv Gy−1 cm−2 for CA and 0.33 ± 0.05 mSv Gy−1 cm−2 for PCI. No significant differences in the E/KAP between males and females were found (0.31 ± 0.05 vs 0.33 ± 0.05; p = 0.08). Again, no significant correlation was found between E/KAP and patient’s weight (r = 0.23; p = 0.07).The correlation between E and KAP was excellent for CA (r = 0.99) and PCI (r = 0.96). The correlation between HT and KAP ranged from r = 0.87 to r = 1 and from r = 0.71 to r = 0.98 for CA and PCI, respectively.A single factor, the total KAP, could be used for a specific acquisition protocol to reliably estimate E and HT without the need of a patient’s specific analysis. Conversion factors might be installation, X-ray beam quality or protocol dependent. 相似文献
