Determination of Diagnostic Reference Levels (DRLs) in General Radiographyin Latin America

The International Atomic Energy Agency (IAEA) through the International Action Plan on Radiation Protection of Patients and the International Commission on Radiological Protection have for some time carried out important efforts to assure that in the medical applications of the ionising radiations, the optimisation of radiological protection of patients is fundamental, to such a point that the IAEA includes it directly as a requirement for these practices (in its International Basic Safety Standards for Protection against Ionising Radiation and for the Safety of Radiation Sources (BSS)-GSR Part 1, 2011). For this reason, among the objectives of Regional Project RLA/9/057 and Regional Project RLA/9/067, the intention was to establish the dose references in conventional radiology for Latin America, for the purposes of determining whether these doses comply with the requirements of the BSS and to tend to improve practices, in order to minimise the dose received by the patients.Fil: Blanco, Susana Alicia Ana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Belgrano. Facultad de Ingenieria; ArgentinaFil: Mora, Patricia. Centro de Investigación en Ciencias Atómicas, Nucleares y Moleculares; Costa RicaFil: Almonte, Narkiss. Comisión Nacional de Energía. Dirección Nuclear; República DominicanaFil: Benavente, Tony. Instituto Peruano de Energía Nuclear; PerúFil: Benson, Nadja. Ministerio de Salud. Dirección General de Salud; Reino UnidoFil: Blanco, Daniel. Universidad de la República. Centro de Investigaciones Nucleares; UruguayFil: Cárdenas, Juan. Centro de Protección e Higiene de las Radiaciones; CubaFil: Defaz Gómez, Yolanda. Hospital Oncológico SOLCA Nucleo de Quito; EcuadorFil: Edding, Oscar. Instituto de Salud Pública; ChileFil: Escobar, Carolina. Ministerio de Salud Pública y Acción Social. Unidad Reguladora de Radiaciones Ionizantes; El SalvadorFil: Fonseca, María. Hospital Nacional Roosevelt; GuatemalaFil: Gamarra, Mirta. Ministerio de Salud Pública y Bienestar Social; ParaguayFil: García Aguilar, Juan. Instituto Nacional de Investigaciones Nucleares; MéxicoFil: Khoury, Helen Jamil. Universidade Federal de Pernambuco; BrasilFil: Quintero, Ana Rosa. Hospital Oncológico "Dr Luis Razetti"; VenezuelaFil: Roas Zuniga, Norma. Universidad Nacional Autónoma de Nicaragua; NicaraguaFil: Zaire, Edgar. Instituto Boliviano de Ciencia y Tecnología Nuclear; BoliviaFil: Nader, Alejandro. International Atomic Energy Agency; Austri

Local diagnostic reference levels for typical radiographic procedures

Bakalářská práce se zabývá problematikou stanovení místních diagnostických referenčních úrovní pro skiagrafická vyšetření. Teoretická část obsahuje nezbytné minimum informací týkajících se záření obecně, dále pak teoretický postup samotného stanovení úrovní. Praktická část je věnována konkrétní ukázce výpočtu s posouzením možné nepřesnosti této metody.Bachelor’s thesis explores the topic of setting local diagnostic reference levels for typical radiographic procedures. Theoretical part presents background information about radiation in general and theoretical calculation procedure. Practical part contains specific calculation demonstration with evaluation of possible deviation of results.

Preliminary diagnostic reference levels for endoscopic retrograde cholangio-pancreatography in Greece

The main objective of this study was to determine the preliminary Diagnostic Reference Levels (DRLs) in terms of Kerma Area Product (KAP) and fluoroscopy time (Tf) during Endoscopic Retrograde Cholangio-Pancreatography (ERCP) procedures. Additionally, an investigation was conducted to explore the statistical relation between KAP and Tf. Data from a set of 200 randomly selected patients treated in 4 large hospitals in Greece (50 patients per hospital) were analyzed in order to obtain preliminary DRLs for KAP and Tf during therapeutic ERCP procedures. Non-parametric statistic tests were performed in order to determine a statistically significant relation between KAP and Tf. The resulting third quartiles for KAP and Tf for hospitals (A, B, C and D) were found as followed: KAPA = 10.7 Gy cm^2, TfA = 4.9 min; KAPB = 7.5 Gy cm^2, TfB = 5.0 min; KAPC = 19.0 Gy cm^2, TfC = 7.3 min; KAPD = 52.4 Gy cm^2, TfD = 15.8 min. The third quartiles, calculated for the total 200 cases sample, are: KAP = 18.8 Gy cm^2 and Tf = 8.2 min. For 3 out of 4 hospitals and for the total sample, p-values of statistical indices (correlation of KAP and Tf) are less than 0.001, while for the Hospital A p-values are ranging from 0.07 to 0.08. Using curve fitting, we finally determine that the relation of Tf and KAP is deriving from a power equation (KAP = Tf^1.282) with R^2 = 0.85. The suggested Preliminary DRLs (deriving from the third quartiles of the total sample) for Greece are: KAP = 19 Gy cm^2 and Tf = 8 min, while the relation between KAP and Tf is efficiently described by a power equatio

The need for national diagnostic reference levels: Entrance surface dose measurement in intraoral radiography

Background: Intraoral radiographies are the most frequent X-ray examinations in humans. According to International Commission on Radiation Protection (ICRP) recommendations, the selection of a diagnostic reference level (DRL) should be specific to a country or region. Critical organs such as thyroid gland are exposed to X-rays in intraoral radiography and these exposures should be kept as low as reasonably achievable. To assist the development of DRLs for intraoral radiography, a National Radiation Protection Department-sponsored pilot study was carried out. Materials and Methods: Thermoluminescent dosimetry (TLD) is widely acknowledged to be the recommended method for measuring entrance surface doses (ESD). In this study, ESD was measured using LiF thermoluminescent dosimeters (TLD-100) on the skin (either mandibular or maxillary arcs) of 40 patients. Three TLD chips were placed on the skin of each patient. The doses were averaged for each radiography and mean ESD of all patients calculated. Results: The mean ± SD entrance surface dose at the center of the beam on the patients' skin in intraoral radiography was 1.173 ± 0.606 mGy (ranged from 0.01 to 0.40 mGy). The mean ESD for male and female patients were 1.380 ± 0.823, and 1.004 ± 0.258 respectively. No statistically significant difference was found between these means. Despite its necessity, in national level, there is no published data on the diagnostic reference levels for intraoral radiography. However, the results obtained in this study are lower than those reported by investigators in other countries. Conclusion: In IR Iran, due to lack of large scale studies, no diagnostic reference levels have been set for X-ray diagnostic procedures. Due to lack of national diagnostic reference levels, it is not possible to clarify whether in intraoral radiographies any dose reduction techniques are needed. We intend to perform similar nationwide studies to set the diagnostic reference level for intraoal radio graphy

Evaluation of the onset of space charge and electroluminescence as a marker for cross linked polyethylene ageing

The aim of the “ARTEMIS” project is to investigate the ageing mechanisms for cross-linked polyethylene under thermo-electrical stress and to identify ageing markers, which can be used to carry out diagnostic procedures. A carefully selected set of techniques which can give cross-correlated information on space charge phenomenology and material degradation were used to investigate specimens peeled from reference and aged cables. The paper shows that ageing induces a change in the density and depth of trapping levels, and an increase in the number and size of mesovoids. Interpretation of these results is discussed in terms of physico-chemical modifications, which can affect trap distribution and microstructure

A contribution to the establishment of diagnostic reference levels in multidetector CT equipments

Actualmente a Tomografia Computorizada (TC) é um dos métodos de diagnóstico por imagem que tem uma maior contribuição para a dose de radiação X recebida pelos pacientes. Pretende-se com este estudo avaliar as doses praticadas em TC e contribuir para o estabelecimento de Níveis de Referência de Diagnóstico (NRD) na região da Grande Lisboa, Portugal. Foram efectuadas medições de dose em 5 equipamentos de TC multidetectores, considerando o abdómen como área anatómica de interesse. Recorreu-se a uma câmara de ionização e a um fantoma para obter o índice de dose de TC (CTDI) e o produto dose-comprimento (DLP), que permitem determinar os NRD. Estes valores foram comparados com os NRD propostos pela Guideline Europeia e com os estudos desenvolvidos em outros países, como o Reino Unido, Grécia e Taiwan. Os resultados revelaram que os valores de NRD obtidos neste estudo (16,7 mGy para o CTDIvol e 436,5 mGy·cm para o DLP) são discrepantes relativamente à Guideline Europeia (±50%), mas muito próximos relativamente aos NRD estabelecidos nos países considerados. Estes valores podem ser eventualmente explicados pelos equipamentos em análise e pela utilização de protocolos de exame adoptados pelos profissionais de Radiologia nas instituições analisadas. ABSTRACT - Nowadays Computed Tomography (CT) is one of the imaging techniques which have a large contribution to radiation dose received by patients. The purpose of this study is to evaluate CT doses and contribute to the establishment of Diagnostic Reference Levels (DRL) in Lisbon, Portugal. Dose measurements on 5 multidetector CT scanners have been performed, considering the abdomen as the anatomic region of interest. All measurements were performed using an ionization chamber and a phantom to obtain the index CT dose (CTDI) and the dose-length product (DLP), which are used to determine DRL. These values were compared not only with European reference dose values but also with DRL studies developed in other countries like United Kingdom, Greece and Taiwan. The results revealed that DRL values obtained in this study (CTDIvol is 16,7 mGy and DLP is 436,5 mGy·cm) have a higher discrepancy to European Guideline (±50%), while the DRL´s of other countries are nearest to values obtained in this study. Those differences may be eventually explained by the type of the evaluated equipments but also by the exam protocols used by the Radiology professionals on the analyzed institutions

Alternative antibody for the detection of CA19-9 antigen: a European multicenter study for the evaluation of the analytical and clinical performance of the Access (R) GI Monitor assay on the UniCel (R) Dxl 800 Immunoassay System

Background: Gastrointestinal cancer antigen CA19-9 is known as a valuable marker for the management of patients with pancreatic cancer. Methods: The analytical and clinical performance of the Access(R) GI Monitor assay (Beckman Coulter) was evaluated on the UniCel(R) Dxl 800 Immunoassay System at five different European sites and compared with a reference method, defined as CA19-9 on the Elecsys System (Roche Diagnostics). Results: Total imprecision (%CV) of the GI Monitor ranged between 3.4% and 7.7%, and inter-laboratory reproducibility between 3.6% and 4.0%. Linearity upon dilution showed a mean recovery of 97.4% (SD+7.2%). Endogenous interferents had no influence on GI Monitor levels (mean recoveries: hemoglobin 103%, bilirubin 106%, triglycerides 106%). There was no high-dose hook effect up to 115,000 kU/L. Clinical performance investigated in sera from 1811 individuals showed a good correlation between the Access' GI Monitor and Elecsys CA19-9 (R = 0.959, slope = 1.004, intercept +0.17). GI Monitor serum levels were low in healthy individuals (n = 267, median = 6.0 kU/L, 95th percentile = 23.1 kU/L), higher in individuals with various benign diseases (n = 550, medians = 5.8-13.4 kU/L, 95th percentiles = 30.1-195.5 kU/L) and even higher in individuals suffering from various cancers (n = 995, medians = 8.4-233.8 kU/L, 95th percentiles = 53.7-13,902 kU/L). Optimal diagnostic accuracy for cancer detection against the relevant benign control group by the GI Monitor was found for pancreatic cancer {[}area under the curve (AUC) 0.83]. Results for the reference CA19-9 assay were comparable (AUC 0.85). Conclusions: The Access(R) GI Monitor provides very good methodological characteristics and demonstrates an excellent analytical and clinical correlation with the Elecsys CA19-9. The GI Monitor shows the best diagnostic accuracy in pancreatic cancer. Our results also suggest a clinical value of the GI Monitor in other cancers

Alternative antibody for the detection of CA125 antigen: a European multicenter study for the evaluation of the analytical and clinical performance of the Access (R) OV Monitor assay on the UniCel (R) Dxl 800 Immunoassay System

Background: Cancer antigen CA125 is known as a valuable marker for the management of ovarian cancer. Methods: The analytical and clinical performance of the Access OV Monitor Immunoassay System (Beckman Coulter) was evaluated at five different European sites and compared with a reference system, defined as CA125 on the Elecsys System (Roche Diagnostics). Results: Total imprecision (%CV) of the OV Monitor ranged between 3.1% and 8.8%, and inter-laboratory reproducibility between 4.7% and 5.0%. Linearity upon dilution showed a mean recovery of 100% (SD+8.1%). Endogenous interferents had no influence on OV Monitor levels (mean recoveries: hemoglobin 107%, bilirubin 103%, triglycericles 103%). There was no high-dose hook effect up to 27,193 kU/L. Clinical performance investigated in sera from 1811 individuals showed a good correlation between the Access OV Monitor and Elecsys CA125 (R = 0.982, slope = 0.921, intercept = + 1.951). OV Monitor serum levels were low in healthy individuals (n = 267, median = 9.7 kU/L, 95th percentile = 30.8 kU/L), higher in individuals with various benign diseases (n = 549, medians = 10.9-16.4 kU/L, 95th percentiles = 44.2-355 kU/L) and even higher in individuals suffering from various cancers (n = 995, medians= 12.4-445 kU/L; 95th percentiles = 53.4-4664 kU/L). Optimal diagnostic accuracy for cancer detection against the relevant benign control group by the OV Monitor was found for ovarian cancer {[}area under the curve (AUC) 0.898]. Results for the reference CA125 assay were comparable (AUC 0.899). Conclusions: The Access OV Monitor provides very good methodological characteristics and demonstrates an excellent analytical and clinical correlation with Elecsys CA125. The best diagnostic accuracy for the OV Monitor was found in ovarian cancer. Our results also suggest a clinical value of the OV Monitor in other cancers

Validation of an automated enzyme immunoassay for interleukin-6 for routine clinical use

Serum levels of Interleukin-6 (IL-6), a proinflammatory cytokine, are increased in early stages of inflammatory diseases such as infection and sepsis. Assay systems which permit its measurement within a few hours and as a single measurement have not been reported so far. We therefore evaluated a now commercially available automated method for IL-6 measurement on the Cobas Core(R) immunological analyzer (Roche Diagnostic Systems) which enables single IL-6 measurement within about 1 hour. The automated assay correlates well with an established, manual microtiter plate assay (Biosource GmbH) which uses the same antibodies and reagents (r=0.98). Accuracy of the automated method was established by adding known amounts of IL-6 international reference preparation. Recovery of the international standard was in the range of 92-104%. The automated assay had a precision of singletons below 6% and was linear up to 2800 pg/ml. This automated assay provides a suitable, convenient and time saving method for measurement of IL-6 serum levels in the routine clinical laboratory

Determining and updating PET/CT and SPECT/CT diagnostic reference levels : a systematic review

The aim of this systematic review is to investigate the national diagnostic reference level (NDRL) methods for positron emission tomography/computed tomography (PET/CT) and single photon emission tomography/computed tomography (SPECT/CT) procedures. A search strategy was based on the preferred, reporting items for systematic review and meta-analysis (PRISMA). Relevant articles retrieved from Medline, Scopus, Web of Science, Embase, Cinahl, and Google Scholar published up to October 2017. The search yielded 1,057 articles. Fourteen articles were included in the review after a screening process. Relevant information from the selected articles were summarised and analysed. Discrepancies were found between the methodologies utilised to establish and report both PET/CT and SPECT/CT NDRLs, e.g. patient sampling and administered activity. Further research should focus on reporting more NDRLs for hybrid PET/CT and SPECT/CT examinations, and establish a robust NDRL standard for the CT portion associated with PET/CT and SPECT/CT examinations. This review provides updated NDRL reommndations to deliver more comparable international radation doses for administered activity and CT dose across PET/CT and SPECT/CT clinics