Anterior approach for pediatric supracondylar humerus fractures: A systematic review.

BACKGROUND AND PURPOSE: Open reduction is rarely performed in pediatric supracondylar humerus fractures. However, clear evidence is lacking regarding the optimal open approach to achieve satisfactory results. The anterior approach provides direct visualization of the fracture and excellent exposure to neurovascular structures, although its utilization is less common. The objective of this study was to review the indications, outcomes, and complications associated with the anterior approach for open reduction of these fractures. METHODS: Our protocol was registered at PROSPERO: CRD42023446923. MEDLINE/PubMed, Embase, Web of Science, Clinicaltrials.gov, and Cochrane Library were searched from database inception to search date (December 2023) and screened in duplicate for relevant studies. Data were collected regarding patient demographics, indications for open reduction, Flynn's functional and cosmetic outcomes, and complications. Study quality was assessed using the Methodological Index for Non-Randomized Studies Criteria. RESULTS: A total of 19 studies involving 483 patients were included. One study was classified as Level 2 evidence, ten as Level 3, and eight as Level 4. The mean MINORS score was 13.05±3.47. The primary indication for open reduction was failed closed reduction, observed in 46% of patients. 97.7% and 98.6% of patients achieved Flynn's functional and cosmetic satisfactory results, respectively. The postsurgical neurovascular injury rate was 1.4%. One patient required reintervention. CONCLUSION: The anterior approach is safe and effective for managing pediatric supracondylar humerus fractures requiring open reduction. LEVEL OF EVIDENCE: Systematic review of Level 2-4 evidence studies.

[Translated article] Risk of venous thromboembolism in thromboprophylaxis between aspirin and low molecular weight heparins after total hip arthroplasty or total knee arthroplasty: Systematic review and meta-analysis.

INTRODUCTION: The aim of this study was to evaluate the efficacy of aspirin versus low molecular weight heparins (LMWH) for the prophylaxis of venous thromboembolism (VTE), deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients undergoing total knee arthroplasty (TKA) and/or total hip arthroplasty (THA). MATERIALS AND METHODS: Systematic review and meta-analysis. Sixteen studies were selected. The risk of VTE, DVT and PE were analysed. Mortality, risk of bleeding and surgical wound complications was also analysed. RESULTS: 248,461 patients were included. 176,406 patients with thromboprophylaxis with LMWH and 72,055 patients with aspirin thromboprophylaxis. There were no significant differences in the risk of VTE (OR=0.93; 95% CI: 0.69-1.26; p=0.64), DVT (OR=0.72; 95% CI: 0.43-1.20; p=0.21) or PE (OR=1.13; 95% CI: 0.86-1.49; p=0.38) between both groups. No significant differences were found in mortality (p=0.30), bleeding (p=0.22), or complications in the surgical wound (p=0.85) between both groups. These same findings were found in the sub-analysis of only randomised clinical trials (p>0.05). CONCLUSIONS: No increased risk of PE, DVT, or VTE was found among patients with aspirin thromboprophylaxis versus patients with LMWH thromboprophylaxis. There was also no greater mortality, greater bleeding, or greater complications in the surgical wound found among patients with aspirin thromboprophylaxis versus patients with LMWH thromboprophylaxis.

Arthroscopic rotator cuff repair using a single or double row technique: A meta-analysis of randomized clinical trial. / Reparación artroscópica del manguito rotador mediante una técnica de hilera simple o doble hilera: un metaanálisis de los ensayos clínicos aleatorizados.

PURPOSE: To compare the double row technique versus the single row technique for arthroscopic rotator cuff repair, in order to assess whether there are clinical differences. METHODS: Systematic review of randomized clinical trials comparing the clinical results of the double-row technique versus the single-row technique in arthroscopic rotator cuff repair. Demographic, clinical, and surgical variables were analyzed, including functional scores, tendon healing rate, and re-tear rate. RESULTS: Thirteen randomized clinical trials were selected. 437 patients in the single row group (50.7%) and 424 patients in the double row group (49.3%) were analyzed. No significant differences were found between the two groups in terms of age (P=.84), sex (P=.23) and loss to follow-up (P=.52). Significant differences were found for the better results of the double row technique at the UCLA level (P=.01). No significant differences were found on the Constant-Murley scale (P=.87) or on the ASES scale (P=.56). Similarly, there was a higher healing rate (P=.006) and less risk of rotator cuff re-tears with the double row technique (P=.006). CONCLUSIONS: In rotator cuff repair, the double row technique was found to be superior to the single row technique in terms of better UCLA score, better tendon healing rate, and lower re-tear rate. No clinically significant differences were found on the Constant-Murley scale or on the ASES scale.

Total hip arthroplasty associated with transverse subtrochanteric shortening osteotomy and conical stem fixation in Crowe type IV hip dysplasia.

PURPOSE: Total hip arthroplasty (THA) in high-dislocated hip dysplasia is a surgical challenge, presenting difficulties in the biomechanical reconstruction of the hip. The purpose of the present study is to analyze clinical and radiological outcomes of a series of patients with Crowe type IV hip dysplasia who underwent a THA with transverse subtrochanteric shortening osteotomy and conical stem fixation in our Hip surgery unit. METHODS: This non-interventional retrospective study included all patients diagnosed with Crowe type IV hip dysplasia who underwent a THA using a subtrochanteric shortening osteotomy and uncemented conical stem fixation between January 1, 2008, and December 31, 2015. Demographic, clinical and radiologic data were analyzed, including Harris Hip Score and Oxford Hip Score. RESULTS: Seventeen hips in 13 patients were included in the final analysis. All patients were women and mean age was 39 years (range 35-45). Mean follow-up was 5.6 years (range 1-8). Average length of the osteotomy was 3.4 cm (range 3-4.5) and mean lowering of the center of rotation was 5.67 cm (range 3.8-9.1). Mean time for bone union was 5.5 months. No nerve palsy or non-union was detected at the end of follow-up period. CONCLUSION: The use of cementless conical stem fixation associated with a transverse subtrochanteric shortening osteotomy for treating Crowe type IV hip dysplasia permits to correct the rotational alterations of the femur and provides good stability of the osteotomy, with very low risk of nerve palsy and non-union rates.

Proyecto PREVENCOT: ¿Seguimos las recomendaciones internacionales para la prevención de la infección del sitio quirúrgico en cirugía ortopédica programada? / PREVENCOT project: Do we follow international guidelines to prevent surgical site infection in orthopedic elective surgery?

Antecedentes y objetivo: La prevención de las infecciones postoperatorias en el sitio quirúrgico es realmente factible. El objetivo de este trabajo es analizar la adhesividad a las guías internacionales para la prevención de las infecciones en cirugía ortopédica protésica electiva a través de una encuesta sobre una muestra representativa de cirujanos ortopédicos españoles, con el fin de establecer unas recomendaciones generales. Material y método: Se realiza una encuesta poblacional en formato online compuesta por 78 preguntas para analizar la práctica clínica habitual de los cirujanos ortopédicos españoles ante las infecciones periprotésicas de cadera y rodilla, y la adhesividad de los mismos a las guías internacionales. Resultados: Los resultados de la encuesta (n=138) muestran que en práctica clínica existe una alta adhesividad de los cirujanos ortopédicos españoles a la mayoría de las recomendaciones internacionales. Conclusiones: La integración de la práctica clínica individual con la mejor evidencia científica disponible a partir de las recomendaciones de las guías internacionales es la mejor vía para el manejo adecuado de la prevención de infección periprotésica en cirugía electiva.(AU)

Background and objective: Prevention of postoperative surgical site infections is indeed feasible. The aim of this work is to analyses adherence to international guidelines for the prevention of infections in elective orthopedic prosthetic surgery by means of a survey of a representative sample of Spanish orthopedic surgeons, with the purpose to establish general recommendations. Material and method: A population survey was conducted in online format consisting of 78 questions to analyze the usual clinical practice of Spanish orthopedic surgeons in the face of periprosthetic infections of the hip and knee, and their adherence to international guidelines. Results: The results of the survey (n=138) show in clinical practice of Spanish orthopedic surgeons a high adherence to most of the international recommendations. Conclusions: The integration high adherence of individual clinical practice with the best available scientific evidence based on the recommendations of international guidelines is the best way to adequately manage the prevention of periprosthetic infection in elective surgery.(AU)

PREVENCOT project: Do we follow international guidelines to prevent surgical site infection in orthopaedic elective surgery? / Proyecto PREVENCOT: ¿Seguimos las recomendaciones internacionales para la prevención de la infección del sitio quirúrgico en cirugía ortopédica programada?

Background and objective: Prevention of postoperative surgical site infections is indeed feasible. The aim of this work is to analyses adherence to international guidelines for the prevention of infections in elective orthopedic prosthetic surgery by means of a survey of a representative sample of Spanish orthopedic surgeons, with the purpose to establish general recommendations. Material and method: A population survey was conducted in online format consisting of 78 questions to analyze the usual clinical practice of Spanish orthopedic surgeons in the face of periprosthetic infections of the hip and knee, and their adherence to international guidelines. Results: The results of the survey (n=138) show in clinical practice of Spanish orthopedic surgeons a high adherence to most of the international recommendations. Conclusions: The integration high adherence of individual clinical practice with the best available scientific evidence based on the recommendations of international guidelines is the best way to adequately manage the prevention of periprosthetic infection in elective surgery.(AU)

Antecedentes y objetivo: La prevención de las infecciones postoperatorias en el sitio quirúrgico es realmente factible. El objetivo de este trabajo es analizar la adhesividad a las guías internacionales para la prevención de las infecciones en cirugía ortopédica protésica electiva a través de una encuesta sobre una muestra representativa de cirujanos ortopédicos españoles, con el fin de establecer unas recomendaciones generales. Material y método: Se realiza una encuesta poblacional en formato online compuesta por 78 preguntas para analizar la práctica clínica habitual de los cirujanos ortopédicos españoles ante las infecciones periprotésicas de cadera y rodilla, y la adhesividad de los mismos a las guías internacionales. Resultados: Los resultados de la encuesta (n=138) muestran que en práctica clínica existe una alta adhesividad de los cirujanos ortopédicos españoles a la mayoría de las recomendaciones internacionales. Conclusiones: La integración de la práctica clínica individual con la mejor evidencia científica disponible a partir de las recomendaciones de las guías internacionales es la mejor vía para el manejo adecuado de la prevención de infección periprotésica en cirugía electiva.(AU)

PREVENCOT project: Do we follow international guidelines to prevent surgical site infection in orthopedic elective surgery? / Proyecto PREVENCOT: ¿Seguimos las recomendaciones internacionales para la prevención de la infección del sitio quirúrgico en cirugía ortopédica programada?

BACKGROUND AND OBJECTIVE: Prevention of postoperative surgical site infections is indeed feasible. The aim of this work is to analyses adherence to international guidelines for the prevention of infections in elective orthopedic prosthetic surgery by means of a survey of a representative sample of Spanish orthopedic surgeons, with the purpose to establish general recommendations. MATERIAL AND METHOD: A population survey was conducted in online format consisting of 78 questions to analyze the usual clinical practice of Spanish orthopedic surgeons in the face of periprosthetic infections of the hip and knee, and their adherence to international guidelines. RESULTS: The results of the survey (n=138) show in clinical practice of Spanish orthopedic surgeons a high adherence to most of the international recommendations. CONCLUSIONS: The integration high adherence of individual clinical practice with the best available scientific evidence based on the recommendations of international guidelines is the best way to adequately manage the prevention of periprosthetic infection in elective surgery.

Investigation of Radionuclide Migration at Sites Adjacent to the 30-km Exclusion Zone of the Chernobyl Nuclear Power Plant.

ABSTRACT: This paper reports the study of the vertical migration of radionuclides in soils at test sites adjacent to the 30-km Chernobyl Exclusion Zone. The results of this effort demonstrate that the migration processes for studied pollution occur similarly to the fuel fallout behavior at the vicinity of the Chernobyl Nuclear Power Plant (ChNPP) Unit 4. It was also observed that the main fallout component, 137Cs, originated from aerosol fallout and was bound in the surface layer. The authors determined a significant increase of 60Co, 94Nb, and 241Am radionuclide concentrations in soils near the ChNPP Unit 4 and suggested their appearance due to the installation of the New Safe Confinement. Niobium-94 activity is proposed as a marker for monitoring the "fresh" fallout in the Chernobyl Exclusion Zone.

Spectroscopy of Radiostrontium in Fuel Materials Retrieved from the Chernobyl Nuclear Power Plant.

ABSTRACT: Some basic methods of measuring radiostrontium activity by spectroscopic methods are considered in this study. These methods of assessing beta spectra and the characteristic radiation that accompanies the breakdown of radiostrontium are described. The sensitivity of these methods based on the assessments of beta spectra both after radiochemical procedures and without radiochemistry is presented. The objective of this paper is to review the spectroscopic procedures that have been developed and used to determine radiostrontium in various matrices; they are focused on modern methods. Samples of fuel particles of different origins, obtained from the Chernobyl Nuclear Power Plant Unit 4, were analyzed using the methods presented in this study.

Retrospective study of 16 acetabular fractures with involvement of the quadrilateral plate treated with an anterior intrapelvic modified Rives-Stoppa approach. / Estudio retrospectivo sobre 16 fracturas de acetábulo con afectación de la lámina cuadrilátera tratadas con un abordaje anterior intrapélvico de Rives-Stoppa modificado.

GOAL: To report our experience with the use of Stoppa approach for fractures of the acetabulum with quadrilateral plate involvement. MATERIAL AND METHOD: Retrospective study; level iv. All patients were operated in a third level trauma center. The surgical team was experienced in the management of pelvic fractures. Data about patients, injuries, treatment features and clinical and radiological results were collected. We performed a statistical analysis; both descriptive and analytical. RESULT: 16 patients integrated the sample. 15 suffered associated fracture patterns. Anatomical plates were used in 15. Four required extended approaches. Reduction was anatomical in 9. 7 suffered some complication, needing the additional surgical procedures in 4. The surgical site infection rate was particularly high, appearing in 3. DISCUSSION: Radiological results were within the previously reported. We had a high complication rate, particularly infection. This outcome may be influenced by the special complexity of our cases and the adaptation process to a new technique. CONCLUSSION: Using the Stoppa approach we achieved lots of good or anatomical reductions. However, is an exigent and not without complications technique.

Analisis comparativo del número de neurofilamentos en nervios isquiáticos de rata sometidos a neuropraxia tratadas con láser de baja intensidad y ultrasonido terapéutico / Comparative analysis of the number of neurofilaments in rat sciatic nerve undergoing neuropraxia treated by low-level laser and therapeutic ultrasound

Es habitual que tras una compresión nerviosa se aplique terapia, ya sea, a través de laser de baja intensidad (LBI) o ultrasonido (US). El objetivo de este trabajo fue determinar la efectividad de dichos tratamientos para reparar el citoesqueleto neuronal evaluando la variación en el número de neurofilamentos. Se realizó un diseño experimental, en el cual se utilizaron 30 ratas que fueron separadas en 6 grupos: 1- control sano; 2- control lesionado; 3- irradiado con LBI 2J/cm2; 4- irradiado con LBI 10 J/cm2; 5- irradiado con US 0,5W/cm2 y 6- irradiado con US 1W/cm2. Con excepción del grupo 1 los especímenes fueron anestesiados y se les realizó la compresión del nervio isquiático derecho utilizando una presión de 40N durante 45 segundos. Veinticuatro horas después de la compresión se inició la irradiación con LBI y US, según protocolo. En nuestra investigación constatamos que el incremento en el número de neurofilamentos se relacionó con la dosis aplicada de LBI y US. El valor medio de neurofilamentos/0,25 mm2 obtenidos en cada grupo fue: 1 - 128; 2 - 100; 3 - 156; 4 - 140; 5 - 100; 6 - 148. La aplicación de LBI de y de US terapéutico aumenta el número de neurofilamentos en nervios isquiáticos de rata sometidos a neuropraxia, siendo el LBI más eficaz en comparación al US. Se agrega que estas terapias para inducir la regeneración del nervio lesionado se relacionan al tipo de protocolo utilizado, lo que demuestra la necesidad de establecer la adecuada dosis de irradiación con el propósito de obtener la mejor respuesta terapéutica.

Therapy by low-level laser (LLL) or ultrasound (US) are commonly used as treatment after nerve crush. The aim of this study was to determine the effectiveness of such treatments to repair the neuronal cytoskeleton evaluating the variation in the number of neurofilaments. For this an experimental design was performed, which involved 30 rats divided into 6 groups: 1 - control healthy; 2 - control injured; 3 - irradiated by LLL 2 J/cm2; 4 - irradiated by LLL 10 J/cm2; 5 - irradiated by US 0.5 W/cm2 and 6 - irradiated by US 1W/cm2. With the exception of group 1 all specimens were anesthetized and underwent right sciatic nerve compression using 40N pressure for 45 seconds. Twenty-four hours after compression irradiation was started by LLL and US according protocol. In our research we found that the increase in the number of neurofilaments was related to the applied dose of LLL and US. The average value of neurofilaments / 0.25 mm2 obtained in each group was: 1 - 128; 2-100; 3-156; 4-140; 5-100; 6-148. We concluded that the application of LLL and therapeutic US increases the number of neurofilaments in rat sciatic nerve undergoing neuropraxia, with LLL being more effective compared to the US. Furthermore we concluded that the effectiveness of therapies to induce regeneration of injured nerve is related to the type of protocol used, demonstrating the need to establish an adequate radiation dose with the purpose of obtaining the best therapeutic response, thus achieving successful treatment.

Locating, quantifying and characterising radiation hazards in contaminated nuclear facilities using a novel passive non-electrical polymer based radiation imaging device.

This paper provides a summary of recent trials which took place at the US Department of Energy Oak Ridge National Laboratory (ORNL) during December 2010. The overall objective for the trials was to demonstrate that a newly developed technology could be used to locate, quantify and characterise the radiological hazards within two separate ORNL hot cells (B and C). The technology used, known as RadBall(®), is a novel, passive, non-electrical polymer based radiation detection device which provides a 3D visualisation of radiation from areas where effective measurements have not been previously possible due to lack of access. This is particularly useful in the nuclear industry prior to the decommissioning of facilities where the quantity, location and type of contamination are often unknown. For hot cell B, the primary objective of demonstrating that the technology could be used to locate, quantify and characterise three radiological sources was met with 100% success. Despite more challenging conditions in hot cell C, two sources were detected and accurately located. To summarise, the technology performed extremely well with regards to detecting and locating radiation sources and, despite the challenging conditions, moderately well when assessing the relative energy and intensity of those sources. Due to the technology's unique deployability, non-electrical nature and its directional awareness the technology shows significant promise for the future characterisation of radiation hazards prior to and during the decommissioning of contaminated nuclear facilities.

Environmental problems associated with decommissioning the Chernobyl Nuclear Power Plant Cooling Pond.

Decommissioning of nuclear power plants and other nuclear fuel cycle facilities associated with residual radioactive contamination of their territories is an imperative issue. Significant problems may result from decommissioning of cooling ponds with residual radioactive contamination. The Chernobyl Nuclear Power Plant (ChNPP) Cooling Pond is one of the largest self-contained water reservoirs in the Chernobyl region and Ukrainian and Belorussian Polesye region. The 1986 ChNPP Reactor Unit Number Four significantly contaminated the ChNPP Cooling Pond. The total radionuclide inventory in the ChNPP Cooling Pond bottom deposits are as follows: ¹³7Cs: 16.28 ± 2.59 TBq; 9°Sr: 2.4 ± 0.48 TBq; and ²³9+²4°Pu: 0.00518 ± 0.00148 TBq. The ChNPP Cooling Pond is inhabited by over 500 algae species and subspecies, over 200 invertebrate species, and 36 fish species. The total mass of the living organisms in the ChNPP Cooling Pond is estimated to range from about 60,000 to 100,000 tons. The territory adjacent to the ChNPP Cooling Pond attracts many birds and mammals (178 bird species and 47 mammal species were recorded in the Chernobyl Exclusion Zone). This article describes several options for the ChNPP Cooling Pond decommissioning and environmental problems associated with its decommissioning. The article also provides assessments of the existing and potential exposure doses for the shoreline biota. For the 2008 conditions, the estimated total dose rate values were 11.4 40 µGy h⁻¹ for amphibians, 6.3 µGy h⁻¹ for birds, 15.1 µGy h⁻¹ for mammals, and 10.3 µGy h⁻¹ for reptiles, with the recommended maximum dose rate being equal to 40 µGy h⁻¹. However, drying the ChNPP Cooling Pond may increase the exposure doses to 94.5 µGy h⁻¹ for amphibians, 95.2 µGy h⁻¹ for birds, 284.0 µGy h⁻¹ for mammals, and 847.0 µGy h⁻¹ for reptiles. All of these anticipated dose rates exceed the recommended values.

Tuberculosis transmission risk and infection control in a hospital emergency department in Lima, Peru.

BACKGROUND: Overcrowded emergency departments (EDs) are used by undiagnosed tuberculosis (TB) patients. TB infection control measures are seldom prioritized, making EDs potential foci of unrecognised nosocomial transmission. OBJECTIVE: To quantify TB infection risk among health care workers in an ED in a high TB-burden setting, Lima, Peru, and to evaluate TB infection control measures. METHODS: Consenting ED staff were tested for TB infection at baseline and after 1 year using the QuantiFERON-TB Gold In-Tube (QFT-G). In parallel, sputum for TB culture was requested from patients spending >2 h in the ED, irrespective of presenting complaint. Infection control measures were documented and room ventilation measured. RESULTS: Over 1 year, there were 2246 TB patient-hours of exposure in the ED from 153 different patients. At baseline, 56% of the 70 staff recruited were QFT-G-positive; 27 of 31 baseline-negatives consented to follow-up after 1 year, and eight (30%, all clinical staff) tested positive. Annual incidence of infection was 1730 per 100,000 population. TB infection control measures were sub-optimal, with no patient screening, no isolation rooms, inadequate ventilation and sporadic respirator use. CONCLUSIONS: ED staff were exposed to an unexpectedly large TB burden in the workplace, resulting in a high rate of TB infection. TB infection control should be prioritized in EDs, especially in high-prevalence settings.

Cirugía reconstructiva del aparato locomotor, nuevas técnicas y opciones terapéuticas / Reconstructive surgery of the locomotor apparatus: new techniques and therapeutic options

La aplicación de criterios tumorales en el tratamiento quirúrgico secuencial de las osteítis crónicas y seudoartrosis sépticas en forma de resecciones segmentarias origina amplios defectos óseos. Una vez controlado el proceso séptico, en un entorno estable y vascularizado, se procede a la reconstrucción en dichas lesiones mediante transporte óseo basado en la osteogénesis a distracción. A pesar de los buenos resultados obtenidos, los periodos de fijación externa y de curación son muy largos, 2,4 meses por centímetro reconstruido. Estos prolongados tratamientos motivan que haya un elevado número de complicaciones. Los avances en ingeniería tisular y regeneración ósea contribuyen con nuevas técnicas y opciones terapéuticas. La estimulación de la formación de hueso nuevo en la zona de distracción o en el punto de atraque del fragmento transportado puede minimizar las complicaciones asociadas a la larga duración del procedimiento. La utilización de un osteoinductor como BMP-7 origina en la práctica un aumento de la formación ósea y el nuevo hueso puede tener incrementadas sus propiedades biomecánicas (AU)

The application of oncologic criteria in the sequential surgical treatment of chronic osteomyelitis foci and septic pseudarthrosis, through segmental resections, produces extensive bone defects. Once the septic process is under control, in a stable and well vascularized atmosphere, we perform reconstruction of intercalary defects through bone transportation based on distraction osteogenesis. Despite the good results, the healing index and the time on ex-fi x are very long, about 10 weeks per centimeter rebuilt. These prolonged treatments lead to a large number of complications. Advances in tissue engineering and bone regeneration have led to new techniques and therapeutic options. Stimulation of new bone formation in the distraction area or in the “docking-site” can minimize the complications associated with the length of time required by the procedure. The use of an osteoinducer, such as BMP-7, increases new bone formation and may enhance its biomechanical properties (AU)

Initial experience with optical-CT scanning of RadBall Dosimeters.

The RadBall dosimeter is a novel device for providing 3-D information on the magnitude and distribution of contaminant sources of unknown radiation in a given hot cell, glovebox, or contaminated room. The device is presently under evaluation by the National Nuclear Lab (NNL, UK) and the Savannah River National Laboratory (SRNL, US), for application as a diagnostic device for such unknown contaminants in the nuclear industry. A critical component of the technique is imaging the dose distribution recorded in the RadBall using optical-CT scanning. Here we present our initial investigations using the Duke Mid-sized Optical-CT Scanner (DMOS) to image dose distributions deposited in RadBalls exposed to a variety of radiation treatments.

Initial investigation OF 222Rn in the Tbilisi urban environment.

Georgia has geological formations with high uranium content, and several buildings are built with local materials. This can create potentially high radon exposures. Consequently, studies to mitigate these exposures have been started. This study presents a preliminary investigation of radon in Tbilisi, the capital of Georgia. An independent radiological monitoring program in Georgia has been initiated by the Radiocarbon and Low-Level Counting Section of I. Javakhishvili Tbilisi State University with the cooperation of the Environmental Monitoring Laboratory of the Physics/Health Physics Department at Idaho State University. At this initial stage the E-PERM systems and GammaTRACER were used for the measurement of gamma exposure and radon concentrations in air and water. Measurements in Sololaki, a densely populated historic district of Tbilisi, revealed indoor radon (222Rn) concentrations of 1.5-2.5 times more than the U.S. Environmental Protection Agency action level of 148 Bq m(-3) (4 pCi L(-1)). Moreover, radon-in-air concentrations of 440 Bq m(-3) and 3,500 Bq m(-3) were observed at surface borehole openings within the residential district. Measurements of water from various tap water supplies displayed radon concentrations of 3-5 Bq L(-1) while radon concentrations in water from the hydrogeological and thermal water boreholes were 5-19 Bq L(-1). In addition, the background gamma absorbed dose rate in air ranged of 70-115 nGy h(-1) at the radon test locations throughout the Tbilisi urban environment.

Individual variations in mucosa and total wall thickness in the stomach and rectum assessed via endoscopic ultrasound.

Endoscopic ultrasound is a unique tool to acquire in vivo data on alimentary tract wall thicknesses of sufficient resolution needed in radiation dosimetry studies. Through their different echo texture and intensity, five layers of differing echo patterns for superficial mucosa, deep mucosa, submucosa, muscularis externa and serosa/adventitia exist within the walls of organs composing the alimentary tract. In this study, retrospective image analyses of patient video data were made for ten examinations of the stomach and eight examinations of the rectum covering a range of patient ages. Thicknesses for stomach mucosa ranged from 1030 +/- 130 microm to 1640 +/- 80 microm (total stomach wall thicknesses from 2.80 +/- 0.12 to 4.23 +/- 0.03 mm). Measurements made for the rectal images revealed rectal mucosal thicknesses from 660 +/- 50 microm to 1130 +/- 250 microm (total rectal wall thicknesses from 2.28 +/- 0.05 to 3.55 +/- 0.43 mm). The mucosa accounted for approximately 32 +/- 7% and approximately 32 +/- 8% of the total thickness of the stomach and rectal wall, respectively. These values can thus be utilized to investigate uncertainties in alimentary tract dosimetry that are based upon fixed reference individual definitions of organ wall structure.

Influences of parameter uncertainties within the ICRP 66 respiratory tract model: particle deposition.

Risk assessment associated with the inhalation of radioactive aerosols requires as an initial step the determination of particle deposition within the various anatomic regions of the respiratory tract. The model outlined in ICRP Publication 66 represents to date one of the most complete overall descriptions of not only particle deposition, but of particle clearance and local radiation dosimetry of lung tissues. In this study, a systematic review of the deposition component within the ICRP 66 respiratory tract model was conducted in which probability density functions were assigned to all input parameters. These distributions were subsequently incorporated within a computer code LUDUC (LUng Dose Uncertainty Code) in which Latin hypercube sampling techniques are used to generate multiple (e.g., 1,000) sets of input vectors (i.e., trials) for all of the model parameters needed to assess particle deposition within the extrathoracic (anterior and posterior), bronchial, bronchiolar, and alveolar-interstitial regions of the ICRP 66 respiratory tract model. Particle deposition values for the various trial simulations were shown to be well described by lognormal probability distributions. Geometric mean deposition fractions from LUDUC were found to be within approximately +/- 10% of the single-value estimates from the LUDEP computer code for each anatomic region and for particle diameters ranging from 0.001 to 50 microm. In all regions of the respiratory tract, LUDUC simulations for an adult male at light exertion show that uncertainties in particle deposition fractions are distributed only over a range of about a factor of approximately 2-4 for particle sizes between 0.005 to 0.2 microm. Below 0.005 microm, uncertainties increase only for deposition within the alveolar region. At particle sizes exceeding 1 microm, uncertainties in the deposition fraction within the extrathoracic regions are relatively small, but approach a factor of 20 for deposition in the bronchial region. Deposition fractions for particles above 1 microm become very uncertain within the deeper regions of the lungs (bronchiolar and alveolar-interstitial).