RESUMEN
This study aimed to determine: (a) the spatial patterns of hamstring activation during the Nordic hamstring exercise (NHE); (b) whether previously injured hamstrings display activation deficits during the NHE; and (c) whether previously injured hamstrings exhibit altered cross-sectional area (CSA). Ten healthy, recreationally active men with a history of unilateral hamstring strain injury underwent functional magnetic resonance imaging of their thighs before and after six sets of 10 repetitions of the NHE. Transverse (T2) relaxation times of all hamstring muscles [biceps femoris long head (BFlh); biceps femoris short head (BFsh); semitendinosus (ST); semimembranosus (SM)] were measured at rest and immediately after the NHE and CSA was measured at rest. For the uninjured limb, the ST's percentage increase in T2 with exercise was 16.8%, 15.8%, and 20.2% greater than the increases exhibited by the BFlh, BFsh, and SM, respectively (P < 0.002 for all). Previously injured hamstring muscles (n = 10) displayed significantly smaller increases in T2 post-exercise than the homonymous muscles in the uninjured contralateral limb (mean difference -7.2%, P = 0.001). No muscles displayed significant between-limb differences in CSA. During the NHE, the ST is preferentially activated and previously injured hamstring muscles display chronic activation deficits compared with uninjured contralateral muscles.
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Músculos Isquiosurales/lesiones , Músculos Isquiosurales/fisiopatología , Esguinces y Distensiones/fisiopatología , Adolescente , Adulto , Estudios Transversales , Ejercicio Físico/fisiología , Prueba de Esfuerzo , Músculos Isquiosurales/diagnóstico por imagen , Músculos Isquiosurales/patología , Humanos , Imagen por Resonancia Magnética , Masculino , Contracción Muscular , Relajación Muscular , Tamaño de los Órganos , Adulto JovenRESUMEN
Biopsies of metastatic tissue are increasingly being performed. Bone is the most frequent site of metastasis in breast cancer patients, but bone remains technically challenging to biopsy. Difficulties with both tissue acquisition and techniques for analysis of hormone receptor status are well described. Bone biopsies can be carried out by either by standard posterior iliac crest bone marrow trephine/aspiration or CT-guided biopsy of a radiologically evident bone metastasis. The differential yield of these techniques is unknown. Results from three prospective studies of similar methodology were pooled. Patients underwent both an outpatient posterior iliac crest bone marrow trephine/aspiration and a CT-guided biopsy of a radiologically evident bone metastasis. Samples were assessed for the presence of malignant cells and where possible also for estrogen (ER) and progesterone receptor (PgR) expression. 40 patients were enrolled. Bone marrow aspiration/trephine biopsy was completed in 39/40 (97.5%) and CT-guided biopsy was completed in 34/40 (85%) of patients. Sufficient tumor cells for hormone receptor analysis were available in 19/39 (48.8%) and 16/34 (47%) of and bone marrow aspiration/trephine and CT-guided biopsies, respectively. Significant discordance in ER and PgR between the primary and the bone metastasis was also seen. Nine patients had tissue available from both bone marrow and CT-guided bone biopsies. ER and PgR concordance between these sites was 100 and 78%, respectively. Performing studies on human bone metastases is technically challenging, with relatively low yields regardless of technique. Given resource issues and similar success rates when comparing both techniques, bone marrow examination may be utilized first and if inadequate tissue is obtained, CT-guided biopsies can then be used.
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Biopsia con Aguja/métodos , Neoplasias Óseas/patología , Neoplasias Óseas/secundario , Neoplasias de la Mama/patología , Adulto , Anciano , Examen de la Médula Ósea , Neoplasias Óseas/metabolismo , Neoplasias de la Mama/metabolismo , Femenino , Humanos , Persona de Mediana Edad , Receptores de Estrógenos/metabolismo , Receptores de Progesterona/metabolismo , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: Doppler sonogram of the graft is used as a routine assessment in renal transplantation. When the resistance index (RI) equals 1, absent end-diastolic flow (AEDF) is observed; the prognostic value of AEDF is presently unknown. PATIENTS AND METHODS: Between 1988 and 1996, 342 patients received a first cadaveric kidney transplant in our ward. AEDF was observed in 30 patients who were compared with 60 controls who showed an RI < 0.75 within the first 7 days after transplantation. They were matched for year of transplantation (+/-1 year); recipient age (+/-2 years); recipient sex; and HLA antibodies (3 classes: 0%, 1-75%, >75%). The follow-up was 4 years. RESULTS: AEDF was observed at day 1 in 64%, at day 3 in 96%, and at day 7 in 28%. Recipient age, donor age, recipient sex, cold and warm ischemia durations, HLA A, B, and DR mismatches, and cytomegalovirus (CMV) status were not different between the 2 groups. Immediate graft function and 3- to 24-month creatinine levels were better in the control than the AEDF group. However, there was no difference in serum creatinine at 3 and 4 years or in patient and graft survivals during follow-up. CONCLUSIONS: AEDF observed within the first week following transplantation is associated with impaired renal functional recovery. However, whether AEDF is a prognostic marker of poor long-term graft function or survival remains to be proven.
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Diástole/fisiología , Trasplante de Riñón/fisiología , Flujometría por Láser-Doppler/métodos , Adulto , Cadáver , Creatinina/sangre , Diuresis , Femenino , Estudios de Seguimiento , Supervivencia de Injerto , Prueba de Histocompatibilidad , Humanos , Riñón/diagnóstico por imagen , Trasplante de Riñón/inmunología , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Retrospectivos , Factores de Tiempo , Donantes de Tejidos , Resultado del Tratamiento , Ultrasonografía , Adulto JovenRESUMEN
A number of factors interfere with the outcome of renal transplantation. Revealing genetic factors that impact on graft outcome may have consequences for clinical practice. Interleukin-12 (IL-12), by stimulating interferon gamma (IFNgamma) production, plays a crucial role in immune responses against both graft and viral agents. An A-to-C single nucleotide polymorphism (SNP) within the 3'-untranslated region (3'UTR) of the IL-12p40 gene has been reported to be both functionally and clinically relevant. Since the impact of this SNP on kidney graft outcome has never been reported, we investigated the impact of the 3'UTR polymorphism on clinical events after transplantation among 253 kidney recipients transplanted between 1995 and 2003. The polymorphism was genotyped using the restriction fragment length polymorphism method. Our results showed that the 3'UTR polymorphism affected neither graft survival (P = .768) nor the occurrence of delayed graft function (DGF; P = .498). C allele carriers in our study displayed more acute rejections in the first year than patients with the A/A genotype, but it did not reach statistical significance (P = .108). In contrast, the C allele appeared to be a significant risk factor for cytomegalovirus infection (odds ratio = 1.77; P = .027). In conclusion, IL12B 3'UTR polymorphism did not affect graft survival, DGF, or acute rejection episodes, but had an impact on the occurrence of cytomegalovirus infection.
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Subunidad p40 de la Interleucina-12/genética , Trasplante de Riñón/fisiología , Polimorfismo Genético , Polimorfismo de Nucleótido Simple , Regiones no Traducidas 3'/genética , Cadáver , Infecciones por Citomegalovirus/epidemiología , Infecciones por Citomegalovirus/genética , Genotipo , Rechazo de Injerto/epidemiología , Rechazo de Injerto/genética , Supervivencia de Injerto , Humanos , Factores de Riesgo , Donantes de Tejidos , Resultado del Tratamiento , Población BlancaRESUMEN
Risk factors for new-onset diabetes after transplantation (NODAT) need to be assessed in large cohorts. We retrospectively evaluated the impact of early (3 and 6 months after transplantation) proteinuria, urinary albumin excretion (UAE) and arterial pressure on NODAT in 828 Caucasian renal transplant recipients (median follow-up: 5.3 years; 5832 patient-years). The 10- and 20-year incidence of NODAT was 15.0% and 22.0%, respectively. Low-grade (<1 g/day) (HR: 2.04 [1.25-3.33], p = 0.0042) and very low-grade (<0.3 g/day) (HR: 2.21 [1.32-3.70], p = 0.0025) proteinuria were independent risk factors for NODAT. There was a dose-dependent relationship across UAE categories (increasing risk from normoalbuminuria to macroalbuminuria) with NODAT. Tacrolimus, sirolimus and beta-blockers (HR: 1.86 [1.07-3.22], p = 0.0277) were significantly associated with NODAT even after multiple adjustments, but not diuretics, angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers. Systolic arterial pressure (HR per 10 mmHg: 1.16 [1.03-1.29], p = 0.0126) and pulse pressure (HR: 1.26 [1.12-1.43], p = 0.0002) were associated with NODAT. Only pulse pressure remained significant after adjustments. Patients at highest risks had early proteinuria and pulse pressure >60 mmHg. Early low-grade proteinuria and pulse pressure (in addition to beta-blockers) constitute independent risk factors for NODAT; they may be markers of the metabolic syndrome and/or vascular damage in renal transplant recipients.
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Presión Sanguínea , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/fisiopatología , Proteinuria/fisiopatología , Adulto , Biomarcadores , Femenino , Supervivencia de Injerto , Humanos , Trasplante de Riñón , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Factores de TiempoRESUMEN
The measurement of the glomerular filtration rate (GFR) is an important tool for physicians to follow kidney transplant recipients. Indeed, renal function has been shown to be predictive of graft outcome in retrospective studies. Several methods have been proposed to measure GFR. In the present study we evaluated the correlation of GFR between a reference method (calculation through the urine to plasma ratio of creatinine [UV/P] formula) and three estimation equations (Cockcroft and Gault; Nankivell; modification of diet in renal disease) in 81 kidney transplant recipients at 3 and 12 months posttransplantation. We showed a significant correlation between the three predictive formulas and UV/P, but none of the predictive equations showed an excellent correlation. The best correlation between an estimation equation and the UV/P formula was the CG formula. Further studies are required to compare the estimated GFR with better reference methods, such as the use of isotopic markers in kidney graft recipients.
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Creatinina/metabolismo , Tasa de Filtración Glomerular , Trasplante de Riñón/fisiología , Humanos , Valor Predictivo de las Pruebas , Estudios RetrospectivosRESUMEN
BACKGROUND: Early proteinuria is associated with reduced long-term graft survival. However, the determinants and mechanisms of proteinuria early after transplantation have not been identified. METHODS: Parameters associated with proteinuria within the first 3 months following transplantation were retrospectively assessed among 484 renal transplant recipients. RESULTS: Proteinuria was more abundant in patients with a history of two or more rejection episodes (0.42 +/- 0.68 vs 0.18 +/- 0.39 g/d; P = .02). Proteinuria was greater when donor age was 60 or more (OR: 4.43; P = .003), when recipient death was due to cardiovascular causes (OR: 1.98; P = .002), or when cold (OR: 1.77; P = .006) or warm (1.21; P = .09) ischemia times were prolonged. CONCLUSIONS: Proteinuria early after transplantation was related to pretransplant renal lesions, ischemia-reperfusion, and immunologic injuries.
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Enfermedades del Sistema Inmune/orina , Trasplante de Riñón/inmunología , Trasplante de Riñón/patología , Proteinuria/etiología , Daño por Reperfusión/orina , Biomarcadores/orina , Creatinina/sangre , Humanos , Persona de Mediana EdadRESUMEN
We compared the influence of induction therapy on 5-year patient and graft survival as well as on renal function in 100 kidney graft recipients at low immunological risk treated with antilymphocyte globulin (n = 50) versus anti-IL-2R monoclonal antibody (n = 50) in a prospective multicenter study. Long-term immunosuppressive treatment included cyclosporine, mycophenolate mofetil, and a short course of steroids in all patients. Five year graft (86% vs 86%) and patient (94% vs 94%) survivals were identical in both study arms. Moreover, neither serum creatinine or proteinuria were significantly different between the two groups. Our results showed that the choice of the induction therapy seemed to not have a major impact on long-term outcomes among renal recipients at low immunological risk.
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Anticuerpos Monoclonales/inmunología , Suero Antilinfocítico/uso terapéutico , Supervivencia de Injerto/inmunología , Trasplante de Riñón/inmunología , Receptores de Interleucina-2/inmunología , Anticuerpos Monoclonales/uso terapéutico , Basiliximab , Humanos , Terapia de Inmunosupresión/métodos , Trasplante de Riñón/mortalidad , Proteínas Recombinantes de Fusión/uso terapéutico , Análisis de SupervivenciaRESUMEN
BACKGROUND: Uremic patients, especially those receiving regular hemodialysis (HD) treatment, are at high risk of oxidative damage by noxious free radicals and reactive oxygen species (ROS). The erythrocyte glutathione-defense system (GSH-DS) is one of the major enzymatic means of scavenging and detoxifying ROS. This study aimed to elucidate the effect of HD and dialyzer biocompatibility on erythrocyte GSH-DS in uremic patients on maintenance HD treatment. METHODS: Twenty-five healthy volunteers and 42 HD patients were enrolled in this study. Blood samples were drawn immediately before and after HD session, and erythrocyte glutathione (GSH) level as well as the activities of the enzymes glucose-6-phosphate dehydrogenase (G6PD), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-Rd), and glutathione S-transferase (GST) were measured. To evaluate the effect of dialyzer type on the studied parameters the patients were were subdivided into two groups: those who had dialysis with cuprophane (CU) membranes (n=23) and those who received dialysis with the aid of polysulfone (PS) membranes (n=19). RESULTS: The activities of G6PD and GSH-Px as well as GSH level were significantly decreased in HD patients as compared with controls. On the other hand, the activities of GSSG-Rd and GST were significantly elevated among HD patients in comparison with control values. A single HD session, regardless of the type of dialyzer, did not induce any significant effect on any of the measured parameters, although G6PD activity increased significantly after dialysis. CU membrane did not result in any change in GSH or its metabolizing enzymes, while PS dialyzers exerted a minor but significant restoration in GSH-DS. CONCLUSION: The antioxidant pool, as represented by GSH-DS, is significantly affected by dialyzer type in HD patients being significantly corrected with polysulfone dialyzer.
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Materiales Biocompatibles , Eritrocitos/metabolismo , Glutatión/sangre , Membranas Artificiales , Diálisis Renal , Adolescente , Adulto , Anciano , Estudios de Casos y Controles , Celulosa/análogos & derivados , Femenino , Glucosafosfato Deshidrogenasa/sangre , Glutatión Peroxidasa/sangre , Glutatión Reductasa/sangre , Glutatión Transferasa/sangre , Humanos , Masculino , Persona de Mediana Edad , Polímeros , SulfonasRESUMEN
INTRODUCTION: Cyclosporine is an immunosuppressive treatment whose side effects limit its usefulness. Among neurological side effects, neuropathies or myopathies have been reported, specially inpatients given combinations of cyclosporine with co-enzyme A reductase inhibitors. CASE REPORT: We report here the case of a 67-year-old woman who developed few months after a kidney graft sensorimotor disorders which progressed rapidly. Since all etiologies of such a disorder were ruled out, the hypothesis of toxicity exclusively induced by cyclosporine was suggested and confirmed by the improvement observed after its withdrawal. CONCLUSION: This observation highlights the fact that cyclosporine may induce neuromyopathies even when given alone at the therapeutic dosage.
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Ciclosporina/efectos adversos , Inmunosupresores/efectos adversos , Enfermedades Neuromusculares/inducido químicamente , Coenzima A/metabolismo , Electromiografía , Femenino , Rechazo de Injerto/complicaciones , Rechazo de Injerto/tratamiento farmacológico , Humanos , Trasplante de Riñón/inmunología , Persona de Mediana Edad , Fibras Nerviosas/patología , Conducción Nerviosa/efectos de los fármacos , Enfermedades Neuromusculares/patologíaRESUMEN
BACKGROUND: The aim of this study was to compare the efficacy and safety of induction treatment with antithymocyte globulins (ATG) followed by tacrolimus therapy with immediate tacrolimus therapy in renal transplant recipients. METHODS: This 12-month, open, prospective study was conducted in 15 centers in France and 1 center in Belgium; 309 patients were randomized to receive either induction therapy with ATG (n=151) followed by initiation of tacrolimus on day 9 or immediate tacrolimus-based triple therapy (n=158). In both study arms, the initial daily tacrolimus dose was 0.2 mg/kg. Steroid boluses were given in the first 2 days and tapered thereafter from 20 mg/day to 5 mg/day. Azathioprine was administered at 1-2 mg/kg per day. RESULTS: At month 12, biopsy-confirmed acute rejections were reported for 15.2% (induction) and 30.4% (noninduction) of patients (P=0.001). The incidence of steroid-sensitive acute rejections was 7.9% (induction) and 22.2% (noninduction)(P=0.001). Steroid-resistant acute rejections were reported for 8.6% (induction) and 8.9% (noninduction) of patients. A total of nine patients died. Patient survival and graft survival at month 12 was similar in both treatment groups (97.4% vs. 96.8% and 92.1% vs. 91.1%, respectively). Statistically significant differences in the incidence of adverse events were found for cytomegalovirus (CMV) infection (induction, 32.5% vs. noninduction, 19.0%, P=0.009), leukopenia (37.3% vs. 9.5%, P<0.001), fever (25.2% vs. 10.1%, P=0.001), herpes simplex (17.9% vs. 5.7%, P=0.001), and thrombocytopenia (11.3% vs. 3.2%, P=0.007). In the induction group, serum sickness was observed in 10.6% of patients. The incidence of new onset diabetes mellitus was 3.4% (induction) and 4.5% (noninduction). CONCLUSION: Low incidences of acute rejection were found in both treatment arms. Induction treatment with ATG has the advantage of a lower incidence of acute rejection, but it significantly increases adverse events, particularly CMV infection.
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Suero Antilinfocítico/uso terapéutico , Inmunosupresores/uso terapéutico , Trasplante de Riñón , Tacrolimus/uso terapéutico , Adulto , Resistencia a Medicamentos , Femenino , Rechazo de Injerto/tratamiento farmacológico , Rechazo de Injerto/epidemiología , Rechazo de Injerto/prevención & control , Supervivencia de Injerto , Humanos , Inmunosupresores/efectos adversos , Incidencia , Riñón/fisiopatología , Trasplante de Riñón/mortalidad , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Esteroides/uso terapéutico , Tacrolimus/efectos adversosRESUMEN
We assessed the long-term (M +/- SE: 68 +/- 3 months) arterial pressure and renal function of cadaveric kidney transplant recipients with and without significant (> 70% diameter reduction) transplant renal artery stenosis (TRAS) at angiography. Baseline clinical, immunological and outcome data for 26 patients with TRAS (incidence of TRAS: 6.6%) before and following angioplasty and 72 patients without stenosis at angiography were reviewed and analyzed. The 2 groups were similar with respect to recipient sex ratio and age (45 vs 46), duration of transplantation (7 months), cause of renal failure, donor sex and age, HLA-antigen mismatches and titers of anti-HLA antibodies, CMV infection and anti-CMV antibodies in donors and recipients. The technical success of angioplasty was 92.3%. Restenosis was documented in 6/26 patients (23.1%). Revascularization resulted in a decrease of arterial pressure and number of antihypertensive medications and a lower serum creatinine compared to baseline values. The long-term arterial pressure and serum creatinine levels were similar in patients with and without stenosis. In conclusion, TRAS after revascularization had no detectable influence on the long-term arterial pressure control and renal function within a follow-up period of 68 +/- 3 months.
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Angioplastia , Trasplante de Riñón/efectos adversos , Obstrucción de la Arteria Renal/etiología , Obstrucción de la Arteria Renal/terapia , Presión Sanguínea , Femenino , Estudios de Seguimiento , Humanos , Pruebas de Función Renal , Masculino , Persona de Mediana Edad , Obstrucción de la Arteria Renal/fisiopatologíaRESUMEN
UNLABELLED: Microalbuminuria (Malb: albuminuria: 30-299 mg/24 h) is associated with many cardiovascular parameters (high systolic (SAP) and diastolic (DAP) arterial pressure, total cholesterol, triglycerides, fasting glucose and body weight, low HDL-cholesterol) and may be a marker of cardiovascular and renal risk in the general population. Whether MAlb could be an integrated marker of cardiovascular and renal risk in transplant recipients is unknown. PATIENTS AND METHODS: 75 hypertensive non-proteinuric renal transplant recipients were selected. Antihypertensive medications were stopped for a month prior to the studies. MAlb (on a 24-hour urine collection), cyclosporine trough levels (CsA-L), fasting glucose and lipids were measured. SAP and DAP were determined with a semi-automatic device. RESULTS: 29 patients (12 W/17M) had normal levels of albuminuria (Nalb: albuminuria < 30 mg/24 h) and 46 had MAlb. As compared to Nalb patients, those with Malb were younger (M +/- SD: 44.3 +/- 13 vs 51.2 +/- 9.7 respectively, p = 0.009), had higher SAP (152 +/- 16 vs 146 +/- 15 mmHg, p = 0.09) et DAP (86 +/- 11 vs 81 +/- 10 mmHg, p = 0.01). No difference in smoking habits, serum creatinine (125 +/- 27 vs 119 +/- 28 mumol/L), total-, HDL- and LDL-cholesterol, triglycerides, fasting glucose, CsA-L (142 +/- 29 vs 144 +/- 26 ng/mL), 24 h-urine urea excretion was observed. History of acute rejection episodes (45.7% vs 17.2%, p = 0.01) was more frequent and 24-hour natriuresis (192 +/- 70 vs 152 +/- 79 mmol/24 h, p < 0.01) was higher in Malb than in Nalb. CONCLUSION: The determinants of microalbuminuria in renal transplant recipients are different from those found in the general population. History of acute rejection episodes was more frequent in renal transplant recipients with Malb than in those with NAlb despite similar renal function, suggesting that Malb may a marker of subclinical renal lesions due to immunological aggression. The relationship between natriuresis and Malb suggests that sodium intake modulates target-organ damage associated with hypertension.
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Albuminuria/etiología , Rechazo de Injerto , Hipertensión/complicaciones , Trasplante de Riñón , Sodio en la Dieta , Adulto , Albuminuria/patología , Biomarcadores/análisis , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de RiesgoRESUMEN
The skin test reactivities to various inhalant allergens in asthmatic children from two different regions in Saudi Arabia were compared. One hundred-twenty subjects each from the Central and Western regions, representing different environmental features, were selected. Prick test reactivity to 24 common allergens were analyzed and compared. Seventy-one (59.2%) patients from Riyadh (Central region) showed positive skin reactions to one or more allergens, while 87 (72.5%) reacted positively to different allergens from Makkah (Western region). The distribution of skin test sensitivity revealed striking differences in the two groups. The most prominent were reactions to the house dust mite (D. farinae) which amounted to 56.3% and to fungal allergens, 31.3% in asthmatics from the Western region, while reactions to the same allergens in subjects from the Central region were 10% and 5.8%, respectively. Similarly, marked variations were noted with pollen grain allergens with 9.3% in Central region and 15.4% in the Western region. The study indicates the presence of different allergen profiles in the two regions and suggests the influence of climatic and environmental factors and their impact on sensitization of susceptible subjects.
RESUMEN
OBJECTIVES: This study aims to demonstrate the effectiveness of leaded glasses in reducing the lens of eye dose and of lead thyroid collars in reducing the dose to the thyroid gland of an adult female from dental cone beam CT (CBCT). The effect of collimation on the radiation dose in head organs is also examined. METHODS: Dose measurements were conducted by placing optically stimulated luminescent dosemeters in an anthropomorphic female phantom. Eye lens dose was measured by placing a dosemeter on the anterior surface of the phantom eye location. All exposures were performed on one commercially available dental CBCT machine, using selected collimation and exposure techniques. Each scan technique was performed without any lead shielding and then repeated with lead shielding in place. To calculate the percent reduction from lead shielding, the dose measured with lead shielding was divided by the dose measured without lead shielding. The percent reduction from collimation was calculated by comparing the dose measured with collimation to the dose measured without collimation. RESULTS: The dose to the internal eye for one of the scans without leaded glasses or thyroid shield was 0.450 cGy and with glasses and thyroid shield was 0.116 cGy (a 74% reduction). The reduction to the lens of the eye was from 0.396 cGy to 0.153 cGy (a 61% reduction). Without glasses or thyroid shield, the thyroid dose was 0.158 cGy; and when both glasses and shield were used, the thyroid dose was reduced to 0.091 cGy (a 42% reduction). CONCLUSIONS: Collimation alone reduced the dose to the brain by up to 91%, with a similar reduction in other organs. Based on these data, leaded glasses, thyroid collars and collimation minimize the dose to organs outside the field of view.
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Tomografía Computarizada de Haz Cónico/métodos , Dispositivos de Protección de los Ojos , Plomo , Fantasmas de Imagen , Dosis de Radiación , Protección Radiológica/instrumentación , Glándula Tiroides , Adulto , Encéfalo/efectos de la radiación , Vértebras Cervicales/efectos de la radiación , Tomografía Computarizada de Haz Cónico/instrumentación , Ojo/efectos de la radiación , Femenino , Humanos , Cristalino/efectos de la radiación , Mandíbula/efectos de la radiación , Dosimetría con Luminiscencia Ópticamente Estimulada/instrumentación , Glándula Parótida/efectos de la radiación , Intensificación de Imagen Radiográfica/métodos , Cráneo/efectos de la radiación , Glándula Tiroides/efectos de la radiaciónRESUMEN
OBJECTIVE: In light of the increased recognition of the potential for lens opacification after low-dose radiation exposures, we investigated the effect of leaded eyeglasses worn during dental cone-beam computerized tomography (CBCT) procedures on the radiation absorbed dose to the eye and suggest simple methods to reduce risk of radiation cataract development. STUDY DESIGN: Dose measurements were conducted with the use of 3 anthropomorphic phantoms: male (Alderson radiation therapy phantom), female (CIRS), and juvenile male (CIRS). All exposures were performed on the same dental CBCT machine (Imtec, Ardmore, OK) using 2 different scanning techniques but with identical machine parameters (120 kVp, 3.8 mA, 7.8 s). Scans were performed with and without leaded glasses and repeated 3 times. All measurements were recorded using calibrated thermoluminescent dosimeters and optical luminescent dosimetry. RESULTS: Leaded glasses worn by adult and pediatric patients during CBCT scans may reduce radiation dose to the lens of the eye by as much as 67% (from 0.135 ± 0.004 mGy to 0.044 ± 0.002 mGy in pediatric patients). CONCLUSIONS: Leaded glasses do not appear to have a deleterious effect on the image quality in the area of clinical significance for dental imaging.