47 resultados para Prospective organ dose estimation
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Treatment strategies for relapsed/refractory AML are limited and disappointing. Recently, high-dose melphalan (HDM) chemotherapy and autologous hematopoietic SCT (HSCT) has been proposed for AML re-induction. We investigated the impact of HDM remission induction in highly advanced relapsed/refractory AML patients planned for allogeneic HSCT. A total of 23 patients with relapsed/refractory AML were prospectively scheduled for HDM with or without stem cell support followed by myeloablative allogeneic HSCT. Patients included nine individuals with a history of previous HSCT (seven allogeneic, two autologous). A total of 18 patients (78%) achieved a leukemia-free state and an additional four had substantial reduction of the initial leukemia burden warranting treatment continuation. There were no differences between patients with or without immediate stem cell support regarding mucositis or other organ toxicity. A total of 20 patients proceeded to myeloablative allogeneic HSCT. Outcome of allogeneic HSCT was poor: 11 patients (55%) relapsed, 7 patients (35%) died from TRM and only 2 patients (10%) were alive at the last follow-up. Our study shows that HDM is effective in inducing a leukemia-free state in patients with highly advanced relapsed/refractory AML. Leukemia burden reduction with HDM, however, did not translate into improved OS.
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AIM of this study was the assessment of the radiation exposure from preparation and application of (90)Y-Zevalin, the measurement of the dose rate at the patient, the exposure of family members as well as the determination of the activity concentration in urine of patients. METHODS: Overall data from 31 therapeutic administrations carried out in four institutions were evaluated. During preparation and application of (90)Y-Zevalin the finger exposures of radiochemists, technicians, and physicians were measured. The dose rate of the patient was measured immediately after radioimmunotherapy. In patients treated in a nuclear medicine therapy unit, urine was collected over a two day period and the corresponding activity was determined. Family members of outpatients were asked to wear a dosimeter over a seven day period. RESULTS: During the preparation we found a maximum skin dose of 6 mSv at the average, and during application of 3 mSv, respectively. After administration of (90)Y the dose rate was 0.4 +/- 0.1 microSv/h at 2 m distance. Urine measurements yielded a cumulated 24 h excretion of 3.9 +/- 1.4% and 4.4 +/- 1.4% within 48 h, respectively, that is equivalent to 43 +/- 18 and 50 +/- 20 MBq of (90)Y, respectively. Family members received a radiation exposure of 40 +/- 14 microSv over seven days. CONCLUSION: During preparation and application of (90)Y-Zevalin appropriate radiation shielding is necessary. For family members as well as nursing staff no additional special radiation protection measures beyond those being common for other nuclear medicine procedures are necessary.
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OBJECTIVE: The purpose of this study was to evaluate in a phantom study the effect of patient size on radiation dose for abdominal MDCT with automatic tube current modulation. MATERIALS AND METHODS: One or two 4-cm-thick circumferential layers of fat-equivalent material were added to the abdomen of an anthropomorphic phantom to simulate patients of three sizes: small (cross-sectional dimensions, 18 x 22 cm), average size (26 x 30 cm), and oversize (34 x 38 cm). Imaging was performed with a 64-MDCT scanner with combined z-axis and xy-axis tube current modulation according to two protocols: protocol A had a noise index of 12.5 H, and protocol B, 15.0 H. Radiation doses to three abdominal organs and the skin were assessed. Image noise also was measured. RESULTS: Despite increasing patient size, the image noise measured was similar for protocol A (range, 11.7-12.2 H) and protocol B (range, 13.9-14.8 H) (p > 0.05). With the two protocols, in comparison with the dose of the small patient, the abdominal organ doses of the average-sized patient and the oversized patient increased 161.5-190.6%and 426.9-528.1%, respectively (p < 0.001). The skin dose increased as much as 268.6% for the average-sized patient and 816.3% for the oversized patient compared with the small patient (p < 0.001). CONCLUSION: Oversized patients undergoing abdominal MDCT with tube current modulation receive significantly higher doses than do small patients. The noise index needs to be adjusted to the body habitus to ensure dose efficiency.
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Objective. The purpose of this study was to determine the dose profile of the Cranex Tome radiography unit and compare it with that of the Scanora machine.Study design. The radiation dose delivered by the Cranex Tome radiography unit during the cross-sectional mode was determined. Single tooth gaps in regions 3 (16) and 30 (46) were simulated. Dosimetry was carried out with 2 phantoms, a head and neck phantom and a full-body phantom loaded with 142 thermoluminescent dosimeters (TLD) and 280 TLD, respectively; all locations corresponded to radiosensitive organs or tissues. The recorded local mean organ doses were compared with those measured in another study evaluating the Scanora machine.Results. Generally, dose values from the Cranex Tome radiography unit reached only 50% to 60% of the values measured for the Scanora machine. The effective dose was calculated as 0.061 mSv and 0.04 mSv for tooth regions 3 (16) and 30 (46), respectively. Corresponding values for the Scanora machine were 0.117 mSv and 0.084 mSv.Conclusion. Cross-sectional imaging in the molar region of the upper and the lower jaw can be performed with the Cranex Tome unit, which delivers only approximately half of the dose that the Scanora machine delivers.
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STUDY DESIGN: A prospective case control study design was conducted. OBJECTIVES: The purpose of the current study was to determine the intraoperative radiation hazard to spine surgeons by occupational radiation exposure during percutaneous vertebroplasty and possible consequences with respect to radiation protection. SUMMARY OF BACKGROUND DATA: The development of minimally invasive surgery techniques has led to an increasing number of fluoroscopically guided procedures being done percutaneously such as vertebroplasty, which is the percutaneous cement augmentation of vertebral bodies. METHODS: Three months of occupational dose data for two spine surgeons was evaluated measuring the radiation doses to the thyroid gland, the upper extremities, and the eyes during vertebroplasty. RESULTS: The annual risk of developing a fatal cancer of the thyroid is 0.0025%, which means a very small to small risk. The annual morbidity (the risk of developing a cancer including nonfatal ones) is 0.025%, which already means a small to medium risk. The dose for the eye lens was about 8% of the threshold dose to develop a radiation induced cataract (150 mSv); therefore, the risk is very low but not negligible. The doses measured for the skin are 10% of the annual effective dose limit (500 mSv) recommended by the ICRP (International Commission on Radiologic Protection); therefore, the annual risk for developing a fatal skin cancer is very low. CONCLUSION: While performing percutaneous vertebroplasty, the surgeon is exposed to a significant amount of radiation. Proper surgical technique and shielding devices to decrease potentially high morbidity are mandatory. Training in radiation protection should be an integral part of the education for all surgeons using minimally invasive radiologic-guided interventional techniques.
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AIM: This study was conducted to delineate partnership-relation functioning over time and specifically matched to various organs such as heart, liver, and kidney. METHOD: Prospective, paralleled case-control-study including patients and their respective partners before and one year after organ transplantation in 23 heart-transplant recipients, 19 liver-transplant patients, and 16 kidney-transplant recipients. To assess partnership functioning, the FB-Z (family assessment measure) of Cierpka and Frevert was used. Statistics included descriptive methods, correlations, and analysis of variance including the items "organ" and "time". RESULTS: Heart-transplant recipients and their partners show significant better overall measures in their partnership ratings (sum-value) in comparison to liver or kidney patients and their partners. In all patient and partner groups, except in kidney-transplant recipients a significant deterioration over time is discernible in the subscales role performance and emotionality. In respect to the item "organ" significant differences were found in overall functioning and the subscale communication where heart-transplant recipients and their partners have significant better functioning compared to kidney or liver transplant patients. In kidney patients and their partners only communication changes to the better in the time course. CONCLUSION: In any organ transplantation the two sides of the coin are important to bear in mind, the one is the live-saving act of transplantation as such, the other is the important distress in the phase before but equally after the operation, mainly in the first year where patients and their respective partners have to be followed and treated even in respect to psychosocial and marital functioning.
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BACKGROUND: Seven prospective studies including 193 patients have been published on high-dose intravenous corticosteroid pulse therapy in alopecia areata (AA).We compare these data with a retrospective analysis of our own consecutive patients. PATIENTS AND METHODS: Between 1998 and 2002,25 patients with severe AA were treated at the Department of Dermatology, University of Bern, with infusions of 500 mg methylprednisolone on 3 consecutive days.In addition to the inpatient records, in 2004 all patients were followed up by a questionnaire. RESULTS: Four of 10 patients with multifocal AA and 3 of 9 patients with ophiasis-type AA had full re-growth of hair, whereas all 6 patients with AA totalis/universalis failed to respond. CONCLUSION: Intravenous corticosteroid pulse therapy may be helpful in the treatment of multifocal and ophiasis-type AA. Patients with an initial episode of short duration have better chances for success.
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OBJECTIVE: To evaluate quality of life and pelvic organ and sexual function before and during pessary use in patients with symptomatic pelvic organ prolapse and to determine reasons which lead to cessation of pessary use. DESIGN: Prospective observational study. SETTING: Tertiary referral center. PATIENT(S): Patients with symptomatic stage II or more prolapse of the anterior, posterior, or apical vaginal wall with or without uterus were included in this study. INTERVENTION(S): We used the Female Sexual Function Index questionnaire and the Sheffield prolapse questionnaire. For quality of life we used the King's Health Questionnaire. MAIN OUTCOME MEASURE(S): Main outcome measures were quality of life and sexual and pelvic organ function. RESULT(S): A total of 73 women participated in this study; 31 were sexually active. Desire, lubrication, and sexual satisfaction showed statistically significant improvement, and orgasm remained unchanged. Statistically significant improvement in the feeling of bulge occurred during therapy, stool outlet problems were significantly improved, overactive bladder symptoms were significantly better, and pessaries did not significantly alter incontinence. CONCLUSION(S): Pessaries have been shown to be a viable noninvasive treatment for pelvic organ prolapse improving organ and sexual function as well as general wellbeing.
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OBJECTIVES: Various imaging techniques, including conventional radiography and computed tomography, are proposed to localize the mandibular canal prior to implant surgery. The aim of this study is to determine the incidence of altered mental nerve sensation after implant placement in the posterior segment of the mandible when a panoramic radiograph is the only preoperative imaging technique used. MATERIAL AND METHODS: The study included 1527 partially and totally edentulous patients who had consecutively received 2584 implants in the posterior segment of the mandible. Preoperative bone height was evaluated from the top of the alveolar crest to the superior border of the mandibular canal on a standard panoramic radiograph. A graduated implant scale from the implant manufacturer was used and 2 mm were subtracted as a safety margin to determine the length of the implant to be inserted. RESULTS: No permanent sensory disturbances of the inferior alveolar nerve were observed. There were two cases of postoperative paresthesia, representing 2/2584 (0.08%) of implants inserted in the posterior segment of the mandible or 2/1527 (0.13%) of patients. These sensory disturbances were minor, lasted for 3 and 6 weeks and resolved spontaneously. CONCLUSIONS: Panoramic examination can be considered a safe preoperative evaluation procedure for routine posterior mandibular implant placement. Panoramic radiography is a quick, simple, low-cost and low-dose presurgical diagnostic tool. When a safety margin of at least 2 mm above the mandibular canal is respected, panoramic radiography appears to be sufficient to evaluate available bone height prior to insertion of posterior mandibular implants; cross-sectional imaging techniques may not be necessary.
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OBJECTIVE: To investigate the effect of plasma concentrations obtained by a low dose constant rate infusion (CRI) of racemic ketamine or S-ketamine on the nociceptive withdrawal reflex (NWR) in standing ponies. STUDY DESIGN: Prospective, blinded, cross-over study. ANIMALS: Six healthy 5-year-old Shetland ponies. METHODS: Ponies received either 0.6 mg kg(-1) racemic ketamine (group RS) or 0.3 mg kg(-1) S-ketamine (group S) intravenously (IV), followed by a CRI of 20 microg kg(-1)minute(-1) racemic ketamine (group RS) or 10 microg kg(-1)minute(-1) S-ketamine (group S) for 59 minutes. The NWR was evoked by transcutaneous electrical stimulation of a peripheral nerve before drug administration, 15 and 45 minutes after the start of the bolus injection and 15 minutes after the end of the CRI. Electromyographic responses were recorded and analysed. Arterial blood was collected before stimulation and plasma concentrations of ketamine and norketamine were measured enantioselectively using capillary electrophoresis. Ponies were video recorded and monitored to assess drug effects on behaviour, heart rate (HR), mean arterial blood pressure (MAP) and respiratory rate. RESULTS: The NWR was significantly depressed in group RS at plasma concentrations between 20 and 25 ng mL(-1) of each enantiomer. In group S, no significant NWR depression could be observed; plasma concentrations of S-ketamine (9-15 ng mL(-1)) were lower, compared to S-ketamine concentrations in group RS, although this difference was not statistically significant. Minor changes in behaviour, HR and MAP only occurred within the first 5-10 minutes after bolus drug administration in both groups. CONCLUSION: Antinociceptive activity in standing ponies, demonstrated as a depression of the NWR, could only be detected after treatment with racemic ketamine. S-ketamine may have lacked this effect as a result of lower plasma concentrations, a more rapid metabolism or a lower potency of S-ketamine in Equidae so further investigation is necessary.
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INTRODUCTION: To report acute and late toxicities in patients with intermediate- and high-risk prostate cancer treated with combined high-dose-rate brachytherapy (HDR-B) and intensity-modulated radiation therapy (IMRT). MATERIALS AND METHODS: From March 2003 to September 2005, 64 men were treated with a single implant HDR-B with 21 Gy given in three fractions, followed by 50 Gy IMRT along with organ tracking. Median age was 66.1 years, and risk of recurrence was intermediate in 47% of the patients or high in 53% of the patients. Androgen deprivation therapy was received by 69% of the patients. Toxicity was scored according to the CTCAE version 3.0. Median follow-up was 3.1 years. RESULTS: Acute grade 3 genitourinary (GU) toxicity was observed in 7.8% of the patients, and late grades 3 and 4 GU toxicity was observed in 10.9% and 1.6% of the patients. Acute grade 3 gastrointestinal (GI) toxicity was experienced by 1.6% of the patients, and late grade 3 GI toxicity was absent. The urethral V(120) (urethral volume receiving > or =120% of the prescribed HDR-B dose) was associated with acute (P=.047) and late > or = grade 2 GU toxicities (P=.049). CONCLUSIONS: Late grades 3 and 4GU toxicity occurred in 10.9% and 1.6% of the patients after HDR-B followed by IMRT in association with the irradiated urethral volume. The impact of V(120) on GU toxicity should be validated in further studies.
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RATIONALE AND OBJECTIVES: The aim of this study was to measure the radiation dose of dual-energy and single-energy multidetector computed tomographic (CT) imaging using adult liver, renal, and aortic imaging protocols. MATERIALS AND METHODS: Dual-energy CT (DECT) imaging was performed on a conventional 64-detector CT scanner using a software upgrade (Volume Dual Energy) at tube voltages of 140 and 80 kVp (with tube currents of 385 and 675 mA, respectively), with a 0.8-second gantry revolution time in axial mode. Parameters for single-energy CT (SECT) imaging were a tube voltage of 140 kVp, a tube current of 385 mA, a 0.5-second gantry revolution time, helical mode, and pitch of 1.375:1. The volume CT dose index (CTDI(vol)) value displayed on the console for each scan was recorded. Organ doses were measured using metal oxide semiconductor field-effect transistor technology. Effective dose was calculated as the sum of 20 organ doses multiplied by a weighting factor found in International Commission on Radiological Protection Publication 60. Radiation dose saving with virtual noncontrast imaging reconstruction was also determined. RESULTS: The CTDI(vol) values were 49.4 mGy for DECT imaging and 16.2 mGy for SECT imaging. Effective dose ranged from 22.5 to 36.4 mSv for DECT imaging and from 9.4 to 13.8 mSv for SECT imaging. Virtual noncontrast imaging reconstruction reduced the total effective dose of multiphase DECT imaging by 19% to 28%. CONCLUSION: Using the current Volume Dual Energy software, radiation doses with DECT imaging were higher than those with SECT imaging. Substantial radiation dose savings are possible with DECT imaging if virtual noncontrast imaging reconstruction replaces precontrast imaging.
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OBJECTIVE: To determine if neurally adjusted ventilatory assist (NAVA) that delivers pressure in proportion to diaphragm electrical activity is as protective to acutely injured lungs (ALI) and non-pulmonary organs as volume controlled (VC), low tidal volume (Vt), high positive end-expiratory pressure (PEEP) ventilation. DESIGN: Prospective, randomized, laboratory animal study. SUBJECTS: Twenty-seven male New Zealand white rabbits. INTERVENTIONS: Anesthetized rabbits with hydrochloric acid-induced ALI were randomized (n = 9 per group) to 5.5 h NAVA (non-paralyzed), VC (paralyzed; Vt 6-ml/kg), or VC (paralyzed; Vt 15-ml/kg). PEEP was adjusted to hemodynamic goals in NAVA and VC6-ml/kg, and was 1 cmH2O in VC15-ml/kg. MEASUREMENTS AND MAIN RESULTS: PaO2/FiO2; lung wet-to-dry ratio; lung histology; interleukin-8 (IL-8) concentrations in broncho-alveolar-lavage (BAL) fluid, plasma, and non-pulmonary organs; plasminogen activator inhibitor type-1 and tissue factor in BAL fluid and plasma; non-pulmonary organ apoptosis rate; creatinine clearance; echocardiography. PEEP was similar in NAVA and VC6-ml/kg. During NAVA, Vt was lower (3.1 +/- 0.9 ml/kg), whereas PaO2/ FiO2, respiratory rate, and PaCO2 were higher compared to VC6-ml/kg (p<0.05 for all). Variables assessing ventilator-induced lung injury (VILI), IL-8 levels, non-pulmonary organ apoptosis rate, and kidney as well as cardiac performance were similar in NAVA compared to VC6-ml/kg. VILI and non-pulmonary organ dysfunction was attenuated in both groups compared to VC15-ml/kg. CONCLUSIONS: In anesthetized rabbits with early experimental ALI, NAVA is as effective as VC6-ml/kg in preventing VILI, in attenuating excessive systemic and remote organ inflammation, and in preserving cardiac and kidney function.
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INTRODUCTION: The inflammatory response to an invading pathogen in sepsis leads to complex alterations in hemostasis by dysregulation of procoagulant and anticoagulant factors. Recent treatment options to correct these abnormalities in patients with sepsis and organ dysfunction have yielded conflicting results. Using thromboelastometry (ROTEM(R)), we assessed the course of hemostatic alterations in patients with sepsis and related these alterations to the severity of organ dysfunction. METHODS: This prospective cohort study included 30 consecutive critically ill patients with sepsis admitted to a 30-bed multidisciplinary intensive care unit (ICU). Hemostasis was analyzed with routine clotting tests as well as thromboelastometry every 12 hours for the first 48 hours, and at discharge from the ICU. Organ dysfunction was quantified using the Sequential Organ Failure Assessment (SOFA) score. RESULTS: Simplified Acute Physiology Score II and SOFA scores at ICU admission were 52 +/- 15 and 9 +/- 4, respectively. During the ICU stay the clotting time decreased from 65 +/- 8 seconds to 57 +/- 5 seconds (P = 0.021) and clot formation time (CFT) from 97 +/- 63 seconds to 63 +/- 31 seconds (P = 0.017), whereas maximal clot firmness (MCF) increased from 62 +/- 11 mm to 67 +/- 9 mm (P = 0.035). Classification by SOFA score revealed that CFT was slower (P = 0.017) and MCF weaker (P = 0.005) in patients with more severe organ failure (SOFA >or= 10, CFT 125 +/- 76 seconds, and MCF 57 +/- 11 mm) as compared with patients who had lower SOFA scores (SOFA <10, CFT 69 +/- 27, and MCF 68 +/- 8). Along with increasing coagulation factor activity, the initially increased International Normalized Ratio (INR) and prolonged activated partial thromboplastin time (aPTT) corrected over time. CONCLUSIONS: Key variables of ROTEM(R) remained within the reference ranges during the phase of critical illness in this cohort of patients with severe sepsis and septic shock without bleeding complications. Improved organ dysfunction upon discharge from the ICU was associated with shortened coagulation time, accelerated clot formation, and increased firmness of the formed blood clot when compared with values on admission. With increased severity of illness, changes of ROTEM(R) variables were more pronounced.
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BACKGROUND: The estimation of physiologic ability and surgical stress (E-PASS) has been used to produce a numerical estimate of expected mortality and morbidity after elective gastrointestinal surgery. The aim of this study was to validate E-PASS in a selected cohort of patients requiring liver resections (LR). METHODS: In this retrospective study, E-PASS predictor equations for morbidity and mortality were applied to the prospective data from 243 patients requiring LR. The observed rates were compared with predicted rates using Fisher's exact test. The discriminative capability of E-PASS was evaluated using receiver-operating characteristic (ROC) curve analysis. RESULTS: The observed and predicted overall mortality rates were both 3.3% and the morbidity rates were 31.3 and 26.9%, respectively. There was a significant difference in the comprehensive risk scores for deceased and surviving patients (p = 0.043). However, the scores for patients with or without complications were not significantly different (p = 0.120). Subsequent ROC curve analysis revealed a poor predictive accuracy for morbidity. CONCLUSIONS: The E-PASS score seems to effectively predict mortality in this specific group of patients but is a poor predictor of complications. A new modified logistic regression might be required for LR in order to better predict the postoperative outcome.