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Radiation Dose (radiation + dose)
Kinds of Radiation Dose Selected AbstractsAnticipation of Radiation Dose to the Conceptus from Occupational Exposure of Pregnant Staff During Fluoroscopically Guided Electrophysiological ProceduresJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2005JOHN DAMILAKIS Ph.D. Introduction: A female employee working in the electrophysiology suite has the right to know potential radiation hazards to the unborn child before she is pregnant or before she decides to formally declare her pregnancy. Moreover, the employer of a declared pregnant worker must evaluate the work situation and ensure that the conceptus dose is kept below the maximum permissible level during the remaining gestation period. The aim of this study was to develop a method for conceptus dose anticipation and determination of maximum workload allowed for the pregnant employee who participates in fluoroscopically guided electrophysiological procedures. Methods and Results: A C-arm fluoroscopy system, an anthropomorphic phantom, and a radiation meter were used to obtain scattered air kerma dose rates separately for each of the three fluoroscopic projections typically used in the electrophysiology suite. Air kerma to conceptus dose conversion factors for all trimesters of gestation were calculated using Monte Carlo simulation. A formula is presented for the anticipation of the conceptus dose from occupational exposure of pregnant staff during fluoroscopically guided electrophysiological procedures. Normalized data are provided for conceptus dose estimation from occupational exposure of pregnant staff working in any electrophysiology laboratory. A methodology for estimation of maximum workload allowed for each month of the remaining gestation period of a worker who declared her pregnancy is proposed, which ensures that the regulatory dose limits are not exceeded. Conclusion: Data presented may be used for the implementation of a radiation protection program designed for pregnant staff working in an electrophysiological suite. [source] Study of UV Radiation Dose Received by the Spanish PopulationPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2007Gonzalo Gurrea Excess exposure to UV radiation can affect our health by causing sunburn, skin cancer, etc. It is therefore useful to determine the UV dosage received by people as a way of protecting them from the possible negative effects that this kind of radiation can cause. In this work, the personal outdoor percentage, which shows the time spent in outdoor activities, as well as personal UV doses, has been calculated by means of global UV radiation on a horizontal plane. A database of average daily UVB radiation on the horizontal plane given by the National Institute of Meteorology has been used. In this work we evaluate the standard erythema dose of the Spanish population throughout the year. [source] Retinoblastoma: Review of 30 years' experience with external beam radiotherapyJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 3 2003Claire Phillips Summary A review of the experience at the Peter MacCallum Cancer Centre (Peter Mac), Melbourne, Australia in treating retinoblastoma with external beam radiotherapy was conducted. Outcomes of particular interest were tumour control, vision preservation and treatment late effects. The review was restricted to patients that had intact eyes treated at Peter Mac from 1965 until 1997 with at least 2 years of follow up. Histories were reviewed regarding patient and tumour characteristics and treatment details. Thirty-five patients were identified in whom 47 eyes were treated. Of the tumours, 47% were Reese,Ellsworth stage IV or V and the majority of others were at high risk for vision loss because of tumour location. The radiation treatment technique became increasingly sophisticated during the study period. Radiation dose and fraction size have similarly evolved but most patients received 30,50 Gy. Since 1989, a highly accurate contact lens immobilization technique has been used to deliver 40 Gy in 20 fractions. Thirteen eyes required additional local therapy. Of the treated eyes, 34 (72%) remain intact and 74% of these have useful vision. One patient died from retinoblastoma and three from second malignant neoplasms. With modern radiotherapy, late toxicities other than growth arrest and non-progressive cataract did not occur during the study period. Tumour control was high and a very acceptable rate of organ and vision preservation was achieved in a relatively high-risk population. Modern radiotherapy continues to develop in an attempt to improve treatment accuracy and minimize late radiation toxicity. [source] Radiation dose optimized lateral expansion of the field of view in synchrotron radiation X-ray tomographic microscopyJOURNAL OF SYNCHROTRON RADIATION, Issue 5 2010David Haberthür Volumetric data at micrometer level resolution can be acquired within a few minutes using synchrotron-radiation-based tomographic microscopy. The field of view along the rotation axis of the sample can easily be increased by stacking several tomograms, allowing the investigation of long and thin objects at high resolution. On the contrary, an extension of the field of view in the perpendicular direction is non-trivial. This paper presents an acquisition protocol which increases the field of view of the tomographic dataset perpendicular to its rotation axis. The acquisition protocol can be tuned as a function of the reconstruction quality and scanning time. Since the scanning time is proportional to the radiation dose imparted to the sample, this method can be used to increase the field of view of tomographic microscopy instruments while optimizing the radiation dose for radiation-sensitive samples and keeping the quality of the tomographic dataset on the required level. This approach, dubbed wide-field synchrotron radiation tomographic microscopy, can increase the lateral field of view up to five times. The method has been successfully applied for the three-dimensional imaging of entire rat lung acini with a diameter of 4.1,mm at a voxel size of 1.48,µm. [source] Management of patients treated with chemoradiotherapy for head and neck cancer without prophylactic feeding tubes: The University of Pittsburgh experienceTHE LARYNGOSCOPE, Issue 1 2010Brian T. McLaughlin MD Abstract Objectives/Hypothesis: Mucositis and dysphagia are common complications of chemoradiotherapy (CRT) for head and neck cancer that may necessitate nutritional support with a gastrostomy tube (G-tube). Methods: We reviewed records of patients who underwent and completed CRT, which included at least one traditional chemotherapeutic, for previously untreated head and neck cancer. G-tubes were placed as needed. The timing and duration of G-tube placement and treatment-related complications and risk factors for long-term G-tube use were analyzed. Results: A total of 91 consecutive patients who received CRT, 68 as primary and 23 as postoperative treatment, were studied. Radiation doses ranged from 59.4 to 74 Gy (median, 70 Gy). Seventy-nine percent of patients received platinum-based therapy during CRT. Severe mucositis occurred in 40% of patients. Forty percent of patients required G-tube placement (15 prior to CRT and 21 during CRT). Median duration of G-tube use was 5.8 months. Two patients who had a G-tube placed during CRT developed a G-tube-related complication. At 6 and 12 months, 15 (18%) and four (6%) patients who were disease free were using G-tubes, respectively. Patients with G-tubes placed prior to CRT or advanced T stage had longer G-tube dependence. Conclusions: With aggressive supportive care it is feasible to avoid G-tubes in the majority of patients undergoing CRT for head and neck cancer. G-tube placement prior to CRT due to pre-existing dysphagia and advanced T stage are associated with prolonged G-tube dependence. Laryngoscope, 2010 [source] Radiation doses to staff involved in sentinel node operations for breast cancerCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 4 2005T. L. Klausen Summary Background:, The use of radioactive compounds for sentinel node biopsy is now a generally accepted part of the surgical treatment of breast cancer and melanoma, with the risk of radiation exposure to the operating team. The aim of this investigation was to study the levels of this exposure in relation to the permissible radiation dose limits. Methods:, The radiation exposure to the hands and bodies of the operating surgeons (the ,risk persons') was measured by thermoluminescent dosemeters in 79 operations and to the pathologists handling the specimens in 17 cases. Radioactivity and dose rate measurement from tumours and breast specimens were also performed. Results:, During an operation the mean skin dose (±SD) to the thermoluminescent dosemeters placed at the hand and the abdominal wall were 0·04 ± 0·04 mSv (79 operations) and 0·01 ± 0·02 mSv (67 operations) respectively. For the pathologist, the mean hand dose per operation was below the detection limit (17 operations). Correlation between the measured dose rate and the radioactive content of the tumours was 0·998. Conclusions:, The radiation exposure to the staff involved in sentinel node (SN) biopsy for breast cancer using radioactive labelled tracers will be considerably below the permissible limits, even with high numbers of SN biopsy procedures. Pregnant staff members should participate in <100 SN operations. [source] Radiation-induced changes in oral carcinoma cells , a multiparametric evaluationCYTOPATHOLOGY, Issue 5 2003L. Bindu The aim of this study was to see whether serial cytological evaluation of various cellular abnormalities in tumours from patients receiving fractionated radiotherapy can predict radio-response in oral carcinoma. Cytological assessment was carried out in scrape smears collected prior to and during the course of radiotherapy in 68 patients with squamous cell carcinoma of the oral cavity planned for radical radiotherapy with accelerated fraction schedule. Smears were evaluated for a set of 15 radiation-induced cellular abnormalities. The relationship between the cellular alterations and the cumulative radiation dose was analysed by Kruskal,Wallis one-way anova. The results showed that among the various quantifiable changes that occur in irradiated cancer cells, karyolysis, karyorrhexis, pyknosis, cytolysis, multinucleation, micronucleation and nuclear budding show significant increase depending on the dose of radiation. The radio-resistant group of patients exhibited a lesser degree of change compared with the radio-sensitive group. This suggests that radio-resistance may be due to the defective induction of cell damage and that these cytological features may have potential use as predictive markers of radio-sensitivity in oral carcinoma. [source] Cancer risk from diagnostic radiology in a deliberate self-harm patientACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2010L. J. Norelli Norelli LJ, Coates AD, Kovasznay BM. Cancer risk from diagnostic radiology in a deliberate self-harm patient. Objective:, Patients who engage in recurrent deliberate self-harm (DSH) behaviours have increased morbidity and mortality and use emergency services more than others. Unrecognized iatrogenic injury may play a role. Specifically, we call attention to the potential danger of cumulative radiation exposure. Method:, Case presentation and discussion. Results:, A 29-year-old woman with multiple episodes of deliberate foreign body ingestion received over 400 diagnostic radiology examinations during a 12 year period. The patient's calculated total radiation dose reached an average of 20.5 mSv per year, a dose comparable to atomic bomb survivors and nuclear industry workers, populations in which there is a significant excess cancer risk. Conclusion:, Patients with recurrent self-injurious behaviours, frequent users of healthcare services who often undergo repeated medical assessment and treatment, are likely at higher risk for iatrogenic adverse events. Multiple diagnostic radiology examinations have recently come under scrutiny for causing increased lifetime risk of cancer. Healthcare providers, in particular psychiatrists and emergency department physicians, should consider the cumulative risks of radiological procedures when assessing and treating patients with DSH. [source] Positive impact of radiation dose on disease free survival and locoregional control in postoperative radiotherapy for squamous cell carcinoma of esophagusDISEASES OF THE ESOPHAGUS, Issue 4 2009S. Moon SUMMARY., The effect of total radiation dose (TRD) on the outcome of patients with postoperative radiotherapy (RT) for squamous cell carcinoma of esophagus was assessed. Sixty-seven patients with esophagectomy, followed by postoperative RT for squamous cell carcinoma of esophagus from June 1984 through February 2001, were retrospectively reviewed. Of these, 13 patients were excluded. No patient had chemotherapy. Patients were classified into two groups based on TRD delivered: TRD of less than 50 Gy (Group A, n = 16) and at least 50 Gy (Group B, n = 38). Follow-up duration of all patients ranged from 4 to 140 months (median, 14). Median TRD of Group A and B were 45 Gy (range, 45,48.6) and 54 Gy (range, 50,59.6), respectively. Median overall survival (OS) and disease-free survival (DFS) of all patients were 15 and 10 months, respectively. Although the TRD of 50 Gy or higher was marginally significant for improved OS (hazard ration [HR] 0.559, P = 0.066), it was statistically significant for improved DFS (HR 0.398, P = 0.011), and locoregional recurrence-free survival (HR 0.165, P = 0.001) with multivariate analysis. Three patients in group A and two in group B experienced a complication of grade 3 or higher. Our study suggests a positive impact of TRD of 50 Gy or higher on DFS and locoregional control, with acceptable morbidity in postoperative RT for patients with squamous cell carcinoma of esophagus. According to the present analysis, TRD should be at least 50 Gy in postoperative RT alone setting. [source] Impact of hemoglobin level on survival in definitive chemoradiotherapy for T4/M1 lymph node esophageal cancerDISEASES OF THE ESOPHAGUS, Issue 3 2008S. Zenda SUMMARY., We retrospectively investigated the impact of the pre-chemoradiotherapy hemoglobin level (pre-CRT Hb level) for T4 and/or M1 lymph node (LYM) squamous cell carcinoma of the esophagus. Chemotherapy consisted of protracted infusion with 5-fluorouracil (5-FU) at 400 mg/m2/day on days 1,5 and 8,12, combined with cisplatin at 40 mg/m2/day on days 1 and 8, repeated twice at a 5-week interval. Concurrent radiation therapy was started on day 1 and delivered at 2 Gy/day for five days a week for a total radiation dose of 60 Gy, with a two-week break after a cumulative dose of 30 Gy. Several factors considered to be related with treatment outcome were evaluated by univariate and multivariate analysis. A total of 48 patients with T4/M1 LYM (lymphocyte) esophageal cancer treated with chemoradiotherapy (CRT) between September 2002 and April 2005 were enrolled. The complete response rate to this regimen was 44% and median survival time was 13.6 months, with a median follow-up period of 26.8 months. Median pre-CRT Hb level was 13.5 (10.4,15.3) g/dL. The CR rate in patients with a pre-CRT Hb level of 13 g/dL or less was only 24% but it was 60% in those with a level that was more than 13 g/dL (P=0.01). As for survival, anovarevealed that a pre-CRT Hb of 13 g/dL or less was a significant prognostic factor with a hazard ratio of 0.45 (95% confidence interval [CI]); 0.21,0.97, P=0.04), while on manova, including performance status, tumor size, TNM stage and pre-CRT Hb level, a pre-CRT Hb level of 13 g/dL or less was the only significant prognostic factor, with a hazard ratio of 0.35 (95% CI; 0.13,0.90, P=0.03). In conclusion, the pre-CRT Hb level may be an important determinant of outcome in patients with T4/M1 LYM squamous cell carcinoma of the esophagus. [source] Chemoradiation therapy is effective for the palliative treatment of malignant dysphagiaDISEASES OF THE ESOPHAGUS, Issue 3 2004J. A. Harvey SUMMARY., Between 1993 and 2001, 106 patients with esophageal cancer were reviewed at a multidisciplinary clinic and treated with palliative intent by chemoradiation therapy. This study assesses the palliative benefit on dysphagia and documents the toxicity of this treatment. The study population comprised 72 men and 34 women with a median age of 69 years. Patients were treated with a median radiation dose of 35 Gy in 15 fractions with a concurrent single course of 5 FU-based chemotherapy. Dysphagia was measured at the beginning and completion of treatment and at monthly intervals until death, using a modified DeMeester (4-point) score. Treatment was well tolerated, with only 5% of patients failing to complete therapy. The treatment-related mortality was 6%. The median survival for the study population was 7 months. The median baseline score at presentation was 2 (difficulty with soft food). Following treatment, 49% of patients were assessed as having a dysphagia score of 0 (no dysphagia). Seventy-eight per cent had an improvement of at least one grade in their dysphagia score after treatment. Only 14% of patients showed no improvement with treatment. Fifty-one per cent maintained improved swallowing until the time of last follow-up or death. This single-institution study shows that chemoradiation therapy administered for the palliation of malignant dysphagia is well tolerated and produces a sustainable normalization in swallowing for almost half of all patients. [source] Salvage laryngectomy and pharyngocutaneous fistulae after primary radiotherapy for head and neck cancer: A national survey from DAHANCAHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 9 2003Cai Grau MD, DMSc Objective. In 1998, the Danish Society for Head and Neck Oncology decided to conduct a nationwide survey at the five head and neck oncology centers with the aim of evaluating the surgical outcome of salvage laryngectomy after radiotherapy with special emphasis on identifying factors that could contribute to the development of pharyngocutaneous fistulae. Patients. A total of 472 consecutive patients undergoing postirradiation salvage laryngectomy in the period July 1, 1987,June 30, 1997 were recorded at the five head and neck oncology centers in Denmark. Age ranged from 36 to 84 years, median 63 years, 405 men and 67 women. Primary tumor site was glottic larynx (n = 242), supraglottic larynx (n = 149), other larynx (n = 45), pharynx (n = 27), and other (n = 9). All patients had received prior radiotherapy. Results. Median time between radiotherapy and laryngectomy was 10 months (range, 1,348 months). A total of 89 fistulae lasting at least 2 weeks were observed, corresponding to an overall average fistulae risk of 19%. The number of performed laryngectomies per year decreased linearly (from 58 to 37), whereas the annual number of fistulae increased slightly (from 7 to 11), which meant that the corresponding estimated fistulae risk increased significantly from 12% in 1987 to 30% in 1997. Other significant risk factors for fistulae in univariate analysis included younger patient age, primary advanced T and N stage, nonglottic primary site, resection of hyoid bone, high total radiation dose, and large radiation fields. Multiple logistic regression analysis of these parameters suggested that nonglottic tumor site, late laryngectomy period (1987,1992 vs 1993,1997), and advanced initial T stage were independent prognostic factors for fistulae risk. Surgical parameters like resection of thyroid/tongue base/trachea or radiotherapy parameters like overall treatment time or fractions per week did not influence fistulae risk. Conclusions. The risk of fistulae is especially high in patients initially treated with radiotherapy for nonglottic advanced stage tumors. A significant decrease in the number of performed salvage laryngectomies over the 10 years was seen. Over the same time period, the annual number of fistulae remained almost constant. The resulting more than doubling of fistulae rate could thus in part be explained by less surgical routine. © 2003 Wiley Periodicals, Inc. Head Neck 25: 711,716, 2003 [source] "FAR" chemoradiotherapy improves laryngeal preservation rates in patients with T2N0 glottic carcinoma,HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 7 2002Yoshihiko Kumamoto MD Abstract Background The appropriate treatment approach for patients with T2N0 laryngeal cancer remains highly controversial. Because radiotherapy alone is associated with a high risk of local recurrence, we have developed a triple combination treatment approach consisting of 5-fluorouracil (250 mg/day, i.v.), vitamin A (50,000 unit/day, i.m.) and external radiation (2.0 Gy/day), which we have termed "FAR therapy." Methods Patients with T2N0 glottic carcinoma were initially treated with 15 days of FAR therapy, which included a cumulative radiation dose of 30Gy (i.e., "30 Gy of FAR therapy"). Those patients who demonstrated a complete response either clinically or pathologically continued to receive further FAR therapy, with up to 60,70 Gy. All other patients received laryngectomy without any additional treatment. Results Ninety-five patients were treated according to this program, and most of the patients (98%) were able to complete this treatment course. Eighty-eight patients (93%) were treated with FAR therapy alone. The local control and ultimate local control rates were 91% (85 of 93), and 99% (92 of 93), respectively. The cumulative 5-year voice preservation and complete laryngeal preservation rates were 91% and 87%, respectively. The cumulative 5-year disease-specific survival rate was 97%. Conclusions Because a high rate of laryngeal preservation was achieved without compromising disease-specific survival, our treatment approach based on FAR therapy may be promising for the treatment of patients with T2N0 glottic carcinoma. © 2002 Wiley Periodicals, Inc. [source] An audit of intra-oral digital radiographs for endodonticsINTERNATIONAL ENDODONTIC JOURNAL, Issue 4 2010R. Austin Aim, The aim of this study was to improve the quality of digital radiographs taken during endodontic treatment at King's College Hospital Dental Institute, UK. There were three phases. The first phase compared the Schick CDR system with Digora Optime. The second and third phases involved ways of improving the quality of the digital radiographs produced by the Schick CDR system. Methodology, The Faculty of General Dental Practitioners Royal College of Surgeons of England (FGDP) guidelines on Selection Criteria for Dental Radiography and Guidance Notes for Dental Practitioners on the Safe Use of X-Ray Equipment-National Radiological Protection Board enabled the use of a three point quality scale (one excellent, two diagnostically acceptable, three unacceptable), which took into consideration sensor angulation, positioning, contrast and focusing. The recommended FGDP guidelines are not less than 70% images scoring excellent. For the first phase 50 exposures recorded with the Schick CDR system were compared with 50 recorded using Digora Optime. For the second and third phases 50 radiographs for each phase were evaluated with images generated by the Schick system with training provided between the phases. Results, Images produced by the Schick system showed an inferior quality compared with the images generated by the Digora method. Both systems failed to reach the desired quality FGDP standard of 70% excellent (Schick 55% Digora 69%). Comparison of the results in the second and third phases showed that training the operator improved the quality but recommended the purchase of a size 1 or 0 Schick sensors to improve positioning errors. Conclusions, This study was carried out in order to minimise the ionising radiation dose to patients and to maximise the clinical and administrative benefits of using a digital system. It demonstrated an improvement in the quality of radiographs across all criteria measured up to and beyond the desired standard, from 55% of radiographs scoring excellent in the first phase to 80% in the third phase. As a result of the study it was decided to install the Schick CDR system because of the speed it produced images even though the first phase of this study demonstrated inferior image quality. The audit had clear, measurable standards with explicit targets. The audits have been through the entire audit cycle, data collection, change and a further data collection to provide evidence of the benefit of the change. A third data collection, demonstrated an ongoing commitment to quality. [source] New dimensions in endodontic imaging: Part 2.INTERNATIONAL ENDODONTIC JOURNAL, Issue 6 2009Cone beam computed tomography Abstract Cone beam computed tomography (CBCT) has been specifically designed to produce undistorted three-dimensional information of the maxillofacial skeleton, including the teeth and their surrounding tissues with a significantly lower effective radiation dose compared with conventional computed tomography (CT). Periapical disease may be detected sooner using CBCT compared with periapical views and the true size, extent, nature and position of periapical and resorptive lesions can be assessed. Root fractures, root canal anatomy and the nature of the alveolar bone topography around teeth may be assessed. The aim of this paper is to review current literature on the applications and limitations of CBCT in the management of endodontic problems. [source] Adenoid cystic carcinoma: A retrospective clinical reviewINTERNATIONAL JOURNAL OF CANCER, Issue 3 2001Atif J. Khan M.D. Abstract Adenoid cystic carcinoma (ACC) are uncommon tumors, representing about 10% to 15% of head and neck tumors. We compare the survival and control rates at our institution with those reported in the literature, and examine putative predictors of outcome. All patients registered with the tumor registry as having had ACC were identified. Demographic and survival variables were retrieved from the database. Additionally, a chart review of all patients was done to obtain specific information. Minor gland tumors were staged using the American Joint Committee on Cancer's criteria for squamous cell carcinomas in identical sites. Histopathologic variables retrieved included grade of the tumor, margins, and perineural invasion. Treatment modalities, field sizes, and radiation doses were recorded in applicable cases. An effort to retrieve archival tumor specimens for immunohistochemical analysis was undertaken. A total of 69 patients were treated for ACC from 1955 to 1999. One patient, who presented with fatal brain metastasis, was excluded from further analysis. Of the remaining 68 patients, 30 were men and 38 were women. The average age at diagnosis was 52 years, and mean follow-up was 13.2 years. Mean survival was 7.7 years. Overall survival (OS) rates at 5, 10, and 15 years were 72%, 44%, and 34%, and cause-specific survival was 83%, 71%, and 55%, respectively. Recurrence-free survival rates were 65%, 52%, and 30% at 5, 10, and 15 years, with a total of 29 of 68 (43%) eventually suffering a recurrence. Overall survival was adversely affected by advancing T and AJCC stage. Higher tumor grades were also associated with decreased OS, although the numbers compared were small. Primaries of the nasosinal region fared poorly when compared with other locations. Total recurrence-free survival, local and distant recurrence rates were distinctly better in primaries of the oral cavity/oropharynx when compared with those in other locations. Reduced distant recurrence-free survival was significantly associated with increasing stage. No other variables were predictive for recurrence. Additionally, we found that nasosinal tumors were more likely to display higher stage at presentation, and were more often associated with perineural invasion. Also of interest was the association of perineural invasion with margin status, with 15 of 20 patients with positive margins displaying perineural invasion, while only 5 of 17 with negative margins showed nerve invasion (P = 0.02). On immunohistochemistry, 2 cases of the 29 (7%) tumor specimens found displayed HER-2/neu positivity. No correlation between clinical behavior and positive staining could be demonstrated. Our data concur with previous reports on ACC in terms of survival and recurrence statistics. Stage and site of primary were important determinants of outcome. Grade may still serve a role in decision making. We could not demonstrate any differences attributable to primary modality of therapy, perhaps due to the nonrandomization of patients into the various treatment tracks and the inclusion of palliative cases. Similarly, perineural invasion, radiation dose and field size, and HER-2/neu positivity did not prove to be important factors in our experience. © 2001 Wiley-Liss, Inc. [source] Potential for controlling codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) in Argentina using the sterile insect technique and egg parasitoidsJOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2010E. Botto Abstract Codling moth is the main pest affecting apples and pears worldwide. Most pest control strategies used against this insect have relied on the use of broad-spectrum insecticides which have led to non-desirable effects like pesticide resistance, residues in the environment, human health concerns and the reduction of access to international markets. Therefore, alternative pest control strategies that would result in sustainable fruit production systems while taking care of the environment are strongly promoted. The use of the sterile insect technique has proven to be a valuable pest control tactic within area-wide integrated pest management strategies, and its synergistic effect for Lepidoptera pests when combined with other biological control tactics such as parasitoids has been documented. The purposes of this research were to evaluate the response of an Argentinean codling moth strain to a sub-sterilizing radiation dose of 100 Gy and to assess the acceptability and suitability of sterile codling moth eggs by the egg parasitoids, Trichogramma cacoeciae (Marchal) and Trichogramma nerudai (Pintureau and Gerding). Irradiated female moths survived better than irradiated male moths and non-irradiated male and female moths. Also, the fecundity of irradiated female moths was reduced by more than 30% as compared to non-irradiated ones whereas their fertility was close to zero. The F1 generation was male biased with a lower fertility (inherited sterility) than the parental generation. Trichogramma cacoeciae and T. nerudai parasitized both fertile and sterile eggs. However, there was a significant reduction in acceptability for sterile eggs. Trichogramma nerudai parasitized more eggs than T. cacoeciae, but egg acceptability for this species was proportionally lower than for T. cacoeciae especially on eggs oviposited by irradiated females. Development to adult of both parasitoids species was not substantially affected by the origin of the eggs and the wasps had acceptable levels of adult emergence, survival and fecundity. These results provided useful information on the potential for controlling the codling moth using egg parasitoids and the sterile insect technique in Argentina. [source] Gamma irradiation alters fatigue-crack behavior and fracture toughness in 1900H and GUR 1050 UHMWPEJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 5 2002Jantzen C. Cole Abstract Pitting and delamination remain causative factors of polyethylene failure in total knee replacement. Gamma irradiation induces cross linking in ultra-high-molecular-weight polyethylene, which has been shown to improve wear resistance. Irradiation may reduce fracture toughness and fatigue strength, however, and the effects of irradiation are dependent upon the resin, processing technique, and radiation dose. The effects of varying levels of gamma irradiation (0, 33, 66, and 100 kGy) on the fracture toughness and fatigue-crack resistance of UHMWPE, isostatically molded from 1900H and GUR 1050 resins, were examined. Paris law regressions were performed to quantify fatigue-crack propagation rates as functions of change in stress intensity, and J -integral methods were used to quantify the elastic,plastic fracture toughness. The results indicated that gamma irradiation reduced the resistance of both materials to fatigue-crack growth, and that the reductions were radiation dosage and resin dependent. Irradiation at any level was detrimental to the fracture toughness of the 1900H specimens. Irradiation at 33 kGy increased fracture toughness for the GUR 1050 specimens, and substantial reductions were observed only at the highest irradiation level. Scanning electron microscopy of the fracture surface revealed diamond-like fracture patterns of the nonirradiated specimens indicative of ductile, multilevel fracture. Pronounced striations were apparent on these fracture surfaces, oriented perpendicular to the direction of crack growth. The striations appeared as folds in surface layers of the GUR 1050 specimens. At the highest irradiation levels, the striations were nearly eliminated on the fracture surfaces of the 1900H specimens, and were markedly less severe for the GUR 1050. These results demonstrated that at higher irradiation levels the materials became more brittle in fatigue, with less ductile folding and tearing of the fracture surfaces. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 559,566, 2002 [source] Electroanatomic Versus Fluoroscopic Mapping for Catheter Ablation Procedures:JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2004A Prospective Randomized Study Introduction: The aim of this prospective randomized study was to compare the routine use of electroanatomic imaging (CARTO) with that of conventional fluoroscopically guided activation mapping (conventional) in an unselected population referred for catheter ablation. We sought to compare the two approaches with respect to procedure outcome and duration, radiation exposure, and cost. Methods and Results: All patients undergoing catheter ablation (with the exception of complete AV nodal ablation) were prospectively randomized to either a CARTO or conventional procedure for mapping and ablation. One hundred two patients were randomized. Acute procedural success was similar with either strategy (CARTO vs conventional 43/47 vs 51/55, P > 0.5), as was procedure duration (144 [58] vs 125 [48] min, P = 0.07 (mean [SD]). CARTO was associated with a substantial reduction in fluoroscopy time (9.3 [7.6] vs 28.8 [19.5] min, P < 0.001) and radiation dose (6.2 [6.1] vs 20.8 [32.7] Gray, P = 0.003). CARTO cases used fewer catheters (2.5 [0.7] vs 4.4 [1.1], P < 0.001), but catheter costs were higher (13.8 vs 9.3 units, P < 0.001, where one unit is equivalent to the cost of a nonsteerable quadripolar catheter). Conclusion: For all catheter ablation procedures, even when a center's "learning curve" for CARTO is included, procedure duration and outcome are similar for CARTO and conventional procedures. CARTO is associated with drastically reduced fluoroscopy time and radiation dose. Although fewer catheters are used with CARTO, catheter costs remain higher. (J Cardiovasc Electrophysiol, Vol. 15, pp. 310-315, March 2004) [source] Sonographic guidance for electron boost planning after breast-conserving surgeryJOURNAL OF CLINICAL ULTRASOUND, Issue 7 2004Antje Warszawski MD Abstract Purpose This study was conducted to determine the feasibility of using sonography for electron boost planning in breast cancer treatment and to define the factors that influence the accuracy and reproducibility of this technique. Patients and Methods Seventy-seven patients underwent 102 sonographic examinations after breast-conserving surgery and before and after radiotherapy. The size of the electron boost field was defined by measuring the postoperative cavity. Reproducibility of the sonographic findings was investigated in 25 of the patients who were examined before and after radiotherapy (at a total dose of 46,50.4 Gy). Depth (distance from the skin surface to the posterior aspect of the postoperative cavity) was measured, and sonographic appearance of the postoperative cavity was evaluated. Type of surgical procedure, time elapsed since surgery, use of systemic therapy, menopausal status, breast size, and radiation dose were investigated for their influence on sonographic appearance and visualization of the postoperative cavity. Results The postoperative cavity was well visualized in 78% of patients and visualized with some difficulty in 22%. In all but 5 patients, it was hypoechoic and inhomogeneous. The mean depth of the postoperative cavity after radiotherapy was 27 ± 4 mm. Smaller breast (p < 0.001) and younger age (p < 0.05) were associated with decreased visibility of the postoperative cavity. Sonographic appearance was the same before and after radiotherapy, but the mean difference in postoperative cavity depth between the 2 measurements was 2 mm (range, 0,4 mm). In 43/77 (56%) of the patients, changes in electron energy or in field size were required after sonographic measurement. Conclusion Sonography is a useful and reproducible means of electron boost planning, helping to avoid underdosage of the postoperative cavity and overdosage of normal tissue. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:333,337, 2004 [source] NUTRITIONAL QUALITY OF IRRADIATED ORANGE JUICE,JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2002XUETONG FAN Single-strength orange juice was exposed to 0, 0.89, 2.24, 4.23 and 8.71 kGy gamma radiation at 5C, and then stored at 23C for 6 days and 7C for 21 days. Conversion of ascorbic acid (AA) to dehydroascorbic acid (DHA), and loss of AA, total AA (TAA = AA plus DHA) and total antioxidants increased with radiation dose. Rate of TAA loss due to irradiation was much less than that of AA loss. Compared to nonirradiated juice (0 kGy), juice irradiated at 2.24 kGy or less had similar rates of AA and TAA loss during storage while juice irradiated at 4.23 and 8.71 kGy had higher rates of AA and TAA loss. Loss of total antioxidants in irradiated orange juice appeared to result from loss of AA. [source] Effectiveness of Radiation Processing for Elimination of Salmonella Typhimurium from Minimally Processed Pineapple (Ananas comosus Merr.)JOURNAL OF FOOD SCIENCE, Issue 3 2007Ravindranath Shashidhar ABSTRACT:, The microbiological quality of market samples of minimally processed (MP) pineapple was examined. The effectiveness of radiation treatment in eliminating Salmonella Typhimurium from laboratory inoculated ready-to-eat pineapple slices was also studied. Microbiological quality of minimally processed pineapple samples from Mumbai market was poor; 8.8% of the samples were positive for Salmonella. D10 (the radiation dose required to reduce bacterial population by 90%) value for S. Typhimurium inoculated in pineapple was 0.242 kGy. Inoculated pack studies in minimally processed pineapple showed that the treatment with a 2-kGy dose of gamma radiation could eliminate 5 log CFU/g of S. Typhimurium. The pathogen was not detected from radiation-processed samples up to 12 d during storage at 4 and 10 °C. The processing of market samples with 1 and 2 kGy was effective in improving the microbiological quality of these products. [source] Formation of Malonaldehyde, Formaldehyde, and Acetaldehyde in Apple Juice Induced by Ionizing RadiationJOURNAL OF FOOD SCIENCE, Issue 7 2002X. Fan And ABSTRACT: We investigated the effects of ionizing radiation on the formation of malonaldehyde (MA), formaldehyde (FA), and acetaldehyde (ACT) in apple juice. The formation of MA, FA, and ACT in both pasteurized and fresh juice increased with radiation dose. The G values (number of species formed per 100 eV absorbed) for MA, FA, and ACT in pasteurized juice were 0.0056, 0.061, and 0.044, respectively. MA concentration decreased rapidly during storage at 5°C, while ACT and FA did not. Irradiation-induced formation of MA, FA, and ACT decreased with decreasing irradiation temperature. Exclusion of oxygen during irradiation reduced formation of ACT and FA, but not MA. Adding 1000 ppm of ascorbate, sorbate, or sulfite to juice before irradiation also decreased MA formation. [source] Percutaneous Left and Right Heart Catheterization in Fully Anticoagulated Patients Utilizing the Radial Artery and Forearm Vein: A Two-Center ExperienceJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 3 2006TED S. N. LO M.R.C.P. Background: Stopping oral anticoagulants prior to cardiac catheterization is associated with an increased risk of thromboembolism. Performing the procedures via the femoral artery and vein without interruption of anticoagulation is associated with a high rate of major access site complications. The transradial technique for left heart catheterization is safe in fully anticoagulated patients but few data are available on the percutaneous right and left heart catheterization utilizing a combination of the radial artery and antecubital vein in this group of patients. Methods: We report our experience in 28 consecutive patients that underwent left and right heart catheterizations via this percutaneous arm approach without interruption of anticoagulation. These were compared to 31 consecutive non-anticoagulated patients that underwent the procedure via a conventional femoral artery and vein approach. Results: Arterial and venous accesses were achieved and complete angiographic and hemodynamic data obtained in all patients. There were no access site complications in the anticoagulated patients despite an International normalized ratio (INR) of 2.5 ± 0.5. Procedural duration was longer in the anticoagulated group of patients, but fluoroscopy time and patient radiation dose were similar in both groups. Conclusion: Our experience suggests that left and right heart catheterization can be safely performed in most fully anticoagulated patients using this technique with a low bleeding and thromboembolic risk and no increase in radiation exposure. [source] Tumor R2* is a prognostic indicator of acute radiotherapeutic response in rodent tumorsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2004Loreta M. Rodrigues MSc Abstract Purpose To test the prognostic potential of tumor R2* with respect to radiotherapeutic outcome. Blood oxygenation level dependent (BOLD) MRI images are sensitive to changes in deoxyhemoglobin concentration through the transverse MRI relaxation rate R2* of tissue water, hence the quantitative measurement of tumor R2* may be related to tissue oxygenation. Methods and Materials Tumor growth inhibition in response to radiation was established for both GH3 prolactinomas and RIF-1 fibrosarcomas with animals breathing either air or carbogen during radiation. In a separate cohort, the baseline R2* and carbogen (95% O2, 5% CO2)-induced ,R2* of rat GH3 prolactinomas and murine RIF-1 fibrosarcomas were quantified using multigradient echo (MGRE) MRI prior to radiotherapy, and correlated with subsequent tumor growth inhibition in response to ionizing radiation, while the animals breathed air. Results A radiation dose of 15 Gy caused pronounced growth delay in both tumor models and transient regression of the GH3 prolactinomas. When the animals breathed carbogen during radiation, the growth delay/regression was enhanced only in the GH3 prolactinomas. The GH3 prolactinomas, which exhibit a relatively fast baseline R2* and large ,R2* in response to carbogen breathing prior to radiotherapy, showed a substantial reduction in normalized tumor volume to 66 ± 3% with air breathing and 36 ± 5% with carbogen seven days after 15 Gy irradiation. In contrast, the effect of 15 Gy on the RIF-1 fibrosarcomas, which give a relatively slow baseline R2* and negligible ,R2* response to carbogen prior to treatment, showed a much smaller growth inhibition (143 ± 3% with air, 133 ± 12% with carbogen). Conclusion Quantitation of tumor R2* and carbogen-induced ,R2* by MGRE MRI provides completely noninvasive prognostic indicators of a potential acute radiotherapeutic response. J. Magn. Reson. Imaging 2004;19:482,488. © 2004 Wiley-Liss, Inc. [source] Dose escalation of radical radiation therapy in non-small-cell lung cancer using positron emission tomography/computed tomography-defined target volumes: Are class solutions obsolete?JOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 2 2008S Everitt Summary This study investigated the maximum theoretical radiation dose that could safely be delivered to 20 patients diagnosed with non-small-cell lung cancer. Two three-dimensional conformal radiation therapy (RT) class-solution techniques (A and B) and an individualized three-dimensional conformal RT technique (C) were compared at the standard dose of 60 Gy (part I). Dose escalation was then attempted for each technique successfully at 60 Gy, constrained by predetermined limits for lung and spinal canal (part II). Part I and part II data were reanalysed to include oesophageal dose constraints (part III). In part I, 60 Gy was successfully planned using techniques A, B and C in 19 (95%), 18 (90%) and 20 (100%) patients, respectively. The mean escalated dose attainable for part II using techniques A, B and C were 76.4, 74 and 97.8 Gy, respectively (P < 0.0005). One (5%) patient was successfully planned for 120 Gy using techniques A and B, whereas four (20%) were successfully planned using technique C. Following the inclusion of additional constraints applied to the oesophagus in part III, the amount of escalated dose remained the same for all patients who were successfully planned at 60 Gy apart from two patients when technique C was applied. In conclusion, individualized three-dimensional conformal RT facilitated greater dose conformation and higher escalation of dose in most patients. With modern planning tools, simple class solutions are obsolete for conventional dose radical RT in non-small-cell lung cancer. Highly individualized conformal planning is essential for dose escalation. [source] Spectroscopic study of the penetration depth of grafted polystyrene onto poly(tetrafluoroethylene- co -perfluoropropylvinylether) substrates.JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2002Abstract This study concerns the radiation grafting of styrene onto poly(tetrafluoroethylene- co -perfluoropropylvinylether) (PFA) substrates and the penetration depth of the graft. Grafting was obtained by the simultaneous irradiation method, and the spectroscopic analysis was made with the micro-Raman technique. Effects of grafting conditions such as the type of solvent, dose rate, and irradiation dose on the grafting yield were investigated. Of the different solvents used, the most efficient in terms of increasing grafting yield were dichloromethane, benzene, and methanol, respectively. A mixture of methanol and dichloromethane used as a solvent for styrene achieved a higher degree of grafting and concentration of grafted polystyrene onto the surface of PFA substrates than solutions of the monomer in the separate solvents. The degree of grafting increased with increasing radiation dose up to 500 kGy, stabilizing above this dose. However, the grafting yield decreased with an increase in the dose rate. The increase in the overall grafting yield was accompanied by a proportional increase in the penetration depth of the grafts into the substrate. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3191,3199, 2002 [source] Radiation dose optimized lateral expansion of the field of view in synchrotron radiation X-ray tomographic microscopyJOURNAL OF SYNCHROTRON RADIATION, Issue 5 2010David Haberthür Volumetric data at micrometer level resolution can be acquired within a few minutes using synchrotron-radiation-based tomographic microscopy. The field of view along the rotation axis of the sample can easily be increased by stacking several tomograms, allowing the investigation of long and thin objects at high resolution. On the contrary, an extension of the field of view in the perpendicular direction is non-trivial. This paper presents an acquisition protocol which increases the field of view of the tomographic dataset perpendicular to its rotation axis. The acquisition protocol can be tuned as a function of the reconstruction quality and scanning time. Since the scanning time is proportional to the radiation dose imparted to the sample, this method can be used to increase the field of view of tomographic microscopy instruments while optimizing the radiation dose for radiation-sensitive samples and keeping the quality of the tomographic dataset on the required level. This approach, dubbed wide-field synchrotron radiation tomographic microscopy, can increase the lateral field of view up to five times. The method has been successfully applied for the three-dimensional imaging of entire rat lung acini with a diameter of 4.1,mm at a voxel size of 1.48,µm. [source] Noncatheter-Based Delivery of a Single-Chamber Lumenless Pacing Lead in Small ChildrenPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 7 2007DAMIEN KENNY M.B.Ch.B., M.R.C.P.C.H. Objectives:The model 3830 lead (SelectSecureÔ Medtronic, Minneapolis, MN, USA) is a bipolar, fixed-screw, 4.1-F pacing lead designed for site-selective pacing. Implantation is usually performed using an 8-F deflectable catheter system. This catheter is not ideal for smaller children because of both the sheath size and the relatively large deflected curves. We describe a simpler noncatheter-based delivery system in seven children. Methods:A 4.1-F SelectSecure lead was introduced via a 5-F SafeSheath (Thomas Medical, Malvern, PA, USA) placed in the left subclavian vein. The SelectSecure lead was passed into the inferior vena cava (IVC) and a loop created, which was then withdrawn into the right atrium. Once in position, the lead was screwed into the myocardium, the SafeSheath was peeled off, and the lead connected to the generator. Results:From March 2005 until September 2006, five right atrial leads and two right ventricular leads were implanted in seven patients (six female) with a median weight of 15 kg (8.1,19.4). All leads were successfully placed with excellent pacing thresholds. The median screening time was 7.1 minutes (4.8,11.4) with a median radiation dose of 83 cGy cm2. There were no procedural complications and no lead displacements seen on a median follow-up of 10 months. Conclusions:Delivery of the 4.1-F SelectSecure pacing lead to the right heart is possible using a noncatheter-based delivery system. This is effective and safe and does not require the use of a larger delivery system. This allows these thin isodiametric pacing leads to be used advantageously in small children. [source] Comparison of gallium and PET scans at diagnosis and follow-up of pediatric patients with Hodgkin lymphomaPEDIATRIC BLOOD & CANCER, Issue 2 2008Melissa Hines-Thomas BS Abstract Background Positron emission tomography (PET) and gallium scans facilitate diagnosis and staging, evaluation of response to therapy, and monitoring for relapse in Hodgkin lymphoma (HL), but have not been compared in pediatric HL. Procedure We performed concurrent PET and gallium scans on 44 pediatric HL patients at diagnosis, early response, off chemotherapy, and off-therapy evaluations. PET and gallium scans were compared to each other and to computed tomography (CT) alone to determine whether either modality led to a change in stage or modified the results of the early response evaluation, which was used to determine the radiation dose. Results PET upstaged four patients at diagnosis (2 from stage I to II, one II to III, and one III to IV), but did not lead to a change in therapy in any of them. It changed response category in two patients at early response evaluation, leading to a change in radiation dose for 1 patient (25.5 Gy instead of 15 Gy to the spleen). Gallium did not change the stage of treatment for any patient. The negative predictive values for eventual lymphoma relapse of PET and gallium scans at off therapy were 89% and 83%, respectively; the positive predictive value of PET at off therapy is 29%. Conclusion PET appears to be superior to gallium in pediatric HL; future studies will determine the optimal timing of PET to assess early response and the utility of quantitative interpretation of the avidity of specific nodal sites. Pediatr Blood Cancer 2008;51:198,203. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||||||||||||||