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Sample records for subantimicrobial dose doxycycline

  1. Subantimicrobial dose doxycycline effects on osteopenic bone loss: microbiologic results.

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    Walker, Clay; Puumala, Susan; Golub, Lorne M; Stoner, Julie A; Reinhardt, Richard A; Lee, Hsi-Ming; Payne, Jeffrey B

    2007-08-01

    Based on microbiologic concerns, the safety of a 24-month regimen of subantimicrobial dose doxycycline (SDD; 20 mg twice a day) was evaluated in postmenopausal osteopenic women with periodontitis in a double-blind, placebo-controlled, randomized clinical trial. Subgingival samples were collected from two sites (probing depth > or = 5 mm) in each of 128 subjects at baseline, with the same sites resampled at the conclusion of the 2-year period. The samples were enumerated on selective and non-selective media and on doxycycline (4 microg/ml) medium. Up to five different colonial morphologies were subcultured from the doxycycline medium, identified to species, and susceptibilities determined to doxycycline and five other antibiotics. Data were analyzed for microbial differences in total colony forming units (CFU), periodontal and opportunistic pathogens, and changes in species and in susceptibilities of isolates recovered on doxycycline medium. There was no significant evidence that changes in total anaerobic counts over the treatment period (P = 0.96) differed between treatment groups. Likewise, periodontal pathogens, opportunistic pathogens, or normal flora did not differ descriptively between groups. Although there was a significant increase (P or = 16 microg/ml) decreased over the 24-month period in both groups and did not differ between the treatment groups (SDD: 79% to 76%; placebo: 83% to 70%; P = 0.2). There were no significant differences (P >0.28 for each) in the change in cross-resistance between the groups for doxycycline and the other five antibiotics. No antimicrobial effect on the subgingival flora was detected following treatment with SDD for 24 months, relative to baseline or to placebo. The increase in initial resistance (at 4 microg/ml) did not translate into a significant increase in the percent resistant to doxycycline (MIC > or = 16 microg/ml) for patients in the SDD group.

  2. Efficacy of subantimicrobial-dose doxycycline against nitrosative stress in chronic periodontitis.

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    Pârvu, Alina Elena; Alb, Sandu Florin; Crăciun, Alexandra; Taulescu, Marian Aurel

    2013-02-01

    To evaluate the effectiveness of subantimicrobial-dose doxycycline (SDD) as an adjunct to scaling and root planing (SRP) treatment against the nitrosative stress of moderate to advanced chronic periodontitis. Adults with untreated chronic periodontitis (n=174) were randomly administered SRP+SDD (n=87) (20 mg of doxycycline twice daily) or SRP+placebo (n=87) treatment for 3 months. At baseline and after 3 months, the probing depths (PD), bleeding on probing (BOP) and clinical attachment level (CAL) were measured, and a gingivomucosal biopsy was collected to assay the induction of nitric oxide synthase (iNOS) and 3-nitrotyrosine (3NT), and blood was collected to assay for total nitrites and nitrates (NO(x)) and 3NT. Compared to baseline, at the completion of treatment, significant decreases in the levels of tissue iNOS and 3NT and serum NO(x) and 3NT were observed in both groups. SRP+SDD yielded a greater reduction in the gingivomucosal and serum nitrosative stress markers than did SRP+placebo. PD, BOP, and CAL reduction were correlated with the nitrosative stress parameters. On a short-term basis, SDD therapy may be used as an adjunct to SRP treatment against nitrosative stress in moderate to advanced chronic periodontitis.

  3. Adjunctive Subantimicrobial Dose Doxycycline in the Treatment of Chronic Periodontitis in Type 2 Diabetic Patients: A Unique Combination Therapy

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    Gomaa Marwa Abdelhakim

    2018-03-01

    Full Text Available Background/Aim: To evaluate the effectiveness of combination therapy including subantimicrobial dose doxycycline (SDD and locally delivered doxycycline (LD as adjuncts to scaling and root planing (SRP in the treatment of chronic periodontitis in patients with type 2 diabetes mellitus (T2DM. Material and Methods: Forty patients with controlled T2DM (HbA1c ≤7% and chronic periodontitis were selected. They were randomly divided into two groups, twenty patients each: Test group (TG, n=20 patients was treated with combination therapy of full mouth SRP, LD gel 10% and SDD 20 mg twice daily for 6 months. Control group (CG, n=20 patients was treated with full mouth SRP only. The periodontal parameters were recorded at baseline, 3, 6 and 9 months and included periodontal probing depth (PD, clinical attachment level (CAL, and bleeding on probing (BOP. Gingival crevicular fluid (GCF samples were collected and a quantitative measurement of matrix metalloproteinase-8 (MMP-8 was carried out by using Enzyme-Linked Immunosorbent Assay (ELIZA at baseline, 3, 6 and 9 months. Results: Statistically significant reduction in all clinical parameters (PPD, CAL, and BOP was observed at TG over CG at 3, 6, and 9 months (p<0.05. Moreover, combination therapy provided significant reductions in the amount of GCF MMP-8 for the TG compared to CG at 3, 6, and 9 months evaluation period (p<0.05. Conclusions: Combination therapy including SRP, SDD, and LD, provided significantly greater clinical benefits than SRP alone in the treatment of chronic periodontitis in patients with controlled T2DM.

  4. Doxycycline

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    ... infections caused by bacteria, including pneumonia and other respiratory tract infections; certain infections of the skin or ... doxycycline, you may take it with food or milk. However, taking doxycycline with milk or food may ...

  5. Effects of different doses of doxycycline hyclate on haematological parameters of dogs with ehrlichiosis

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    Mariana Cristina Hoeppner Rondelli

    2016-11-01

    Full Text Available This study aimed to compare the effects of two doses of doxycycline hyclate on red blood cells, hemoglobin, hematocrit, white blood cells and platelets of dogs with ehrlichiosis. Group I, comprised of healthy dogs (n=6, negative on serology for Ehrlichia canis and Leptospira spp., real time PCR for E. canis and Anaplasma platys, and on semi–nested PCR for Babesia canis; Groups II (n=6 and III (n=6, comprised of dogs with suggestive clinical history, positive serology and/or real time PCR for E. canis, negative on research for anti-Leptospira spp. antibodies and real time PCR for A. platys, and on semi–nested PCR for B. canis were studied. Sick dogs were treated with doxycycline hyclate every 12 hours, by mouth, for 30 days (5 mg/kg, group II; 10 mg/kg, group III. Complete blood counts were performed before, after 15 days, and 10 days after period of treatment was complete. No difference between groups at the studied time points were noticed for red blood cells, hemoglobin, haematocrit and white blood cells. Difference was observed for platelets between group I and groups II and III (p<0.0001 at the study onset. After 15 days of treatment, the mean platelet for group III was lower than groups I (p=0.008 and II (p=0.0007, indicative of persistent thrombocytopenia, already absent in group II. No difference between groups was noticed at final time point, which suggests that both treatments increased platelets in dogs naturally infected with E. canis.

  6. Doxycycline-loaded nanotube-modified adhesives inhibit MMP in a dose-dependent fashion.

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    Palasuk, Jadesada; Windsor, L Jack; Platt, Jeffrey A; Lvov, Yuri; Geraldeli, Saulo; Bottino, Marco C

    2018-04-01

    This article evaluated the drug loading, release kinetics, and matrix metalloproteinase (MMP) inhibition of doxycycline (DOX) released from DOX-loaded nanotube-modified adhesives. DOX was chosen as the model drug, since it is the only MMP inhibitor approved by the U.S. Food and Drug Administration. Drug loading into the nanotubes was accomplished using DOX solution at distinct concentrations. Increased concentrations of DOX significantly improved the amount of loaded DOX. The modified adhesives were fabricated by incorporating DOX-loaded nanotubes into the adhesive resin of a commercial product. The degree of conversion (DC), Knoop microhardness, DOX release kinetics, antimicrobial, cytocompatibility, and anti-MMP activity of the modified adhesives were investigated. Incorporation of DOX-loaded nanotubes did not compromise DC, Knoop microhardness, or cell compatibility. Higher concentrations of DOX led to an increase in DOX release in a concentration-dependent manner from the modified adhesives. DOX released from the modified adhesives did not inhibit the growth of caries-related bacteria, but more importantly, it did inhibit MMP-1 activity. The loading of DOX into the nanotube-modified adhesives did not compromise the physicochemical properties of the adhesives and the released levels of DOX were able to inhibit MMP activity without cytotoxicity. Doxycycline released from the nanotube-modified adhesives inhibited MMP activity in a concentration-dependent fashion. Therefore, the proposed nanotube-modified adhesive may hold clinical potential as a strategy to preserve resin/dentin bond stability.

  7. Doxycycline Injection

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    ... is in a class of medications called tetracycline antibiotics. It works by killing bacteria that cause infections.Antibiotics such as doxycycline injection will not work for colds, flu, or other viral infections. Taking ...

  8. A histomorphometric study of the effect of doxycycline and erythromycin on bone formation in dental alveolar socket of rat

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    Mohammad Shahabooei

    2015-01-01

    Full Text Available Background: The aim of the present study was to evaluate whether subantimicrobial doses of doxycycline (DOX and erythromycin (EM used for the treatment of peri-implant osteolysis due to their anti-osteoclastogenesis can interfere with the osseous wound healing process in rat alveolar socket. Materials and Methods: Forty-five male Wistar rats had their first maxillary right molar extracted and were divided into three groups. DOX and EM at the doses of 5 mg/kg/day orally (p.o. and 2 mg/kg/day intraperitoneally (i.p. were administered respectively to two separate groups for 7 days after operation. In the control group the animals received normal saline (5 ml/kg. Five rats were sacrificed at 7, 14 and 21 days post-extraction in each study group. A histomorphometric analysis was used to evaluate new bone formation inside the alveolar socket. Significant level was set at 0.05. Results: The findings showed that the percentage of new bone formation (NBF enhanced significantly on days 7 and 14. There was no significant difference in the NBF between DOX and EM groups. Conclusion: Short-term treatment with both DOX and EM enhanced new bone formation without any advances in favor of each drug.

  9. Comparison of a single-dose vectored thermal pulsation procedure with a 3-month course of daily oral doxycycline for moderate-to-severe meibomian gland dysfunction.

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    Hagen, Kerry B; Bedi, Raman; Blackie, Caroline A; Christenson-Akagi, Kellie J

    2018-01-01

    The aim of this study was to compare the efficacy of a single bilateral 12-minute vectored thermal pulsation (VTP) procedure versus daily oral doxycycline for 3 months for moderate-to-severe meibomian gland dysfunction (MGD). This prospective, randomized, parallel-group, single-masked study included 28 subjects who received either a single-dose VTP or 3 months of doxycycline treatment. At baseline and 3 months post treatment, all subjects were evaluated for the following: dry eye symptoms with a standard dry eye questionnaire (the Standard Patient Evaluation for Eye Dryness [SPEED]), meibomian gland (MG) function by counting the number of glands yielding liquid secretion with the MG evaluator (MGE), tear breakup time (TBUT) and corneal and conjunctival staining. In the VTP group, at 3 months, there was a significant improvement in MG function (4.00±1.47 to 7.73±5.53), SPEED score (11.00±3.30 to 5.42±2.15), TBUT (6.26±2.01 to 8.44±1.81), corneal staining (0.38±0.50 to 0.12±0.33) and conjunctival staining (1.69±1.93 to 0.62±0.85). In the doxycycline group, there was a significant improvement in MG function (4.63±1.41 to 10.63±5.91), SPEED score (13.42±4.17 to 9.42±5.47) and conjunctival staining (2.38±1.88 to 1.13±1.51), but the improvement in TBUT (6.90±2.56 to 7.59±2.03) and corneal staining (0.21±0.41 to 0.13±0.34) was not statistically significant ( p =0.262 and p =0.414, respectively). At 3 months, SPEED score was significantly better in the VTP group ( p oral doxycycline at improving the dry eye symptoms secondary to MGD. A single 12-minute VTP treatment was at least as effective as a dose of doxycycline for 3 months, in improving MG function and all measured signs of MGD. Given the minimal risk profile of the single VTP procedure over long-term doxycycline use, a single VTP presents a favorable alternative to long-term antibiotic use.

  10. Assessment of solid microneedle rollers to enhance transmembrane delivery of doxycycline and inhibition of MMP activity.

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    Omolu, Abbie; Bailly, Maryse; Day, Richard M

    2017-11-01

    Many chronic wounds exhibit high matrix metalloproteinase (MMP) activity that impedes the normal wound healing process. Intradermal delivery (IDD) of sub-antimicrobial concentrations of doxycycline, as an MMP inhibitor, could target early stages of chronic wound development and inhibit further wound progression. To deliver doxycycline intradermally, the skin barrier must be disrupted. Microneedle rollers offer a minimally invasive technique to penetrate the skin by creating multiple microchannels that act as temporary conduits for drugs to diffuse through. In this study, an innovative and facile approach for delivery of doxycycline across Strat-M TM membrane was investigated using microneedle rollers. The quantity and rate of doxycycline diffusing through the micropores directly correlated with increasing microneedle lengths (250, 500 and 750 μm). Treatment of Strat-M TM with microneedle rollers resulted in a reduction in fibroblast-mediated collagen gel contraction and MMP activity compared with untreated Strat-M TM . Our results show that treatment of an epidermal mimetic with microneedle rollers provides sufficient permeabilization for doxycycline diffusion and inhibition of MMP activity. We conclude that microneedle rollers are a promising, clinically ready tool suitable for delivery of doxycycline intradermally to treat chronic wounds.

  11. Comparison of a single-dose vectored thermal pulsation procedure with a 3-month course of daily oral doxycycline for moderate-to-severe meibomian gland dysfunction

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    Hagen KB

    2018-01-01

    Full Text Available Kerry B Hagen,1 Raman Bedi,2 Caroline A Blackie,3 Kellie J Christenson-Akagi1 1EyeHealth Northwest, Portland, OR, USA; 2Iris Advanced Eye Centre, Chandigarh, India; 3TearScience, Inc., Morrisville, NC, USA Purpose: The aim of this study was to compare the efficacy of a single bilateral 12-minute vectored thermal pulsation (VTP procedure versus daily oral doxycycline for 3 months for moderate-to-severe meibomian gland dysfunction (MGD.Methods: This prospective, randomized, parallel-group, single-masked study included 28 subjects who received either a single-dose VTP or 3 months of doxycycline treatment. At baseline and 3 months post treatment, all subjects were evaluated for the following: dry eye symptoms with a standard dry eye questionnaire (the Standard Patient Evaluation for Eye Dryness [SPEED], meibomian gland (MG function by counting the number of glands yielding liquid secretion with the MG evaluator (MGE, tear breakup time (TBUT and corneal and conjunctival staining.Results: In the VTP group, at 3 months, there was a significant improvement in MG function (4.00±1.47 to 7.73±5.53, SPEED score (11.00±3.30 to 5.42±2.15, TBUT (6.26±2.01 to 8.44±1.81, corneal staining (0.38±0.50 to 0.12±0.33 and conjunctival staining (1.69±1.93 to 0.62±0.85. In the doxycycline group, there was a significant improvement in MG function (4.63±1.41 to 10.63±5.91, SPEED score (13.42±4.17 to 9.42±5.47 and conjunctival staining (2.38±1.88 to 1.13±1.51, but the improvement in TBUT (6.90±2.56 to 7.59±2.03 and corneal staining (0.21±0.41 to 0.13±0.34 was not statistically significant (p=0.262 and p=0.414, respectively. At 3 months, SPEED score was significantly better in the VTP group (p<0.05; other parameters were comparable between the two groups.Conclusion: A single 12-minute bilateral VTP procedure was significantly more effective than the 3-month daily course of oral doxycycline at improving the dry eye symptoms secondary to MGD. A single

  12. Effectiveness of low-dose doxycycline (LDD on clinical symptoms of Sjögren's Syndrome: a randomized, double-blind, placebo controlled cross-over study

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    Vuotila Tuija

    2007-12-01

    Full Text Available Abstract Background Matrix metalloproteinases (MMPs are proteolytic enzymes that may contribute to tissue destruction in Sjögren's syndrome (SS. Low-dose doxycycline (LDD inhibits MMPs. We evaluated the efficacy of LDD for the subjective symptoms in primary SS patients. This was a randomized, double blind, placebo controlled cross-over study. 22 patients were randomly assigned to receive either 20 mg LDD or matching placebo twice a day for 10 weeks. The first medication period was followed by 10-week washout period, after which the patient received either LDD or placebo, depending on the first drug received, followed by the second washout period. Stimulated saliva flow rates and pH were measured before and after one and ten weeks of each medication and after washout periods. VAS scale was used to assess the effect of LDD and placebo on following six subjective symptoms: xerostomia; xerophtalmia; difficulty of swallowing; myalgia; arthralgia; and fatigue. The effect was evaluated for each medication and washout period separately. Results Overall, the effects of medications on subjective symptoms were minor. Wilcoxon test demonstrated increased fatigue with LDD during medication (p Conclusion LDD may not be useful in reducing the primary SS symptoms.

  13. Fixed-Dose Combination Gel of Adapalene and Benzoyl Peroxide plus Doxycycline 100 mg versus Oral Isotretinoin for the Treatment of Severe Acne: Efficacy and Cost Analysis.

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    Penna, Pete; Meckfessel, Matthew H; Preston, Norman

    2014-01-01

    Acne vulgaris is a chronic skin disease with a high prevalence. Left untreated or inadequately treated, acne vulgaris can lead to psychological and physical scarring, as well as to unnecessary medical expenses. Oral isotretinoin is an effective treatment for severe resistant nodular and conglobate acne vulgaris. A regimen consisting of a fixed-dose combination of adapalene and benzoyl peroxide gel, 0.1%/2.5% (A-BPO) with oral doxycycline 100 mg (A-BPO/D) has been demonstrated to be efficacious and well tolerated in patients with severe acne and may be an alternative to oral isotretinoin for some patients with severe acne. The objective of this analysis was to compare the relative efficacy and associated costs of A-BPO/D versus oral isotretinoin. In this analysis, comparisons of relative efficacy were made using previously published studies involving similar patient populations with severe acne that warrant the use of oral isotretinoin. The pricing for oral doxycycline and oral isotretinoin was estimated based on the maximum allowable cost from 9 states, and the pricing for A-BPO was calculated as the range between the average wholesale price and the wholesale acquisition cost. For this analysis, 2 treatment models were generated to compare costs: (1) a basic treatment model that examined the costs of an initial regimen of either A-BPO/D or oral isotretinoin without considering probable outcomes, and (2) a long-term model that factored in likely treatment outcomes and subsequent treatments into associated costs. The basic treatment model assumed that patients would be prescribed a single regimen of A-BPO/D for 12 weeks or oral isotretinoin for 20 weeks. The long-term model considered the probability of each treatment successfully managing patients' acne, as well as likely additional regimens of A-BPO monotherapy or an additional regimen of oral isotretinoin. As a result of different treatment durations, the costs for each treatment were normalized to weekly cost of

  14. Doxycycline desensitization in chronic Q fever—A critical tool for the clinician

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    Aila Luise Caplunik-Pratsch

    2018-01-01

    Full Text Available We present the case of a 45 year old woman with acute Q fever pneumonia who progressed to the chronic phase of the disease despite azithromycin therapy. A trial of doxycycline was halted because of severe allergy and she was put on clarithromycin and later moxifloxacin. Failure of both drugs required desensitization to doxycycline with escalating doses. After two-year treatment with doxycycline-hydroxychloroquine combination, complete recovery was declared. Our case highlights the option of doxycycline desensitization when an acute allergic reaction poses an obstacle to optimal treatment.

  15. The effect of doxycycline treatment on the postvaccinal immune response in pigs

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    Pomorska-Mól, Małgorzata, E-mail: mpomorska@piwet.pulawy.pl; Kwit, Krzysztof; Markowska-Daniel, Iwona; Pejsak, Zygmunt

    2014-07-01

    The effect of a seven-day antibiotic therapy with doxycycline was investigated on the postvaccinal humoral and cellular immune response in pigs. The selected parameters of non-specific immunity were also studied. Fifty pigs were used (control not vaccinated (C, n = 10), control vaccinated (CV, n = 20), and experimental — received doxycycline (DOXY, n = 20)). For vaccination live-attenuated vaccine against pseudorabies (PR) was used. From day − 1 to day 5 pigs from DOXY group received doxycycline orally with drinking water, at the recommended dose. Pigs from DOXY and CV groups were vaccinated at 8 and 10 weeks of age. The results of the present study showed that cell-mediated postvaccinal immune response can be modulated by oral treatment with doxycycline. Significantly lower values of stimulation index were observed after PRV restimulation in doxycycline-treated pigs. Moreover, in the DOXY group a significant decrease in IFN-γ production after PRV restimulation was noted. The significantly lower number of CD4+CD8 + cells was also observed in doxy-treated, vaccinated pigs, 2 weeks after final vaccination. Simultaneously, specific humoral response was not disturbed. This study demonstrated the importance of defining the immune modulatory activity of doxycycline because it may alter the immune responses to vaccines. The exact mechanism of T-cell response suppression by doxycycline remains to be elucidated, however the influence of doxycycline on the secretion of various cytokines, including IFN-γ, may be considered as a possible cause. The present observations should prompt further studies on the practical significance of such phenomena in terms of clinical implications. - Highlights: • We examine the postvaccinal immune response in pigs treated with doxycycline. • Doxycycline negatively influenced the specific proliferation after recall stimulation. • Doxycycline negatively influenced secretion of IFN-γ after recall stimulation. • The lower number of

  16. The effect of doxycycline treatment on the postvaccinal immune response in pigs

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    Pomorska-Mól, Małgorzata; Kwit, Krzysztof; Markowska-Daniel, Iwona; Pejsak, Zygmunt

    2014-01-01

    The effect of a seven-day antibiotic therapy with doxycycline was investigated on the postvaccinal humoral and cellular immune response in pigs. The selected parameters of non-specific immunity were also studied. Fifty pigs were used (control not vaccinated (C, n = 10), control vaccinated (CV, n = 20), and experimental — received doxycycline (DOXY, n = 20)). For vaccination live-attenuated vaccine against pseudorabies (PR) was used. From day − 1 to day 5 pigs from DOXY group received doxycycline orally with drinking water, at the recommended dose. Pigs from DOXY and CV groups were vaccinated at 8 and 10 weeks of age. The results of the present study showed that cell-mediated postvaccinal immune response can be modulated by oral treatment with doxycycline. Significantly lower values of stimulation index were observed after PRV restimulation in doxycycline-treated pigs. Moreover, in the DOXY group a significant decrease in IFN-γ production after PRV restimulation was noted. The significantly lower number of CD4+CD8 + cells was also observed in doxy-treated, vaccinated pigs, 2 weeks after final vaccination. Simultaneously, specific humoral response was not disturbed. This study demonstrated the importance of defining the immune modulatory activity of doxycycline because it may alter the immune responses to vaccines. The exact mechanism of T-cell response suppression by doxycycline remains to be elucidated, however the influence of doxycycline on the secretion of various cytokines, including IFN-γ, may be considered as a possible cause. The present observations should prompt further studies on the practical significance of such phenomena in terms of clinical implications. - Highlights: • We examine the postvaccinal immune response in pigs treated with doxycycline. • Doxycycline negatively influenced the specific proliferation after recall stimulation. • Doxycycline negatively influenced secretion of IFN-γ after recall stimulation. • The lower number of

  17. Doxycycline induced Esophagitis

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    Banu Karakus Yilmaz

    2014-02-01

    Full Text Available Esophagitis is a hazardous condition such as acid reflux of esophageal mucosa, infection, systemic diseases, radiation, drugs and trauma. Drug- induced esophagial injury (DIEI is a disease with the use of variety of drugs that caused serious damage and ulcer in the mucosa of the esophagus. The most commonly implicated drugs are non-steroidal anti-inflammatory drugs (NSAIDs, chloride and especially antibiotics. Thirty-six year-old female patient presented to the emergency department with odynophagia during swallowing and complaining of retrosternal pain. One week before 100 mg doxycycline (2x1 PO for therapeutic abortion were prescribed. It was learned that in the third day of the initiation of medication, the patient\\'s symptoms began and stopped using drug by the fourth day due to advers effect of drugs, but her symptoms didn’t regressed although she didn’t use them. Endoscopy appointment was taken, proton pump inhibitor and antiacid treatment was given, than patient was discharged from the emergency department. In the endoscopy, 20 mm segment esophageal ulcer was seen approximately in the 30.th cm of the esophagius. DIEI is a relatively common, although under-recognized, so this case was presented for remainding DIEI to emergency medicine personals and reweiving its diagnosis, treatment and follow-up.

  18. Doxycycline concentration over time after storage in a compounded veterinary preparation.

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    Papich, Mark G; Davidson, Gigi S; Fortier, Lisa A

    2013-06-15

    To determine the concentration of doxycycline compounded from doxycycline hyclate tablets into liquid formulations for oral administration in veterinary species and stored for 28 days. Evaluation study. Doxycycline hyclate tablets (100 mg) crushed and mixed with a 50:50 mixture of syrup and suspension vehicles for oral administration to produce 3 batches each of 2 doxycycline formulations: 33.3 and 166.7 mg/mL. Formulations were stored, protected from light, at room temperature (22° to 26°C [71.6° to 78.8°F]) and at a controlled cold temperature (refrigerated 2° to 8°C [35.6° to 46.4°F]). Doxycycline was extracted from the formulations, and concentration was measured by high-pressure liquid chromatography on days 0 (date of preparation), 1, 4, 7, 14, 21, and 28. Concentrations were compared with those of a US Pharmacopeial Convention reference standard. Formulation quality at each point was also assessed through color change, formulation consistency, and suspension uniformity. On days 0, 1, 4, and 7, the concentration of each formulation was within 90% to 110% of the reference standard (range, 93% to 109%), which was deemed acceptable. However, doxycycline concentrations had decreased dramatically by day 14 and remained low for the duration of the study period. Doxycycline concentrations on days 14, 21, and 28 were all < 20% (range, 14% to 18%) of the reference standard, and the quality of the formulations decreased as well. No effect of storage temperatures on doxycycline concentration was identified. The concentration of doxycycline, compounded from commercial tablets in the vehicles evaluated to yield doses of 33.3 and 166.7 mg/mL, cannot be assured beyond 7 days.

  19. Increased incidence of postoperative infections during prophylaxis with cephalothin compared to doxycycline in intestinal surgery

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    Baatrup, Gunnar; Nilsen, Roy M; Svensen, Rune

    2009-01-01

    BACKGROUND: The antibiotics used for prophylaxis during surgery may influence the rate of surgical site infections. Tetracyclines are attractive having a long half-life and few side effects when used in a single dose regimen. We studied the rate of surgical site infections during changing regimens...... controls. The registration included time periods when the regimen was changed from doxycycline to cephalothin and back again. RESULTS: The SSI in the colorectal department increased from 19% to 30% (p=0.002) when doxycycline was substituted with cephalothin and decreased to 17% when we changed back...... to doxycycline (p=0.005). In the gynaecology department the surgical site infection rate did not increase significantly. Subgroup analysis showed major changes in infections in rectal resections from 20% to 35% (p=0.02) and back to 12% (p=0.003). CONCLUSION: Doxycycline combined with metronidazole...

  20. Doxycycline reduces nitric oxide production in guinea pig inner ears.

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    Helling, Kai; Wodarzcyk, Karl; Brieger, Jürgen; Schmidtmann, Irene; Li, Huige; Mann, Wolf J; Heinrich, Ulf-Rüdiger

    2011-12-01

    Gentamicin application is an important therapeutic option to control vertigo spells in Ménière's disease. However, even in the case of low-dose intratympanic application, gentamicin might contribute to a pathological NO-increase leading to cochlear damage and hearing impairment. The study was performed to evaluate the nitric oxide (NO) reducing capacity of doxycycline in the inner ear after NO-induction by gentamicin. In a prospective animal study, a single dose of gentamicin (10mg/kg body weight) was injected intratympanically into male guinea pigs (n=48). The auditory brainstem responses (ABRs) were recorded prior to application and 3, 5 and 7 days afterwards. The organ of Corti and the lateral wall of 42 animals were isolated after 7 days and incubated separately for 6h in cell culture medium. Doxycycline was adjusted to organ cultures of 5 animals. Two NOS inhibitors, N(G)-Nitro-l-arginine methyl ester (l-NAME) and NG-monomethyl-l-arginine monoacetate (l-NMMA), were applied in three different concentrations to the organ cultures of 30 animals in total (5 animals per concentration). As controls, seven animals received no further substance except gentamicin. The NO-production was quantified by chemiluminescence. Additional six gentamicin-treated animals were used for immunohistochemical studies. The ABRs declined continuously from the first to the seventh day after gentamicin application. Doxycycline reduced NO-production in the lateral wall by 54% (p=.029) comparable to the effect of the applied nitric oxide inhibitors. In the organ of Corti, NO-production was reduced by about 41% showing no statistical significance in respect to great inter-animal variations. The application of doxycycline might offer a new therapeutic approach to prevent NO-induced cochlea damage through ototoxic substances. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  1. Pharmacokinetics of an oral extended-release formulation of doxycycline hyclate containing acrylic acid and polymethacrylate in dogs.

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    Ruiz, Sara Melisa Arciniegas; Olvera, Lilia Gutiérrez; Chacón, Sara del Carmen Caballero; Estrada, Dinorah Vargas

    2015-04-01

    To determine the pharmacokinetics of doxycycline hyclate administered orally in the form of experimental formulations with different proportions of acrylic acid-polymethacrylate-based matrices. 30 healthy adult dogs. In a crossover study, dogs were randomly assigned (in groups of 10) to receive a single oral dose (20 mg/kg) of doxycycline hyclate without excipients (control) or extended-release formulations (ERFs) containing doxycycline, acrylic acid polymer, and polymethacrylate in the following proportions: 1:0.5:0.0075 (ERF1) or 1:1:0.015 (ERF2). Serum concentrations of doxycycline were determined for pharmacokinetic analysis before and at several intervals after each treatment. Following oral administration to the study dogs, each ERF resulted in therapeutic serum doxycycline concentrations for 48 hours, whereas the control treatment resulted in therapeutic serum doxycycline concentrations for only 24 hours. All pharmacokinetic parameters for ERF1 and ERF2 were significantly different; however, findings for ERF1 did not differ significantly from those for the control treatment. Results indicated that both ERFs containing doxycycline, acrylic acid polymer, and polymethacrylate had an adequate pharmacokinetic-pharmacodynamic relationship for a time-dependent drug and a longer release time than doxycycline alone following oral administration in dogs. Given the minimum effective serum doxycycline concentration of 0.26 μg/mL, a dose interval of 48 hours can be achieved for each tested ERF. This minimum inhibitory concentration has the potential to be effective against several susceptible bacteria involved in important infections in dogs. Treatment of dogs with either ERF may have several benefits over treatment with doxycycline alone.

  2. Effect of doxycycline in patients of moderate to severe chronic obstructive pulmonary disease with stable symptoms

    Directory of Open Access Journals (Sweden)

    Prashant S Dalvi

    2011-01-01

    Full Text Available Background: The protease-antiprotease hypothesis proposes that inflammatory cells and oxidative stress in chronic obstructive pulmonary disease (COPD produce increased levels of proteolytic enzymes (neutrophil elastase, matrix metalloproteinases [MMP] which contribute to destruction of parenchyma resulting in progressive decline in forced expiratory volume in one second. Doxycycline, a tetracycline analogue, possesses anti-inflammatory properties and inhibits MMP enzymes. Objectives: To assess the effect of 4 weeks doxycycline in a dose of 100 mg once a day in patients of moderate to severe COPD with stable symptoms. Methods : In an interventional, randomized, observer-masked, parallel study design, the effect of doxycycline (100 mg once a day for 4 weeks was assessed in patients of COPD having stable symptoms after a run-in period of 4 weeks. The study participants in reference group did not receive doxycycline. The parameters were pulmonary functions, systemic inflammation marker C-reactive protein (CRP, and medical research council (MRC dyspnea scale. Use of systemic corticosteroids or antimicrobial agents was not allowed during the study period. Results: A total of 61 patients completed the study (31 patients in doxycycline group and 30 patients in reference group. At 4 weeks, the pulmonary functions significantly improved in doxycycline group and the mean reduction in baseline serum CRP was significantly greater in doxycycline group as compared with reference group. There was no significant improvement in MRC dyspnea scale in both groups at 4 weeks. Conclusion: The anti-inflammatory and MMP-inhibiting property of doxycycline might have contributed to the improvement of parameters in this study.

  3. Treatment Outcomes for Rectal Lymphogranuloma Venereum in Men Who Have Sex with Men Using Doxycycline, Azithromycin, or Both: A Review of Clinical Cases.

    Science.gov (United States)

    Leeyaphan, Charussri; Ong, Jason J; Chow, Eric P F; Dimovski, Karolina; Kong, Fabian Y S; Hocking, Jane S; Howden, Ben; Bissessor, Melanie; Fairley, Christopher K; Bradshaw, Catriona; Read, Timothy; Chen, Marcus

    2017-04-01

    Treatment for rectal lymphogranuloma venereum where doxycycline 100 mg twice daily for 21 days was used-either alone or together with azithromycin 1 g single dose-resulted in microbiological cure of 97%. These data support doxycycline 100 mg twice daily for 21 days as the preferred treatment for rectal lymphogranuloma venereum.

  4. Considerations for using minocycline vs doxycycline for treatment of canine heartworm disease.

    Science.gov (United States)

    Papich, Mark G

    2017-11-09

    Doxycycline has been considered the first drug of choice for treating Wolbachia, a member of the Rickettsiaceae, which has a symbiotic relationship with filarial worms, including heartworms. Wolbachia, is susceptible to tetracyclines, which have been used as adjunctive treatments for heartworm disease. Treatment with doxycycline reduces Wolbachia numbers in all stages of heartworms and improves outcomes and decreased microfilaremia in dogs treated for heartworm disease. The American Heartworm Society recommends treatment with doxycycline in dogs diagnosed with heartworm disease at a dose of 10 mg/kg twice daily for 28 days. If doxycycline is not available, minocycline can be considered as a substitute. However, minocycline has not undergone an evaluation in dogs with heartworm disease, nor has an effective dose been established. Minocycline is an attractive option because of the higher cost of doxycycline and new pharmacokinetic information for dogs that provides guidance for appropriate dosage regimens to achieve pharmacokinetic-pharmacodynamic (PK-PD) targets. Published reports from the Anti-Wolbachia Consortium (A-WOL) indicate superior in vitro activity of minocycline over doxycycline. Studies performed in mouse models to measure anti-Wolbachia activity showed that minocycline was 1.7 times more effective than doxycycline, despite a 3-fold lower pharmacokinetic exposure. To achieve the same exposure as achieved in the mouse infection model, a pharmacokinetic-pharmacodynamic (PK-PD) analysis was conducted to determine optimal dosages for dogs. The analysis showed that an oral minocycline dose of 3.75 to 5 mg/kg administered twice daily would attain similar targets as observed in mice and predicted for human infections. There are potentially several advantages for use of minocycline in animals. It is well absorbed from oral administration, it has less protein binding than doxycycline (65% vs 92%) allowing for better distribution into tissue, and it is

  5. Pharmacokinetics, tissue residues and efficacy of D-Tylo50/25® (tylosin-doxycycline combination) in broiler chickens

    OpenAIRE

    Mohamed Aboubakr; Mohamed Elbadawy

    2017-01-01

    Background: Pharmacokinetic study of a commercial tylosin-doxycycline combination product (D-Tylo50/25®) was conducted in broiler chickens following intravenous (IV) and oral (PO) administration at doses of 50 mg/kgb. wt. (tylosin) and 25 mg/kg b. wt. (doxycycline). Methods: Serum drug concentrations were determined by a validated high performance liquid chromatography (HPLC) using UV detection. Results: A rapid and nearly complete absorption of both drugs with a mean PO bioavailabili...

  6. Susceptibility of Porphyromonas gingivalis in biofilms to amoxicillin, doxycycline and metronidazole

    DEFF Research Database (Denmark)

    Larsen, T.

    2002-01-01

    Biofilm, Porphyromonas gingivalis, susceptibility testing, amoxicillin, doxycycline, metronidazole......Biofilm, Porphyromonas gingivalis, susceptibility testing, amoxicillin, doxycycline, metronidazole...

  7. Effect of Process Factors on the Properties of Doxycycline ...

    African Journals Online (AJOL)

    ... in order to achieve a transdermal and/or systemic nanocarier of doxycycline. ... The resulting system can be applied for the formulation of doxycycline niosomes. Keywords: Doxycicline, Vesicles, Drug delivery, Ascorbyl palmitate, Niosomes.

  8. Doxycycline and Tigecycline: Two Friendly Drugs with a Low Association with Clostridium Difficile Infection

    Directory of Open Access Journals (Sweden)

    Yuan-Pin Hung

    2015-06-01

    Full Text Available Clostridium difficile infection (CDI is known to be associated with prior exposure to many classes of antibiotics. Standard therapy for CDI (i.e., metronidazole and vancomycin is associated with high recurrence rates. Although tetracycline derivatives such as tetracycline, doxycycline or tigecycline are not the standard therapeutic choices for CDI, they may serve as an alternative or a component of combination therapy. Previous tetracycline or doxycycline usage had been shown to have less association with CDI development. Tigecycline, a broad-spectrum glycylcycline with potency against many gram-positive or gram-negative pathogens, had been successfully used to treat severe or refractory CDI. The in vitro susceptibility of C. difficile clinical isolates to tigecycline in many studies showed low minimal inhibitory concentrations. Tigecycline can suppress in vitro toxin production in both historical and hypervirulent C. difficile strains and reduce spore production in a dose-dependent manner. Tetracycline compounds such as doxycycline, minocycline, and tigecycline possess anti-inflammatory properties that are independent of their antibiotic activity and may contribute to their therapeutic effect for CDI. Although clinical data are limited, doxycycline is less likely to induce CDI, and tigecycline can be considered one of the therapeutic choices for severe or refractory CDI.

  9. Comparative Efficacy of Penicillin and Doxycycline in Gonococcal Urethritis

    Directory of Open Access Journals (Sweden)

    Vinod K Sharma

    1987-01-01

    Full Text Available Ninety two episodes of gonococcal urethritis treated with one of the following regimens viz: (A 3 m. u. of fortified procaine penicillin made by adding 1 m.u. of crystalline penicillin to 2 m.u. of fortified procaine penicillin intramuscularly with one gram of probenecid orally, (B 3 m.u. of above fortified procaine penicillin intramuscularly alone, and (C 400 mg single oral dose of doxycycline produced success rates of 95,76.2 and 66.7% respectively. Post gonococcal urethritis was detected in 37% patients. Thirty four (45.94% of the 74 isolates of N. gonorrhoeae were relatively resistant (MIC 0. 12 units ml to penicillin. None of the 74 Neisseria gonorrhoeac strains was beta lactamase producing.

  10. Doxycycline Impairs Mitochondrial Function and Protects Human Glioma Cells from Hypoxia-Induced Cell Death: Implications of Using Tet-Inducible Systems.

    Science.gov (United States)

    Luger, Anna-Luisa; Sauer, Benedikt; Lorenz, Nadja I; Engel, Anna L; Braun, Yannick; Voss, Martin; Harter, Patrick N; Steinbach, Joachim P; Ronellenfitsch, Michael W

    2018-05-17

    Inducible gene expression is an important tool in molecular biology research to study protein function. Most frequently, the antibiotic doxycycline is used for regulation of so-called tetracycline (Tet)-inducible systems. In contrast to stable gene overexpression, these systems allow investigation of acute and reversible effects of cellular protein induction. Recent reports have already called for caution when using Tet-inducible systems as the employed antibiotics can disturb mitochondrial function and alter cellular metabolism by interfering with mitochondrial translation. Reprogramming of energy metabolism has lately been recognized as an important emerging hallmark of cancer and is a central focus of cancer research. Therefore, the scope of this study was to systematically analyze dose-dependent metabolic effects of doxycycline on a panel of glioma cell lines with concomitant monitoring of gene expression from Tet-inducible systems. We report that doxycycline doses commonly used with inducible expression systems (0.01⁻1 µg/mL) substantially alter cellular metabolism: Mitochondrial protein synthesis was inhibited accompanied by reduced oxygen and increased glucose consumption. Furthermore, doxycycline protected human glioma cells from hypoxia-induced cell death. An impairment of cell growth was only detectable with higher doxycycline doses (10 µg/mL). Our findings describe settings where doxycycline exerts effects on eukaryotic cellular metabolism, limiting the employment of Tet-inducible systems.

  11. Occurrence of doxycycline resistant bacteria in the oral cavity after local administration of doxycycline in patients with periodontal disease

    DEFF Research Database (Denmark)

    Larsen, T

    1991-01-01

    patients with advanced marginal periodontitis were scaled, and one approximal pocket in each patient was additionally treated with locally delivered doxycycline. Microbiological samples were obtained from the test site, a contralateral control site and tongue and tonsils before treatment and 3, 13, 26......Topical antimicrobial treatment is appearing as a means of therapy in patients with advanced periodontal disease. The purpose of the present study was to examine the occurrence of doxycycline resistant bacteria in subgingival plaque and oral cavity after local administration of doxycycline. Five...... and 52 weeks after treatment. The occurrence and morphological distribution of doxycycline resistant bacteria was determined after anaerobic cultivation on enriched tryptic soy agar with and without doxycycline incorporated. At the test site and on tongue and tonsils the percentage of doxycycline...

  12. Influence of enrofloxacin traces in drinking water to doxycycline tissue pharmacokinetics in healthy and infected by Mycoplasma gallisepticum broiler chickens.

    Science.gov (United States)

    Gbylik-Sikorska, Malgorzata; Posyniak, Andrzej; Sniegocki, Tomasz; Sell, Bartosz; Gajda, Anna; Sawicka, Anna; Olszewska-Tomczyk, Monika; Bladek, Tomasz; Tomczyk, Grzegorz; Zmudzki, Jan

    2016-04-01

    Most of antibiotics, administrated in the treatment of poultry diseases are dissolved in drinking water, and it can lead to water supply systems contamination, especially when the regular cleaning is not using. This situation can lead to unconscious administration of low doses of antibiotics to untreated animals. The aim of this study was to clarify the impact of the exposure of enrofloxacin traces (500 μg l(-1)) to doxycycline pharmacokinetics in healthy and experimentally Mycoplasma gallisepticum infected broiler chickens., Two experimental groups, received of enrofloxacin in water and all groups, received 20 mg kg(-1) bw of doxycycline. The compounds concentrations in muscles and livers were determined by LC-MS/MS. The maximum drug tissue concentration (Cmax) of doxycycline was highest in liver obtained from infected chickens which, received enrofloxacin traces (ENR + DC/MG). It was about 40% higher than in healthy chickens from group I which received only doxycycline. It was found that the concentration-time curve AUC(0-t) values in group ENR + DC/MG were almost 75% higher than in the group (DC) and 35% higher than in group (ENR + DC) which also received enrofloxacin traces. The constant exposure of broiler chickens on enrofloxacin traces as well as infection, may significantly influenced on doxycycline tissue pharmacokinetic profile. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Doxycycline Compliance at Bagram Air Field

    Science.gov (United States)

    2014-05-01

    could be traced back to any indivudal. The survey instrument (Attachment 1) was developed using National Institute of Health instructional doxycycline...Survey Number Completing Age Groups- Years Survey 18-21 29 22-30 189 31-40 131 >41 75 Total 424 Table 2 - Gender of Members Taking Survey Number...of season (temp above 50-60 F) TOY The day off, usually takes it with all employees at same time The only time I ever get sick is when the

  14. Clinical benefits of incorporating doxycycline into a canine heartworm treatment protocol

    Directory of Open Access Journals (Sweden)

    C. Thomas Nelson

    2017-11-01

    Full Text Available Abstract Background The objective of heartworm treatment is to improve the clinical condition of the patient and to eliminate pre-cardiac, juvenile, and adult worm stages with minimal complications. Pulmonary thromboembolisms are an inevitable consequence of worm death and can result in severe pulmonary reactions and even death of the patient. To minimize these reactions, various treatment protocols involving melarsomine, the only adulticidal drug approved by the US Food and Drug Administrations (FDA, in conjunction with macrocyclic lactone heartworm preventives and glucocorticosteroids have been advocated. The discovery of the bacterial endosymbiont Wolbachia in Dirofilaria immitis has led to several experimental studies examining the effects of administering doxycycline to reduce or eliminate Wolbachia organism. These studies have shown a decrease in gross and microscopic pathology of pulmonary parenchyma in experimental heartworm infections pretreated with doxycycline before melarsomine administration. Methods Electronic medical records from a large veterinary practice in northeast Alabama were searched to identify dogs treated for heartworms with melarsomine from January 2005 through December 2012. The search was refined further to select for dogs that met the following criteria: 1 received two or three doses of ivermectin heartworm preventive prior to melarsomine injections, 2 received one injection of melarsomine followed by two injections 4 to 8 weeks later, and 3 were treated with prednisone following melarsomine injections. The dogs were then divided into those that also were treated with doxycycline 10 mg/kg BID for 4 weeks (Group A, n = 47 and those that did not receive doxycycline (Group B, n = 47. The medical notes of all 94 cases were then reviewed for comments concerning coughing, dyspnea, or hemoptysis in the history, physical exam template, or from telephone conversations with clients the week following each visit. Any

  15. Clinical benefits of incorporating doxycycline into a canine heartworm treatment protocol.

    Science.gov (United States)

    Nelson, C Thomas; Myrick, Elizabeth S; Nelson, Thomas A

    2017-11-09

    The objective of heartworm treatment is to improve the clinical condition of the patient and to eliminate pre-cardiac, juvenile, and adult worm stages with minimal complications. Pulmonary thromboembolisms are an inevitable consequence of worm death and can result in severe pulmonary reactions and even death of the patient. To minimize these reactions, various treatment protocols involving melarsomine, the only adulticidal drug approved by the US Food and Drug Administrations (FDA), in conjunction with macrocyclic lactone heartworm preventives and glucocorticosteroids have been advocated. The discovery of the bacterial endosymbiont Wolbachia in Dirofilaria immitis has led to several experimental studies examining the effects of administering doxycycline to reduce or eliminate Wolbachia organism. These studies have shown a decrease in gross and microscopic pathology of pulmonary parenchyma in experimental heartworm infections pretreated with doxycycline before melarsomine administration. Electronic medical records from a large veterinary practice in northeast Alabama were searched to identify dogs treated for heartworms with melarsomine from January 2005 through December 2012. The search was refined further to select for dogs that met the following criteria: 1) received two or three doses of ivermectin heartworm preventive prior to melarsomine injections, 2) received one injection of melarsomine followed by two injections 4 to 8 weeks later, and 3) were treated with prednisone following melarsomine injections. The dogs were then divided into those that also were treated with doxycycline 10 mg/kg BID for 4 weeks (Group A, n = 47) and those that did not receive doxycycline (Group B, n = 47). The medical notes of all 94 cases were then reviewed for comments concerning coughing, dyspnea, or hemoptysis in the history, physical exam template, or from telephone conversations with clients the week following each visit. Any dog that died within one year of treatment

  16. Comparison between Efficacy of Ciprofioxacin -Doxycycline with Rifampin – Doxycycline Regimens inrelapse of Brucellosis

    Directory of Open Access Journals (Sweden)

    Hossein Sarmadian

    2014-08-01

    Full Text Available Background: Brucellosis is one of the endemic diseases in Iran that has a worldwide spread and is associated with chronic disabilities in humans. Combination therapy of Brucellosis leads to recovery of symptoms, shortening of the symptomatic intervals, and decrease in the rate of relapse and drug resistance. Considering the use of rifampin in the treatment of tuberculosis, and the necessity for an alternative treatment in regions endemic for both tuberculosis and brucellosis, the aim ofthis study was to compare the efficiency of the regimen of rifampin-Doxycycline with ciprofloxacin-Doxycycline in relapse of brucellosis. Materials and methods: This randomized controlled trial was performed on 90 patients, older than 17 years old, affected with brucellosis, which were referred to the Infectious Disease Clinics at ArakUniversity of medical sciences between the years 1384-1387. The patients were randomly divided into two groups: the DR groups, receiving 100 mg of Doxycycline twice a day and 300 mg of rifampin Bid daily for eight weeks and the CD group, receiving 100 mg of Doxycycline plus 500 mg of ciprofloxacin twice a day for eight weeks. The patients were analyzed for the relief of symptoms, drug side effects, and laboratory findings during the treatment. Results:In this study, the rate of relapse in both groups were similar. The relapse was seen in 4.5% and 3.2% of the patients for the DR and CD groups, respectively (P=0.168. The drug side effects were slight in both of groups, with no significant difference, and did not lead to discontinuation of the therapy. Conclusion: According to the same rate of relapse in both CD and DR regimens in the treatment of brucellosis and considering the usage of rifampin in regions with high prevalence of tuberclusis, the CD regimen is recommended as an appropriate one.

  17. Impact of Flow Rate, Collection Devices, and Extraction Methods on Tear Concentrations Following Oral Administration of Doxycycline in Dogs and Cats.

    Science.gov (United States)

    Sebbag, Lionel; Showman, Lucas; McDowell, Emily M; Perera, Ann; Mochel, Jonathan P

    2018-04-30

    Compare the precision of doxycycline quantification in tear fluid collected with either Schirmer strips or polyvinyl acetal (PVA) sponges following oral drug administration. Three dogs and 3 cats were administered doxycycline orally at a dose of 4.2-5 mg/kg every 12 h for 6 consecutive days. At day 5 and 6, blood and tear fluid were sampled to capture doxycycline trough and maximal concentrations. Tear fluid was collected 3 times (spaced 10 min apart) at each session with the absorbent material placed in the lower conjunctival fornix until the 20-mm mark was reached (Schirmer strip, one eye) or for 1 min (PVA sponge, other eye). Tear extraction was performed with either centrifugation or elution in methanol. Doxycycline concentrations were measured with liquid chromatography-mass spectrometry. Low (100 ng/mL) and high (1,000 ng/mL) tear concentrations measured in vivo were spiked into each absorbent material in vitro to evaluate percentage drug recovery. After oral administration of doxycycline, the drug reached the tear compartment at concentrations of 45.1-900.7 ng/mL in cats and 45.4-632.0 ng/mL in dogs, representing a tear-to-serum ratio of 12% and 16%, respectively. Doxycycline tear concentrations were significantly more precise when tear collection was performed with Schirmer strips rather than PVA sponges (P = 0.007), but were not correlated with tear flow rate. In vitro doxycycline recovery was poor to moderate (<75%). Schirmer strips represent a good option for lacrimal doxycycline quantification, although the collection and subsequent extraction have to be optimized to improve drug recovery.

  18. Suppression of MMP-9 by doxycycline in brain arteriovenous malformations

    Directory of Open Access Journals (Sweden)

    Li Jenny F

    2005-01-01

    Full Text Available Abstract Background The primary aim of this study is to demonstrate the feasibility of utilizing doxycycline to suppress matrix metalloproteinase-9 (MMP-9 in brain arteriovenous malformations (AVMs. Methods Ex-vivo treatment of AVM tissues: Intact AVM tissues were treated with doxycycline for 48 hours. Active and total MMP-9 in the medium were measured. Pilot trial: AVM patients received either doxycycline (100 mg or placebo twice a day for one week prior to AVM resection. Active and total MMP-9 in BVM tissues were measured. Results Ex-vivo treatment of AVM tissues: Doxycycline at 10 and 100 μg/ml significantly decreased MMP-9 levels in AVM tissues ex-vivo (total: control vs 10 vs 100 μg/ml = 100 ± 6 vs 60 ± 16 vs 61 ± 9%; active: 100 ± 8 vs 48 ± 16 vs 59 ± 10%. Pilot trial: 10 patients received doxycycline, and 4 patients received placebo. There was a trend for both MMP-9 levels to be lower in the doxycycline group than in the placebo group (total: 2.18 ± 1.94 vs 3.26 ± 3.58, P = .50; active: 0.48 ± 0.48 vs 0.95 ± 1.01 ng/100 μg protein, P = .25. Conclusions A clinically relevant concentration of doxycycline decreased MMP-9 in ex-vivo AVM tissues. Furthermore, there was a trend that oral doxycycline for as short as one week resulted in a decrease in MMP-9 in AVM tissues. Further studies are warranted to justify a clinical trial to test effects of doxycycline on MMP-9 expression in AVM tissues.

  19. Doxycycline and its quaternary ammonium derivative for adjuvant therapies of chondrosarcoma.

    Science.gov (United States)

    Miladi, Imen; Vivier, Magali; Dauplat, Marie-Mélanie; Chatard, Morgane; Besse, Sophie; Vidal, Aurélien; Chassain, Karine; Jean, Betty; Forestier, Christiane; Chezal, Jean-Michel; Rédini, Francoise; Degoul, Francoise; Miot-Noirault, Elisabeth

    2017-09-01

    This study was conducted during the development of innovative treatment targeting the microenvironment of chondrosarcoma. In this context, MMP inhibitors were conjugated with a quaternary ammonium (QA) function as a targeting ligand to proteoglycans of chondrosarcoma extracellular matrix. Here we report the proof of concept of this strategy applied to the MMP13 inhibitor, doxycycline (Dox). A quaternary ammonium derivative of the MMP13 inhibitor doxycycline (QA-Dox) was synthesized, and its anticancer activity was evaluated in the Swarm rat chondrosarcoma (SRC) model compared with the parent drug doxycycline, in vitro and in vivo. In vivo, dox and QA-Dox efficiency was assessed at equimolar doses according to a q4dx4 schedule by monitoring tumour volume by MRI and PG-targeted scintigraphy. Molecular mechanism (MMP13 expression, proteoglycan level) and histology studies were performed on tumours. The link of QA targeting function to Dox maintained the MMP13 inhibitory activity in vitro. Interestingly, the bacteriostatic activity was lost. SRC cells incubated with both drugs were blocked in S and G2 M phases. Tumour growth inhibition (confirmed by histology) was observed for both Dox and QA-Dox. Undesirable blood effects (leukocyte decrease) were reduced when Dox was targeted to tumour tissue using the QA function. In the SRC model, the MMP13 inhibitor Dox and its QA derivative are promising as adjuvant therapies for chondrosarcoma management.

  20. Effect of Process Factors on the Properties of Doxycycline ...

    African Journals Online (AJOL)

    HP

    Drug release from the vesicles was slow (< 60 % after 8 h). Nanovesicle size was ... can be applied for the formulation of doxycycline niosomes. Keywords: Doxycicline, Vesicles ..... Pharmacokinetic study of an injectable long- acting parenteral ...

  1. Effect of cathodic polarization on coating doxycycline on titanium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Geißler, Sebastian; Tiainen, Hanna; Haugen, Håvard J., E-mail: h.j.haugen@odont.uio.no

    2016-06-01

    Cathodic polarization has been reported to enhance the ability of titanium based implant materials to interact with biomolecules by forming titanium hydride at the outermost surface layer. Although this hydride layer has recently been suggested to allow the immobilization of the broad spectrum antibiotic doxycycline on titanium surfaces, the involvement of hydride in binding the biomolecule onto titanium remains poorly understood. To gain better understanding of the influence this immobilization process has on titanium surfaces, mirror-polished commercially pure titanium surfaces were cathodically polarized in the presence of doxycycline and the modified surfaces were thoroughly characterized using atomic force microscopy, electron microscopy, secondary ion mass spectrometry, and angle-resolved X-ray spectroscopy. We demonstrated that no hydride was created during the polarization process. Doxycycline was found to be attached to an oxide layer that was modified during the electrochemical process. A bacterial assay using bioluminescent Staphylococcus epidermidis Xen43 showed the ability of the coating to reduce bacterial colonization and planktonic bacterial growth. - Highlights: • Titanium hydride was found not to be involved in immobilization of doxycycline. • Doxycycline coating was strongly bound to a modified surface oxide layer. • Effect of coatings tested using a dynamic bacteria assay based on bioluminescence. • Topmost layer of adsorbed doxycycline was shown to have strong antibacterial effect.

  2. Doxycyclin induced esophageal injury: A Case series

    Directory of Open Access Journals (Sweden)

    İsmail Demiryılmaz

    2013-01-01

    Full Text Available Some drugs have been known to damage to esophagusfor a long time. Half of the cases reported are of tetracyclineand its derivatives. The damage caused by thesedrugs is depends on the drug itself and the patient.In this paper we present 5 patients having diagnosedesophageal damage endoscopically after due to doxycyclinuse. The mean age of the patients was 26 years.Three of them for acne and 2 for heir complaints gynecologicalinfection were taking these drugs. Lesions werelocated at the middle in 4 cases and lover part in 1 patient.The common complaint was retrosternal pain and heartburnafter taking the drug with insufficient water or withoutwater. All the patients were relieved by symtomatic teratment.Esophageal damage is to be remembered in patientscomplaning sudden pain and difficult swallowing on doxycyclintreatment and endoscopic procedure should beemployed for definition of diagnosis and evaluation of theseverity of the damage. After treatment, endoscopic controlis not necessary. Physicians must not forget to advicethe patients to take these drugs with splendid amount ofwater.Key words: Doxycycline, esophagus damage, endoscopy

  3. Efficacy of Doxycycline in the Treatment of Syphilis.

    Science.gov (United States)

    Dai, Ting; Qu, Rui; Liu, Jinfen; Zhou, Pingyu; Wang, Qianqiu

    2017-01-01

    Doxycycline is an alternative antibiotic drug for the treatment of syphilis, but data on its efficacy, especially data on its efficacy against late latent syphilis, are limited. A retrospective study was conducted to evaluate the effectiveness of doxycycline for the treatment of patients with different stages of syphilis. Patients who received doxycycline treatment between June 2011 and June 2014 were involved. The serological response to doxycycline was defined as either a negative toluidine red unheated serum test (TRUST) result or a ≥4-fold decrease in titer at 12 months following the treatment. Univariate and multivariate logistic regression analyses were performed to identify factors associated with the serological response. During the study period, a total of 163 syphilis patients were treated with doxycycline, and 118 patients completed doxycycline treatment and the 12-month follow-up. Among the 118 patients, the serological response rate at 12 months was 100.0% (7/7) in patients with primary syphilis, 96.9% (62/64) in patients with secondary syphilis, 91.3% (21/23) in patients with early latent syphilis, and 79.2% (19/24) in patients with late latent syphilis. The total serological response rates were 92.4% (109/118) for preprotocol (PP) patients and 66.9% (109/163) for all intention-to-treat (ITT) patients. In multivariate analysis, patients who serologically responded at 12 months following treatment were positively associated with a higher baseline TRUST titer and an earlier syphilis stage than nonresponders. Our study showed excellent treatment outcomes in patients with different stages of syphilis. Our data, along with those from other reports, support the usage of doxycycline as a good alternative therapeutic option in the treatment of syphilis. Copyright © 2016 American Society for Microbiology.

  4. Suboptimal adherence to doxycycline and treatment outcomes among men with non-gonococcal urethritis: a prospective cohort study.

    Science.gov (United States)

    Khosropour, Christine M; Manhart, Lisa E; Colombara, Danny V; Gillespie, Catherine W; Lowens, M Sylvan; Totten, Patricia A; Golden, Matthew R; Simoni, Jane

    2014-02-01

    Doxycycline, one of two recommended therapies for non-gonococcal urethritis (NGU), consists of a 7-day course of therapy (100 mg BID). Since suboptimal adherence may contribute to poor treatment outcomes, we examined the association between self-reported imperfect adherence to doxycycline and clinical and microbiologic failure among men with NGU. Men aged ≥16 years with NGU attending a Seattle, WA, sexually transmitted diseases clinic were enrolled in a double-blind, parallel-group superiority trial from January 2007 to July 2011. Men were randomised to active doxycycline/placebo azithromycin or placebo doxycycline/active azithromycin. Imperfect adherence was defined as missing ≥1 dose in 7 days. Urine was tested for Chlamydia trachomatis (CT), Mycoplasma genitalium (MG), and Ureaplasma urealyticum-biovar 2 (UU-2) using nucleic acid amplification tests. Clinical failure (symptoms and ≥5 PMNs/HPF or discharge) and microbiologic failure (positive tests for CT, MG, and/or UU-2) were determined after 3 weeks. 184 men with NGU were randomised to active doxycycline and provided data on adherence. Baseline prevalence of CT, MG and UU-2 was 26%, 13% and 27%, respectively. 28% of men reported imperfect adherence, and this was associated with microbiologic failure among men with CT (aRR=9.33; 95% CI 1.00 to 89.2) and UU-2 (aRR=3.08; 95% CI 1.31 to 7.26) but not MG. Imperfect adherence was not significantly associated with clinical failure overall or for any specific pathogens, but it was more common among imperfectly adherent men with CT (aRR=2.63; 0.93-7.41, p=0.07). Adherence may be important for microbiologic cure of select pathogens. Factors other than adherence should be considered for CT-negative men with persistent NGU.

  5. Sub-optimal adherence to doxycycline and treatment outcomes among men with non-gonococcal urethritis: a prospective cohort study

    Science.gov (United States)

    Khosropour, Christine M.; Manhart, Lisa E.; Colombara, Danny V.; Gillespie, Catherine W.; Lowens, M. Sylvan; Totten, Patricia A.; Golden, Matthew R.; Simoni, Jane

    2014-01-01

    Objective Doxycycline, one of two recommended therapies for non-gonococcal urethritis (NGU), consists of a seven-day course of therapy (100mg BID). Since suboptimal adherence may contribute to poor treatment outcomes, we examined the association between self-reported imperfect adherence to doxycycline and clinical and microbiologic failure among men with NGU. Methods Men aged ≥16 years with NGU attending a Seattle, WA sexually transmitted diseases clinic were enrolled in a double-blind, parallel-group superiority trial from January 2007 to July 2011. Men were randomized to active doxycycline/placebo azithromycin or placebo doxycycline/active azithromycin. Imperfect adherence was defined as missing ≥1 dose in 7 days. Urine was tested for Chlamydia trachomatis (CT), Mycoplasma genitalium (MG), and Ureaplasma urealyticum-biovar2 (UU-2) using nucleic acid amplification tests. Clinical failure (symptoms and ≥5 PMNs/HPF or discharge) and microbiologic failure (positive tests for CT, MG, and/or UU-2) were determined after 3-weeks. Results 184 men with NGU were randomized to active doxycycline and provided data on adherence. Baseline prevalence of CT, MG, and UU-2 was 26%, 13%, and 27%, respectively. 28% of men reported imperfect adherence and this was associated with microbiologic failure among men with CT (aRR=9.33; 95% CI=1.00–89.2) and UU-2 (aRR=3.08; 95% CI=1.31–7.26) but not MG. Imperfect adherence was not significantly associated with clinical failure overall or for any specific pathogens, but it was more common among imperfectly adherent men with CT (aRR=2.63; 0.93–7.41, p=0.07). Conclusions Adherence may be important for microbiologic cure of select pathogens. Factors other than adherence should be considered for CT-negative men with persistent NGU. PMID:24106340

  6. Doxycycline induced photodamage to human neutrophils and tryptophan

    International Nuclear Information System (INIS)

    Sandberg, S.; Glette, J.; Hopen, G.; Solberg, C.O.

    1984-01-01

    Neutrophil function were studied following irradiation (340-380 nm) of the cells in the presence of 22 μM doxycycline. At increasing light fluence the locomotion, chemiluminescence and glucose oxidation (by the hexose monophosphate shunt) of the neutrophils steadily decreased. The photodamage increased with increasing preincubation temperature and time and was enhanced in D 2 O, reduced in azide and abolished in anaerobiosis. Superoxide dismutase, catalase or mannitol did not influence the photodamage. Photooxidation of tryptophan in the presence of doxycycline was increased 9-10-fold in D 2 O and nearly abolished in the presence of 0.25 mM NaN 3 , indicating that singlet oxygen is the most important reactive oxygen species in the doxycycline-induced photodamage. The results may explain some of the features of tetracycline-induced photosensitivity and why other authors have obtained diverging results when studying the influence of tetracyclines on neutrophil functions. (author)

  7. Extensive Darier Disease Successfully Treated with Doxycycline Monotherapy

    Directory of Open Access Journals (Sweden)

    Alicia Sfecci

    2015-10-01

    Full Text Available Darier disease (DD is a rare dominantly inherited genodermatosis characterized by loss of intercellular adhesion (acantholysis and abnormal keratinization. DD is often difficult to manage. Numerous treatments have reportedly been used for the treatment of DD, with limited success. Systemic retinoids are considered the drug of choice for treating DD. However, their use is limited by potential deleterious side effects. Considering the recently reported efficacy of doxycycline for Hailey-Hailey disease, an inherited acantholytic skin disorder pathogenetically similar to DD, we report the case of a patient with extensive DD who showed a dramatic response to oral doxycycline monotherapy.

  8. The effect of sucralfate tablets vs. suspension on oral doxycycline absorption in dogs.

    Science.gov (United States)

    KuKanich, K; KuKanich, B

    2015-04-01

    The purpose of this study was to determine the effect of concurrent sucralfate (tablet or suspension) on doxycycline pharmacokinetics and to determine the effects of delaying sucralfate by 2 h on doxycycline absorption. Five dogs were included in a crossover study receiving: doxycycline alone; doxycycline concurrently with sucralfate tablet; doxycycline followed 2 h by sucralfate tablet; doxycycline concurrently with sucralfate suspension; and doxycycline followed 2 h by sucralfate suspension. Doxycycline plasma concentrations were evaluated with liquid chromatography with mass spectrometry. No interaction was seen when sucralfate was administered as a tablet. Sucralfate tablet fragments were frequently observed in some dogs' feces. The area under the curve (AUC) and maximum plasma concentration (CMAX ) were significantly lower (P < 0.001) in the concurrent sucralfate suspension group (AUC 7.2 h·μg/mL, CMAX 0.43 μg/mL) than with doxycycline alone (AUC 36.0 h·μg/mL, CMAX 2.53 μg/mL) resulting in a relative bioavailability of 20%. Delaying sucralfate suspension by 2 h after doxycycline administration resulted in no difference in doxycycline absorption as compared with doxycycline administration alone with a relative bioavailability of 74%. The lack of an interaction with sucralfate tablets suggests sucralfate should be administered as a suspension rather than tablet in dogs. © 2014 John Wiley & Sons Ltd.

  9. Delayed Microbial Cure of Lymphogranuloma Venereum Proctitis with Doxycycline Treatment

    NARCIS (Netherlands)

    de Vries, H.J.C.; Smelov, V.; Middelburg, J.G.; Pleijster, J.; Speksnijder, A.G.; Morré, S.A.

    2009-01-01

    Microbial cure of chlamydia proctitis (lymphogranuloma venereum [LGV] and non-LGV) with doxycycline treatment was evaluated by chlamydia DNA and RNA persistence in anal swab specimens. In LGV proctitis, RNA persisted for up to 16 days. In non-LGV chlamydia proctitis, DNA was undetectable after 7

  10. Chemical Pleurodesis Using Doxycycline and Viscum album Extract

    Directory of Open Access Journals (Sweden)

    Kyung Sub Song

    2017-08-01

    Full Text Available Background: In chemical pleurodesis for managing pulmonary air leak, tetracycline derivatives are commonly used, and their effectiveness has been established in many studies. Recently, a Viscum album extract was used in chemical pleurodesis. We compared the effects of V. album with those of a tetracycline derivative (doxycycline to demonstrate the therapeutic effectiveness of the V. album extract in chemical pleurodesis for managing pulmonary air leak. Methods: Between October 2010 and October 2016, chemical pleurodesis was performed using doxycycline in 40 patients and the V. album extract in 37 patients. Thirty-three patients were in the postoperative state after pulmonary resection, and 44 patients suffered from spontaneous pneumothorax. Results: No statistically significant difference in the success rate was observed between the 2 groups (V. album e xtract a nd d oxycycline . In b oth groups, chest pain w as t he m ost common complication. More patients in the doxycycline group complained of severe chest pain (42.1% vs. 13.5%, p=0.006. In the V. album extract group, 24.3% of the patients required a chest tube to drain the pleural effusion after cessation of the air leak (doxycycline group: 5%, p=0.022. Further, the amount of pleural effusion drained on the day after the last chemical pleurodesis in the V. album extract group was greater than that in the doxycycline group (162.2±170.2 mL vs. 97.0±77.2 mL, p=0.032. All patients were discharged from the hospital without complications after pleural effusion drainage. Conclusion: Considering that treatment using the V. album extract was less painful, V. album might be a feasible option for chemical pleurodesis. However, pleural effusion should be monitored carefully when using V. album extract for treating patients suffering from air leak.

  11. Doxycyclin ameliorates a starvation-induced germline tumor in C. elegans daf-18/PTEN mutant background.

    Science.gov (United States)

    Wolf, Tim; Qi, Wenjing; Schindler, Verena; Runkel, Eva Diana; Baumeister, Ralf

    2014-08-01

    Managing available resources is a key necessity of each organism to cope with the environment. The nematode C. elegans responds to nutritional deprivation or harsh environmental conditions with a multitude of developmental adaptations, among them a starvation-induced quiescence at early larval development (L1). daf-18, the C. elegans homolog of the human tumor suppressor gene PTEN, is essential for the maintenance of survival and germline stem cell arrest during the L1 diapause. We show here that daf-18 mutants, independently to their failure to maintain G2 arrest of the primordial germ cells, develop a gonad phenotype after refeeding. This highly penetrant gonadal phenotype is further enhanced by a mutation in shc-1, encoding a protein homologous to the human adaptor ShcA. Features of this phenotype are a tumor-like phenotype encompassing hyper-proliferation of germ cell nuclei and disruption/invasion of the basement membrane surrounding the gonad. The penetrance of this phenotype is reduced by decreasing starvation temperature. In addition, it is also ameliorated in a dose-dependent way by exposure to the antibiotic doxycyclin either during starvation or during subsequent refeeding. Since, in eukaryotic cells, doxycyclin specifically blocks mitochondrial translation, our results suggest that daf-18 and shc-1;daf-18 mutants fail to adapt mitochondrial activity to reduced nutritional availability during early larval developing. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Use of doxycycline for leptospirosis after high-risk exposure in São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Claudio R. GONSALEZ

    1998-01-01

    Full Text Available A clinical trial pilot study, double-blinded, randomized, and controlled with a placebo to assess the effectiveness of oral doxycycline (200 mg, single dose in preventing leptospirosis after high exposure to potentially contamined water was performed in São Paulo, SP, Brazil. Confirmed cases were defined as those with leptospira IgM antibody and symptoms; asymptomatic cases were those presenting with IgM antibodies but no symptoms; and suspected cases were individuals with symptoms but no IgM antibody. Forty subjects were given doxycycline and 42 were given placebo. In the drug-treated group there were 2 confirmed cases, 11 asymptomatic cases, and 6 suspected cases. In the placebo group there were 5 confirmed, 6 symptomatic, and 5 suspected cases. Even though we found a protective association of doxycycline for confirmed leptospirosis cases (RR = 2.3 and seroconversion only (RR = 2.0, the association was not statistically significant because of the small number of individuals enrolled in this pilot study. We observed that the 22% of the volunteers already had IgM antibodies to leptospirosis at the first sampling. Finally, the attack rate to confirmed, asymptomatic, and suspected cases of Leptospirosis was 8.5%, 22%, and 13%, respectively, in this population.Um ensaio clínico, duplo-cego, ao acaso, e controlado com placebo para aferir a eficácia da doxiciclina (200 mg, dose única em prevenir leptospirose após exposição de alto risco com água potencialmente contaminada foi realizado em São Paulo, SP, Brasil. Casos confirmados foram definidos como aqueles que apresentavam anticorpos IgM anti-Leptospira e sintomas; casos assintomáticos eram aqueles que apresentavam somente anticorpo IgM, casos suspeitos apresentavam sintomas, porém sem anticorpo IgM. 40 indivíduos tomaram doxaciclina e 42 tomaram placebo. No grupo tratado houve 2 casos confirmados, 11 assintomáticos e 6 casos suspeitos. No grupo placebo houve 5 casos confirmados, 6

  13. Influence of Mycotoxin Binders on the Oral Bioavailability of Doxycycline in Pigs.

    Science.gov (United States)

    De Mil, Thomas; Devreese, Mathias; De Saeger, Sarah; Eeckhout, Mia; De Backer, Patrick; Croubels, Siska

    2016-03-16

    Mycotoxin binders are feed additives that aim to adsorb mycotoxins in the gastrointestinal tract of animals, making them unavailable for systemic absorption. The antimicrobial drug doxycycline (DOX) is often used in pigs and is administered through feed or drinking water; hence, DOX can come in contact with mycotoxin binders in the gastrointestinal tract. This paper describes the effect of four mycotoxin binders on the absorption of orally administered DOX in pigs. Two experiments were conducted: The first used a setup with bolus administration to fasted pigs at two different dosages of mycotoxin binder. In the second experiment, DOX and the binders were mixed in the feed at dosages recommended by the manufacturers (= field conditions). Interactions are possible between some of the mycotoxin binders dosed at 10 g/kg feed but not at 2 g/kg feed. When applying field conditions, no influences were seen on the plasma concentrations of DOX.

  14. A doxycycline-loaded polymer-lipid encapsulation matrix coating for the prevention of implant-related osteomyelitis due to doxycycline-resistant methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Metsemakers, Willem-Jan; Emanuel, Noam; Cohen, Or; Reichart, Malka; Potapova, Inga; Schmid, Tanja; Segal, David; Riool, Martijn; Kwakman, Paulus H S; de Boer, Leonie; de Breij, Anna; Nibbering, Peter H; Richards, R Geoff; Zaat, Sebastian A J; Moriarty, T Fintan

    2015-07-10

    Implant-associated bone infections caused by antibiotic-resistant pathogens pose significant clinical challenges to treating physicians. Prophylactic strategies that act against resistant organisms, such as methicillin-resistant Staphylococcus aureus (MRSA), are urgently required. In the present study, we investigated the efficacy of a biodegradable Polymer-Lipid Encapsulation MatriX (PLEX) loaded with the antibiotic doxycycline as a local prophylactic strategy against implant-associated osteomyelitis. Activity was tested against both a doxycycline-susceptible (doxy(S)) methicillin-susceptible S. aureus (MSSA) as well as a doxycycline-resistant (doxy(R)) methicillin-resistant S. aureus (MRSA). In vitro elution studies revealed that 25% of the doxycycline was released from the PLEX-coated implants within the first day, followed by a 3% release per day up to day 28. The released doxycycline was highly effective against doxy(S) MSSA for at least 14days in vitro. A bolus injection of doxycycline mimicking a one day release from the PLEX-coating reduced, but did not eliminate, mouse subcutaneous implant-associated infection (doxy(S) MSSA). In a rabbit intramedullary nail-related infection model, all rabbits receiving a PLEX-doxycycline-coated nail were culture negative in the doxy(S) MSSA-group and the surrounding bone displayed a normal physiological appearance in both histological sections and radiographs. In the doxy(R) MRSA inoculated rabbits, a statistically significant reduction in the number of culture-positive samples was observed for the PLEX-doxycycline-coated group when compared to the animals that had received an uncoated nail, although the reduction in bacterial burden did not reach statistical significance. In conclusion, the PLEX-doxycycline coating on titanium alloy implants provided complete protection against implant-associated MSSA osteomyelitis, and resulted in a significant reduction in the number of culture positive samples when challenged with a

  15. In vitro activities of doxycycline and enrofloxacin against European Chlamydia psittaci strains from turkeys.

    OpenAIRE

    Butaye, P; Ducatelle, R; De Backer, P; Vermeersch, H; Remon, J P; Haesebrouck, F

    1997-01-01

    The in vitro susceptibility of 14 European Chlamydia psittaci strains from turkeys to the antibiotics doxycycline and enrofloxacin was tested. For doxycycline the MIC ranged from 0.05 to 0.2 microg/ml, with an average of 0.1 microg/ml. For enrofloxacin the MIC was 0.25 microg/ml. Acquired resistance was not detected against doxycycline and enrofloxacin.

  16. The effects of doxycycline and micronized purified flavonoid fraction on human vein wall remodeling are not hypoxia-inducible factor pathway-dependent.

    Science.gov (United States)

    Lim, Chung Sim; Kiriakidis, Serafim; Paleolog, Ewa M; Davies, Alun H

    2012-10-01

    Doxycycline and micronized purified flavonoid fraction (MPFF) modulate vein wall remodeling that may be associated with hypoxia in varicose veins (VVs), vein graft stenosis, and deep venous thrombosis. We recently reported that in vitro exposure of non-VV (NVVs) and VVs to hypoxic conditions activates the hypoxia-inducible factor (HIF) pathway. This study investigated the in vitro effects of doxycycline and MPFF on the HIF pathway in hypoxic NVVs and VVs. Six NVVs and six VVs obtained from surgery were used to prepare vein organ cultures, which were exposed to hypoxia (1% O(2)), with and without MPFF (10(-5) mol/L) or doxycycline (5 μg/mL) for 16 hours. The veins were analyzed for HIF-1α, HIF-2α, and their target gene expression, with real-time polymerase chain reaction and Western blot. The differences between gene expressions were tested with one-way analysis of variance with repeated measures, followed by the Dunnett test for multiple comparisons. P factor, B-cell lymphoma 2/adenovirus E1B 19-kDa protein-interacting protein 3, prolyl hydroxylase domain-2, and prolyl hydroxylase domain-3, was not significantly altered in NVVs and VVs exposed to hypoxia and treated with doxycycline or MPFF compared with those untreated. Doxycycline and MPFF at a concentration corresponding to a therapeutic dose do not alter the activation of the HIF pathway in NVV and VV organ cultures exposed to hypoxia. Our findings suggest vein wall remodeling actions in NVVs and VVs are likely not HIF-dependent. Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  17. 76 FR 72935 - Amended Authorization of Emergency Use of Doxycycline Hyclate Tablet Emergency Kits for Eligible...

    Science.gov (United States)

    2011-11-28

    ...] Amended Authorization of Emergency Use of Doxycycline Hyclate Tablet Emergency Kits for Eligible United... to the Emergency Use Authorization (EUA) (the Authorization) for doxycycline hyclate tablet emergency... Doxycyline Hyclate Tablet Emergency Kits, as Amended In 2004, the Secretary of the Department of Homeland...

  18. Inhibition of MMP synthesis by doxycycline and chemically modified tetracyclines (CMTs) in human endothelial cells

    NARCIS (Netherlands)

    Hanemaaijer, R.; Visser, H.; Koolwijk, P.; Sorsa, T.; Salo, T.; Golub, L.M.; Hinsbergh, V.W. van

    1998-01-01

    Doxycycline is a commonly used broad-spectrum antibiotic. Recently, it has been shown that it also inhibits the activity of mammalian collagenases and gelatinases, an activity unrelated to its antimicrobial efficacy. In this study, we show that doxycycline not only inhibits MMP-8 and MMP-9

  19. DsRed gene expression by doxycycline in porcine fibroblasts and ...

    African Journals Online (AJOL)

    Goo

    2013-05-22

    May 22, 2013 ... Pigs are one of the valuable animal models for human ... 48 h, 7: without doxycycline after 96 h, 8: without doxycycline after 144 h, Upper panel is for RFP .... Chimeric piggyBac transposases for genomic targeting in human.

  20. New intracanal formulations containing doxycycline or chlorhexidine against Enterococcus faecalis.

    Science.gov (United States)

    Silva, Ana Rita Marques da; Pinto, Shelon Cristina Souza; Santos, Elizabete Brasil dos; Santos, Fábio André dos; Farago, Paulo Vitor; Gomes, João Carlos; Pina-Vaz, Irene; Carvalho, Manuel Fontes

    2014-01-01

    The present study aims to evaluate the antimicrobial effect of two new intracanal preparations against E. faecalis. Thirty single-rooted human canine teeth were used. The crowns were removed and the roots were instrumented using a conventional technique. Three groups of ten teeth each were infected with 108 CFU/ ml of E. faecalis for 21 days. The root canals were flled with new intracanal medications containing 3% doxycycline hydrochloride (DX) or 2% chlorhexidine digluconate (CHX). Ten teeth received no medication (NM)-negative control. Microbial samples were obtained 21 days after contamination: 14 days under the effect of the intracanal medications and 7 days after replacing the medications by BHI broth. The samples were homogenized, diluted, seeded on BHI agar and incubated for 48h/36°C. The number of colony forming units (CFU/ml) was obtained and analyzed statistically. All intracanal dressings significantly reduced the number of bacterial cells in the root canal after 14 days with medication. After the period with 7 days with BHI broth, the CFU counts of E. faecalis remained at low values. However, the NM group showed a significant increase of CFU in this period to similar values of the initial contamination. 3% doxycycline hydrochloride gel and 2% CHX gel were effective to eliminate E. faecalis from the root canal system.

  1. A new therapeutic association to manage relapsing experimental colitis: Doxycycline plus Saccharomyces boulardii.

    Science.gov (United States)

    Garrido-Mesa, José; Algieri, Francesca; Rodriguez-Nogales, Alba; Utrilla, Maria Pilar; Rodriguez-Cabezas, Maria Elena; Zarzuelo, Antonio; Ocete, Maria Angeles; Garrido-Mesa, Natividad; Galvez, Julio

    2015-07-01

    Immunomodulatory antibiotics have been proposed for the treatment of multifactorial conditions such as inflammatory bowel disease. Probiotics are able to attenuate intestinal inflammation, being considered as safe when chronically administered. The aim of the study was to evaluate the anti-inflammatory effects of doxycycline, a tetracycline with immunomodulatory properties, alone and in association with the probiotic Saccharomyces boulardii CNCMI-745. Doxycycline was assayed both in vitro (Caco-2 epithelial cells and RAW 264.7 macrophages) and in vivo, in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis and the dextran sodium sulfate (DSS) model of mouse colitis. In addition, the anti-inflammatory effect of the association of doxycycline and the probiotic was evaluated in vitro and in vivo in a DSS model of reactivated colitis in mice. Doxycycline displayed immunomodulatory activity in vitro, reducing IL-8 production by intestinal epithelial cells and nitric oxide by macrophages. Doxycycline administration to TNBS-colitic rats (5, 10 and 25 mg/kg) ameliorated the intestinal inflammatory process, being its efficacy comparable to that previously showed by minocycline. Doxycycline treatment was also effective in reducing acute intestinal inflammation in the DSS model of mouse colitis. The association of doxycycline and S. boulardii helped managing colitis in a reactivated model of colitis, by reducing intestinal inflammation and accelerating the recovery and attenuating the relapse. This was evidenced by a reduced disease activity index, colonic tissue damage and expression of inflammatory mediators. This study confirms the intestinal anti-inflammatory activity of doxycycline and supports the potential use of its therapeutic association with S. boulardii for the treatment of inflammatory bowel diseases, in which doxycycline is used to induce remission and long term probiotic administration helps to prevent the relapses. Copyright © 2015 Elsevier Ltd. All

  2. Application of novel metal organic framework, MIL-53(Fe) and its magnetic hybrid: For removal of pharmaceutical pollutant, doxycycline from aqueous solutions.

    Science.gov (United States)

    Naeimi, Shakiba; Faghihian, Hossein

    2017-07-01

    As a pharmaceutical pollutant, doxycycline causes contamination when enters into the environment. In this research MIL-53(Fe), and its magnetic hybrid MIL-53(Fe)/Fe 3 O 4 were synthesized and employed for removal of doxycycline from aqueous solutions. The adsorbents were characterized by XRD, SEM, BET, FTIR, EDAX, VSM and TG-DTG technique. The effect of different variables such as DOC concentration, pH, contacting time, and adsorbent dose on the removal efficiency was studied and under optimized conditions the adsorption capacity of 322mgg -1 was obtained. The adsorption process was kinetically fast and the equilibration was attained within 30min. The used adsorbent was easily separated from the solution by applying external magnetic field. The regenerated adsorbent retained most of its initial capacity after six regeneration steps. The effect of ionic strength was studied and it was indicated that removal of doxycycline from salt-containing water with moderate ionic strengths was quite feasible. Langmuir, Freundlich, Tempkin and Dubinin-Redushkevich isotherms were employed to describe the nature of adsorption process. The sorption data was well interpreted by the Longmuir model. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. A multifunctional molecularly imprinted polymer-based biosensor for direct detection of doxycycline in food samples

    DEFF Research Database (Denmark)

    Ashley, Jon; Feng, Xiaotong; Sun, Yi

    2018-01-01

    In this study, we developed a new type of multifunctional molecularly imprinted polymer (MIP) composite as an all-in-one biosensor for the low-cost, rapid and sensitive detection of doxycycline in pig plasma. The MIP composite consisted of a magnetic core for ease of manipulation, and a shell...... of fluorescent MIPs for selective recognition of doxycycline. By simply incorporating a small amount of fluorescent monomer (fluorescein-Oacrylate), the fluorescent MIP layer was successfully grafted onto the magnetic core via a surface imprinting technique. The resultant MIP composites showed significant....... The multifunctional MIP composites were used to directly extract doxycycline from spiked pig plasma samples and quantify the antibiotics based on the quenched fluorescence signals. Recoveries of doxycycline were found in the range of 88–107%....

  4. The end of a dogma: the safety of doxycycline use in young children for malaria treatment.

    Science.gov (United States)

    Gaillard, Tiphaine; Briolant, Sébastien; Madamet, Marylin; Pradines, Bruno

    2017-04-13

    Anti-malarial drug resistance to chloroquine and sulfadoxine-pyrimethamine has spread from Southeast Asia to Africa. Furthermore, the recent emergence of resistance to artemisinin-based combination therapy (ACT) in Southeast Asia highlights the need to identify new anti-malarial drugs. Doxycycline is recommended for malaria chemoprophylaxis for travel in endemic areas, or in combination with the use of quinine for malaria treatment when ACT is unavailable or when the treatment of severe malaria with artesunate fails. However, doxycycline is not used in young children under 8 years of age due to its contraindication due to the risk of yellow tooth discolouration and dental enamel hypoplasia. Doxycycline was developed after tetracycline and was labelled with the same side-effects as the earlier tetracyclines. However, recent studies report little or no effects of doxycycline on tooth staining or dental enamel hypoplasia in children under 8 years of age. In the United States, the Centers for Disease Control and Prevention have recommended the use of doxycycline for the treatment of acute and chronic Q fever and tick-borne rickettsial diseases in young children. It is time to rehabilitate doxycycline and to recommend it for malaria treatment in children under 8 years of age.

  5. No visible dental staining in children treated with doxycycline for suspected Rocky Mountain Spotted Fever.

    Science.gov (United States)

    Todd, Suzanne R; Dahlgren, F Scott; Traeger, Marc S; Beltrán-Aguilar, Eugenio D; Marianos, Donald W; Hamilton, Charlene; McQuiston, Jennifer H; Regan, Joanna J

    2015-05-01

    To evaluate whether cosmetically relevant dental effects occurred among children who had received doxycycline for treatment of suspected Rocky Mountain spotted fever (RMSF). Children who lived on an American Indian reservation with high incidence of RMSF were classified as exposed or unexposed to doxycycline, based on medical and pharmacy record abstraction. Licensed, trained dentists examined each child's teeth and evaluated visible staining patterns and enamel hypoplasia. Objective tooth color was evaluated with a spectrophotometer. Fifty-eight children who received an average of 1.8 courses of doxycycline before 8 years of age and who now had exposed permanent teeth erupted were compared with 213 children who had never received doxycycline. No tetracycline-like staining was observed in any of the exposed children's teeth (0/58, 95% CI 0%-5%), and no significant difference in tooth shade (P=.20) or hypoplasia (P=1.0) was found between the 2 groups. This study failed to demonstrate dental staining, enamel hypoplasia, or tooth color differences among children who received short-term courses of doxycycline at <8 years of age. Healthcare provider confidence in use of doxycycline for suspected RMSF in children may be improved by modifying the drug's label. Published by Elsevier Inc.

  6. Seven days of doxycycline is an effective treatment for asymptomatic rectal Chlamydia trachomatis infection.

    Science.gov (United States)

    Elgalib, A; Alexander, S; Tong, C Y W; White, J A

    2011-08-01

    There are no evidence-based guidelines for the specific management of rectal Chlamydia trachomatis (CT) infection. All men who have sex with men (MSM) diagnosed with asymptomatic rectal CT by nucleic acid amplification test (NAAT) at a large London genitourinary (GU) medicine clinic between September 2006 and September 2009 were offered oral doxycycline 100 mg twice daily for seven days and invited for a test of cure (TOC) by CT NAAT four weeks after treatment. A total of 487 asymptomatic rectal CT infections were diagnosed and analysis was restricted to 165 TOCs from men whose only treatment had been doxycycline for seven days. The median time post-treatment for TOC was 45 days (interquartile range [IQR], 34-88). Only two patients tested CT-positive at follow-up. One had taken doxycycline only for three days; the other attended for TOC 240 days after the completion of doxycycline treatment and at this time presented with new symptoms in the context of ongoing high sexual risk. Our findings show that doxycycline 100 mg twice daily for seven days is highly effective treatment for asymptomatic rectal CT infection, achieving clearance of CT in 98.8% (163/165; 95% CI 95.4-99.9%) of cases. We advocate doxycycline for seven days as first-line therapy for asymptomatic rectal CT.

  7. Comparative efficacy of some quinolones and doxycycline against chronic infection of brucella melitensis 16M in balb/c mice

    International Nuclear Information System (INIS)

    Safi, M.; Albalaa, B.; Mahmoud, N.H.; Mariri, A.A.

    2016-01-01

    This study was under taken to observe various treatment methods for brucellosis caused by Brucella melitensis . The effect of therapeutic regimens with ciprofloxacin, ofloxacin and levofloxacin alone or in combination with doxycycline was assessed against B. melitensis chronic infection using 200 mice. Doxycycline alone or in combination with ciprofloxacin was significantly found to reduce the infection till 135 days post-infection (p<0.0001). Moreover, doxycycline was more effective than ciprofloxacin and ofloxacin 135 days post-infection (p = 0.04 and p = 0.02, respectively). However, treatment with quinolone-doxycycline combinations revealed synergistic effects as they were able to reduce the splenic cell forming unit (CFU) from day 45 post-infection. Similarly, doxycycline treatment reduced the splenic colony forming unit (CFU) from day 90 post-infection. In conclusion, doxycycline seems to be the most effective agent against Brucella chronic infection. (author)

  8. Therapeutic effects of topical doxycycline in a benzalkonium chloride-induced mouse dry eye model.

    Science.gov (United States)

    Zhang, Zhen; Yang, Wen-Zhao; Zhu, Zhen-Zhen; Hu, Qian-Qian; Chen, Yan-Feng; He, Hui; Chen, Yong-Xiong; Liu, Zu-Guo

    2014-05-06

    We investigated the therapeutic effects and underlying mechanisms of topical doxycycline in a benzalkonium chloride (BAC)-induced mouse dry eye model. Eye drops containing 0.025%, 0.1% doxycycline or solvent were administered to a BAC-induced dry eye model four times daily. The clinical evaluations, including tear break-up time (BUT), fluorescein staining, inflammatory index, and tear volume, were performed on days 0, 1, 4, 7, and 10. Global specimens were collected on day 10 and processed for immunofluorescent staining, TUNEL, and periodic acid-Schiff assay. The levels of inflammatory mediators in the corneas were determined by real-time PCR. The total and phosphorylated nuclear factor-κB (NF-κB) were detected by Western blot. Both 0.025% and 0.1% doxycycline treatments resulted in increased BUT, lower fluorescein staining scores, and inflammatory index on days 4, 7, and 10, while no significant change in tear volume was observed. The 0.1% doxycycline-treated group showed more improvements in decreasing fluorescein staining scores, increasing Ki-67-positive cells, and decreasing TUNEL- and keratin-10-positive cells than other groups. The mucin-filled goblet cells in conjunctivas were increased, and the expression of CD11b and levels of matrix metalloproteinase-9, IL-1β, IL-6, TNF-α, macrophage inflammatory protein-2, and cytokine-induced neutrophil chemoattractant in corneas were decreased in both doxycycline-treated groups. In addition, doxycycline significantly reduced the phosphorylation of NF-κB activated in the BAC-treated corneas. Topical doxycycline showed clinical improvements and alleviated ocular surface inflammation on BAC-induced mouse dry eye, suggesting a potential as an anti-inflammatory agent in the clinical treatment of dry eye.

  9. A randomized, comparative study of dual therapy (doxycycline-rifampin) versus triple therapy (doxycycline-rifampin-levofloxacin) for treating acute/subacute brucellosis.

    Science.gov (United States)

    Hasanain, Ahmad; Mahdy, Reem; Mohamed, Asmaa; Ali, Mostafa

    2016-01-01

    The aim of this study was to compare both the efficacy and safety profile of the WHO-recommended, dual therapy (doxycycline-rifampin) to a quinolone-based, triple therapy (doxycycline-rifampin-levofloxacin) for treating acute/subacute brucellosis. We studied 107 consecutive, naïve patients with acute/subacute brucellosis admitted to Assiut University Hospital. Patients were randomly allocated to receive the dual therapy of doxycycline-rifampin (group-A) or to receive the triple therapy of doxycycline-rifampin-levofloxacin (group-B). Acute/subacute brucellosis was diagnosed based on the presence of: (1) contact with animals or fresh animal products, (2) suggestive clinical manifestations of less than one-year duration, and (3) positive antibody titer (1:160) by standard tube agglutination test. There was no significant difference between the two groups regarding their demographic data. Fever was the most frequent manifestation (96.3%). Epigastric pain was the most frequent adverse effect of treatment (12.1%). Group-A patients had a significantly higher relapse rate compared to group-B patients (22.6% versus 9.3%, p-value=0.01). The rate of treatment adverse effects was higher among group-B patients, although not reaching statistical significance (20.4% versus 11.3%, p-value=0.059). Adding levofloxacin to the dual therapy for acute/subacute brucellosis (doxycycline-rifampin) may increase its efficacy in terms of lowering the relapse rate of the disease. Further, larger scale studies are needed before considering modifying the standard, dual therapy for brucellosis. Copyright © 2016 Elsevier Editora Ltda. All rights reserved.

  10. Influence of mycotoxin binders on the oral bioavailability of tylosin, doxycycline, diclazuril, and salinomycin in fed broiler chickens.

    Science.gov (United States)

    De Mil, T; Devreese, M; Maes, A; De Saeger, S; De Backer, P; Croubels, S

    2017-07-01

    The presence of mycotoxins in broiler feed can have deleterious effects on the wellbeing of the animals and their performance. Mycotoxin binders are feed additives that aim to adsorb mycotoxins in the intestinal tract and thereby prevent the oral absorption of the mycotoxin. The simultaneous administration of coccidiostats and/or antimicrobials with mycotoxin binders might lead to a reduced oral bioavailability of these veterinary medicinal products. This paper describes the influence of 3 mycotoxin binders (i.e., clay 1 containing montmorillonite, mica, and feldspars; clay 2 containing montmorillonite and quartz; and yeast 1 being a modified glucomannan fraction of inactivated yeast cells) and activated carbon on the oral bioavailability and pharmacokinetic parameters of the antimicrobials doxycycline and tylosin, and the coccidiostats diclazuril and salinomycin. A feeding study with 40 15 day-old broilers was performed evaluating the effects of long-term feeding 2 g mycotoxin binder/kg of feed. The birds were randomly divided into 5 groups of 8 birds each, i.e., a control group receiving no binder and 4 test groups receiving either clay 1, clay 2, yeast 1, or activated carbon mixed in the feed. After 15 d of feeding, both the control and each test group were administered doxycycline, tylosin, diclazuril, and salinomycin, consecutively, respecting a wash-out period of 2 to 3 d between each administration. The 4 medicinal products were dosed using a single bolus administration directly in the crop. After each bolus administration, blood was collected for plasma analysis and calculation of the main pharmacokinetic parameters and relative oral bioavailability (F = area under the plasma concentration-time curve (AUC0-8 h) in the test groups/AUC0-8 h in the control group)*100). No effects were observed of any of the mycotoxin binders on the relative oral bioavailability of the coccidiostats (i.e., F between 82 and 101% and 79 and 93% for diclazuril and salinomycin

  11. Effects of Doxycycline on gene expression in Wolbachia and Brugia malayi adult female worms in vivo

    Directory of Open Access Journals (Sweden)

    Rao Ramakrishna U

    2012-02-01

    Full Text Available Abstract Background Most filarial nematodes contain Wolbachia symbionts. The purpose of this study was to examine the effects of doxycycline on gene expression in Wolbachia and adult female Brugia malayi. Methods Brugia malayi infected gerbils were treated with doxycycline for 6-weeks. This treatment largely cleared Wolbachia and arrested worm reproduction. RNA recovered from treated and control female worms was labeled by random priming and hybridized to the Version 2- filarial microarray to obtain expression profiles. Results and discussion Results showed significant changes in expression for 200 Wolbachia (29% of Wolbachia genes with expression signals in untreated worms and 546 B. malayi array elements after treatment. These elements correspond to known genes and also to novel genes with unknown biological functions. Most differentially expressed Wolbachia genes were down-regulated after treatment (98.5%. In contrast, doxycycline had a mixed effect on B. malayi gene expression with many more genes being significantly up-regulated after treatment (85% of differentially expressed genes. Genes and processes involved in reproduction (gender-regulated genes, collagen, amino acid metabolism, ribosomal processes, and cytoskeleton were down-regulated after doxycycline while up-regulated genes and pathways suggest adaptations for survival in response to stress (energy metabolism, electron transport, anti-oxidants, nutrient transport, bacterial signaling pathways, and immune evasion. Conclusions Doxycycline reduced Wolbachia and significantly decreased bacterial gene expression. Wolbachia ribosomes are believed to be the primary biological target for doxycycline in filarial worms. B. malayi genes essential for reproduction, growth and development were also down-regulated; these changes are consistent with doxycycline effects on embryo development and reproduction. On the other hand, many B. malayi genes involved in energy production, electron

  12. [Study on the interaction of doxycycline with human serum albumin].

    Science.gov (United States)

    Hu, Tao-Ying; Chen, Lin; Liu, Ying

    2014-05-01

    The present study was designed to investigate the interaction of doxycycline (DC) with human serum albumin (HSA) by the inner filter effects, displacement experiments and molecular docking methods, based on classic multi-spectroscopy. With fluorescence quenching method at 298 and 310 K, the binding constants Ka, were determined to be 2. 73 X 10(5) and 0. 74X 10(5) L mol-1, respectively, and there was one binding site between DC and HSA, indicating that the binding of DC to HSA was strong, and the quenching mechanism was a static quenching. The thermodynamic parameters (enthalpy change, AH and enthropy change, delta S) were calculated to be -83. 55 kJ mol-1 and -176. 31 J mol-1 K-1 via the Vant' Hoff equation, which indicated that the interaction of DC with HSA was driven mainly by hydrogen bonding and van der Waals forces. Based on the Föster's theory of non-radiation energy transfer, the specific binding distance between Trp-214 (acceptor) and DC (donor) was 4. 98 nm, which was similar to the result confirmed by molecular docking. Through displacement experiments, sub-domain IIA of HSA was assigned to possess the high-affinity binding site of DC. Three-dimensional fluorescence spectra indicated that the binding of DC to HSA induced the conformation change of HSA and increased the disclosure of some part of hydrophobic regions that had been buried before. The results of FTIR spectroscopy showed that DC bound to HSA led to the slight unfolding of the polypeptide chain of HSA. Furthermore, the binding details between DC and HSA were further confirmed by molecular docking methods, which revealed that DC was bound at sub-domain IIA through multiple interactions, such as hydrophobic effect, polar forces and pi-pi interactions. The experimental results provide theoretical basis and reliable data for the study of the interaction between small drug molecule and human serum albumin

  13. Antibacterial effect of doxycycline-coated dental abutment surfaces

    International Nuclear Information System (INIS)

    Xing, Rui; Tiainen, Hanna; Shabestari, Maziar; Lyngstadaas, Ståle P; Haugen, Håvard J; Witsø, Ingun L; Lönn-Stensrud, Jessica; Jugowiec, Dawid

    2015-01-01

    Biofilm formation on dental abutment may lead to peri-implant mucositis and subsequent peri-implantitis. These cases are clinically treated with antibiotics such as doxycycline (Doxy). Here we used an electrochemical method of cathodic polarization to coat Doxy onto the outer surface of a dental abutment material. The Doxy-coated surface showed a burst release in phosphate-buffered saline during the first 24 h. However, a significant amount of Doxy remained on the surface for at least 2 weeks especially on a 5 mA–3 h sample with a higher Doxy amount, suggesting both an initial and a long-term bacteriostatic potential of the coated surface. Surface chemistry was analyzed by x-ray photoelectron spectroscopy and secondary ion mass spectrometry. Surface topography was evaluated by field emission scanning electron microscopy and blue-light profilometry. Longer polarization time from 1 h to 5 h and higher current density from 1 to 15 mA cm −2 resulted in a higher amount of Doxy on the surface. The surface was covered by a layer of Doxy less than 100 nm without significant changes in surface topography. The antibacterial property of the Doxy-coated surface was analyzed by biofilm and planktonic growth assays using Staphylococcus epidermidis. Doxy-coated samples reduced both biofilm accumulation and planktonic growth in broth culture, and also inhibited bacterial growth on agar plates. The antibacterial effect was stronger for samples of 5 mA–3 h coated with a higher amount of Doxy compared to that of 1 mA–1 h. Accordingly, an abutment surface coated with Doxy has potential for preventing bacterial colonization when exposed to the oral cavity. Doxy-coating could be a viable way to control peri-implant mucositis and prevent its progression into peri-implantitis. (paper)

  14. Doxycycline delivery from PLGA microspheres prepared by a modified solvent removal method.

    Science.gov (United States)

    Patel, Roshni S; Cho, Daniel Y; Tian, Cheng; Chang, Amy; Estrellas, Kenneth M; Lavin, Danya; Furtado, Stacia; Mathiowitz, Edith

    2012-01-01

    We report on the development of a modified solvent removal method for the encapsulation of hydrophilic drugs within poly(lactic-co-glycolic acid) (PLGA). Using a water/oil/oil double emulsion, hydrophilic doxycycline was encapsulated within PLGA spheres with particle diameters ranging from approximately 600 nm to 19 µm. Encapsulation efficiencies of up to 74% were achieved for theoretical loadings from 1% to 10% (w/w), with biphasic release over 85 days with nearly complete release at the end of this time course. About 1% salt was added to the formulations to examine its effects on doxycycline release; salt modulated release only by increasing the magnitude of initial release without altering kinetics. Fourier transform infrared spectroscopy indicated no characteristic differences between doxycycline-loaded and control spheres. Differential scanning calorimetry and X-ray diffraction suggest that there may be a molecular dispersion of the doxycycline within the spheres and the doxycycline may be in an amorphous state, which could explain the slow, prolonged release of the drug.

  15. Doxycycline attenuates acrolein-induced mucin production, in part by inhibiting MMP-9.

    Science.gov (United States)

    Ren, Shuang; Guo, Ling-Li; Yang, Jie; Liu, Dai-Shun; Wang, Tao; Chen, Lei; Chen, Ya-Juan; Xu, Dan; Feng, Yu-Lin; Wen, Fu-Qiang

    2011-01-10

    Matrix metalloproteinases (MMPs), especially MMP-9, have been found to increase the expression of epidermal growth factor (EGF) receptor, a possible regulator of acrolein-induced mucin expression in the airway epithelium. The aim of this study was to investigate whether doxycycline, a tetracycline antibiotic that inhibits MMPs, attenuates mucus production and synthesis of mucin MUC5AC in acrolein-exposed rats. Sprague-Dawley rats were exposed to acrolein aerosol [3.0parts/million (ppm), 6h/day, 12days] and they received 20mg/kg doxycycline daily by gavage, beginning two days before exposure to acrolein until the end of the experiment. The production of mucin glycoproteins and expression of the MMP-9 and MUC5AC genes were measured in rat trachea. The increase in levels of MMP-9 mRNA and protein in airway epithelium after acrolein exposure was accompanied by an increase in MUC5AC mRNA expression. Doxycycline significantly prevented these increases in acrolein-induced expression of MMP-9 and MUC5AC and attenuated mucus production in tracheal epithelium. These results indicate that doxycycline attenuated acrolein-induced mucin synthesis, in part by inhibiting expression of MMP-9. Thus doxycycline may have a prophylactic effect in the treatment of smoking-induced mucus hypersecretion. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

  16. Treatment of ocular rosacea: comparative study of topical cyclosporine and oral doxycycline.

    Science.gov (United States)

    Arman, Aysegul; Demirseren, Duriye Deniz; Takmaz, Tamer

    2015-01-01

    To compare the effectiveness of topical cyclosporine A emulsion with that of oral doxycycline for rosacea associated ocular changes and dry eye complaints. One hundred and ten patients with rosacea were screened. Thirty-eight patients having rosacea associated eyelid and ocular surface changes and dry eye complaints were included in the study. Patients were randomly divided into two groups: nineteen patients were given topical cyclosporine twice daily and nineteen patients were given oral doxycycline 100 mg twice daily for the first month and once daily for the following two months. Symptom and sign scores, ocular surface disease index questionnarie and tear function tests were evaluated at baseline and monthly for 3mo. Three months after results were compared with that of baseline. Mean values of symptom, eyelid sign and corneal/conjunctival sign scores of each treatment group at baseline and 3mo after treatments were compared and both drugs were found to be effective on rosacea associated ocular changes (Ptreatment of eyelid signs (P=0.01). There was statistically significant increase in the mean Schirmer score with anesthesia and tear break up time scores in the cyclosporine treatment group compared to the doxycycline treatment group (Ptreatment of rosacea associated ocular complications because it is more effective than doxycycline. In addition ocular rosacea as a chronic disease requires long term treatment and doxycycline has various side effects limiting its long term usage.

  17. Macrofilaricidal Activity in Wuchereria bancrofti after 2 Weeks Treatment with a Combination of Rifampicin plus Doxycycline

    Directory of Open Access Journals (Sweden)

    Alexander Yaw Debrah

    2011-01-01

    Full Text Available Infection with the filarial nematode Wuchereria bancrofti can lead to lymphedema, hydrocele, and elephantiasis. Since adult worms cause pathology in lymphatic filariasis (LF, it is imperative to discover macrofilaricidal drugs for the treatment of the infection. Endosymbiotic Wolbachia in filariae have emerged as a new target for antibiotics which can lead to macrofilaricidal effects. In Ghana, a pilot study was carried out with 39 LF-infected men; 12 were treated with 200 mg doxycycline/day for 4 weeks, 16 were treated with a combination of 200 mg doxycycline/day + 10 mg/kg/day rifampicin for 2 weeks, and 11 patients received placebo. Patients were monitored for Wolbachia and microfilaria loads, antigenaemia, and filarial dance sign (FDS. Both 4-week doxycycline and the 2-week combination treatment reduced Wolbachia load significantly. At 18 months posttreatment, four-week doxycycline resulted in 100% adult worm loss, and the 2-week combination treatment resulted in a 50% adult worm loss. In conclusion, this pilot study with a combination of 2-week doxycycline and rifampicin demonstrates moderate macrofilaricidal activity against W. bancrofti.

  18. Efficacy of Doxycycline, Azithromycin, or Trovafloxacin for Treatment of Experimental Rocky Mountain Spotted Fever in Dogs

    Science.gov (United States)

    Breitschwerdt, E. B.; Papich, M. G.; Hegarty, B. C.; Gilger, B.; Hancock, S. I.; Davidson, M. G.

    1999-01-01

    Dogs were experimentally inoculated with Rickettsia rickettsii (canine origin) in order to compare the efficacies of azithromycin and trovafloxacin to that of the current antibiotic standard, doxycycline, for the treatment of Rocky Mountain spotted fever. Clinicopathologic parameters, isolation of rickettsiae in tissue culture, and PCR amplification of rickettsial DNA were used to evaluate the response to therapy or duration of illness (untreated infection control group) in the four groups. Concentrations of the three antibiotics in plasma and blood cells were measured by high-performance liquid chromatography. Doxycycline and trovafloxacin treatments resulted in more-rapid defervescence, whereas all three antibiotics caused rapid improvement in attitudinal scores, blood platelet numbers, and the albumin/total-protein ratio. Based upon detection of retinal vascular lesions by fluorescein angiography, trovafloxacin and doxycycline substantially decreased rickettsia-induced vascular injury to the eye, whereas the number of ocular lesions in the azithromycin group did not differ from that in the infection control group. As assessed by tissue culture isolation, doxycycline resulted in the earliest apparent clearance of viable circulating rickettsiae; however, rickettsial DNA could still be detected in the blood of some dogs from all four groups on day 21 postinfection, despite our inability to isolate viable rickettsiae at that point. As administered in this study, trovafloxacin was as efficacious as doxycycline but azithromycin proved less efficacious, possibly due to the short duration of administration. PMID:10103185

  19. Efficacy of single application of topical doxycycline hyclate and triamcinolone acetonide in denture adhesive in the management of recurrent aphthous stomatitis: A comparative study

    Directory of Open Access Journals (Sweden)

    Rakhi Chandak

    2017-01-01

    Conclusion: Healing of the ulcer was significantly faster with doxycycline treatment compared to triamcinolone ointment with no adverse effects. Doxycycline is proved to be one of the modalities for the treatment of aphthous ulcer.

  20. Low concentrations of doxycycline attenuates FasL-induced apoptosis in HeLa cells.

    Science.gov (United States)

    Yoon, Jung Mi; Koppula, Sushruta; Huh, Se Jong; Hur, Sun Jin; Kim, Chan Gil

    2015-07-24

    Doxycycline (DC) has been shown to possess non-antibiotic properties including Fas/Fas Ligand (FasL)-mediated apoptosis against several tumor types in the concentration range of 10-40 µg/mL. However, the effect of DC in apoptotic signaling at much low concentrations was not studied. The present study investigated the attenuation effect of low dose of DC on FasL-induced apoptosis in HeLa cell by the methods of MTT assay, fluorescence microscopy, DNA fragmentation, flow cytometry analysis, and western blotting. In the present findings we showed that low concentration of DC (HeLa cells. FasL treatment to HeLa cells resulted in a concentration-dependent induction of cell death, and treatment with low concentrations of DC (0.1-2 µg/mL) significantly (p cell death as measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Further, the FasL-induced apoptotic features in HeLa cells, such as morphological changes, DNA fragmentation and cell cycle arrest was also inhibited by DC (0.5 µg/mL). Tetracycline and minocycline also showed similar anti-apoptotic effects but were not significant when compared to DC, tested at same concentrations. Further, DC (0.01-16 µg/mL) did not influence the hydrogen peroxide- or cisplatin-induced intrinsic apoptotic pathway in HeLa cells. Protein analysis using Western blotting confirmed that FasL-induced cleavage/activation of caspase-8 and caspase-3, were inhibited by DC treatment at low concentration (0.5 µg/mL). Considering the overall data, we report for the first time that DC exhibited anti-apoptotic effects at low concentrations in HeLa cells by inhibition of caspase activation via FasL-induced extrinsic pathway.

  1. Serological Response to Treatment of Syphilis with Doxycycline Compared with Penicillin in HIV-infected Individuals

    DEFF Research Database (Denmark)

    Salado-Rasmussen, Kirsten; Hoffmann, Steen; Cowan, Susan

    2016-01-01

    Serological response to treatment of syphilis with orally administered doxycycline or intramuscularly administered penicillin was assessed in patients with concurrent HIV. All HIV-infected individuals diagnosed with syphilis attending 3 hospitals in Copenhagen, Denmark were included. Odds ratios...... (ORs) with 95% confidence intervals (CI) associated with serological outcome were modelled using propensity-score-adjusted logistic regression analysis. In total, 202 cases were treated with doxycycline or intramuscular penicillin. At 12 months, serological failure was observed in 12 cases (15......%) treated with doxycycline and in 8 cases (17%) treated with penicillin (OR 0.78 (95% CI 0.16-3.88), p = 0.76). The serological cure rate at 12 months was highest in patients with primary syphilis (100%), followed by patients with secondary (89%), early latent (71%) and late latent (67%) syphilis (p = 0...

  2. A novel treatment modality for recurrent aphthous stomatitis – Single application of doxycycline hyclate

    Directory of Open Access Journals (Sweden)

    R Thriveni

    2018-01-01

    Full Text Available Background and Objectives: Recurrent aphthous ulcers are common painful mucosal conditions affecting the oral cavity. Despite of so many treatment modalities, there is no specific and definitive treatment. Hence a study was carried out to evaluate the clinical effects Single Application of Doxycycline Hyclate 100 mg for Recurrent apthous Stomatitis (RAS. Materials and Methods: Forty study subjects were included in the study. Patients were randomly assigned into two groups. There were 20 patients in each group; Group A patients received Doxycycline Hyclate 100 mg in the first visit, Group B patients received placebo. The results were analyzed with unpaired 't' test. Results: The data indicated a significant reduction in pain in group A (i.e., faster reduction in pain compared with group B. Interpretation and Conclusion: A single application of doxycycline hyclate decreased pain and speeded recovery.

  3. Genetic diversity of Streptococcus equi subsp. zooepidemicus and doxycycline resistance in kennelled dogs.

    Science.gov (United States)

    Chalker, Victoria J; Waller, Andrew; Webb, Katy; Spearing, Emma; Crosse, Patricia; Brownlie, Joe; Erles, Kerstin

    2012-06-01

    The genetic diversity and antibiotic resistance profiles of 38 Streptococcus equi subsp. zooepidemicus isolates were determined from a kennelled canine population during two outbreaks of hemorrhagic pneumonia (1999 to 2002 and 2007 to 2010). Analysis of the szp gene hypervariable region and the 16S-23S rRNA intergenic spacer region and multilocus sequence typing (MLST) indicated a predominant tetO-positive, doxycycline-resistant ST-10 strain during 1999 to 2002 and a predominant tetM-positive doxycycline-resistant ST-62 strain during 2007 to 2010.

  4. In Vitro Adsorption and in Vivo Pharmacokinetic Interaction between Doxycycline and Frequently Used Mycotoxin Binders in Broiler Chickens.

    Science.gov (United States)

    De Mil, Thomas; Devreese, Mathias; Broekaert, Nathan; Fraeyman, Sophie; De Backer, Patrick; Croubels, Siska

    2015-05-06

    Mycotoxin binders are readily mixed in feeds to prevent uptake of mycotoxins by the animal. Concerns were raised for nonspecific binding with orally administered veterinary drugs by the European Food Safety Authority in 2010. This paper describes the screening for in vitro adsorption of doxycycline-a broad-spectrum tetracycline antibiotic-to six different binders that were able to bind >75% of the doxycycline. Next, an in vivo pharmacokinetic interaction study of doxycycline with two of the binders, which demonstrated significant in vitro binding, was performed in broiler chickens using an oral bolus model. It was shown that two montmorillonite-based binders were able to lower the area under the plasma concentration-time curve of doxycycline by >60% compared to the control group. These results may indicate a possible risk for reduced efficacy of doxycycline when used concomitantly with montmorillonite-based mycotoxin binders.

  5. Effects of matrix metalloproteinase inhibitor doxycycline and CD147 antagonist peptide-9 on gallbladder carcinoma cell lines.

    Science.gov (United States)

    Wang, Shihang; Liu, Chao; Liu, Xinjiang; He, Yanxin; Shen, Dongfang; Luo, Qiankun; Dong, Yuxi; Dong, Haifeng; Pang, Zhigang

    2017-10-01

    Gallbladder carcinoma is the most common and aggressive malignancy of the biliary tree and highly expresses CD147, which is closely related to disease prognosis in a variety of human cancers. Doxycycline exhibited anti-tumor properties in many cancer cells. CD147 antagonist peptide-9 is a polypeptide and can specifically bind to CD147. The effect of these two drugs on gallbladder cancer cells has not been studied. The aim of this study is to investigate the effect of doxycycline and antagonist peptide-9 on gallbladder carcinoma cells and the possible mechanism of inhibition on cancer cell of doxycycline. To investigate the effects of doxycycline and antagonist peptide-9 on gallbladder carcinoma cells (GBC-SD and SGC-996), cell proliferation, CD147 expression, and early-stage apoptosis rate were measured after treated with doxycycline. Matrix metalloproteinase-2 and matrix metalloproteinase-9 activities were measured after treated with different concentrations of doxycycline, antagonist peptide-9, and their combination. The results demonstrated that doxycycline inhibited cell proliferation, reduced CD147 expression level, and induced an early-stage apoptosis response in GBC-SD and SGC-996 cells. The matrix metalloproteinase-2 and matrix metalloproteinase-9 activities were inhibited by antagonist peptide-9 and doxycycline, and the inhibitory effects were enhanced by combined drugs in gallbladder carcinoma cell lines. Taken together, doxycycline showed inhibitory effects on gallbladder carcinoma cell lines and reduced the expression of CD147, and this may be the mechanism by which doxycycline inhibits cancer cells. This study provides new information and tries to implement the design of adjuvant therapy method for gallbladder carcinoma.

  6. The cre-inducer doxycycline lowers cytokine and chemokine transcript levels in the gut of mice

    DEFF Research Database (Denmark)

    Hansen, Axel Kornerup; Malm, Sara Astrup; Metzdorff, Stine B.

    2017-01-01

    The antibiotic doxycycline is used as an inducer of recombinase (cre)-based conditional gene knockout in mice, which is a common tool to show the effect of disrupted gene functions only in one period of a research animal’s life. However, other types of such antibiotics have been shown to have...

  7. A Sensitive Cell-Based Assay to Measure the Doxycycline Concentration in Biological Samples

    NARCIS (Netherlands)

    Kleibeuker, Wendy; Zhou, Xue; Centlivre, Mireille; Legrand, Nicolas; Page, Mark; Almond, Neil; Berkhout, Ben; Das, Atze T.

    2009-01-01

    Doxycycline (DOX) is widely used as a pharmacological agent and as an effector molecule in inducible gene expression systems. For most applications, it is important to determine whether the DOX concentration reaches the level required for optimal efficacy. We developed a sensitive bioassay for

  8. DsRed gene expression by doxycycline in porcine fibroblasts and ...

    African Journals Online (AJOL)

    DsRed gene expression by doxycycline in porcine fibroblasts and cloned embryos using transposon. SuJin Kim, JoonHo Moon, BegoRoibas da Torre, Islam M Saadeldin, JungTaek Kang, JiYei Choi, SolJi Park, Byeong-Chun Lee, Goo Jang Goo Jang ...

  9. Sealing ability of mineral trioxide aggregate (MTA) combined with distilled water, chlorhexidine, and doxycycline.

    Science.gov (United States)

    Arruda, Roberta A A; Cunha, Rodrigo S; Miguita, Kenner B; Silveira, Cláudia F M; De Martin, Alexandre S; Pinheiro, Sérgio L; Rocha, Daniel G P; Bueno, Carlos E S

    2012-09-01

    The aim of this study was to evaluate the sealing ability of mineral trioxide aggregate (MTA Bio) combined with different mixing agents (distilled water, chlorhexidine, doxycycline), used as an apical root-end filling material. Forty-two extracted human teeth were divided into three groups (n = 12); six teeth were used as controls. Root-ends were resected at 90 degrees, 3 mm from the apex. Root-end cavities were prepared using ultrasonic tips and filled with MTA Bio plus distilled water, 2% chlorhexidine solution, or 10% doxycycline solution. Apical sealing was assessed by microleakage of 50% silver nitrate solution. Roots were longitudinally sectioned in a buccolingual plane and analyzed using an operating microscope (20× magnification). Depth of dye leakage into the dentinal walls was measured in millimeters. Results were analyzed using ANOVA and Tukey's test (P = 0.05). MTA Bio plus distilled water showed significantly higher mean leakage results (1.06 mm) when compared with MTA Bio plus doxycycline (0.61 mm), and higher, although not significant, results when compared with MTA Bio plus chlorhexidine (0.79 mm). In conclusion, replacing distilled water with two biologically active mixing agents (doxycycline and chlorhexidine) did not alter the sealing properties of MTABio. The antimicrobial properties of these combinations should be further investigated.

  10. Simple colorimetric detection of doxycycline and oxytetracycline using unmodified gold nanoparticles

    Science.gov (United States)

    Li, Jie; Fan, Shumin; Li, Zhigang; Xie, Yuanzhe; Wang, Rui; Ge, Baoyu; Wu, Jing; Wang, Ruiyong

    2014-08-01

    The interaction between tetracycline antibiotics and gold nanoparticles was studied. With citrate-coated gold nanoparticles as colorimetric probe, a simple and rapid detection method for doxycycline and oxytetracycline has been developed. This method relies on the distance-dependent optical properties of gold nanoparticles. In weakly acidic buffer medium, doxycycline and oxytetracycline could rapidly induce the aggregation of gold nanoparticles, resulting in red-to-blue (or purple) colour change. The experimental parameters were optimized with regard to pH, the concentration of the gold nanoparticles and the reaction time. Under optimal experimental conditions, the linear range of the colorimetric sensor for doxycycline/oxytetracycline was 0.06-0.66 and 0.59-8.85 μg mL-1, respectively. The corresponding limit of detection for doxycycline and oxytetracycline was 0.0086 and 0.0838 μg mL-1, respectively. This assay was sensitive, selective, simple and readily used to detect tetracycline antibiotics in food products.

  11. In vitro release of doxycycline from bioabsorbable materials and acrylic strips

    DEFF Research Database (Denmark)

    Larsen, T

    1990-01-01

    Treatment of marginal periodontitis may include use of local antibiotics. In the present in vitro study the bioabsorbable materials Surgicel, Tissell, and CollaCote and acrylic strips were examined for release of doxycycline into liquids and residual antibacterial activity of the materials. Pieces...

  12. Effects of amoxicillin, ceftiofur, doxycycline, tiamulin and tulathromycin on pig humoral immune responses induced by erysipelas vaccination.

    Science.gov (United States)

    Pomorska-Mól, M; Kwit, K; Wierzchosławski, K; Dors, A; Pejsak, Z

    2016-05-28

    It addition to their antimicrobial properties, antibiotics can influence the host immune system (modulation of cytokine secretion, antibody production and T-cell proliferation). In the present study, the authors studied the effects of therapeutic doses of amoxicillin (AMX), ceftiofur (CEF), doxycycline (DOXY), tiamulin (TIAM) and tulathromycin (TUL) on the postvaccinal immune response after pigs had been vaccinated against erysipelas. Because humoral immunity is considered as the most important in the protection against swine erysipelas, the present study focused on the interactions between antibiotics and postvaccinal humoral immunity. One hundred and five, eight-week-old pigs of both sexes were used. Specific antibodies to the Erysipelothrix rhusiopathiae antigen were determined using a commercial ELISA test. In pigs treated with DOXY or CEF or TIAM, a significant reduction in the number of positive pigs was observed four and six weeks after the second dose of vaccine, compared with the remaining vaccinated groups. In pigs treated with CEF, the ELISA score was significantly lower than in non-treated vaccinated pigs. While in vaccinated pigs treated with AMX or TUL, the ELISA score was significantly higher than in pigs treated with the remaining antibiotics and than in non-treated vaccinated controls. The results of the present study indicate that vaccination of pigs against erysipelas in the presence of antibiotics may result in a decrease (CEF, DOXY, TIAM) or enhancement (AMX, TUL) in the production of specific antibodies. British Veterinary Association.

  13. Antimicrobial synergy between carprofen and doxycycline against methicillin-resistant Staphylococcus pseudintermedius ST71.

    Science.gov (United States)

    Brochmann, Rikke Prejh; Helmfrid, Alexandra; Jana, Bimal; Magnowska, Zofia; Guardabassi, Luca

    2016-06-24

    New therapeutic strategies are needed to face the rapid spread of multidrug-resistant staphylococci in veterinary medicine. The objective of this study was to identify synergies between antimicrobial and non-antimicrobial drugs commonly used in companion animals as a possible strategy to restore antimicrobial susceptibility in methicillin-resistant Staphylococcus pseudintermedius (MRSP). A total of 216 antimicrobial/non-antimicrobial drug combinations were screened by disk diffusion using a clinical MRSP sequence type (ST) 71 strain resistant to all six antimicrobials tested (ampicillin, ciprofloxacin, clindamycin, doxycycline, oxacillin and trimethoprim/sulfamethoxazole). The most promising drug combination (doxycycline-carprofen) was further assessed by checkerboard testing extended to four additional MRSP strains belonging to ST71 or ST68, and by growth inhibition experiments. Seven non-antimicrobial drugs (bromhexine, acepromazine, amitriptyline, clomipramine, carprofen, fluoxetine and ketoconazole) displayed minimum inhibitory concentrations (MICs) ranging between 32 and >4096 mg/L, and enhanced antimicrobial activity of one or more antimicrobials. Secondary screening by checkerboard assay revealed a synergistic antimicrobial effect between carprofen and doxycycline, with the sum of the fractional inhibitory concentration indexes (ΣFICI) ranging between 0.3 and 0.5 depending on drug concentration. Checkerboard testing of multiple MRSP strains revealed a clear association between synergy and carriage of tetK, which is a typical feature of MRSP ST71. An increased growth inhibition was observed when MRSP ST71 cells in exponential phase were exposed to 0.5/32 mg/L of doxycycline/carprofen compared to individual drug exposure. Carprofen restores in vitro susceptibility to doxycycline in S. pseudintermedius strains carrying tetK such as MRSP ST71. Further research is warranted to elucidate the molecular mechanism behind the identified synergy and its linkage to

  14. Treatment of ocular rosacea:comparative study of topical cyclosporine and oral doxycycline

    Directory of Open Access Journals (Sweden)

    Aysegul Arman

    2015-06-01

    Full Text Available AIM:To compare the effectiveness of topical cyclosporine A emulsion with that of oral doxycycline for rosacea associated ocular changes and dry eye complaints.METHODS:One hundred and ten patients with rosacea were screened. Thirty-eight patients having rosacea associated eyelid and ocular surface changes and dry eye complaints were included in the study. Patients were randomly divided into two groups:nineteen patients were given topical cyclosporine twice daily and nineteen patients were given oral doxycycline 100 mg twice daily for the first month and once daily for the following two months. Symptom and sign scores, ocular surface disease index questionnarie and tear function tests were evaluated at baseline and monthly for 3mo. Three months after results were compared with that of baseline.RESULTS:Mean values of symptom, eyelid sign and corneal/conjunctival sign scores of each treatment group at baseline and 3mo after treatments were compared and both drugs were found to be effective on rosacea associated ocular changes (P<0.001. Cyclosporine was more effective in symptomatic relief and in the treatment of eyelid signs (P=0.01. There was statistically significant increase in the mean Schirmer score with anesthesia and tear break up time scores in the cyclosporine treatment group compared to the doxycycline treatment group (P<0.05.CONCLUSION:Cyclosporine as a topical drug can be used in the treatment of rosacea associated ocular complications because it is more effective than doxycycline. In addition ocular rosacea as a chronic disease requires long term treatment and doxycycline has various side effects limiting its long term usage.

  15. Is caffeic acid phenethyl ester more protective than doxycycline in experimental periodontitis?

    Science.gov (United States)

    Yiğit, Umut; Kırzıoğlu, Fatma Yeşim; Uğuz, Abdülhadi Cihangir; Nazıroğlu, Mustafa; Özmen, Özlem

    2017-09-01

    Host modulation therapies (anti-inflammatory drugs, bone-stimulating agents, anti-proteinase etc.) target the inhibition or stabilization of tissue breakdown. The aim of the present study was to evaluate the effects of caffeic acid phenethyl ester (CAPE) and/or low dose doxycycline (LDD) administrations on alveolar bone loss (ABL), serum cytokines and gingival apoptosis, as well as the levels of oxidants and anti-oxidants in rats with ligature-induced periodontitis. The animals were randomly divided into five groups: Group C (periodontally healthy), Group PC (Periodontitis+CAPE), Group PD (Periodontitis+LDD), Group PCD (Periodontitis+CAPE+LDD), Group P (Periodontitis). Experimental periodontitis was induced for 14days. Levels of ABL, and the serum cytokines, interleukin (IL)-1 β, IL-6, tumor necrosis factor-α (TNF-α) and IL-10 were assessed as were the levels of the oxidants and anti-oxidants, malondialdehyde (MDA), glutathione (GSH) and glutathione peroxidase (GSH-Px), and levels of gingival apoptosis. The lowest ABL levels was evident in the PC group, among the experimental groups. There was also less inflammatory infiltration in the PC group than the PD group. IL-1β, IL-6, and IL-10 were lower in the PC group and higher in the P group in comparison to the levels in the other experiment groups. TNF-α levels in the PD group were higher than levels in the PC and PCD groups. The PC and PCD groups did not differ from the C group in regard to MDA levels. The highest GSH-Px level was found in the PC group. Gingival apoptosis in the PC group was not only lower than the PD and PCD groups, but also lower than in the C group. The present study suggests that CAPE has more anti-inflammatory, anti-oxidant and anti-apoptotic effects than LDD, with no additive benefits of a CAPE+LDD combination being evident in rats with periodontitis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Low concentrations of doxycycline attenuates FasL-induced apoptosis in HeLa cells

    Directory of Open Access Journals (Sweden)

    Jung Mi Yoon

    2015-01-01

    Full Text Available BACKGROUND: Doxycycline (DC has been shown to possess non-antibiotic properties including Fas/Fas Ligand (FasL-mediated apoptosis against several tumor types in the concentration range of 10-40 μg/mL. However, the effect of DC in apoptotic signaling at much low concentrations was not studied. METHODS: The present study investigated the attenuation effect of low dose of DC on FasL-induced apoptosis in HeLa cell by the methods of MTT assay, fluorescence microscopy, DNA fragmentation, flow cytometry analysis, and western blotting. RESULTS AND CONCLUSION: In the present findings we showed that low concentration of DC (<2.0 μg/mL exhibited protective effects against FasL-induced apoptosis in HeLa cells. FasL treatment to HeLa cells resulted in a concentration-dependent induction of cell death, and treatment with low concentrations of DC (0.1-2 μg/mL significantly (p < 0.001 attenuated the FasL-induced cell death as measured by 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazo-lium bromide (MTT assay. Further, the FasL-induced apoptotic features in HeLa cells, such as morphological changes, DNA fragmentation and cell cycle arrest was also inhibited by DC (0.5 μg/mL. Tetracycline and minocycline also showed similar anti-apoptotic effects but were not significant when compared to DC, tested at same concentrations. Further, DC (0.01-16 μg/mL did not influence the hydrogen peroxide- or cisplatin-induced intrinsic apoptotic pathway in HeLa cells. Protein analysis using Western blotting confirmed that FasL-induced cleavage/activation of cas-pase-8 and caspase-3, were inhibited by DC treatment at low concentration (0.5 μg/mL. Considering the overall data, we report for the first time that DC exhibited anti-apoptotic effects at low concentrations in HeLa cells by inhibition of caspase activation via FasL-induced extrinsic pathway.

  17. Silibinin, dexamethasone, and doxycycline as potential therapeutic agents for treating vesicant-inflicted ocular injuries

    International Nuclear Information System (INIS)

    Tewari-Singh, Neera; Jain, Anil K.; Inturi, Swetha; Ammar, David A.; Agarwal, Chapla; Tyagi, Puneet; Kompella, Uday B.; Enzenauer, Robert W.; Petrash, J. Mark; Agarwal, Rajesh

    2012-01-01

    There are no effective and approved therapies against devastating ocular injuries caused by vesicating chemical agents sulfur mustard (SM) and nitrogen mustard (NM). Herein, studies were carried out in rabbit corneal cultures to establish relevant ocular injury biomarkers with NM for screening potential efficacious agents in laboratory settings. NM (100 nmol) exposure of the corneas for 2 h (cultured for 24 h), showed increases in epithelial thickness, ulceration, apoptotic cell death, epithelial detachment microbullae formation, and the levels of VEGF, cyclooxygenase-2 (COX-2) and matrix metalloproteinase-9 (MMP-9). Employing these biomarkers, efficacy studies were performed with agent treatments 2 h and every 4 h thereafter, for 24 h following NM exposure. Three agents were evaluated, including prescription drugs dexamethasone (0.1%; anti-inflammatory steroid) and doxycycline (100 nmol; antibiotic and MMP inhibitor) that have been studied earlier for treating vesicant-induced eye injuries. We also examined silibinin (100 μg), a non-toxic natural flavanone found to be effective in treating SM analog-induced skin injuries in our earlier studies. Treatments of doxycycline + dexamethasone, and silibinin were more effective than doxycycline or dexamethasone alone in reversing NM-induced epithelial thickening, microbullae formation, apoptotic cell death, and MMP-9 elevation. However, dexamethasone and silibinin alone were more effective in reversing NM-induced VEGF levels. Doxycycline, dexamethasone and silibinin were all effective in reversing NM-induced COX-2 levels. Apart from therapeutic efficacy of doxycycline and dexamethasone, these results show strong multifunctional efficacy of silibinin in reversing NM-induced ocular injuries, which could help develop effective and safe therapeutics against ocular injuries by vesicants. -- Highlights: ► Established injury biomarkers in rabbit corneal culture with nitrogen mustard (NM) ► This NM model is a cost effective

  18. Silibinin, dexamethasone, and doxycycline as potential therapeutic agents for treating vesicant-inflicted ocular injuries

    Energy Technology Data Exchange (ETDEWEB)

    Tewari-Singh, Neera, E-mail: Neera.Tewari-Singh@ucdenver.edu [Department of Pharmaceutical Sciences, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO 80045 (United States); Jain, Anil K., E-mail: Anil.Jain@ucdenver.edu [Department of Pharmaceutical Sciences, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO 80045 (United States); Inturi, Swetha, E-mail: Swetha.Inturi@ucdenver.edu [Department of Pharmaceutical Sciences, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO 80045 (United States); Ammar, David A., E-mail: David.Ammar@ucdenver.edu [Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO 80045 (United States); Agarwal, Chapla, E-mail: Chapla.Agarwal@ucdenver.edu [Department of Pharmaceutical Sciences, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO 80045 (United States); Tyagi, Puneet, E-mail: Puneet.Tyagi@ucdenver.edu [Department of Pharmaceutical Sciences, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO 80045 (United States); Kompella, Uday B., E-mail: Uday.Kompella@ucdenver.edu [Department of Pharmaceutical Sciences, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO 80045 (United States); Enzenauer, Robert W., E-mail: Robert.Enzenauer@ucdenver.edu [Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO 80045 (United States); Petrash, J. Mark, E-mail: Mark.Petrash@ucdenver.edu [Department of Ophthalmology, University of Colorado School of Medicine, Aurora, CO 80045 (United States); Agarwal, Rajesh, E-mail: Rajesh.Agarwal@ucdenver.edu [Department of Pharmaceutical Sciences, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO 80045 (United States)

    2012-10-01

    There are no effective and approved therapies against devastating ocular injuries caused by vesicating chemical agents sulfur mustard (SM) and nitrogen mustard (NM). Herein, studies were carried out in rabbit corneal cultures to establish relevant ocular injury biomarkers with NM for screening potential efficacious agents in laboratory settings. NM (100 nmol) exposure of the corneas for 2 h (cultured for 24 h), showed increases in epithelial thickness, ulceration, apoptotic cell death, epithelial detachment microbullae formation, and the levels of VEGF, cyclooxygenase-2 (COX-2) and matrix metalloproteinase-9 (MMP-9). Employing these biomarkers, efficacy studies were performed with agent treatments 2 h and every 4 h thereafter, for 24 h following NM exposure. Three agents were evaluated, including prescription drugs dexamethasone (0.1%; anti-inflammatory steroid) and doxycycline (100 nmol; antibiotic and MMP inhibitor) that have been studied earlier for treating vesicant-induced eye injuries. We also examined silibinin (100 μg), a non-toxic natural flavanone found to be effective in treating SM analog-induced skin injuries in our earlier studies. Treatments of doxycycline + dexamethasone, and silibinin were more effective than doxycycline or dexamethasone alone in reversing NM-induced epithelial thickening, microbullae formation, apoptotic cell death, and MMP-9 elevation. However, dexamethasone and silibinin alone were more effective in reversing NM-induced VEGF levels. Doxycycline, dexamethasone and silibinin were all effective in reversing NM-induced COX-2 levels. Apart from therapeutic efficacy of doxycycline and dexamethasone, these results show strong multifunctional efficacy of silibinin in reversing NM-induced ocular injuries, which could help develop effective and safe therapeutics against ocular injuries by vesicants. -- Highlights: ► Established injury biomarkers in rabbit corneal culture with nitrogen mustard (NM) ► This NM model is a cost effective

  19. Systematic Review and Meta-Analysis of Doxycycline Efficacy for Rectal Lymphogranuloma Venereum in Men Who Have Sex with Men.

    Science.gov (United States)

    Leeyaphan, Charussri; Ong, Jason J; Chow, Eric P F; Kong, Fabian Y S; Hocking, Jane S; Bissessor, Melanie; Fairley, Christopher K; Chen, Marcus

    2016-10-01

    Rectal lymphogranuloma venereum (LGV) has reemerged as a sexually transmitted infection among men who have sex with men (MSM), particularly those who are HIV-positive. We undertook a systematic review and meta-analysis to determine the efficacy of doxycycline (100 mg 2×/d for 21 days) for rectal LGV in MSM. Nine studies were included: 4 prospective, 4 retrospective, and 1 combined retrospective and prospective. In total, 282 MSM with rectal LGV were included in the studies. All studies reported using nucleic acid amplification tests to assess microbial cure. Most patients (>80%) had symptomatic rectal infection. The fixed-effects pooled efficacy for doxycycline was 98.5% (95% CI 96.3%-100%, I (2)  = 0%; p = 0.993). Doxycycline at 100 mg twice daily for 21 days demonstrated a high microbial cure rate. These data support doxycycline at this dosage and duration as first-line therapy for rectal LGV in MSM.

  20. Observed Treatment Responses to Short-Course Doxycycline Therapy for Rectal Lymphogranuloma Venereum in Men Who Have Sex With Men.

    Science.gov (United States)

    Simons, Rebecca; Candfield, Sophie; French, Patrick; White, John A

    2018-06-01

    Lymphogranuloma venereum (LGV) has reestablished itself as an endemic sexually transmitted infection in the United Kingdom and elsewhere in Europe and North America over the last decade. Current guidelines suggest treatment with 21 days of doxycycline; however, the evidence base for LGV treatment including its duration is very limited. We conducted a retrospective review in 2 central London genitourinary medicine clinics of men who have sex with men (MSM) with LGV in whom less than 21 days of doxycycline was used initially. Sixty MSM were treated initially with less than 21 days of doxycycline, of whom 50 (83%) were prescribed a 7-day course. Fifty percent of patients were asymptomatic, with the rest having rectal or other symptoms. Fifty-nine (97%) of 60 had a negative test of cure for LGV at a median of 31 days (7-200 days). Reinfection as opposed to treatment failure was considered likely in the patient testing positive. A second test of cure at a median of 139 days later (37-638 days) was completed in 30 patients, of whom 28 (93%) were negative for LGV. Seven to 14 days of doxycycline is effective in most cases of LGV with negative TOCs in 59 of 60 patients. These data suggest that 7 days of doxycycline is effective in achieving cure of rectal LGV in most MSM. There is a case for a randomized controlled trial of LGV treatment including a 7-day regimen of doxycycline.

  1. Preparation and evaluation of doxycycline hydrochloride and bromhexine hydrochloride dosage forms for pigeons / Marga le Roux

    OpenAIRE

    Le Roux, Marga

    2004-01-01

    Objective: To prepare and evaluate three different dosage forms, containing doxycycline hydrochloride (HCI) and bromhexine hydrochloride (HCI) respectively and in combination, for the treatment of respiratory diseases in pigeons. Background: Birds have held a place in man's affection since the ancient Egyptians and Romans kept birds. Europeans have successfully bred birds, especially smaller birds and pigeons, for centuries. Only in recent years, however, have science and me...

  2. Doxycycline Attenuates Leptospira-Induced IL-1β by Suppressing NLRP3 Inflammasome Priming

    OpenAIRE

    Zhang, Wenlong; Xie, Xufeng; Wu, Dianjun; Jin, Xuemin; Liu, Runxia; Hu, Xiaoyu; Fu, Yunhe; Ding, Zhuang; Zhang, Naisheng; Cao, Yongguo

    2017-01-01

    Doxycycline (Dox), a semisynthetic antibiotic, has been reported to exert multiple immunomodulatory effects. Treatment with Dox has a satisfactory curative effect against leptospirosis. In addition to its antibacterial action, we supposed that Dox also modulated immune response in controlling leptospira infection. Using J774A.1 mouse macrophages, the effects of Dox on protein and mRNA levels of IL-1β and TNF-α were investigated after infection with live or sonicated Leptospira interrogans ser...

  3. Verification of dissolution test for doxycycline hyclate in capsules to implement into the pharmacopoeial monograph

    OpenAIRE

    Dobrova, Anna; Golovchenko, Olga; Georgiyants, Victoria

    2018-01-01

    The study of dissolution profiles is important as a cheap and easy supplement to bioequivalence research, and as a variation to such studies. This method is not outlined in the State Pharmacopoeia of Ukraine for the doxycycline capsules. Therefore, according to the current requirements, it was necessary to verify the procedure recommended by the US Pharmacopeia to confirm that this laboratory test will be reproduced correctly, and to use it in our further studies.The aim of our research was t...

  4. Effect of doxycycline vs placebo on retinal function and diabetic retinopathy progression in patients with severe nonproliferative or non-high-risk proliferative diabetic retinopathy

    DEFF Research Database (Denmark)

    Scott, Ingrid U; Jackson, Gregory R; Quillen, David A

    2014-01-01

    IMPORTANCE: Inflammation may contribute to the pathogenesis of diabetic retinopathy (DR). OBJECTIVES: To investigate, in a proof-of-concept clinical trial, whether low-dose oral doxycycline monohydrate can (1) slow the deterioration of, or improve, retinal function or (2) induce regression or slow......: We conducted a randomized, double-masked, 24-month proof-of-concept clinical trial. Thirty patients (from hospital-based retina practices) with 1 or more eyes with severe NPDR or PDR less than Early Treatment Diabetic Retinopathy Study-defined high-risk PDR. INTERVENTIONS: Patients were randomized...... adaptation, visual acuity, and quality of life) and anatomic factors (Early Treatment Diabetic Retinopathy Study DR severity level, area of retinal thickening, central macular thickness, macular volume, and retinal vessel diameters). RESULTS: From baseline to month 24, mean FDP foveal sensitivity decreased...

  5. Systemic provocation in doxycycline induced fixed drug eruption: a case report

    Directory of Open Access Journals (Sweden)

    Anik Murwaningsih Rosmarini Estri Sih Hananti Niken Indrastuti

    2014-04-01

    Full Text Available Fixed drug eruption (FDE is recurrent lesions that upon repeated uptake of causative drug, always appears at the same skin and mucosal site. Determination of causal relationship in drug allergy is very important. In this case report, cases of doxycycline-induced FDE was reported. The subject of the research was a 29-year-old male, referred by dermatologist, with history of reccurent FDE. Physical examination revealed an oval well demarcated patch hyperpigmentation. Patch test was perfomed on previous involved and uninvolved site. The result of the patch test was irrelevant. Retesting patch test gave similar result. Systemic provocation test or drug provocation test (DPT  with doxcycline were done with suspected drug under ambulatory survelance and gave positive result. In this case, the DPT succeeded to identify doxycycline as the causal agent of FDE. The work-up of a suspected drug hypersensitivity includes a detailed clinical history, physical examination, skin tests, and provocation tests. The DPT is recommended to confirm drug’s hypersensitivity reactions. Systemic provocation test is considered as the gold standard for diagnosing FDE. Keywords:   fixed drug eruption - doxycycline - causal relationship - patch test - systemic provocation test

  6. Addition of doxycycline to ciprofloxacin for infection prophylaxis during autologous stem cell transplants for multiple myeloma.

    Science.gov (United States)

    Sivik, J M; Davidson, J; Hale, C M; Drabick, J J; Talamo, G

    2018-03-21

    The most commonly used antibacterial prophylaxis during autologous stem cell transplants (ASCT) for multiple myeloma (MM) involves a fluoroquinolone, such as ciprofloxacin or levofloxacin. We assessed the impact of adding doxycycline to ciprofloxacin as routine antibacterial prophylaxis in these patients. We retrospectively reviewed electronic medical records and our ASCT database to analyze rates and types of bacterial infections in MM patients who underwent ASCT in our institution. Among 419 patients, 118 received ciprofloxacin alone (cipro group), and 301 ciprofloxacin and doxycycline (cipro-doxy group). Neutropenic fever (NF) developed in 63 (53%) and 108 (36%) patients of the cipro and cipro-doxy groups, respectively (p = 0.010). The number of documented bacteremic episodes was 13 (11%) and 14 (4.7%) in the two groups, respectively (p = 0.017). Antimicrobial resistance and Clostridium difficile infections were uncommon. Transplant-related mortality was 1% in both groups. The addition of doxycycline to standard prophylaxis with ciprofloxacin seems to reduce the number of NF episodes and documented bacterial infections in patients with MM undergoing ASCT, without increasing rate of serious complications.

  7. Determination of ATP as a fluorescence probe with europium(III)-doxycycline.

    Science.gov (United States)

    Hou, Faju; Wang, Xiaolei; Jiang, Chongqiu

    2005-03-01

    A new spectrofluorimetric method has been developed for the determination of adenosine disodium triphosphate (ATP). We studied the interactions between the doxycycline (DC)-Eu3+ complex and adenosine disodium triphosphate (ATP) by using UV-visible absorption and fluorescence spectra. Using doxycycline (DC)-Eu3+ as a fluorescence probe, under the optimum conditions, ATP could remarkably enhance the fluorescence intensity of the DC-Eu3+ complex at lambda = 612 nm. The enhanced fluorescence intensity of the Eu3+ ion was in proportion to the concentration of ATP. The optimum conditions for the determination of ATP were also investigated. The linear ranges for ATP were 1.00 x 10(-7) - 2.00 x 10(-6) mol L(-1) with detection limits of 4.07 x 10(-8) mol L(-1). This method is simple, practical and relatively free of interference from coexisting substances, and can be successfully applied to the determination of ATP in samples. The mechanism of fluorescence enhancement between the doxycycline (DC)-Eu3+ complex and ATP was also studied.

  8. Metabolic Abnormalities Detected in Phase II Evaluation of Doxycycline in Dogs with Multicentric B-Cell Lymphoma.

    Science.gov (United States)

    Hume, Kelly R; Sylvester, Skylar R; Borlle, Lucia; Balkman, Cheryl E; McCleary-Wheeler, Angela L; Pulvino, Mary; Casulo, Carla; Zhao, Jiyong

    2018-01-01

    Doxycycline has antiproliferative effects in human lymphoma cells and in murine xenografts. We hypothesized that doxycycline would decrease canine lymphoma cell viability and prospectively evaluated its clinical tolerability in client-owned dogs with spontaneous, nodal, multicentric, substage a, B-cell lymphoma, not previously treated with chemotherapy. Treatment duration ranged from 1 to 8 weeks (median and mean, 3 weeks). Dogs were treated with either 10 ( n  = 6) or 7.5 ( n  = 7) mg/kg by mouth twice daily. One dog had a stable disease for 6 weeks. No complete or partial tumor responses were observed. Five dogs developed grade 3 and/or 4 metabolic abnormalities suggestive of hepatopathy with elevations in bilirubin, ALT, ALP, and/or AST. To evaluate the absorption of oral doxycycline in our study population, serum concentrations in 10 treated dogs were determined using liquid chromatography tandem mass spectrometry. Serum levels were variable and ranged from 3.6 to 16.6 µg/ml (median, 7.6 µg/ml; mean, 8.8 µg/ml). To evaluate the effect of doxycycline on canine lymphoma cell viability in vitro , trypan blue exclusion assay was performed on canine B-cell lymphoma cell lines (17-71 and CLBL) and primary B-cell lymphoma cells from the nodal tissue of four dogs. A doxycycline concentration of 6 µg/ml decreased canine lymphoma cell viability by 80%, compared to matched, untreated, control cells (mixed model analysis, p  canine lymphoma, combination therapy may be worthwhile if future research determines that doxycycline can alter cell survival pathways in canine lymphoma cells. Due to the potential for metabolic abnormalities, close monitoring is recommended with the use of this drug in tumor-bearing dogs. Additional research is needed to assess the tolerability of chronic doxycycline therapy.

  9. Topical azithromycin and oral doxycycline therapy of meibomian gland dysfunction: a comparative clinical and spectroscopic pilot study.

    Science.gov (United States)

    Foulks, Gary N; Borchman, Douglas; Yappert, Marta; Kakar, Shelley

    2013-01-01

    Meibomian gland dysfunction (MGD) is a common clinical problem that is often associated with evaporative dry eye disease. Alterations of the lipids of the meibomian glands have been identified in several studies of MGD. This prospective, observational, open-label clinical trial documents the improvement in both clinical signs and symptoms of disease as well as spectroscopic characteristics of the meibomian gland lipids after therapy with topical azithromycin ophthalmic solution and oral doxycycline treatment. Subjects with symptomatic MGD were recruited. Signs of MGD were evaluated with a slit lamp. Symptoms of MGD were measured by the response of subjects to a questionnaire. Meibum lipid-lipid interaction strength, conformation, and phase transition parameters, and meibum protein content were measured using Fourier transform infrared spectroscopy and principal component analysis. Terpenoids, short-chain CH3 moieties, lipid oxidation, wax, cholesterylesters and glycerides were measured with a proton nuclear magnetic resonance (H-NMR) spectrometer. Topical therapy with azithromycin and oral therapy with doxycycline relieved signs and symptoms and restored the lipid properties of the meibomian gland secretion toward normal. Compared with 4 weeks of azithromycin treatment reported in our previous study, oral doxycycline treatment was slightly less effective in improving foreign body sensation and the signs of plugging and secretion. In subjects with clinical evidence of MGD, changes in ordering of the lipids and phase transition temperature were brought closer to normal with azithromycin treatment than doxycycline treatment. Treatment with doxycycline but not azithromycin restored the Fourier transform infrared spectroscopy-principal component analysis scores and relative area of the H-NMR resonance at 1.26 ppm. Both doxycycline and azithromycin treatment restored the levels of the relative areas of the H-NMR resonance at 5.2 and 7.9 ppm to normal levels. The levels

  10. Osteogenic activity of cyclodextrin-encapsulated doxycycline in a calcium phosphate PCL and PLGA composite

    Energy Technology Data Exchange (ETDEWEB)

    Trajano, V.C.C.; Costa, K.J.R. [Restorative Dentistry Department, Faculty of Dentistry, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais (Brazil); Lanza, C.R.M. [Department of Oral Clinical, Surgery and Pathology, Faculty of Dentistry, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais (Brazil); Sinisterra, R.D. [Chemistry Department, ICEX, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais (Brazil); Cortés, M.E., E-mail: mecortes@ufmg.br [Restorative Dentistry Department, Faculty of Dentistry, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2016-07-01

    Composites of biodegradable polymers and calcium phosphate are bioactive and flexible, and have been proposed for use in tissue engineering and bone regeneration. When associated with the broad-spectrum antibiotic doxycycline (DOX), they could favor antimicrobial action and enhance the action of osteogenic composites. Composites of polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and a bioceramic of biphasic calcium phosphate Osteosynt® (BCP) were loaded with DOX encapsulated in β-cyclodextrin (βCD) and were evaluated for effects on osteoblastic cell cultures. The DOX/βCD composite was prepared with a double mixing method. Osteoblast viability was assessed with methyl tetrazolium (MTT) assays after 1 day, 7 day, and 14 days of composite exposure; alkaline phosphatase (AP) activity and collagen production were evaluated after 7 days and 14 days, and mineral nodule formation after 14 days. Composite structures were evaluated by scanning electron microscopy (SEM). Osteoblasts exposed to the composite containing 25 μg/mL DOX/βCD had increased cell proliferation (p < 0.05) compared to control osteoblast cultures at all experimental time points, reaching a maximum in the second week. AP activity and collagen secretion levels were also elevated in osteoblasts exposed to the DOX/βCD composite (p < 0.05 vs. controls) and reached a maximum after 14 days. These results were corroborated by Von Kossa test results, which showed strong formation of mineralization nodules during the same time period. SEM of the composite material revealed a surface topography with pore sizes suitable for growing osteoblasts. Together, these results suggest that osteoblasts are viable, proliferative, and osteogenic in the presence of a DOX/βCD-containing BCP ceramic composite. - Highlights: • Doxycycline encapsulated in β-cyclodextrin was incorpored into a polycaprolactone - poly(lactic-co-glycolic acid) - calcium phosphate • Composite’s scaffold carrying doxycycline

  11. Lyme carditis with isolated left bundle branch block and myocarditis successfully treated with oral doxycycline.

    Science.gov (United States)

    Cunha, Burke A; Elyasi, Maekal; Singh, Prince; Jimada, Ismail

    2018-01-01

    Lyme disease may present with a variety of cardiac manifestations ranging from first degree to third degree heart block. Cardiac involvement with Lyme disease may be asymptomatic, or symptomatic. Atrioventrical conduction abnormalities are the most common manifestation of Lyme carditis. Less common, are alternating right bundle branch block (RBBB) and left bundle branch block (LBBB). We present an interesting case of a young male whose main manifestation of Lyme carditis was isolated LBBB. He also had mild Lyme myocarditis. The patient was successfully treated with oral doxycycline, and his isolated LBBB and myocarditis rapidly resolved.

  12. Adverse effect of tetracycline and doxycycline on reproductive tract development of CD1 mice

    Czech Academy of Sciences Publication Activity Database

    Elzeinová, Fatima; Pěknicová, Jana; Děd, Lukáš; Dorosh, Andriy; Kubátová, Alena; Margaryan, Hasmik; Makovický, P.; Rajmon, R.

    2012-01-01

    Roč. 67, Issue Supplement s1 (2012), s. 47-48 ISSN 1046-7408. [13th International Symposium for Immunology of reproduction "From the roots to the tops of Reproductive Immunology". 22.06.2012-24.06.2012, Varna] R&D Projects: GA ČR(CZ) GA523/09/1793; GA ČR(CZ) GAP503/12/1834 Institutional research plan: CEZ:AV0Z50520701 Keywords : tetracycline * doxycycline * CD1 mice * reproduction Subject RIV: DN - Health Impact of the Environment Quality

  13. Doxycycline in the treatment of respiratory tract infections. Results of a pan-European multi-centre trial.

    Science.gov (United States)

    Pestel, M

    1975-01-01

    In the winter of 1973-4, general practitioners from seven European countries took part in a multi-centre trial of doxycycline in the treatment of infections of the respiratory tract. The carefully designed protocol was observed by all participants. A total of 1,747 patients were admitted to the trial; their ages ranged from 6 years to over 80. The commonest diagnoses (50%) were acute bronchitis and acute exacerbations of chronic bronchitis. On the recommended dosage of 200 mg doxycycline on the first day, followed by 100 mg daily thereafter (though 200 mg could be continued daily in severe cases), 87% of patients achieved good or very good results. Both subjective (pain) and objective (sputum volume and viscosity, temperature, cough) measures showed rapid improvement, usually by the third to fifth days. Side-effects were minimal and mainly gastrointestinal and caused only 4 patients to discontinue treatment. Overall, doxycycline proved its effectiveness and rapidity of action.

  14. Photocatalytic removal of doxycycline from aqueous solution using ZnO nano-particles: a comparison between UV-C and visible light.

    Science.gov (United States)

    Pourmoslemi, Shabnam; Mohammadi, Ali; Kobarfard, Farzad; Amini, Mohsen

    2016-10-01

    Zinc oxide nano-particles were synthesized, characterized and used for photocatalytic degradation of doxycycline using UV-C and visible light. Effects of several operational factors including initial pH of antibiotic solution, initial antibiotic concentration and ZnO nano-particles loading amount were investigated. Comparing photocatalytic degradation and mineralization of doxycycline under UV-C and visible light showed successful application of the method under both light sources. However, reaction rate was higher under UV-C irradiation, which degraded doxycycline almost completely in 5 hours, and 68% mineralization was achieved. Synthesized ZnO nano-particles were successfully applied for photocatalytic degradation of doxycycline in a pharmaceutical wastewater sample. The process was fitted to the pseudo first order kinetic model with rate constants in the range of 6-22(×10 -3 ) mg L -1 min -1 with respect to initial concentration of doxycycline under UV-C irradiation. The Langmuir-Hinshelwood model was also employed for describing the photocatalytic reaction with surface reaction kinetic constant k c and equilibrium adsorption constant K LH values calculated as 0.12 mg L -1 min -1 and 2.2 L mg -1 , respectively. Degradation of doxycycline was followed by UV-visible spectroscopy and a validated stability indicating high-performance liquid chromatography method that was developed using stressed samples of doxycycline and could selectively determine doxycycline in the presence of its degradation products. Mass spectrometry was used for determining final degradation products.

  15. Metabolic Abnormalities Detected in Phase II Evaluation of Doxycycline in Dogs with Multicentric B-Cell Lymphoma

    Directory of Open Access Journals (Sweden)

    Kelly R. Hume

    2018-02-01

    Full Text Available Doxycycline has antiproliferative effects in human lymphoma cells and in murine xenografts. We hypothesized that doxycycline would decrease canine lymphoma cell viability and prospectively evaluated its clinical tolerability in client-owned dogs with spontaneous, nodal, multicentric, substage a, B-cell lymphoma, not previously treated with chemotherapy. Treatment duration ranged from 1 to 8 weeks (median and mean, 3 weeks. Dogs were treated with either 10 (n = 6 or 7.5 (n = 7 mg/kg by mouth twice daily. One dog had a stable disease for 6 weeks. No complete or partial tumor responses were observed. Five dogs developed grade 3 and/or 4 metabolic abnormalities suggestive of hepatopathy with elevations in bilirubin, ALT, ALP, and/or AST. To evaluate the absorption of oral doxycycline in our study population, serum concentrations in 10 treated dogs were determined using liquid chromatography tandem mass spectrometry. Serum levels were variable and ranged from 3.6 to 16.6 µg/ml (median, 7.6 µg/ml; mean, 8.8 µg/ml. To evaluate the effect of doxycycline on canine lymphoma cell viability in vitro, trypan blue exclusion assay was performed on canine B-cell lymphoma cell lines (17-71 and CLBL and primary B-cell lymphoma cells from the nodal tissue of four dogs. A doxycycline concentration of 6 µg/ml decreased canine lymphoma cell viability by 80%, compared to matched, untreated, control cells (mixed model analysis, p < 0.0001; Wilcoxon signed rank test, p = 0.0313. Although the short-term administration of oral doxycycline is not associated with the remission of canine lymphoma, combination therapy may be worthwhile if future research determines that doxycycline can alter cell survival pathways in canine lymphoma cells. Due to the potential for metabolic abnormalities, close monitoring is recommended with the use of this drug in tumor-bearing dogs. Additional research is needed to assess the tolerability of chronic

  16. Macrofilaricidal activity after doxycycline only treatment of Onchocerca volvulus in an area of Loa loa co-endemicity: a randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Joseph D Turner

    2010-04-01

    Full Text Available The risk of severe adverse events following treatment of onchocerciasis with ivermectin in areas co-endemic with loiasis currently compromises the development of control programmes and the treatment of co-infected individuals. We therefore assessed whether doxycycline treatment could be used without subsequent ivermectin administration to effectively deliver sustained effects on Onchocerca volvulus microfilaridermia and adult viability. Furthermore we assessed the safety of doxycycline treatment prior to ivermectin administration in a subset of onchocerciasis individuals co-infected with low to moderate intensities of Loa loa microfilaraemia.A double-blind, randomized, field trial was conducted of 6 weeks of doxycycline (200 mg/day alone, doxycycline in combination with ivermectin (150 microg/kg at +4 months or placebo matching doxycycline + ivermectin at +4 months in 150 individuals infected with Onchocerca volvulus. A further 22 individuals infected with O. volvulus and low to moderate intensities of Loa loa infection were administered with a course of 6 weeks doxycycline with ivermectin at +4 months. Treatment efficacy was determined at 4, 12 and 21 months after the start of doxycycline treatment together with the frequency and severity of adverse events.One hundred and four (60.5% participants completed all treatment allocations and follow up assessments over the 21-month trial period. At 12 months, doxycycline/ivermectin treated individuals had lower levels of microfilaridermia and higher frequency of amicrofilaridermia compared with ivermectin or doxycycline only groups. At 21 months, microfilaridermia in doxycycline/ivermectin and doxycycline only groups was significantly reduced compared to the ivermectin only group. 89% of the doxycycline/ivermectin group and 67% of the doxycycline only group were amicrofilaridermic, compared with 21% in the ivermectin only group. O. volvulus from doxycycline groups were depleted of Wolbachia and all

  17. Construction of Nef-positive doxycycline-dependent HIV-1 variants using bicistronic expression elements

    Energy Technology Data Exchange (ETDEWEB)

    Velden, Yme U. van der; Kleibeuker, Wendy; Harwig, Alex; Klaver, Bep; Siteur-van Rijnstra, Esther; Frankin, Esmay; Berkhout, Ben; Das, Atze T., E-mail: a.t.das@amc.uva.nl

    2016-01-15

    Conditionally replicating HIV-1 variants that can be switched on and off at will are attractive tools for HIV research. We previously developed a genetically modified HIV-1 variant that replicates exclusively when doxycycline (dox) is administered. The nef gene in this HIV-rtTA variant was replaced with the gene encoding the dox-dependent rtTA transcriptional activator. Because loss of Nef expression compromises virus replication in primary cells and precludes studies on Nef function, we tested different approaches to restore Nef production in HIV-rtTA. Strategies that involved translation via an EMCV or synthetic internal ribosome entry site (IRES) failed because these elements were incompatible with efficient virus replication. Fusion protein approaches with the FMDV 2A peptide and human ubiquitin were successful and resulted in genetically-stable Nef-expressing HIV-rtTA strains that replicate more efficiently in primary T-cells and human immune system (HIS) mice than Nef-deficient variants, thus confirming the positive effect of Nef on in vivo virus replication. - Highlights: • Different approaches to encode additional proteins in the HIV-1 genome were tested. • IRES translation elements are incompatible with efficient HIV-1 replication. • Ubiquitin and 2A fusion protein approaches allow efficient HIV-1 replication. • Doxycycline-controlled HIV-1 variants that encode all viral proteins were developed. • Nef stimulates HIV-rtTA replication in primary cells and human immune system mice.

  18. Doxycycline hinders phenylalanine fibril assemblies revealing a potential novel therapeutic approach in phenylketonuria.

    Science.gov (United States)

    De Luigi, Ada; Mariani, Alessandro; De Paola, Massimiliano; Re Depaolini, Andrea; Colombo, Laura; Russo, Luca; Rondelli, Valeria; Brocca, Paola; Adler-Abramovich, Lihi; Gazit, Ehud; Del Favero, Elena; Cantù, Laura; Salmona, Mario

    2015-10-29

    A new paradigm for the aetiopathology of phenylketonuria suggests the presence of amyloid-like assemblies in the brains of transgenic mouse models and patients with phenylketonuria, possibly shedding light on the selective cognitive deficit associated with this disease. Paralleling the amyloidogenic route that identifies different stages of peptide aggregation, corresponding to different levels of toxicity, we experimentally address for the first time, the physico-chemical properties of phenylalanine aggregates via Small Angle, Wide Angle X-ray Scattering and Atomic Force Microscopy. Results are consistent with the presence of well-structured, aligned fibres generated by milliMolar concentrations of phenylalanine. Moreover, the amyloid-modulating doxycycline agent affects the local structure of phenylalanine aggregates, preventing the formation of well-ordered crystalline structures. Phenylalanine assemblies prove toxic in vitro to immortalized cell lines and primary neuronal cells. Furthermore, these assemblies also cause dendritic sprouting alterations and synaptic protein impairment in neurons. Doxycycline counteracts these toxic effects, suggesting an approach for the development of future innovative non-dietary preventive therapies.

  19. Development of a standardized susceptibility test for Campylobacter with quality control ranges for ciprofloxacin, doxycycline, erythromycin, gentamicin, and meropenem

    DEFF Research Database (Denmark)

    McDermott, P. F.; Bodeis, S. M.; Aarestrup, Frank Møller

    2004-01-01

    -control (QC) strain. Minimal inhibitory concentration (MIC) QC ranges were determined for two incubation time/temperature combinations: 36degreesC for 48 hr and 42degreesC for 24 hr. Quality-control ranges were determined for ciprofloxacin, doxycycline, erythromycin, gentamicin, and meropenem. For all...

  20. Modulation of cytokine and cytokine receptor/antagonist by treatment with doxycycline and tetracycline in patients with dengue fever.

    Science.gov (United States)

    Castro, J E Z; Vado-Solis, I; Perez-Osorio, C; Fredeking, T M

    2011-01-01

    Dengue virus infection can lead to dengue fever (DF) or dengue hemorrhagic fever (DHF). Disease severity has been linked to an increase in various cytokine levels. In this study, we evaluated the effectiveness of doxycycline and tetracycline to modulate serum levels of IL-6, IL-1B, and TNF and cytokine receptor/receptor antagonist TNF-R1 and IL-1RA in patients with DF or DHF. Hospitalized patients were randomized to receive standard supportive care or supportive care combined with doxycycline or tetracycline therapy. Serum cytokine and cytokine receptor/antagonist levels were determined at the onset of therapy and after 3 and 7 days. Cytokine and cytokine receptor/antagonist levels were substantially elevated at day 0. IL-6, IL-1β, and TNF remained at or above day 0 levels throughout the study period in untreated patients. Treatment with tetracycline or doxycycline resulted in a significant decline in cytokine levels. Similarly, IL-1RA and TNF-R1 serum concentrations were elevated at baseline and showed a moderate increase among untreated patients. Both drugs resulted in a significant rise in IL-1Ra levels by day 3 in patients. In contrast, treatment did not affect a similar result for TNF-R1. When compared to the control group, however, a significant rise post-treatment was seen upon intragroup analysis. Further analysis demonstrated that doxycycline was significantly more effective at modulating cytokine and cytokine receptor/antagonist levels than tetracycline.

  1. The role of long-term doxycycline in patients of idiopathic pulmonaryfibrosis: The results of an open prospective trial

    Directory of Open Access Journals (Sweden)

    Bhattacharyya Parthasarathi

    2009-01-01

    Full Text Available Objective: To evaluate the effect of long term use of doxycycline in IPF patients. Materials and Methods: Patients of IPF, selected randomly from out patient services and diagnosed on the basis of HRCT chest, were put on doxycycline in an open prospective trial. They were followed up with monitoring of subjective well being along with measurement of pulse rate and arterial oxygen saturation at rest and after a fixed and certain exercise, forced vital capacity, six minutes walk test, St Georges Respiratory questionnaire, and serial chest X-rays. Results: Out of seven patients put on doxycycline, six of them continued the drug for a mean period of 531.43 (± 328.88 days. All the patients tolerated the drug well and had shown uniform subjective and overall objective improvement in all the parameters concerned; the change in the radiological parameter being statistically significant. Conclusion: Doxycycline merits an appropriate clinical trial in the management of idiopathic pulmonary fibrosis. This widely used and relatively safe drug can add a new dimension to the therapeutic regimen. However, further in-depth studies will be required to evaluate its role in the management of IPF.

  2. Influence of microplastics on the toxicity of the pharmaceuticals procainamide and doxycycline on the marine microalgae Tetraselmis chuii.

    Science.gov (United States)

    Prata, Joana C; Lavorante, Beatriz R B O; B S M Montenegro, Maria da Conceição; Guilhermino, Lúcia

    2018-04-01

    Microplastics and pharmaceuticals are considered ubiquitous and emergent pollutants of high concern but the knowledge on their effects on primary producers is still limited, especially those caused by mixtures. Thus, the goal of the present study was to investigate if the presence of microplastics (1-5 μm diameter) influences the toxicity of the pharmaceuticals procainamide and doxycycline to the marine microalga Tetraselmis chuii. Bioassays (96 h) to investigate the toxicity of those substances individually and in mixtures (i.e. microplastics-procainamide mixtures and microplastics-doxycycline mixtures) were carried out. Effect criteria were the average specific growth rate (growth rate) and chlorophyll a concentration (chlorophyll). EC 10 , EC 20 and EC 50 were determined. Microplastics alone had no significant effects on growth rate up to 41.5 mg/l, whereas chlorophyll was significantly reduced at 0.9 and 2.1 mg/l of microplastics, but not at higher concentrations. The 96 h EC 50 (growth rate and chlorophyll, respectively) determined for the other bioassays were: 104 and 143 mg/l for procainamide alone; 125 and 31 mg/l for procainamide in the presence of microplastics; 22 and 14 mg/l for doxycycline alone; 11 and 7 mg/l for doxycycline in the presence of microplastics. Significant differences (p microplastics were found for procainamide (chlorophyll), and doxycycline (both parameters). Thus, both pharmaceuticals were toxic to T. chuii in the low ppm range, and microplastics-pharmaceutical mixtures were more toxic than the pharmaceuticals alone. Very high decreases of doxycycline concentrations in test media were found, indicating degradation of the antibiotic. Thus, although the biological results are expressed in relation to doxycycline concentration, the effects were likely caused by a mixture of the parental compound and its degradation products. The concentrations of microplastics and pharmaceuticals tested (low ppm range) are higher

  3. Spectrophotometric Determination of Doxycycline Hyclate in Pure and Capsule using Diazotization Reaction

    Directory of Open Access Journals (Sweden)

    Ruba Fahmi Abbas

    2017-07-01

    Full Text Available A sensitive spectrophotometric method has been developed for the determination of Doxycycline hyclate (DCH as pure and  capsule forms. This method is based on diazotization of primary amine group of benzocaine with sodium nitrite in hydrochloric acid medium; the formed diazonium salt is then reacted with DCH in sodium hydroxide medium, to form yellow – orange Azo dye. Beer's law is obeyed in the concentration rang 16-34mg. ml-1 at 480 nm with detection limit LOD and molar absorptivity Є were found to be 0.418 mg.ml-1 and 2.214× 10+4 L.mol-1.cm-1, respectively.

  4. A rapid and reliable determination of doxycycline hyclate by HPLC with UV detection in pharmaceutical samples

    Directory of Open Access Journals (Sweden)

    SNEZANA S. MITIC

    2008-06-01

    Full Text Available An accurate, sensitive and reproducible high performance liquid chromatographic (HPLC method for the quantification of doxycycline hyclate in pharmaceutical samples has been developed and validated. The drug and the standard were eluted from a Lichrosorb RP-8 (250 mm´4.6 mm, 10 mm particle size at 20 °C with a mobile phase consisting of methanol, acetonitrile and 0.010 M aqueous solution of oxalic acid (2:3:5, v/v/v. The flow rate was 1.25 ml min-1. A UV detector set at 350 nm was used to monitor the effluent. Each analysis required no longer than 4 min. The limits of detection and quantification were 1.15 and 3.84 μg ml-1, respectively. Recoveries for different concentrations ranged from 99.58 to 101.93 %.

  5. Use of quartz crystal nanobalance to study the binding and stabilization of albumin and doxycycline on a thin layer of hydroxyapatite

    Science.gov (United States)

    Victor, Sunita Prem; Sharma, Chandra P.; Sreenivasan, K.

    2011-12-01

    This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two model molecules namely albumin and doxycycline by hydroxyapatite (HA). The work focuses on the deposition of a stable coating of HA on the quartz crystal, modification of the coating using doxycycline and its subsequent effects on albumin adsorption. The uniformity and thickness of the HA coating has been studied using atomic force microscopy (AFM). The functional groups to ascertain the presence of the selected moieties have been characterized by Raman spectroscopy. The results indicate that the mass of albumin deposited on the surface of the HA coated quartz crystal functionalized with doxycycline shows a substantial increase when compared to the standard HA coated quartz crystal. The adsorbed albumin has also been found to be retained for an enhanced period of time. This surface immobilization of doxycycline and subsequent albumin adsorption seem to be a promising approach to confer biomaterials with antithrombogenic and antibacterial surfaces.

  6. Use of quartz crystal nanobalance to study the binding and stabilization of albumin and doxycycline on a thin layer of hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Victor, Sunita Prem [Biosurface Technology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum 695012, Kerala (India); Sharma, Chandra P., E-mail: sharmacp@sctmist.ac.in [Biosurface Technology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum 695012, Kerala (India); Sreenivasan, K. [Biosurface Technology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum 695012, Kerala (India); Laboratory for Polymer Analysis, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum 695012, Kerala (India)

    2011-12-15

    This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two model molecules namely albumin and doxycycline by hydroxyapatite (HA). The work focuses on the deposition of a stable coating of HA on the quartz crystal, modification of the coating using doxycycline and its subsequent effects on albumin adsorption. The uniformity and thickness of the HA coating has been studied using atomic force microscopy (AFM). The functional groups to ascertain the presence of the selected moieties have been characterized by Raman spectroscopy. The results indicate that the mass of albumin deposited on the surface of the HA coated quartz crystal functionalized with doxycycline shows a substantial increase when compared to the standard HA coated quartz crystal. The adsorbed albumin has also been found to be retained for an enhanced period of time. This surface immobilization of doxycycline and subsequent albumin adsorption seem to be a promising approach to confer biomaterials with antithrombogenic and antibacterial surfaces.

  7. Use of quartz crystal nanobalance to study the binding and stabilization of albumin and doxycycline on a thin layer of hydroxyapatite

    International Nuclear Information System (INIS)

    Victor, Sunita Prem; Sharma, Chandra P.; Sreenivasan, K.

    2011-01-01

    This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two model molecules namely albumin and doxycycline by hydroxyapatite (HA). The work focuses on the deposition of a stable coating of HA on the quartz crystal, modification of the coating using doxycycline and its subsequent effects on albumin adsorption. The uniformity and thickness of the HA coating has been studied using atomic force microscopy (AFM). The functional groups to ascertain the presence of the selected moieties have been characterized by Raman spectroscopy. The results indicate that the mass of albumin deposited on the surface of the HA coated quartz crystal functionalized with doxycycline shows a substantial increase when compared to the standard HA coated quartz crystal. The adsorbed albumin has also been found to be retained for an enhanced period of time. This surface immobilization of doxycycline and subsequent albumin adsorption seem to be a promising approach to confer biomaterials with antithrombogenic and antibacterial surfaces.

  8. Poor man medical pneumoplasty: Bronchoscopic lung volume reduction with hot saline versus dissolved doxycycline as a neoteric remedy of pulmonary emphysema

    Directory of Open Access Journals (Sweden)

    A.M. Abumossalam

    2016-01-01

    Conclusion: Bronchoscopic lung volume reduction by hot saline and dissolved doxycycline comes into sight to be a safe and feasible profile with an acceptable outcome that presents an attractive substitute to COPD patients who are physiologically friable.

  9. Radiolabeling, quality control and kit formulation of a new 99mTc-labeled antibiotic. 99mTc-doxycycline hyclate

    International Nuclear Information System (INIS)

    Derya Ilem-Oezdemir; Makbule Asikoglu; Hayal Oezkilic

    2013-01-01

    Since radiolabeled antibiotics specifically bind to the bacterial components they are promising radiopharmaceuticals for the precise diagnosis and detection of infectious lesions. Doxycycline hyclate (DOX) was chosen to investigate as a new radiolabeled antibacterial agent since its bacteriostatic activity against a wide variety of microorganisms. The aim of the present study is to develop simple and easy formulation of DOX with 99m Tc ready to use kit. 99m Tc-DOX was developed and standardized under varying conditions of reducing and antioxidant agent concentration, pH, radioactivity dose and reducing agent type. Labeling studies were performed by changing the selected parameters one by one and optimum labeling conditions were determined. After observing the conditions for maximum labeling efficiency and stability, lyophilized freeze dry kits were prepared accordingly. Radiochemical purity was determined with RTLC and RHPLC which was found more than >95 %. Two different freeze dry kits were formulated with optimum labeling conditions. The improved kits were found stable up to 6 months. (author)

  10. Facile synthesis of Cu(II) impregnated biochar with enhanced adsorption activity for the removal of doxycycline hydrochloride from water.

    Science.gov (United States)

    Liu, Su; Xu, Wei-Hua; Liu, Yun-Guo; Tan, Xiao-Fei; Zeng, Guang-Ming; Li, Xin; Liang, Jie; Zhou, Zan; Yan, Zhi-Li; Cai, Xiao-Xi

    2017-08-15

    In this study, the effect factors and mechanisms of doxycycline hydrochloride (DOX) adsorption on copper nitrate modified biochar (Cu-BC) was investigated. Cu-BC absorbent was synthesized through calcination of peanut shells biomass at 450°C and then impregnation with copper nitrate. The Cu-BC has exhibited excellent sorption efficiency about 93.22% of doxycycline hydrochloride from aqueous solution, which was double higher than that of the unmodified biochar. The experimental results suggest that the adsorption efficiency of DOX on the Cu-BC is dominated by the strong complexation, electrostatic interactions between DOX molecules and the Cu-BC samples. Comprehensively considering the cost, efficiency and the application to realistic water, the Cu-BC hold the significant potential for enhancing the effectiveness to remove DOX from water. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Oral doxycycline for the prevention of postoperative trachomatous trichiasis in Ethiopia: a randomised, double-blind, placebo-controlled trial

    Directory of Open Access Journals (Sweden)

    Esmael Habtamu, PhD

    2018-05-01

    Full Text Available Summary: Background: Trachomatous trichiasis is treated surgically to prevent sight loss. Unfavourable surgical outcomes remain a major challenge. We investigated the hypothesis that doxycycline might reduce the risk of postoperative trichiasis following surgery in patients with trachomatous trichiasis through anti-matrix metalloproteinase and anti-inflammatory activity. Methods: In this randomised, double-blind, placebo-controlled trial, adults (aged >18 years with upper lid trachomatous trichiasis in association with tarsal conjunctive scarring were recruited through community-based screening and surgical outreach campaigns in Ethiopia. Individuals who had previously had eyelid surgery were excluded. Participants were randomly assigned (1:1, with random block sizes of four or six, to receive oral doxycycline (100 mg once a day or placebo for 28 days immediately after trichiasis surgery. Randomisation was stratified by surgeon. Patients, investigators, surgeons, and all other study team members were masked to study group allocation and treatment. Participants were examined at 10 days, and 1, 6, and 12 months after surgery. The primary outcome was the cumulative proportion of individuals who developed postoperative trichiasis by 12 months. Primary analyses were done in all participants who attended at least one of the four follow-up assessments. Safety analyses were done in all participants who attended either the 10 day or 1 month follow-up assessments. This trial is registered with the Pan African Clinical Trials Registry, number PACTR201512001370307. Findings: Between Dec 21, 2015, and April 6, 2016, 1000 patients with trichiasis were enrolled and randomly assigned to treatment (499 patients to doxycycline, 501 patients to placebo. All but one participant attended at least one follow-up assessment. Thus, 999 participants were assessed for the primary outcome: 498 in the doxycycline group and 501 in the placebo group. By month 12, 58 (12% of

  12. Corrigendum to Development of a Doxycycline Hydrochloride-Loaded Electro spun Nano fibrous Membrane for GTR/GB R Applications

    International Nuclear Information System (INIS)

    Jia, L. N.; Xu, H. Y.; Hu, X. G.; Xie, Q.; Wang, W.; Jia, J.; Zhang, X.; Hua, F.

    2016-01-01

    In the article titled Development of a Doxycycline Hydrochloride-Loaded Electro spun Nano fibrous Membrane for GTR/GBR Applications [1], there was an error in the Acknowledgments section, which should be corrected as follows: The authors would like to acknowledge the financial support by the National Science Foundation of China (no. 81271136). This investigation was supported by School of Stomatology, Institute of Material Medical School of Pharmacy, and Department of Military Toxicology, the Fourth Military Medical University.

  13. Adverse effect of tetracycline and doxycycline on testicular tissue and sperm parameters in CD1 outbred mice

    Czech Academy of Sciences Publication Activity Database

    Elzeinová, Fatima; Pěknicová, Jana; Děd, Lukáš; Kubátová, Alena; Margaryan, Hasmik; Dorosh, Andriy; Makovický, P.; Rajmon, R.

    2013-01-01

    Roč. 65, Sep (2013), s. 911-917 ISSN 0940-2993 R&D Projects: GA MŠk(CZ) 1M06011; GA ČR(CZ) GA523/09/1793; GA ČR(CZ) GAP503/12/1834 Institutional research plan: CEZ:AV0Z50520701 Keywords : Tetracycline * Doxycycline * Testes * Sperm * Apoptosis * Puberty Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 2.005, year: 2013

  14. Poly(lactide-co-glycolide) encapsulated hydroxyapatite microspheres for sustained release of doxycycline

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaoyun [School of Pharmacy, Shenyang Pharmaceutical University, 103, Wenhua Road, Shenyang 110016 (China); Department of Pharmacy, Shandong Drug and Food Vocational College, Science and Technology Town, Hightech Industrial Development Zone, Weihai 264210 (China); Xu Hui; Zhao Yanqiu [School of Pharmacy, Shenyang Pharmaceutical University, 103, Wenhua Road, Shenyang 110016 (China); Wang Shaoning, E-mail: wsn-xh@126.com [School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103, Wenhua Road, Shenyang 110016 (China); Abe, Hiroya; Naito, Makio [Joining and Welding Research Institute, Osaka University, 11-1, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Liu Yanli [School of Pharmacy, Shenyang Pharmaceutical University, 103, Wenhua Road, Shenyang 110016 (China); Wang Guoqing [School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103, Wenhua Road, Shenyang 110016 (China)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer PLGA encapsulated HAP-MSs were used for the sustained delivery of Doxycycline (Doxy, a broad spectrum tetracycline antibiotic). Black-Right-Pointing-Pointer Sustained Doxy release without obvious burst was observed. Black-Right-Pointing-Pointer Mechanism of the sustained Doxy release was illustrated. Black-Right-Pointing-Pointer Sustained Doxy release character in vivo was also obtained, the plasma Doxy levels were relatively lower and steady compared to that of the un-encapsulated HAP-MSs. - Abstract: The purpose of this study was to prepare a poly(lactide-co-glycolide) (PLGA) encapsulated hydroxyapatite microspheres (HAP-MSs) as injectable depot for sustained delivery of Doxycycline (Doxy). Doxy loaded HAP-MSs (Doxy-HAP-MSs) were encapsulated with PLGA by solid-in-oil-in-water (S/O/W) emulsion-solvent evaporation technique, the effects of the PLGA used (various intrinsic viscosity and LA/GA ratio) and ratio of PLGA/HAP-MSs on the formation of Doxy-HAP-MSs and in vitro release of Doxy were studied. The results showed that sustained drug release without obvious burst was obtained by using PLGA encapsulated HAP-MSs as the carrier, also the drug release rate could be tailored by changing the ratio of PLGA/HAP-MSs, or PLGA of various intrinsic viscosities or LA/GA ratio. Lower ratio of PLGA/HAP-MSs corresponded faster Doxy release, e.g. for the microspheres of PLGA/HAP-MSs ratio of 8 and 0.25, the in vitro Doxy release percents at the end of 7days were about 23% and 76%, respectively. Higher hydrophilicity (higher ratio of GA to LA) and lower molecular weight of PLGA corresponded to higher Doxy release rates. For in vivo release study, PLGA encapsulated HAP-MSs were subcutaneously injected to the back of mice, and the results showed good correlation between the in vivo and in vitro drug release. Meanwhile, the plasma Doxy levels after subcutaneous administration of PLGA encapsulated Doxy-HAP-MSs were relatively lower and steady

  15. Poly(lactide-co-glycolide) encapsulated hydroxyapatite microspheres for sustained release of doxycycline

    International Nuclear Information System (INIS)

    Wang Xiaoyun; Xu Hui; Zhao Yanqiu; Wang Shaoning; Abe, Hiroya; Naito, Makio; Liu Yanli; Wang Guoqing

    2012-01-01

    Highlights: ► PLGA encapsulated HAP-MSs were used for the sustained delivery of Doxycycline (Doxy, a broad spectrum tetracycline antibiotic). ► Sustained Doxy release without obvious burst was observed. ► Mechanism of the sustained Doxy release was illustrated. ► Sustained Doxy release character in vivo was also obtained, the plasma Doxy levels were relatively lower and steady compared to that of the un-encapsulated HAP-MSs. - Abstract: The purpose of this study was to prepare a poly(lactide-co-glycolide) (PLGA) encapsulated hydroxyapatite microspheres (HAP-MSs) as injectable depot for sustained delivery of Doxycycline (Doxy). Doxy loaded HAP-MSs (Doxy-HAP-MSs) were encapsulated with PLGA by solid-in-oil-in-water (S/O/W) emulsion-solvent evaporation technique, the effects of the PLGA used (various intrinsic viscosity and LA/GA ratio) and ratio of PLGA/HAP-MSs on the formation of Doxy-HAP-MSs and in vitro release of Doxy were studied. The results showed that sustained drug release without obvious burst was obtained by using PLGA encapsulated HAP-MSs as the carrier, also the drug release rate could be tailored by changing the ratio of PLGA/HAP-MSs, or PLGA of various intrinsic viscosities or LA/GA ratio. Lower ratio of PLGA/HAP-MSs corresponded faster Doxy release, e.g. for the microspheres of PLGA/HAP-MSs ratio of 8 and 0.25, the in vitro Doxy release percents at the end of 7days were about 23% and 76%, respectively. Higher hydrophilicity (higher ratio of GA to LA) and lower molecular weight of PLGA corresponded to higher Doxy release rates. For in vivo release study, PLGA encapsulated HAP-MSs were subcutaneously injected to the back of mice, and the results showed good correlation between the in vivo and in vitro drug release. Meanwhile, the plasma Doxy levels after subcutaneous administration of PLGA encapsulated Doxy-HAP-MSs were relatively lower and steady compared to that of the un-encapsulated microspheres. In conclusion, PLGA encapsulated HAP-MSs may

  16. Short Communication - Study on quality and efficacy of commercial tylosin and doxycycline products against local isolates of mycoplasma in broilers.

    Science.gov (United States)

    Riazuddin, -; Khan, Sarzamin; Imtiaz, Naila; Aslam, Saima; Ahmad, Shakoor; Khan, Hamayun; Rabbani, Masood; Muhammad, Javed; Tanveer, Zafar Iqbal; Ali, Sakhawat

    2017-03-01

    The present study was conducted to investigate the quality and efficacy of commercially available preparations of tylosin and doxycycline available in the local market at Peshawar for poultry. In vitro and in vivo, tests were conducted to check the quality of these antimicrobial drugs. In vitro quality control test was performed by High performance liquid chromatographic (HPLC) and micro dilution method. In vivo, efficacy of the test drugs was checked in broilers infected with Mycoplasma gallisepticum. Results of HPLC indicated that test drug-2 contains doxycycline hydrochloride within specified limits but contain high quantity of active ingredient (Tylosin tartrate 120%). Recovery percentage of test drugs (3, 4, 5) were below the pharmacopoeial limit, which contained low quantity of tylosin tartrate (85%, 87.5%, 85%) respectively however, percent recovery of doxycycline were in the appropriate limits. All the tested drugs were effective against Mycoplasma gallisepticum and showed minimum inhibitory concentration (MIC) at 1.9μg/ml. The in vivo result indicated that all tested drugs decreased morbidity and mortality in infected chicks. The birds treated with test drugs (3 and 5) showed mortality of 9.5%, which was slightly higher than the other test groups. The current study suggested that there are incidences of substandard drugs in Pakistan and the drug regularity authorities should take strict actions against the manufacturing companies.

  17. Doxycycline-loaded coaxial nanofiber coating of titanium implants enhances osseointegration and inhibits Staphylococcus aureus infection.

    Science.gov (United States)

    Song, Wei; Seta, Joseph; Chen, Liang; Bergum, Christopher; Zhou, Zhubin; Kanneganti, Praveen; Kast, Rachel E; Auner, Gregory W; Shen, Ming; Markel, David C; Ren, Weiping; Yu, Xiaowei

    2017-07-05

    Few studies have been reported that focus on developing implant surface nanofiber (NF) coating to prevent infection and enhance osseointegration by local drug release. In this study, coaxial doxycycline (Doxy)-doped polycaprolactone/polyvinyl alcohol (PCL/PVA) NFs were directly deposited on a titanium (Ti) implant surface during electrospinning. The interaction of loaded Doxy with both PVA and PCL NFs was characterized by Raman spectroscopy. The bonding strength of Doxy-doped NF coating on Ti implants was confirmed by a stand single-pass scratch test. The improved implant osseointegration by PCL/PVA NF coatings in vivo was confirmed by scanning electron microscopy, histomorphometry and micro computed tomography (μCT) at 2, 4 and 8 weeks after implantation. The bone contact surface (%) changes of the NF coating group (80%) is significantly higher than that of the no NF group (coating effectively inhibited bacterial infection and enhanced osseointegration in an infected (Staphylococcus aureus) tibia implantation rat model. Doxy released from NF coating inhibited bacterial growth up to 8 weeks in vivo. The maximal push-in force of the Doxy-NF coating (38 N) is much higher than that of the NF coating group (6.5 N) 8 weeks after implantation (p coating doped with Doxy and/or other drugs have great potential in enhancing implant osseointegration and preventing infection.

  18. Engineering of polymer-surfactant nanoparticles of doxycycline hydrochloride for ocular drug delivery.

    Science.gov (United States)

    Pokharkar, Varsha; Patil, Vikram; Mandpe, Leenata

    2015-01-01

    Physiologic barriers of the eye, short precorneal drug residence time and poor corneal penetration are the few reasons for reduced ocular bioavailability. This study was aimed to develop novel polymer-surfactant nanoparticles of hydrophilic drug doxycycline hydrochloride (DXY) to improve precorneal residence time and drug penetration. Nanoparticles were formulated using emulsion cross-linking method and the formulation was optimized using factorial design. The prepared formulation was characterized for particle size, ζ potential, encapsulation efficiency, in vitro drug release and ex vivo drug diffusion studies. The antibacterial activity studies were also carried out against Escherichia coli and Staphylococcus aureus using the cup-plate method. In vivo eye irritation study was carried out by a modified Draize test in rabbits. The particle size was found to be in the range of 331-850 nm. About 45-80% of the drug was found to be encapsulated in the nanoparticles. In vitro release demonstrated sustained release profile. Lower flux values in case of nanoparticles as compared to DXY pure drug solution in ex vivo diffusion studies confirmed the sustained release. The nanoparticles were found to be significantly effective (p nanoparticles in both the E. coli and S. aureus strains. The formulation was found to be stable over entire stability period. The developed formulation is safe and suitable for sustained ocular drug delivery.

  19. Structural and thermodynamic characterization of doxycycline/β-cyclodextrin supramolecular complex and its bacterial membrane interactions.

    Science.gov (United States)

    Suárez, Diego F; Consuegra, Jessika; Trajano, Vivianne C; Gontijo, Sávio M L; Guimarães, Pedro P G; Cortés, Maria E; Denadai, Ângelo L; Sinisterra, Rubén D

    2014-06-01

    Doxycycline is a semi-synthetic antibiotic commonly used for the treatment of many aerobic and anaerobic bacteria. It inhibits the activity of matrix metalloproteinases (MMPs) and affects cell proliferation. In this study, the structural and thermodynamic parameters of free DOX and a DOX/βCD complex were investigated, as well as their interactions and effects on Staphylococcus aureus cells and cellular cytotoxicity. Complexation of DOX and βCD was confirmed to be an enthalpy- and entropy-driven process, and a low equilibrium constant was obtained. Treatment of S. aureus with higher concentrations of DOX or DOX/βCD resulted in an exponential decrease in S. aureus cell size, as well as a gradual neutralization of zeta potential. These thermodynamic profiles suggest that ion-pairing and hydrogen bonding interactions occur between DOX and the membrane of S. aureus. In addition, the adhesion of βCD to the cell membrane via hydrogen bonding is hypothesized to mediate a synergistic effect which accounts for the higher activity of DOX/βCD against S. aureus compared to pure DOX. Lower cytotoxicity and induction of osteoblast proliferation was also associated with DOX/βCD compared with free DOX. These promising findings demonstrate the potential for DOX/βCD to mediate antimicrobial activity at lower concentrations, and provides a strategy for the development of other antimicrobial formulations. Copyright © 2014. Published by Elsevier B.V.

  20. Effect of citric acid, tetracycline, and doxycycline on instrumented periodontally involved root surfaces: A SEM study

    Directory of Open Access Journals (Sweden)

    Gurparkash Singh Chahal

    2014-01-01

    Full Text Available Background: A surface smear layer consisting of organic and inorganic material is formed on the root surface following mechanical instrumentation and may inhibit the formation of new connective tissue attachment to the root surface. Modification of the tooth surface by root conditioning has resulted in improved connective tissue attachment and has advanced the goal of reconstructive periodontal treatment. Aim: The aim of this study was to compare the effects of citric acid, tetracycline, and doxycycline on the instrumented periodontally involved root surfaces in vitro using a scanning electron microscope. Settings and Design: A total of 45 dentin samples obtained from 15 extracted, scaled, and root planed teeth were divided into three groups. Materials and Methods: The root conditioning agents were applied with cotton pellets using the "Passive burnishing technique" for 5 minutes. The samples were then examined by the scanning electron microscope. Statistical Analysis Used: The statistical analysis was carried out using Statistical Package for Social Sciences (SPSS Inc., Chicago, IL, version 15.0 for Windows. For all quantitative variables means and standard deviations were calculated and compared. For more than two groups ANOVA was applied. For multiple comparisons post hoc tests with Bonferroni correction was used. Results: Upon statistical analysis the root conditioning agents used in this study were found to be effective in removing the smear layer, uncovering and widening the dentin tubules and unmasking the dentin collagen matrix. Conclusion: Tetracycline HCl was found to be the best root conditioner among the three agents used.

  1. Comprehensive adsorption studies of doxycycline and ciprofloxacin antibiotics by biochars prepared at different temperatures

    Science.gov (United States)

    Zeng, Zhi-wei; Tan, Xiao-fei; Liu, Yun-guo; Tian, Si-rong; Zeng, Guang-ming; Jiang, Lu-hua; Liu, Shao-bo; Li, Jiang; Liu, Ni; Yin, Zhi-hong

    2018-03-01

    This paper comparatively investigated the removal efficiency and mechanisms of rice straw biochars prepared under three pyrolytic temperatures for two kinds of tetracycline and quinolone antibiotics (doxycycline and ciprofloxacin). The influencing factors of antibiotic adsorption (including biochar dosage, pH, background electrolytes, humic acid, initial antibiotics concentration, contact time, and temperature) were comprehensively studied. The results suggest that biochars produced at high-temperature (i.e., 700°C (BC700)), have higher adsorption capacity for the two antibiotics than low-temperature (i.e., 300-500°C) biochars (BC300 and BC500). Higher surface area gives rise to greater volume of micropores and mesopores, and higher graphitic surfaces of the BC700 contributed to its higher functionality. The maximum adsorption capacity was found to be in the following order: DOX > CIP. The π-π EDA interaction and hydrogen bonding might be the predominant adsorption mechanisms. Findings in this study highlight the important roles of high-temperature biochars in controlling the contamination of tetracycline and quinolone antibiotics in the environment.

  2. Comprehensive Adsorption Studies of Doxycycline and Ciprofloxacin Antibiotics by Biochars Prepared at Different Temperatures

    Science.gov (United States)

    Zeng, Zhi-wei; Tan, Xiao-fei; Liu, Yun-guo; Tian, Si-rong; Zeng, Guang-ming; Jiang, Lu-hua; Liu, Shao-bo; Li, Jiang; Liu, Ni; Yin, Zhi-hong

    2018-01-01

    This paper comparatively investigated the removal efficiency and mechanisms of rice straw biochars prepared under three pyrolytic temperatures for two kinds of tetracycline and quinolone antibiotics (doxycycline and ciprofloxacin). The influencing factors of antibiotic adsorption (including biochar dosage, pH, background electrolytes, humic acid, initial antibiotics concentration, contact time, and temperature) were comprehensively studied. The results suggest that biochars produced at high-temperature [i.e., 700°C (BC700)], have higher adsorption capacity for the two antibiotics than low-temperature (i.e., 300–500°C) biochars (BC300 and BC500). Higher surface area gives rise to greater volume of micropores and mesopores, and higher graphitic surfaces of the BC700 contributed to its higher functionality. The maximum adsorption capacity was found to be in the following order: DOX > CIP. The π-π EDA interaction and hydrogen bonding might be the predominant adsorption mechanisms. Findings in this study highlight the important roles of high-temperature biochars in controlling the contamination of tetracycline and quinolone antibiotics in the environment. PMID:29637067

  3. The use of oral antibiotics in treating acne vulgaris: a new approach.

    Science.gov (United States)

    Farrah, Georgia; Tan, Ernest

    2016-09-01

    Although acne is not an infectious disease, oral antibiotics have remained a mainstay of treatment over the last 40 years. The anti-inflammatory properties of oral antibiotics, particularly the tetracyclines, are efficacious in treating inflammatory acne lesions. Common prescribing practices in Dermatology exert significant selection pressure on bacteria, contributing to the development of antibiotic resistance. Antibiotic use for acne not only promotes resistance in Propionibacterium acnes, but also affects other host bacteria with pathogenic potential. This review will summarize the commonly used treatments for acne vulgaris, and how they should be combined as rational treatment. The indications for using oral antibiotics in acne will be highlighted. Strategies described in the literature to conserve the utility of oral antibiotics will be summarized. These include limiting the duration of antibiotic therapy, concomitant use of a topical non-antibiotic agent, use of subantimicrobial dose doxycycline, and the introduction of topical dapsone. © 2016 Wiley Periodicals, Inc.

  4. Doxycycline Attenuates Leptospira-Induced IL-1β by Suppressing NLRP3 Inflammasome Priming

    Directory of Open Access Journals (Sweden)

    Wenlong Zhang

    2017-07-01

    Full Text Available Doxycycline (Dox, a semisynthetic antibiotic, has been reported to exert multiple immunomodulatory effects. Treatment with Dox has a satisfactory curative effect against leptospirosis. In addition to its antibacterial action, we supposed that Dox also modulated immune response in controlling leptospira infection. Using J774A.1 mouse macrophages, the effects of Dox on protein and mRNA levels of IL-1β and TNF-α were investigated after infection with live or sonicated Leptospira interrogans serovar Lai strain Lai (56601. Specifically, the level of IL-1β but not TNF-α was sharply decreased when treated with Dox in leptospira-infected macrophages. Western blot analysis showed that Dox suppressed the activation of leptospira-induced MAPK and NF-κB signaling pathways. Using NLRP3-deficient and NLRC4-deficient mice, the data showed that the expression of leptospira-induced IL-1β was mainly dependent on the presence of NLRP3 inflammasome in macrophages. Meanwhile, Dox suppressed leptospira-induced NLRP3 inflammasome priming with the upregulation of the Na/K-ATPase Pump β1 subunit. The inhibition effect of Dox on IL-1β was also conspicuous in cells with lipopolysaccharide and ATP stimulation. These results were confirmed in vivo, as peritoneal fluids of mice and organs of hamsters expressed less IL-1β after treatment of leptospiral infection with Dox. Our results indicated that Dox also modulated immune response to attenuate leptospira-induced IL-1β by suppressing p38, JNK, p65, and NLRP3 inflammasome priming.

  5. Doxycycline Attenuates Leptospira-Induced IL-1β by Suppressing NLRP3 Inflammasome Priming

    Science.gov (United States)

    Zhang, Wenlong; Xie, Xufeng; Wu, Dianjun; Jin, Xuemin; Liu, Runxia; Hu, Xiaoyu; Fu, Yunhe; Ding, Zhuang; Zhang, Naisheng; Cao, Yongguo

    2017-01-01

    Doxycycline (Dox), a semisynthetic antibiotic, has been reported to exert multiple immunomodulatory effects. Treatment with Dox has a satisfactory curative effect against leptospirosis. In addition to its antibacterial action, we supposed that Dox also modulated immune response in controlling leptospira infection. Using J774A.1 mouse macrophages, the effects of Dox on protein and mRNA levels of IL-1β and TNF-α were investigated after infection with live or sonicated Leptospira interrogans serovar Lai strain Lai (56601). Specifically, the level of IL-1β but not TNF-α was sharply decreased when treated with Dox in leptospira-infected macrophages. Western blot analysis showed that Dox suppressed the activation of leptospira-induced MAPK and NF-κB signaling pathways. Using NLRP3-deficient and NLRC4-deficient mice, the data showed that the expression of leptospira-induced IL-1β was mainly dependent on the presence of NLRP3 inflammasome in macrophages. Meanwhile, Dox suppressed leptospira-induced NLRP3 inflammasome priming with the upregulation of the Na/K-ATPase Pump β1 subunit. The inhibition effect of Dox on IL-1β was also conspicuous in cells with lipopolysaccharide and ATP stimulation. These results were confirmed in vivo, as peritoneal fluids of mice and organs of hamsters expressed less IL-1β after treatment of leptospiral infection with Dox. Our results indicated that Dox also modulated immune response to attenuate leptospira-induced IL-1β by suppressing p38, JNK, p65, and NLRP3 inflammasome priming. PMID:28791016

  6. Doxycycline inhibits experimental cerebral malaria by reducing inflammatory immune reactions and tissue-degrading mediators.

    Directory of Open Access Journals (Sweden)

    Kim E Schmidt

    Full Text Available Malaria ranks among the most important infectious diseases worldwide and affects mostly people living in tropical countries. Mechanisms involved in disease progression are still not fully understood and specific treatments that might interfere with cerebral malaria (CM are limited. Here we show that administration of doxycycline (DOX prevented experimental CM (ECM in Plasmodium berghei ANKA (PbA-infected C57BL/6 wildtype (WT mice in an IL-10-independent manner. DOX-treated mice showed an intact blood-brain barrier (BBB and attenuated brain inflammation. Importantly, if WT mice were infected with a 20-fold increased parasite load, they could be still protected from ECM if they received DOX from day 4-6 post infection, despite similar parasitemia compared to control-infected mice that did not receive DOX and developed ECM. Infiltration of T cells and cytotoxic responses were reduced in brains of DOX-treated mice. Analysis of brain tissue by RNA-array revealed reduced expression of chemokines and tumour necrosis factor (TNF in brains of DOX-treated mice. Furthermore, DOX-administration resulted in brains of the mice in reduced expression of matrix metalloproteinase 2 (MMP2 and granzyme B, which are both factors associated with ECM pathology. Systemic interferon gamma production was reduced and activated peripheral T cells accumulated in the spleen in DOX-treated mice. Our results suggest that DOX targeted inflammatory processes in the central nervous system (CNS and prevented ECM by impaired brain access of effector T cells in addition to its anti-parasitic effect, thereby expanding the understanding of molecular events that underlie DOX-mediated therapeutic interventions.

  7. Doxycycline inhibits experimental cerebral malaria by reducing inflammatory immune reactions and tissue-degrading mediators.

    Science.gov (United States)

    Schmidt, Kim E; Kuepper, Janina M; Schumak, Beatrix; Alferink, Judith; Hofmann, Andrea; Howland, Shanshan W; Rénia, Laurent; Limmer, Andreas; Specht, Sabine; Hoerauf, Achim

    2018-01-01

    Malaria ranks among the most important infectious diseases worldwide and affects mostly people living in tropical countries. Mechanisms involved in disease progression are still not fully understood and specific treatments that might interfere with cerebral malaria (CM) are limited. Here we show that administration of doxycycline (DOX) prevented experimental CM (ECM) in Plasmodium berghei ANKA (PbA)-infected C57BL/6 wildtype (WT) mice in an IL-10-independent manner. DOX-treated mice showed an intact blood-brain barrier (BBB) and attenuated brain inflammation. Importantly, if WT mice were infected with a 20-fold increased parasite load, they could be still protected from ECM if they received DOX from day 4-6 post infection, despite similar parasitemia compared to control-infected mice that did not receive DOX and developed ECM. Infiltration of T cells and cytotoxic responses were reduced in brains of DOX-treated mice. Analysis of brain tissue by RNA-array revealed reduced expression of chemokines and tumour necrosis factor (TNF) in brains of DOX-treated mice. Furthermore, DOX-administration resulted in brains of the mice in reduced expression of matrix metalloproteinase 2 (MMP2) and granzyme B, which are both factors associated with ECM pathology. Systemic interferon gamma production was reduced and activated peripheral T cells accumulated in the spleen in DOX-treated mice. Our results suggest that DOX targeted inflammatory processes in the central nervous system (CNS) and prevented ECM by impaired brain access of effector T cells in addition to its anti-parasitic effect, thereby expanding the understanding of molecular events that underlie DOX-mediated therapeutic interventions.

  8. Construction of doxycycline-mediated BMP-2 transgene combining with APA microcapsules for bone repair.

    Science.gov (United States)

    Qian, Dongyang; Bai, Bo; Yan, Guangbin; Zhang, Shujiang; Liu, Qi; Chen, Yi; Tan, Xiaobo; Zeng, Yanjun

    2016-01-01

    The repairing of large segmental bone defects is difficult for clinical orthopedists at present. Gene therapy is regarded as a promising method for bone defects repair. The present study aimed to construct an effective and controllable Tet-On expression system for transferring hBMP-2 gene into bone marrow mesenchymal progenitor cells (BMSCs). Meanwhile, with combination of alginate-poly-L-lysine-alginate (APA) microencapsulation technology, we attempted to reduce the influence of immunologic rejection and examine the effect of the Tet-On expression system on osteogenesis of BMSCs. The adenovirus encoding hBMP-2 (ADV-hBMP2) was constructed using the means of molecular cloning. The ADV-hBMP2 and Adeno-X Tet-On virus was respectively transfected to the HEK293 for amplification and afterward BMSCs were co-infected with the virus of ADV-hBMP2 and the Adeno-X Tet-On. The expression of hBMP-2 was measured with induction by doxycycline (DOX) at different concentration by means of RT-PCR and ELISA. Combining Tet-On expression system and APA microcapsules with the use of the pulsed high-voltage electrostatic microcapsule instrument, we examined the expression level of hBMP-2 in APA microcapsules by ELISA as well as the osteogenesis by alizarin red S staining. An effective Tet-On expression system for transferring hBMP-2 gene into BMSCs was constructed successfully. Also, the expression of hBMP-2 could be regulated by concentration of DOX. The data exhibited that BMSCs in APA microcapsules maintained the capability of proliferation and differentiation. The combination of Tet-On expression system and APA microcapsules could promote the osteogenesis of BMSCs. According to the results, microencapsulated Tet-On expression system showed the effective characteristics of secreting hBMP-2 and enhancing osteogenesis, which would provide a promising way for bone repair.

  9. Effect of doxycycline concentrations in chicken tissues as a consequence of permanent exposure to enrofloxacin traces in drinking water

    Directory of Open Access Journals (Sweden)

    Gbylik-Sikorska Małgorzata

    2016-09-01

    Full Text Available Introduction: The main problem in poultry farming is the difficulty in producing food of animal origin without using antibacterial agents. Because most antibacterial compounds are dispensed in water, some water supply systems can be contaminated by antibiotics which are then administered to the animals unintentionally. This can lead to unexpected increases in antibiotic residues in food of animal origin. The aim of the present study was to determine whether the constant exposure of chicken broilers to enrofloxacin affects the withdrawal time of a therapeutic doxycycline that is intentionally administered to the chickens.

  10. Development and Validation of a Stability-Indicating RP-HPLC Method for Rapid Determination of Doxycycline in Pharmaceutical Bulk and Dosage Forms

    OpenAIRE

    Shabnam Pourmoslemi, Soroush Mirfakhraee, Saeid Yaripour, Ali Mohammadi

    2016-01-01

    Background: A rapid stability-indicating RP-HPLC method for analysis of doxycycline in the presence of its degradation products was developed and validated. Methods: Forced degradation studies were carried out on bulk samples and capsule dosage forms of doxycycline using acid, base, H2O2, heat, and UV light as described by ICH for stress conditions to demonstrate the stability-indicating power of the method. Separations were performed on a Perfectsil® Target ODS column (3-5µm, 125 mm×4 mm), u...

  11. Optimization of the doxycycline-dependent simian immunodeficiency virus through in vitro evolution

    Directory of Open Access Journals (Sweden)

    Piatak Mike

    2008-06-01

    Full Text Available Abstract Background Vaccination of macaques with live attenuated simian immunodeficiency virus (SIV provides significant protection against the wild-type virus. The use of a live attenuated human immunodeficiency virus (HIV as AIDS vaccine in humans is however considered unsafe because of the risk that the attenuated virus may accumulate genetic changes during persistence and evolve to a pathogenic variant. We earlier presented a conditionally live HIV-1 variant that replicates exclusively in the presence of doxycycline (dox. Replication of this vaccine strain can be limited to the time that is needed to provide full protection through transient dox administration. Since the effectiveness and safety of such a conditionally live virus vaccine should be tested in macaques, we constructed a similar dox-dependent SIV variant. The Tat-TAR transcription control mechanism in this virus was inactivated through mutation and functionally replaced by the dox-inducible Tet-On regulatory system. This SIV-rtTA variant replicated in a dox-dependent manner in T cell lines, but not as efficiently as the parental SIVmac239 strain. Since macaque studies will likely require an efficiently replicating variant, we set out to optimize SIV-rtTA through in vitro viral evolution. Results Upon long-term culturing of SIV-rtTA, additional nucleotide substitutions were observed in TAR that affect the structure of this RNA element but that do not restore Tat binding. We demonstrate that the bulge and loop mutations that we had introduced in the TAR element of SIV-rtTA to inactivate the Tat-TAR mechanism, shifted the equilibrium between two alternative conformations of TAR. The additional TAR mutations observed in the evolved variants partially or completely restored this equilibrium, which suggests that the balance between the two TAR conformations is important for efficient viral replication. Moreover, SIV-rtTA acquired mutations in the U3 promoter region. We demonstrate

  12. Role of clove oil in solvent exchange-induced doxycycline hyclate-loaded Eudragit RS in situ forming gel

    Directory of Open Access Journals (Sweden)

    Thawatchai Phaechamud

    2018-03-01

    Full Text Available Solvent exchange induced in situ forming gel (ISG is the promising drug delivery system for periodontitis treatment owing to the prospect of maintaining an effective high drug level in the gingival crevicular fluid. In the present study, the influence of clove oil (CO on the characteristics of doxycycline hyclate (DH-loaded ISG comprising Eudragit RS (ERS was investigated including viscosity/rheology, syringeability, in vitro gel formation/drug release, matrix formation/solvent diffusion and antimicrobial activities. CO could dissolve ERS and increase the viscosity of ISG and its hydrophobicity could also retard the diffusion of solvent and hinder the drug diffusion; thus, the minimization of burst effect and sustained drug release were achieved effectively. All the prepared ISGs comprising CO could expel through the 27-gauge needle for administration by injection and transform into matrix depot after exposure to the simulated gingival crevicular fluid. The antimicrobial activities against Staphylococcus aureus, Escherichia coli, Streptococcus mutans and Porphyromonas gingivalis were increased when the ratio of CO and N-methyl pyrrolidone (NMP was decreased from 1:1 to 1:10 owing to higher diffusion of DH except that for C. albicans was increased as CO amount was higher. Therefore, CO could minimize the burst while prolonging the drug release of DH-loaded ERS ISG for use as a local drug delivery system for periodontitis treatment. Keywords: In situ forming gel, Eudragit RS, Clove oil, Doxycycline hyclate, Periodonditis, Burst release

  13. Anti-inflammatory and Anti-apoptotic Effect of Valproic Acid and Doxycycline Independent from MMP Inhibition in Early Radiation Damage

    Directory of Open Access Journals (Sweden)

    Ferda Hoşgörler

    2016-10-01

    Full Text Available Background: Matrix metalloproteinase (MMP inhibitors decrease inflammation in normal tissues and suppress cancer progress in normal tissues. Valproic acid (VA and doxycycline (DX are MMP inhibitors that have radio-protective effects. Their ability to inhibit MMPs in irradiated tissue is unknown and the role of MMPs in radio-protective effects has not been tested to date. Aims: The purpose of this study was to examine whether administration of VA and DX to rats before irradiation affects tissue inflammation and apoptosis in the early phase of radiation, and whether the effect of these drugs is mediated by MMP inhibition. Study Design: Animal experimentation. Methods: Twenty-six Wistar rats were randomized into four groups: control (CTRL, radiation (RT, VA plus radiation (VA+RT, and DX plus radiation (DX+RT.Three study groups were exposed to a single dose of abdominal 10 Gy gamma radiation; the CTRL group received no radiation. Single doses of VA 300 mg/kg and DX 100 mg/kg were administered to each rat before radiation and all rats were sacrificed 8 hours after irradiation, at which point small intestine tissue samples were taken for analyses. Levels of inflammatory cytokines (TNF-α, IL-1β, and IL-6 and matrix metalloproteinases (MMP-2 and MMP 9 were measured by ELISA, MMP activities were measured by gelatin and casein zymography and apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Results: VA decreased the levels of TNF-α and IL-1β proteins insignificantly and decreased apoptosis significantly in the irradiated tissue, but did not inhibit MMPs. In contrast, VA protected the basal MMP activities, which decreased in response to irradiation. No effect of DX was observed on the levels of inflammatory cytokines or activities of MMPs in the early phases of radiation apoptosis. Conclusion: Our findings indicated that VA protects against inflammation and apoptosis, and DX exhibits anti-apoptotic effects in

  14. Different effect of doxycycline and enrofloxacin on ca¬thelicidin-3 mRNA expression in chickens with or without probiotics supplementati

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    I. Pavlova

    2017-12-01

    Full Text Available The function of immune system of poultry has a significant impact on poultry husbandry sustainabi¬lity. Therefore the aim of this study was to investigate the effect of lactic acid bacteria administered with enrofloxacin or doxycycline on expression levels of antimicrobial peptide cathelicidin-3 (CATH3 at mRNA level in the duodenum, jejunum and liver of broilers. A day-old Ross (n=24 and Duc (n=24 chickens were included in experiments with enrofloxacin and doxycycline, respectively. They were divided into four groups (n=6 for each experiment: control, supplemented with probiotics (15 days via feed, 5 days after hatching, treated with either enrofloxacin or doxycycline (10 mg.kg-1 for 5 days, via drinking water and treated with antibiotic and probiotics. Expression levels of CATH3 mRNA in liver, duodenum and jejunum were determined by RT-PCR and were statistically evaluated by Mann-Whitney test.Administration of probiotics led to insignificant down-regulation of CATH3 mRNA in the investigated tissues. The combination of doxycycline with probiotics led to statistically significant down-regulation of CATH3 mRNA in the duodenum (P<0.01. Statistically significant up-regulation of mRNA of the studied gene was found in the jejunum of enrofloxacin treated Ross chickens. The data suggest the existence of an interaction between antibiotics and innate immunity. Further evaluation in infected poultry would shed more light on the pharmacodynamics of antibacterials.

  15. Development and Validation of a Stability-Indicating RP-HPLC Method for Rapid Determination of Doxycycline in Pharmaceutical Bulk and Dosage Forms

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    Shabnam Pourmoslemi, Soroush Mirfakhraee, Saeid Yaripour, Ali Mohammadi

    2016-06-01

    Full Text Available Background: A rapid stability-indicating RP-HPLC method for analysis of doxycycline in the presence of its degradation products was developed and validated. Methods: Forced degradation studies were carried out on bulk samples and capsule dosage forms of doxycycline using acid, base, H2O2, heat, and UV light as described by ICH for stress conditions to demonstrate the stability-indicating power of the method. Separations were performed on a Perfectsil® Target ODS column (3-5µm, 125 mm×4 mm, using a mobile phase consisting of methanol-50 mM ammonium acetate buffer (containing 0.1% v/v trifluoroacetic acid and 0.1% v/v triethylamine, pH 2.5 (50:50 v/v at room temperature. The flow rate was 0.8 mL/min. Results: The method linearity was investigated in the range of 25–500 µg/mL (r > 0.9999. The LOD and LOQ were 5 and 25 µg/mL, respectively. The method selectivity was evaluated by peak purity test using a diode array detector. There was no interference among detection of doxycycline and its stressed degradation products. Total peak purity numbers were in the range of 0.94-0.99, indicating the homogeneity of DOX peaks. Conclusion: These data show the stability-indicating nature of the method for quality control of doxycycline in bulk samples and capsule dosage forms.

  16. The etiology of community-acquired pneumonia in Australia: why penicillin plus doxycycline or a macrolide is the most appropriate therapy.

    Science.gov (United States)

    Charles, Patrick G P; Whitby, Michael; Fuller, Andrew J; Stirling, Robert; Wright, Alistair A; Korman, Tony M; Holmes, Peter W; Christiansen, Keryn J; Waterer, Grant W; Pierce, Robert J P; Mayall, Barrie C; Armstrong, John G; Catton, Michael G; Nimmo, Graeme R; Johnson, Barbara; Hooy, Michelle; Grayson, M L

    2008-05-15

    Available data on the etiology of community-acquired pneumonia (CAP) in Australia are very limited. Local treatment guidelines promote the use of combination therapy with agents such as penicillin or amoxycillin combined with either doxycycline or a macrolide. The Australian CAP Study (ACAPS) was a prospective, multicenter study of 885 episodes of CAP in which all patients underwent detailed assessment for bacterial and viral pathogens (cultures, urinary antigen testing, serological methods, and polymerase chain reaction). Antibiotic agents and relevant clinical outcomes were recorded. The etiology was identified in 404 (45.6%) of 885 episodes, with the most frequent causes being Streptococcus pneumoniae (14%), Mycoplasma pneumoniae (9%), and respiratory viruses (15%; influenza, picornavirus, respiratory syncytial virus, parainfluenza virus, and adenovirus). Antibiotic-resistant pathogens were rare: only 5.4% of patients had an infection for which therapy with penicillin plus doxycycline would potentially fail. Concordance with local antibiotic recommendations was high (82.4%), with the most commonly prescribed regimens being a penicillin plus either doxycycline or a macrolide (55.8%) or ceftriaxone plus either doxycycline or a macrolide (36.8%). The 30-day mortality rate was 5.6% (50 of 885 episodes), and mechanical ventilation or vasopressor support were required in 94 episodes (10.6%). Outcomes were not compromised by receipt of narrower-spectrum beta-lactams, and they did not differ on the basis of whether a pathogen was identified. The vast majority of patients with CAP can be treated successfully with narrow-spectrum beta-lactam treatment, such as penicillin combined with doxycycline or a macrolide. Greater use of such therapy could potentially reduce the emergence of antibiotic resistance among common bacterial pathogens.

  17. Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter

    International Nuclear Information System (INIS)

    Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L.; Smith, Charles D.; Lemasters, John J.

    2013-01-01

    Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 μM of each tetracycline-derived compound 20 min prior to exposure to 500 μM iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs–Ringer–HEPES buffer at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca 2+ uptake was measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometry was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca 2+ uptake and suppressed the Ca 2+ -induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca 2+ uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition, could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU. - Highlights: • Minocycline and doxycycline are the only cytoprotective tetracyclines of those tested • Cytoprotective tetracyclines inhibit the MPT and mitochondrial calcium and iron uptake. • Cytoprotective tetracyclines protect

  18. Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L.; Smith, Charles D. [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC (United States); Lemasters, John J., E-mail: JJLemasters@musc.edu [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC (United States); Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC (United States)

    2013-11-15

    Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 μM of each tetracycline-derived compound 20 min prior to exposure to 500 μM iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs–Ringer–HEPES buffer at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca{sup 2+} uptake was measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometry was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca{sup 2+} uptake and suppressed the Ca{sup 2+}-induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca{sup 2+} uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition, could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU. - Highlights: • Minocycline and doxycycline are the only cytoprotective tetracyclines of those tested • Cytoprotective tetracyclines inhibit the MPT and mitochondrial calcium and iron uptake. • Cytoprotective

  19. Adeno-associated virus-mediated doxycycline-regulatable TRAIL expression suppresses growth of human breast carcinoma in nude mice

    International Nuclear Information System (INIS)

    Zheng, Liu; Weilun, Zhang; Minghong, Jiang; Yaxi, Zhang; Shilian, Liu; Yanxin, Liu; Dexian, Zheng

    2012-01-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) functions as a cytokine to selectively kill various cancer cells without toxicity to most normal cells. Numerous studies have demonstrated the potential use of recombinant soluble TRAIL as a cancer therapeutic agent. We have showed previous administration of a recombinant adeno-associated virus (rAAV) vector expressing soluble TRAIL results in an efficient suppression of human tumor growth in nude mice. In the present study, we introduced Tet-On gene expression system into the rAAV vector to control the soluble TRAIL expression and evaluate the efficiency of the system in cancer gene therapy. Controllability of the Tet-On system was determined by luciferase activity assay, and Western blotting and enzyme-linked immunoabsorbent assay. Cell viability was determined by MTT assay. The breast cancer xenograft animal model was established and recombinant virus was administrated through tail vein injection to evaluate the tumoricidal activity. The expression of soluble TRAIL could be strictly controlled by the Tet-On system in both normal and cancer cells. Transduction of human cancer cell lines with rAAV-TRE-TRAIL&rAAV-Tet-On under the presence of inducer doxycycline resulted in a considerable cell death by apoptosis. Intravenous injection of the recombinant virus efficiently suppressed the growth of human breast carcinoma in nude mice when activated by doxycycline. These data suggest that rAAV-mediated soluble TRAIL expression under the control of the Tet-On system is a promising strategy for breast cancer therapy

  20. Adeno-associated virus-mediated doxycycline-regulatable TRAIL expression suppresses growth of human breast carcinoma in nude mice

    Directory of Open Access Journals (Sweden)

    Zheng Liu

    2012-04-01

    Full Text Available Abstract Background Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL functions as a cytokine to selectively kill various cancer cells without toxicity to most normal cells. Numerous studies have demonstrated the potential use of recombinant soluble TRAIL as a cancer therapeutic agent. We have showed previous administration of a recombinant adeno-associated virus (rAAV vector expressing soluble TRAIL results in an efficient suppression of human tumor growth in nude mice. In the present study, we introduced Tet-On gene expression system into the rAAV vector to control the soluble TRAIL expression and evaluate the efficiency of the system in cancer gene therapy. Methods Controllability of the Tet-On system was determined by luciferase activity assay, and Western blotting and enzyme-linked immunoabsorbent assay. Cell viability was determined by MTT assay. The breast cancer xenograft animal model was established and recombinant virus was administrated through tail vein injection to evaluate the tumoricidal activity. Results The expression of soluble TRAIL could be strictly controlled by the Tet-On system in both normal and cancer cells. Transduction of human cancer cell lines with rAAV-TRE-TRAIL&rAAV-Tet-On under the presence of inducer doxycycline resulted in a considerable cell death by apoptosis. Intravenous injection of the recombinant virus efficiently suppressed the growth of human breast carcinoma in nude mice when activated by doxycycline. Conclusion These data suggest that rAAV-mediated soluble TRAIL expression under the control of the Tet-On system is a promising strategy for breast cancer therapy.

  1. Eradication of Biofilm-like Microcolony Structures of Borrelia burgdorferi by Daunomycin and Daptomycin but not Mitomycin C in Combination with Doxycycline and Cefuroxime

    Directory of Open Access Journals (Sweden)

    Jie eFeng

    2016-02-01

    Full Text Available Lyme disease, caused by Borrelia burgdorferi, is the most common vector-borne disease in the United States and Europe. While the majority of Lyme disease patients can resolve their symptoms if treated promptly, 10-20% of patients suffer from prolonged symptoms called post-treatment Lyme disease syndrome (PTLDS. Although the cause for PTLDS is unclear, one possibility is the presence of bacterial persisters not effectively cleared by the current Lyme antibiotics. Recent studies identified several drug candidates including daptomycin, daunomycin, doxorubicin, and mitomycin C that had good activity against B. burgdorferi persisters. However, their relative activities against B. burgdorferi persisters have not been evaluated under the same conditions. In this study, we tested the anti-persister activities of these drugs against both 7-day and 15-day old stationary phase cultures of B. burgdorferi individually as well as in combination with Lyme antibiotics doxycycline and cefuroxime (Ceftin. Our findings demonstrate daunomycin and daptomycin were more active than mitomycin C in single drug comparison at 10 and 20 µM, as well as in drug combinations with doxycycline and cefuroxime. In addition, daunomycin was more active than doxorubicin which correlated with their ability to stain and accumulate in B. burgdorferi. The two drug combination of doxycycline and cefuroxime was unable to eradicate biofilm-like microcolonies of B. burgdorferi persisters. However, the addition of either daunomycin or daptomycin to the doxycycline + cefuroxime combination completely eradicated the biofilm-like structures and produced no visible bacterial regrowth after 7 days and 21 days, while the addition of doxorubicin was unable to prevent regrowth at either 7 day or 21 day subculture. Mitomycin C in combination with doxycycline and cefuroxime caused no regrowth at 7 days but visible spirochetal regrowth occurred after 21 day subculture. Furthermore, we found that

  2. Efficacy of Chitosan gel mucoadhesive containing Doxycycline associated or not to Meloxicam as adjuvant to treatment of gingivitis in dogs with periodontal disease

    Directory of Open Access Journals (Sweden)

    Rita de Cassia da Costa Silva

    2016-06-01

    Full Text Available ABSTRACT. Silva R.C.C., Campos D. R., Oliveira P., Laguna A.G.V., Magalhães V.S., Cid Y.P., Almeida M.B., Scott F.B. & Fernandes J.I. [Efficacy of Chitosan gel mucoadhesive containing Doxycycline associated or not to Meloxicam as adjuvant to treatment of gingivitis in dogs with periodontal disease.] Eficácia de um gel de Quitosano Mucoadesivo contendo Doxiciclina associada ou não ao Meloxicam como coadjuvante ao tratamento da gengivite em cães portadores de doença periodontal. Revista Brasileira de Medicina Veterinária, 38(Supl.2:40-44, 2016. Programa de Pós-Graduação em Medicina Veterinária, Universidade Federal Rural do Rio de Janeiro, BR 465 Km 7, Seropédica, RJ 23897-000, Brasil. E-mail: vetjulio@yahoo.com.br Periodontal disease is the highest occurrence condition in the pet clinic, affecting mainly older animals because of its characteristic of chronicity. Among the clinical signs observed in afflicted animals, gingivitis is the first to be observed. The goal of this study was to develop a mucoadhesive gel, containing doxycycline and meloxicam, and evaluate its efficacy as an adjuvant in the treatment of gingivitis induced by periodontal disease, with a clinical and histopathological rating. Eighteen Beagle dogs presenting gingivitis secondary to periodontal disease were divided into three experimental groups. Group I – animals treated with placebo formulation. Group II – Animals treated with a chitosan gel formulation containing doxycycline. Group III - Animals treated with a chitosan gel formulation containing doxycycline and meloxicam. All animals were treated for seven days, every twelve hours, in the gingival margin of the right maxilla. During the clinic evaluation, only the animals treated with the product containing doxycycline had improved. Contrasting, in the histopathologic evaluation, only animals treated with association of doxycycline and meloxicam presented improvements in their clinical score, although no

  3. Determination of the Mutant Selection Window and Evaluation of the Killing of Mycoplasma gallisepticum by Danofloxacin, Doxycycline, Tilmicosin, Tylvalosin and Valnemulin

    OpenAIRE

    Zhang, Nan; Ye, Xiaomei; Wu, Yuzhi; Huang, Zilong; Gu, Xiaoyan; Cai, Qinren; Shen, Xiangguang; Jiang, Hongxia; Ding, Huanzhong

    2017-01-01

    Mycoplasma gallisepticum is a common etiological cause of a chronic respiratory disease in chickens; its increasing antimicrobial resistance compromises the use of tetracyclines, macrolides and quinolones in the farm environment. Mutant selection window (MSW) determination was used to investigate the propensity for future resistance induction by danofloxacin, doxycycline, tilmicosin, tylvalosin and valnemulin. Killing of M. gallisepticum strain S6 by these antimicrobials was also studied by i...

  4. Spectroscopic investigation of the pH controlled inclusion of doxycycline and oxytetracycline antibiotics in cationic micelles and their magnesium driven release.

    Science.gov (United States)

    Cesaretti, Alessio; Carlotti, Benedetta; Gentili, Pier Luigi; Clementi, Catia; Germani, Raimondo; Elisei, Fausto

    2014-07-24

    This work presents a steady-state and time-resolved UV-visible spectroscopic investigation of two antibiotics belonging to the family of tetracyclines (doxycycline and oxytetracycline) in the micellar medium provided by p-dodecyloxybenzyltrimethylammonium bromide (pDoTABr). The spectroscopic analysis has been performed in absorption and emission with femtosecond time resolution, and at pH 5.0 and 8.7 where doxycycline and oxytetracycline are present in their neutral-zwitterionic and monoanionic forms, respectively. The experimental data have been processed by sophisticated data mining methods such as global/target analysis and the maximum entropy method. The results unambiguously indicate that, when doxycycline and oxytetracycline are in their zwitterionic form, they are entrapped within the micelle, while when they are in their monoanionic form, they preferentially show a strong one-to-one interaction with the positively charged surfactant heads. Thus, the pH of the solution controls the inclusion of the investigated drugs into the micelle. When the drugs are entrapped inside the micelles, their spectroscopic and dynamical properties after photoexcitation change appreciably. Interestingly, the entrapped drugs are still able to strongly bind Mg(2+) cations, crucial in determining the biological functioning of tetracyclines. The femtosecond resolved measurements reveal that the drugs are efficiently pulled out of the micelles by Mg(2+). In fact, magnesium-tetracycline complexes are detected in the aqueous phase. The present study suggests the potential promising use of ammonium surfactant micelles embedding doxycycline and oxytetracycline as "smart" drug delivery systems allowing their pH controlled inclusion and Mg(2+) induced release.

  5. Outcome of Intravenous Azithromycin Therapy in Patients with Complicated Scrub Typhus Compared with That of Doxycycline Therapy Using Propensity-Matched Analysis

    Science.gov (United States)

    Jang, Mi-Ok; Jang, Hee-Chang; Kim, Uh Jin; Ahn, Joon Hwan; Kang, Seung-Ji; Jung, Sook-In; Shin, Hee-Young

    2014-01-01

    There are no well-matched, controlled studies comparing azithromycin with doxycycline for the treatment of complicated scrub typhus. A retrospective propensity score-matched case-control study was performed for patients who presented with complicated scrub typhus and were treated with doxycycline or azithromycin between 2001 and 2011. Data on comorbidities, clinical manifestations, laboratory studies, treatments, and outcomes were extracted for analysis. The clinical characteristics and outcomes of the azithromycin-treated group (n = 73) were compared to those of the doxycycline-treated group (n = 108). Of 181 patients, 73 from each group were matched by propensity scores. There were no significant differences in baseline characteristics between the matched groups. The treatment success and survival rates were not significantly different (89% [65/73 patients] versus 96% [70/73 patients] and 96% [70/73 patients] versus 96% [70/73 patients], respectively [P > 0.05]). No difference was observed in the time to defervescence or length of hospital stay between the two groups (P > 0.05). In complicated scrub typhus patients (n = 181), multivariate analysis showed that only APACHE II score was an independent risk factor for mortality (95% confidence interval, 1.11 to 1.56; P scrub typhus. PMID:24366734

  6. Two types of Tet-On transgenic lines for doxycycline-inducible gene expression in zebrafish rod photoreceptors and a gateway-based tet-on toolkit.

    Directory of Open Access Journals (Sweden)

    Leah J Campbell

    Full Text Available The ability to control transgene expression within specific tissues is an important tool for studying the molecular and cellular mechanisms of development, physiology, and disease. We developed a Tet-On system for spatial and temporal control of transgene expression in zebrafish rod photoreceptors. We generated two transgenic lines using the Xenopus rhodopsin promoter to drive the reverse tetracycline-controlled transcriptional transactivator (rtTA, one with self-reporting GFP activity and one with an epitope tagged rtTA. The self-reporting line includes a tetracycline response element (TRE-driven GFP and, in the presence of doxycycline, expresses GFP in larval and adult rods. A time-course of doxycycline treatment demonstrates that maximal induction of GFP expression, as determined by the number of GFP-positive rods, is reached within approximately 24 hours of drug treatment. The epitope-tagged transgenic line eliminates the need for the self-reporting GFP activity by expressing a FLAG-tagged rtTA protein. Both lines demonstrate strong induction of TRE-driven transgenes from plasmids microinjected into one-cell embryos. These results show that spatial and temporal control of transgene expression can be achieved in rod photoreceptors. Additionally, system components are constructed in Gateway compatible vectors for the rapid cloning of doxycycline-inducible transgenes and use in other areas of zebrafish research.

  7. Doxycycline reduces the expression and activity of matrix metalloproteinase-2 in the periodontal ligament of the rat incisor without altering the eruption process.

    Science.gov (United States)

    Gomes, J R; Omar, N F; Neves, J D S; Novaes, P D

    2017-06-01

    Doxycycline is an antibiotic agent that inhibits the activity of matrix metalloproteinases (MMPs) present in the extracellular matrix. In this study, the rat incisor was submitted to a hypofunctional condition, and the effects of doxycycline (80 mg/kg/d) on the expression and activity of MMP-2, as well as on eruption rate, were determined in the odontogenic region and in the periodontal ligament for 14 d. Rats were distributed into four groups: normofunctional (NF); doxycyline normofunctional (DNF); hypofunctional (HP); and doxycyline hypofunctional (DHP). The left lower incisors of 10 rats were shortened every 2 d, using a high-rotation drill, to produce the HP and DHP groups, after starting doxycycline treatment (80 mg/kg) by gavage. Eruption was measured using a millimeter ocular, from the gingival margin to the top of the tooth in the HP and DHP groups, and also by a mark made in the tooth previously, in the NF and DNF groups. The hemimandibles were removed and the teeth were extracted to collect the periodontal and odontogenic tissues for immunohistochemical analyses and zymography. The eruption rates were higher in the HP and the DHP groups than in the NF and DNF groups, respectively (p matrix of the periodontal ligament during the tooth-eruption process. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Systematic review and meta-analysis on the nonsurgical treatment of chronic periodontitis by means of scaling and root planing with or without adjuncts.

    Science.gov (United States)

    Smiley, Christopher J; Tracy, Sharon L; Abt, Elliot; Michalowicz, Bryan S; John, Mike T; Gunsolley, John; Cobb, Charles M; Rossmann, Jeffrey; Harrel, Stephen K; Forrest, Jane L; Hujoel, Philippe P; Noraian, Kirk W; Greenwell, Henry; Frantsve-Hawley, Julie; Estrich, Cameron; Hanson, Nicholas

    2015-07-01

    Conduct a systematic review and meta-analysis on nonsurgical treatment of patients with chronic periodontitis by means of scaling and root planing (SRP) with or without adjuncts. A panel of experts convened by the American Dental Association Council on Scientific Affairs conducted a search of PubMed (MEDLINE) and Embase for randomized controlled trials of SRP with or without the use of adjuncts with clinical attachment level (CAL) outcomes in trials at least 6 months in duration and published in English through July 2014. The authors assessed individual study bias by using the Cochrane Risk of Bias Tool and conducted meta-analyses to obtain the summary effect estimates and their precision and to assess heterogeneity. The authors used funnel plots and Egger tests to assess publication bias when there were more than 10 studies. The authors used a modified version of the US Preventive Services Task Force methods to assess the overall level of certainty in the evidence. The panel included 72 articles on the effectiveness of SRP with or without the following: systemic antimicrobials, a systemic host modulator (subantimicrobial-dose doxycycline), locally delivered antimicrobials (chlorhexidine chips, doxycycline hyclate gel, and minocycline microspheres), and a variety of nonsurgical lasers (photodynamic therapy with a diode laser, a diode laser, neodymium:yttrium-aluminum-garnet lasers, and erbium lasers). With a moderate level of certainty, the panel found approximately a 0.5-millimeter average improvement in CAL with SRP. Combinations of SRP with assorted adjuncts resulted in a range of average CAL improvements between 0.2 and 0.6 mm over SRP alone. The panel judged the following 4 adjunctive therapies as beneficial with a moderate level of certainty: systemic subantimicrobial-dose doxycycline, systemic antimicrobials, chlorhexidine chips, and photodynamic therapy with a diode laser. There was a low level of certainty in the benefits of the other included adjunctive

  9. Soil texture-depending effects of doxycycline and streptomycin applied with manure on the bacterial community composition and resistome.

    Science.gov (United States)

    Blau, Khald; Casadevall, Laia; Wolters, Birgit; Van den Meersche, Tina; Kreuzig, Robert; Smalla, Kornelia; Jechalke, Sven

    2018-02-01

    Veterinary antibiotics, bacteria carrying antibiotic resistance determinants located on mobile genetic elements and nutrients are spread on agricultural soil using manure as fertilizer. However, systematic quantitative studies linking antibiotic concentrations and antimicrobial resistance genes (ARGs) in manure and the environment are scarce but needed to assess environmental risks. In this microcosm study, a sandy and a loamy soil were mixed with manure spiked with streptomycin or doxycycline at five concentrations. Total-community DNA was extracted on days 28 and 92, and the abundances of ARGs (aadA, strA, tet(A), tet(M), tet(W), tet(Q), sul1, qacE/qacEΔ1) and class 1 and 2 integron integrase genes (intI1 and intI2) were determined by qPCR relative to 16S rRNA genes. Effects on the bacterial community composition were evaluated by denaturing gradient gel electrophoresis of 16S rRNA gene amplicons. Manure application to the soils strongly increased the relative abundance of most tested genes. Antibiotics caused further enrichments which decreased over time and were mostly seen at high concentrations. Strikingly, the effects on relative gene abundances and soil bacterial community composition were more pronounced in sandy soil. The concept of defining antibiotic threshold concentrations for environmental risk assessments remains challenging due to the various influencing factors. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Application of Metal-Organic Framework Nano-MIL-100(Fe) for Sustainable Release of Doxycycline and Tetracycline.

    Science.gov (United States)

    Taherzade, Seyed Dariush; Soleimannejad, Janet; Tarlani, Aliakbar

    2017-08-06

    Nanostructures of MIL-100 were synthesized and used as a drug delivery platform for two members of the Tetracycline family. Doxycycline monohydrate (DOX) and Tetracycline hydrochloride (TC) were loaded separately on nano-MIL-100 (nanoparticles of drug@carrier were abbreviated as DOX@MIL-100 and TC@MIL-100). Characterizations were carried out using FT-IR, XRD, BET, DLS, and SEM. The FT-IR spectra revealed that the drugs were loaded into the framework of the carrier. The XRD patterns of DOX@MIL-100 and TC@MIL-100 indicated that no free DOX or TC were present. It could be concluded that the drugs are well dispersed into the pores of nano-MIL-100. The microporosity of the carrier was confirmed by BJH data. BET analysis showed a reduction in the free surface for both DOX@MIL-100 and TC@MIL-100. The release of TC and DOX was investigated, and it was revealed that MIL-100 mediated the drug solubility in water, which in turn resulted in a decrease in the release rate of TC (accelerating in DOX case) without lowering the total amount of released drug. After 48 h, 96 percent of the TC was sustain released, which is an unprecedented amount in comparison with other methods.

  11. Doxiciclina em pacientes com linfangioleiomiomatose: biomarcadores e resposta funcional pulmonar Doxycycline use in patients with lymphangioleiomyomatosis: biomarkers and pulmonary function response

    Directory of Open Access Journals (Sweden)

    Suzana Pinheiro Pimenta

    2013-02-01

    Full Text Available OBJETIVO: Avaliar o bloqueio da metaloproteinase da matriz (MMP-2 e da MMP-9 e a variação do VEF1 em pacientes com linfangioleiomiomatose (LAM após o uso de doxiciclina, um conhecido inibidor de MMP, durante 12 meses. MÉTODOS: Ensaio clínico aberto de braço único no qual as pacientes com diagnóstico de LAM receberam doxiciclina (100 mg/dia durante 12 meses. Elas foram submetidas a prova de função pulmonar completa, teste de caminhada de seis minutos, avaliação da qualidade de vida e coleta de amostras séricas e urinárias para dosagem de MMP-2, MMP-9 e VEGF-D antes do início do tratamento com doxiciclina e após 6 e 12 meses de tratamento. RESULTADOS: Trinta e uma pacientes com LAM receberam doxiciclina durante 12 meses. Embora tenha havido um bloqueio efetivo da MMP-9 urinária e da MMP-2 sérica após o tratamento, os níveis séricos de MMP-9 e VEGF-D permaneceram estáveis. Com base na resposta à doxiciclina (determinada pela variação do VEF1, as pacientes foram divididas em dois grupos: respondedoras (doxi-R; n = 13 e não respondedoras (doxi-NR; n = 18. As pacientes com alterações espirométricas leves apresentaram melhor resposta à doxiciclina. Os efeitos colaterais mais comuns foram epigastralgia, náusea e diarreia, todos de leve intensidade. CONCLUSÕES: Em pacientes com LAM, o tratamento com doxiciclina resulta em um bloqueio eficaz das MMP, além de melhorar a função pulmonar e a qualidade de vida daqueles com doença menos grave. No entanto, esses benefícios não parecem estar relacionados ao bloqueio das MMP, o que sugere um mecanismo de ação diferente. (Registro Brasileiro de Ensaios Clínicos - ReBEC; número de identificação RBR-6g8yz9 [http://www.ensaiosclinicos.gov.br]OBJECTIVE: To assess blockade of matrix metalloproteinase (MMP-2 and MMP-9, as well as the variation in FEV1, in patients with lymphangioleiomyomatosis (LAM treated with doxycycline (a known MMP inhibitor for 12 months. METHODS: An open

  12. Doxycycline-containing glass ionomer cement for arresting residual caries: an in vitro study and a pilot trial

    Science.gov (United States)

    Duque, Cristiane; Kreling, Paula Fernanda; Pereira, Jesse Augusto; de Paula, Andreia Bolzan; Sinhoreti, Mario Alexandre Coelho; Puppin-Rontani, Regina Maria

    2018-01-01

    Abstract In a previous study, we demonstrated that the incorporation of doxycycline hyclate (DOX) into resin-modified glass ionomer cement (RMGIC) inhibited important cariogenic microorganisms, without modifying its biological and mechanical characteristics. In this study, we keep focused on the effect of that experimental material as a potential therapy for arresting residual caries by analyzing other in vitro properties and conducting a pilot clinical trial assessing the in vivo effect of DOX-containing RMGIC on residual mutans streptococci after partial carious removal in primary molars. Specimens of the groups RMGIC (control); RMGIC + 1.5% DOX; RMGIC + 3% DOX; and RMGIC + 4.5% DOX were made to evaluate the effect of DOX incorporation on surface microhardness and fluoride release of RMGIC and against biofilm of Streptococcus mutans. Clinical intervention consisted of partial caries removal comparing RMGIC and RMGIC + 4.5% DOX as lining materials. After 3 months, clinical and microbiologic evaluations were performed. Data were submitted to ANOVA/Tukey or Wilcoxon/Mann-Whitney set as α=0.05. Fluoride release and surface microhardness was not influenced by the incorporation of DOX (p>0.05). There was a significant reduction of S. mutans biofilm over the material surface with the increase of DOX concentration. After clinical trial, the remaining dentin was hard and dry. Additionally, mutans streptococci were completely eliminated after 3 months of treatment with RMGIC + 4.5% DOX. The incorporation of DOX provided better antibiofilm effect, without jeopardizing fluoride release and surface microhardness of RMGIC. This combination also improved the in vivo shortterm microbiological effect of RMGIC after partial caries removal. PMID:29742263

  13. Doxycycline-containing glass ionomer cement for arresting residual caries: an in vitro study and a pilot trial.

    Science.gov (United States)

    Castilho, Aline Rogéria Freire de; Duque, Cristiane; Kreling, Paula Fernanda; Pereira, Jesse Augusto; Paula, Andreia Bolzan de; Sinhoreti, Mario Alexandre Coelho; Puppin-Rontani, Regina Maria

    2018-01-01

    In a previous study, we demonstrated that the incorporation of doxycycline hyclate (DOX) into resin-modified glass ionomer cement (RMGIC) inhibited important cariogenic microorganisms, without modifying its biological and mechanical characteristics. In this study, we keep focused on the effect of that experimental material as a potential therapy for arresting residual caries by analyzing other in vitro properties and conducting a pilot clinical trial assessing the in vivo effect of DOX-containing RMGIC on residual mutans streptococci after partial carious removal in primary molars. Specimens of the groups RMGIC (control); RMGIC + 1.5% DOX; RMGIC + 3% DOX; and RMGIC + 4.5% DOX were made to evaluate the effect of DOX incorporation on surface microhardness and fluoride release of RMGIC and against biofilm of Streptococcus mutans. Clinical intervention consisted of partial caries removal comparing RMGIC and RMGIC + 4.5% DOX as lining materials. After 3 months, clinical and microbiologic evaluations were performed. Data were submitted to ANOVA/Tukey or Wilcoxon/Mann-Whitney set as α=0.05. Fluoride release and surface microhardness was not influenced by the incorporation of DOX (p>0.05). There was a significant reduction of S. mutans biofilm over the material surface with the increase of DOX concentration. After clinical trial, the remaining dentin was hard and dry. Additionally, mutans streptococci were completely eliminated after 3 months of treatment with RMGIC + 4.5% DOX. The incorporation of DOX provided better antibiofilm effect, without jeopardizing fluoride release and surface microhardness of RMGIC. This combination also improved the in vivo shortterm microbiological effect of RMGIC after partial caries removal.

  14. No evidential correlation between veterinary antibiotic degradation ability and resistance genes in microorganisms during the biodegradation of doxycycline.

    Science.gov (United States)

    Wen, Xin; Wang, Yan; Zou, Yongde; Ma, Baohua; Wu, Yinbao

    2018-01-01

    Biodegradation of antibiotic residues in the environment by microorganisms may lead to the generation of antibiotic resistance genes (ARGs), which are of great concern to human health. The aim of this study was to determine whether there is a relationship between the ability to degrade antibiotic doxycycline (DOX) and the development of resistance genes in microorganisms. We isolated and identified ten bacterial strains from a vegetable field that had received long-term manure application as fertilizer and were capable of surviving in a series of DOX concentrations (25, 50, 80, and 100mg/L). Our results showed no evidential correlation between DOX degradation ability and the development of resistance genes among the isolated microorganisms that had high DOX degradation capability (P > 0.05). This was based on the fact that Escherichia sp. and Candida sp. were the most efficient bacterial strains to degrade DOX (92.52% and 91.63%, respectively), but their tetracycline resistance genes showed a relatively low risk of antibiotic resistance in a 7-day experiment. Moreover, the tetM of the ribosomal protection protein genes carried by these two preponderant bacteria was five-fold higher than that carried by other isolates (P genes of three isolates, except for Escherichia sp. and Candida sp., showed remarkable negative correlations (P < 0.05), mainly because tetG markedly increased during the DOX degradation process. Our results concluded that the biodegradation of antibiotic residues may not necessarily lead to the development of ARGs in the environment. In addition, the two bacteria that we isolated, namely, Escherichia sp. and Candida sp., are potential candidates for the engineering of environmentally friendly bacteria. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Idiopathic Facial Aseptic Granuloma in a 13-Year-Old Boy Dramatically Improved with Oral Doxycycline and Topical Metronidazole: Evidence for a Link with Childhood Rosacea

    Directory of Open Access Journals (Sweden)

    Camille Orion

    2016-07-01

    Full Text Available Idiopathic facial aseptic granuloma (IFAG is a rare, benign pediatric dermatological lesion that occurs in children between 8 months and 13 years of age. The pathogenesis of IFAG is still unclear but it is likely to be associated with granulomatous rosacea in childhood. Here we describe a case of IFAG in a 13-year-old boy who showed a dramatic response to oral doxycycline and topical metronidazole, which supports the hypothesis that IFAG may belong to the spectrum of rosacea.

  16. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  17. Synthesis and characterization of core-shell bimetallic nanoparticles for synergistic antimicrobial effect studies in combination with doxycycline on burn specific pathogens.

    Science.gov (United States)

    Fakhri, Ali; Tahami, Shiva; Naji, Mahsa

    2017-04-01

    Nano-medicine is a breakthrough discovery in the healthcare sector. Doxycycline is a new generation antibiotic which is proved to be a boon in the treatment of patients with complicated skin infections. We have tried to explore the benefits of synthesized bimetallic silver-gold nanoparticles in combination with new generation antibiotic for burn infections. The bimetallic nanoparticles synthesized by core-shell method were characterized using scanning electron microscopy equipped with an energy dispersive spectrometer, transmission electron microscopy, X-ray diffraction and UV-Vis spectroscopy. The calculated average particle sizes of the Ag-Au NPs were found to be 27.5nm. The Ag-Au core-shell BNPs show a characteristic Plasmon peak at 525nm which is broad and red shifted. The synergistic antimicrobial activity of doxycycline conjugated bimetallic nanoparticles was investigated against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Micrococcus luteus. This combined therapeutic agent showed greater bactericidal activity. Synergy of antibiotic with bimetallic nanoparticles is quite promising for significant application in burn healing therapy. The mechanism of the antibacterial activity was studied through the formation of reactive oxygen species (ROS) that was later suppressed with antioxidant to establish correlation with the Ag-Au NPs antimicrobial activity. Ag-Au NPs showed effective antiproliferative activity toward A549 human lung cancer (CCL-185) and MCF-7 human breast cancer (HTB-22) cell lines. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Determination of the Mutant Selection Window and Evaluation of the Killing of Mycoplasma gallisepticum by Danofloxacin, Doxycycline, Tilmicosin, Tylvalosin and Valnemulin.

    Science.gov (United States)

    Zhang, Nan; Ye, Xiaomei; Wu, Yuzhi; Huang, Zilong; Gu, Xiaoyan; Cai, Qinren; Shen, Xiangguang; Jiang, Hongxia; Ding, Huanzhong

    2017-01-01

    Mycoplasma gallisepticum is a common etiological cause of a chronic respiratory disease in chickens; its increasing antimicrobial resistance compromises the use of tetracyclines, macrolides and quinolones in the farm environment. Mutant selection window (MSW) determination was used to investigate the propensity for future resistance induction by danofloxacin, doxycycline, tilmicosin, tylvalosin and valnemulin. Killing of M. gallisepticum strain S6 by these antimicrobials was also studied by incubating M. gallisepticum into medium containing the compounds at the minimal concentration that inhibits colony formation by 99% (MIC99) and the mutant prevention concentration (MPC). Based on the morphology and colony numbers of M. gallisepticum on agar plates, the four kinds of sera in the order of the applicability for culturing M. gallisepticum were swine serum > horse serum > bovine serum > mixed serum. The MPC/MIC99 values for each agent were as follows: danofloxacin > tilmicosin > tylvalosin > doxycycline > valnemulin. MPC generated more rapid and greater magnitude killing than MIC99 against M. gallisepticum. Under exposure of 105-109 CFU/mL at MPC drug levels, valnemulin had the slowest rate of reduction in viable organisms and danofloxacin had the highest rate of reduction.

  19. Determination of the Mutant Selection Window and Evaluation of the Killing of Mycoplasma gallisepticum by Danofloxacin, Doxycycline, Tilmicosin, Tylvalosin and Valnemulin.

    Directory of Open Access Journals (Sweden)

    Nan Zhang

    Full Text Available Mycoplasma gallisepticum is a common etiological cause of a chronic respiratory disease in chickens; its increasing antimicrobial resistance compromises the use of tetracyclines, macrolides and quinolones in the farm environment. Mutant selection window (MSW determination was used to investigate the propensity for future resistance induction by danofloxacin, doxycycline, tilmicosin, tylvalosin and valnemulin. Killing of M. gallisepticum strain S6 by these antimicrobials was also studied by incubating M. gallisepticum into medium containing the compounds at the minimal concentration that inhibits colony formation by 99% (MIC99 and the mutant prevention concentration (MPC. Based on the morphology and colony numbers of M. gallisepticum on agar plates, the four kinds of sera in the order of the applicability for culturing M. gallisepticum were swine serum > horse serum > bovine serum > mixed serum. The MPC/MIC99 values for each agent were as follows: danofloxacin > tilmicosin > tylvalosin > doxycycline > valnemulin. MPC generated more rapid and greater magnitude killing than MIC99 against M. gallisepticum. Under exposure of 105-109 CFU/mL at MPC drug levels, valnemulin had the slowest rate of reduction in viable organisms and danofloxacin had the highest rate of reduction.

  20. Changes in Inflammatory and Bone Turnover Markers After Periodontal Disease Treatment in Patients With Diabetes.

    Science.gov (United States)

    Izuora, Kenneth E; Ezeanolue, Echezona E; Neubauer, Michael F; Gewelber, Civon L; Allenback, Gayle L; Shan, Guogen; Umpierrez, Guillermo E

    2016-06-01

    The underlying mechanisms for increased osteopenia and fracture rates in patients with diabetes are not well understood, but may relate to chronic systemic inflammation. We assessed the effect of treating periodontal disease (POD), a cause of chronic inflammation, on inflammatory and bone turnover markers in patients with diabetes. Using an investigator-administered questionnaire, we screened a cross-section of patients presenting for routine outpatient diabetes care. We recruited 22 subjects with POD. Inflammatory and bone turnover markers were measured at baseline and 3 months following POD treatment (scaling, root planing and subantimicrobial dose doxycycline). There were nonsignificant reductions in high-sensitivity C-reactive protein (6.34-5.52mg/L, P = 0.626) and tumor necrosis factor-alpha (10.37-10.01pg/mL, P = 0.617). There were nonsignificant increases in urinary C-terminal telopeptide (85.50-90.23pg/mL, P = 0.684) and bone-specific alkaline phosphatase (7.45-8.79pg/mL, P = 0.074). Patients with >90% adherence with doxycycline were 6.4 times more likely to experience reduction in tumor necrosis factor-alpha (P = 0.021) and 2.8 times more likely to experience reductions in high-sensitivity C-reactive protein (P = 0.133). Treatment of POD in patients with diabetes resulted in nonsignificant lowering of inflammatory markers and nonsignificant increase in bone turnover markers. However, adherence to doxycycline therapy resulted in better treatment effects. Copyright © 2016 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.

  1. Controllable dose

    International Nuclear Information System (INIS)

    Alvarez R, J.T.; Anaya M, R.A.

    2004-01-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  2. Regenerative surgical therapy for peri-implantitis using deproteinized bovine bone mineral with 10% collagen, enamel matrix derivative and Doxycycline-A prospective 3-year cohort study.

    Science.gov (United States)

    Mercado, Faustino; Hamlet, Stephen; Ivanovski, Saso

    2018-05-16

    There is limited evidence regarding the long-term efficacy of regenerative treatment for peri-implantitis. The aim of this study was to evaluate a combination therapy of deproteinized bovine bone mineral with 10% collagen (DBBMC), enamel matrix derivative (EMD) and Doxycycline in the regeneration of bone defects associated with peri-implantitis. Thirty patients diagnosed with peri-implantitis (BoP/suppuration, probing depth greater than 4 mm, minimum radiographic bone loss of 20%, at least 2 years in function) were enrolled in the study. Clinical measurements included probing depths, recession, radiographic bone fill, gingival inflammation and bleeding on probing/suppuration. Following surgical access and debridement, the implant surfaces were decontaminated with 24% EDTA for 2 min, and the bone defects were filled with a combined mixture of DBBMC, EMD and Doxycycline powder. The defects were covered with connective tissue grafts where necessary. Clinical measurements were recorded after 12, 24 and 36 months. The mean probing depth and bone loss at the initial visit was 8.9 mm (±1.9) and 6.92 mm (±1.26), respectively. Both mean probing depth and bone loss reduced significantly from baseline to 3.55 mm (±0.50) and 2.85 mm (±0.73) at 12 months, 3.50 (±0.50) and 2.62 mm (±0.80) at 24 months and 3.50 mm (±0.50) and 2.60 mm (±0.73) at 36 months. 56.6% of the implants were considered successfully treated (according to Successful Treatment Outcome Criterion: PD 10%, no BoP/suppuration, no recession >0.5 mm for anterior implants and >1.5 mm for posterior implants) after 36 months. Regenerative treatment of peri-implantitis using a combined mixture of DBBMC, EMD and Doxycycline achieved promising results. The benefits of this protocol incorporating EMD should be tested in randomized clinical trials. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Simultaneous UHPLC-UV analysis of hydroxychloroquine, minocycline and doxycycline from serum samples for the therapeutic drug monitoring of Q fever and Whipple's disease.

    Science.gov (United States)

    Armstrong, Nicholas; Richez, Magali; Raoult, Didier; Chabriere, Eric

    2017-08-15

    A fast UHPLC-UV method was developed for the simultaneous analysis of Hydroxychloroquine, Minocycline and Doxycycline drugs from 100μL of human serum samples. Serum samples were extracted by liquid-liquid extraction and injected into a phenyl hexyl reverse phase column. Compounds were separated using a mobile phase linear gradient and monitored by UV detection at 343nm. Chloroquine and Oxytetracycline were used as internal standards. Lower and upper limits of quantifications, as well as the other levels of calibration, were validated with acceptable accuracy (<15% deviation) and precision (<15% coefficient of variation) according to the European Medicines Agency guidelines. This new method enables cost and time reduction and was considered suitable for the clinical laboratory. It is the first published assay for the therapeutic drug monitoring of patients diagnosed with Q fever or Whipple's disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Dose and dose rate monitor

    International Nuclear Information System (INIS)

    Novakova, O.; Ryba, J.; Slezak, V.; Svobodova, B.; Viererbl, L.

    1984-10-01

    The methods are discussea of measuring dose rate or dose using a scintillation counte. A plastic scintillator based on polystyrene with PBD and POPOP activators and coated with ZnS(Ag) was chosen for the projected monitor. The scintillators were cylindrical and spherical in shape and of different sizes; black polypropylene tubes were chosen as the best case for the probs. For the counter with different plastic scintillators, the statistical error 2σ for natural background was determined. For determining the suitable thickness of the ZnS(Ag) layer the energy dependence of the counter was measured. Radioisotopes 137 Cs, 241 Am and 109 Cd were chosen as radiation sources. The best suited ZnS(Ag) thickness was found to be 0.5 μm. Experiments were carried out to determine the directional dependence of the detector response and the signal to noise ratio. The temperature dependence of the detector response and its compensation were studied, as were the time stability and fatigue manifestations of the photomultiplier. The design of a laboratory prototype of a dose rate and dose monitor is described. Block diagrams are given of the various functional parts of the instrument. The designed instrument is easiiy portable, battery powered, measures dose rates from natural background in the range of five orders, i.e., 10 -2 to 10 3 nGy/s, and allows to determine a dose of up to 10 mGy. Accouracy of measurement in the energy range of 50 keV to 1 MeV is better than +-20%. (E.S.)

  5. Dose rate constants for new dose quantities

    International Nuclear Information System (INIS)

    Tschurlovits, M.; Daverda, G.; Leitner, A.

    1992-01-01

    Conceptual changes and new quantities made is necessary to reassess dose rate quantities. Calculations of the dose rate constant were done for air kerma, ambient dose equivalent and directional dose equivalent. The number of radionuclides is more than 200. The threshold energy is selected as 20 keV for the dose equivalent constants. The dose rate constant for the photon equivalent dose as used mainly in German speaking countries as a temporary quantity is also included. (Author)

  6. Host modulation therapeutics in periodontics: role as an adjunctive periodontal therapy.

    Science.gov (United States)

    Shinwari, Muhammad Saad; Tanwir, Farzeen; Hyder, Pakiza Raza; Bin Saeed, Muhammad Humza

    2014-09-01

    Host Modulation Therapy (HMT) is a treatment concept that reduces tissue destruction and stabilizes or even regenerates inflammatory tissue by modifying host response factors. It has been used for treating osteoporosis and arthritis for several decades. However, its use in dentistry has only been recently reported. The objective of this article is to present a review of the various literatures available on HMT and also its role as adjunct therapy in periodontics. For identifying studies for this review, a PUBMED search was carried out in 2013 for all articles published till December 2012. The search was restricted to English language publications only. Longitudinal prospective and retrospective studies were included in the search. The key words used were: Host Modulation Therapy; Sub antimicrobial dose doxycycline and Non-Surgical Periodontal Therapy. The main outcomes sought were host modulation therapeutics in periodontics. Exclusion criteria included cross sectional studies, short case series as well as studies with short follow-up periods. There is a paucity of literature on HMT in periodontics although the only drug approved by United States Food and Drug Administration (FDA) is a subantimicrobial dose of doxycycline (SDD) with highly predictable results as a host modulating agent in periodontal diseases and also an effective adjunctive therapy in various diseases of periodontium. However, more randomized controlled trials are needed to obtain clinical guidelines on the usage of other host modulating agents as adjunct as well as definite therapy for periodontal diseases. SDD is an effective adjunct therapy when used in dosage of 20mg twice daily for minimum 3 months duration in various periodontal diseases with predictable clinical outcomes. It is also recommended that future clinical research on anti cytokine drugs, chemically modified tetracycline and other HMT agents should be conducted so that new drugs are available with highly predictable results.

  7. Non-antibacterial tetracycline formulations: clinical applications in dentistry and medicine

    Directory of Open Access Journals (Sweden)

    Ying Gu

    2012-10-01

    Full Text Available In 1983, it was first reported that tetracyclines (TCs can modulate the host response, including (but not limited to inhibition of pathologic matrix metalloproteinase (MMP activity, and by mechanisms unrelated to the antibacterial properties of these drugs. Soon thereafter, strategies were developed to generate non-antibacterial formulations (subantimicrobial-dose doxycycline; SDD and compositions (chemically modified tetracyclines; CMTs of TCs as host-modulating drugs to treat periodontal and other inflammatory diseases. This review focuses on the history and rationale for the development of: (a SDD which led to two government-approved medications, one for periodontitis and the other for acne/rosacea and (b CMTs, which led to the identification of the active site of the drugs responsible for MMP inhibition and to studies demonstrating evidence of efficacy of the most potent of these, CMT-3, as an anti-angiogenesis agent in patients with the cancer, Kaposi's sarcoma, and as a potential treatment for a fatal lung disease (acute respiratory distress syndrome; ARDS. In addition, this review discusses a number of clinical studies, some up to 2 years’ duration, demonstrating evidence of safety and efficacy of SDD formulations in humans with oral inflammatory diseases (periodontitis, pemphigoid as well as medical diseases, including rheumatoid arthritis, post-menopausal osteopenia, type II diabetes, cardiovascular diseases, and a rare and fatal lung disease, lymphangioleiomyomatosis.

  8. A novel approach to the use of doxycycline-loaded biodegradable membrane and EDTA root surface etching in chronic periodontitis: a randomized clinical trial.

    Science.gov (United States)

    Gamal, Ahmed Y; Kumper, Radi M

    2012-09-01

    The release profile of 25% doxycycline (DOX) gel loaded on a biodegradable collagen membrane (COL) after 24% EDTA root surface etching was evaluated. Thirty systemically healthy patients, each with at least one pair of contralateral interproximal intrabony defects ≥4 mm deep, along with an interproximal probing depth ≥6 mm and clinical attachment loss ≥4 mm, were randomized into two groups. Group 1 consisted of sites treated with open-flap debridement followed by placement of DOX gel-loaded COL (DOX-COL), whereas group 2 sites were treated with flap surgery followed by the placement of DOX-COL after EDTA etching of the exposed root surfaces (DOX-COL + EDTA). Samples of gingival crevicular fluid were obtained 1, 3, 7, 14, and 21 days after surgery. Separation was performed, and quantitative measurements of DOX were taken with a high-performance liquid chromatography. Clinical evaluation and follow-up for 6 months were performed. At 21 days, DOX-COL + EDTA group showed 5.3 μg/mL value. However, no DOX was detected in samples of the DOX-COL group. DOX-COL + EDTA-treated group retained more DOX during the periods of 3, 7, 10, and 14 days than did the DOX-COL group. EDTA root surface etching could enhance DOX availability in the gingival crevicular fluid after its release from the collagen membrane.

  9. Residues of chlortetracycline, doxycycline and sulfadiazine-trimethoprim in intestinal content and feces of pigs due to cross-contamination of feed.

    Science.gov (United States)

    Peeters, Laura E J; Daeseleire, Els; Devreese, Mathias; Rasschaert, Geertrui; Smet, Annemieke; Dewulf, Jeroen; Heyndrickx, Marc; Imberechts, Hein; Haesebrouck, Freddy; Butaye, Patrick; Croubels, Siska

    2016-09-20

    Cross-contamination of feed with low concentrations of antimicrobials can occur at production, transport and/or farm level. Concerns are rising about possible effects of this contaminated feed on resistance selection in the intestinal microbiota. Therefore, an experiment with pigs was set up, in which intestinal and fecal concentrations of chlortetracycline (CTC), doxycycline (DOX) and sulfadiazine-trimethoprim (SDZ-TRIM) were determined after administration of feed containing a 3 % carry-over level of these antimicrobials. The poor oral bioavailability of tetracyclines resulted in rather high concentrations in cecal and colonic content and feces at steady-state conditions. A mean concentration of 10 mg/kg CTC and 4 mg/kg DOX in the feces was reached, which is higher than concentrations that were shown to cause resistance selection. On the other hand, lower mean levels of SDZ (0.7 mg/kg) and TRIM (< limit of detection of 0.016 mg/kg) were found in the feces, corresponding with the high oral bioavailability of SDZ and TRIM in pigs. The relation between the oral bioavailability and intestinal concentrations of the tested antimicrobials, may be of help in assessing the risks of cross-contaminated feed. However, future research is needed to confirm our results and to evaluate the effects of these detected concentrations on resistance selection in the intestinal microbiota of pigs.

  10. Short communication: Interaction of the isomers carvacrol and thymol with the antibiotics doxycycline and tilmicosin: In vitro effects against pathogenic bacteria commonly found in the respiratory tract of calves.

    Science.gov (United States)

    Kissels, W; Wu, X; Santos, R R

    2017-02-01

    Bovine respiratory disease is the major problem faced by cattle, specially calves, leading to reduced animal performance and increased mortality, consequently causing important economic losses. Hence, calves must be submitted to antibiotic therapy to counteract this infection usually initiated by the combination of environmental stress factors and viral infection, altering the animal's defense mechanism, and thus allowing lung colonization by the opportunistic bacteria Mannheimia haemolytica and Pasteurella multocida. Essential oils appear to be candidates to replace antibiotics or to act as antibiotic adjuvants due to their antimicrobial properties. In the present study, we aimed to evaluate the 4 essential oil components carvacrol, thymol, trans-anethole, and 1,8 cineole as antibacterial agents or as adjuvants for the antibiotics doxycycline and tilmicosin against M. haemolytica and P. multocida. Bacteria were cultured according to standard protocols, followed by the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration. A checkerboard assay was applied to detect possible interactions between components, between antibiotics, and between components and antibiotics. Doxycycline at 0.25 and 0.125 μg/mL inhibited the growth of P. multocida and M. haemolytica, respectively, whereas tilmicosin MIC values were 1.0 and 4.0 μg/mL for P. multocida and M. haemolytica, respectively. Carvacrol MIC values were 2.5 and 1.25 mM for P. multocida and M. haemolytica, respectively, whereas thymol MIC values were 1.25 and 0.625 mM for P. multocida and M. haemolytica, respectively. Trans-anethole and 1,8 cineole did not present any antibacterial effect even at 40 mM against the investigated pathogens. All minimum bactericidal concentration values were the same as MIC, except when thymol was tested against M. haemolytica, being twice the MIC data (i.e., 1.25 mM thymol). Based on fractional inhibitory concentration checkerboard assay, no

  11. From personnel dose to personal dose

    International Nuclear Information System (INIS)

    Hoefert, M.; Raffnsoe, R.C.; Tuyn, J.W.N.; Wittekind, D.

    1985-01-01

    From following the development of personnel doses at CERN over the past six years it has become evident that work in areas of induced radioactivity is the principal cause of exposure. The results of photon dose measurements free-in-air and around a phantom are presented and discussed in the light of new quantities in individual monitoring. The importance of these results, with respect to the practical situation, is discussed and the problem of phantom size is mentioned. Finally, the results of dose measurements in the phantom are presented, since such information is important in cases where it becomes necessary to transform personnel doses into personal doses. (author)

  12. Dose sculpting with generalized equivalent uniform dose

    International Nuclear Information System (INIS)

    Wu Qiuwen; Djajaputra, David; Liu, Helen H.; Dong Lei; Mohan, Radhe; Wu, Yan

    2005-01-01

    With intensity-modulated radiotherapy (IMRT), a variety of user-defined dose distribution can be produced using inverse planning. The generalized equivalent uniform dose (gEUD) has been used in IMRT optimization as an alternative objective function to the conventional dose-volume-based criteria. The purpose of this study was to investigate the effectiveness of gEUD optimization to fine tune the dose distributions of IMRT plans. We analyzed the effect of gEUD-based optimization parameters on plan quality. The objective was to determine whether dose distribution to selected structures could be improved using gEUD optimization without adversely altering the doses delivered to other structures, as in sculpting. We hypothesized that by carefully defining gEUD parameters (EUD 0 and n) based on the current dose distributions, the optimization system could be instructed to search for alternative solutions in the neighborhood, and we could maintain the dose distributions for structures already satisfactory and improve dose for structures that need enhancement. We started with an already acceptable IMRT plan optimized with any objective function. The dose distribution was analyzed first. For structures that dose should not be changed, a higher value of n was used and EUD 0 was set slightly higher/lower than the EUD value at the current dose distribution for critical structures/targets. For structures that needed improvement in dose, a higher to medium value of n was used, and EUD 0 was set to the EUD value or slightly lower/higher for the critical structure/target at the current dose distribution. We evaluated this method in one clinical case each of head and neck, lung and prostate cancer. Dose volume histograms, isodose distributions, and relevant tolerance doses for critical structures were used for the assessment. We found that by adjusting gEUD optimization parameters, the dose distribution could be improved with only a few iterations. A larger value of n could lead to

  13. Pocket total dose meter

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; Endres, G.W.R.

    1984-10-01

    Laboratory measurements have demonstrated that it is possible to simultaneously measure absorbed dose and dose equivalent using a single tissue equivalent proportional counter. Small, pocket sized instruments are being developed to determine dose equivalent as the worker is exposed to mixed field radiation. This paper describes the electronic circuitry and computer algorithms used to determine dose equivalent in these devices

  14. On dose distribution comparison

    International Nuclear Information System (INIS)

    Jiang, Steve B; Sharp, Greg C; Neicu, Toni; Berbeco, Ross I; Flampouri, Stella; Bortfeld, Thomas

    2006-01-01

    In radiotherapy practice, one often needs to compare two dose distributions. Especially with the wide clinical implementation of intensity-modulated radiation therapy, software tools for quantitative dose (or fluence) distribution comparison are required for patient-specific quality assurance. Dose distribution comparison is not a trivial task since it has to be performed in both dose and spatial domains in order to be clinically relevant. Each of the existing comparison methods has its own strengths and weaknesses and there is room for improvement. In this work, we developed a general framework for comparing dose distributions. Using a new concept called maximum allowed dose difference (MADD), the comparison in both dose and spatial domains can be performed entirely in the dose domain. Formulae for calculating MADD values for various comparison methods, such as composite analysis and gamma index, have been derived. For convenience in clinical practice, a new measure called normalized dose difference (NDD) has also been proposed, which is the dose difference at a point scaled by the ratio of MADD to the predetermined dose acceptance tolerance. Unlike the simple dose difference test, NDD works in both low and high dose gradient regions because it considers both dose and spatial acceptance tolerances through MADD. The new method has been applied to a test case and a clinical example. It was found that the new method combines the merits of the existing methods (accurate, simple, clinically intuitive and insensitive to dose grid size) and can easily be implemented into any dose/intensity comparison tool

  15. When is a dose not a dose?

    International Nuclear Information System (INIS)

    Green, Patrick

    1992-01-01

    There is confusion over radiation dose limits between the International Commission on Radiological Protection, the National Radiological Protection Board and the Ministry of Agriculture, Fisheries and Food (MAFF), reports a Friends of the Earth's radiation campaigner. MAFF is suggesting the inadequate ICRP public dose limit does not apply to public exposures which arise from environmental contamination from past radioactive discharges. (author)

  16. Dose from radiological examinations

    International Nuclear Information System (INIS)

    Imamura, Keiko; Uji, Teruyuki; Sakuyama, Keiko; Fujikawa, Mitsuhiro; Fujii, Masamichi

    1976-01-01

    Relatively high gonad doses, several hundred to one thousand mR, have been observed in case of pelvis, hip-joint, coccyx, lower abdomen and lumber examination. Dose to the ovary is especially high in barium enema and I.V.P. examinations. About 12 per cent of the 4-ray examination are high-dose. The gonad dose is relatively high in examination of abdomen and lower extremities, in infants. The dose to the eyes is especially high, 1.0 to 2.5R per exposure, in temporal bone and nasal sinuses tomography. X-ray doses have been compared with dose limits recommended by ICRP and with the gonad dose from natural radiations. The gonad dose in lumbar examination, barium enema, I.V.P. etc. is as high as the maximum permissible dose per year recommended by ICRP. Several devices have been made for dose reduction in the daily examinations: (1) separating the radiation field from the gonad by one centimeter decreases the gonad dose about one-half. (2) using sensitive screens and films. In pelvimetry and in infant hip-joint examination, the most sensitive screen and film are used. In the I.V.P. examination of adult, use of MS screen in place of FS screen decreases the dose to one-third, in combination with careful setting of radiation field, (3) use of grid increases the dose about 50 percent and the lead rubber protection (0.1mm lead equivalent) decreases the gonad dose to one-thirtieth in the spinal column examination of infant, (4) A lead protector, 1mm thickness and 2.5cm in diameter, on the eyes decreases the dose to about one-eighth in the face and nead examinations. These simple and effective methods for dose reduction. Should be carried out in as many examinations as possible in addition to observing dose limits recommended by ICRP. (Evans, J.)

  17. Insignificant levels of dose

    International Nuclear Information System (INIS)

    Webb, G.A.M.; McLean, A.S.

    1977-01-01

    The procedures recommended by the International Commission on Radiological Protection (ICRP) for making decisions concerning controllable sources of radiation exposure of the public include 'justification' and 'optimisation'. The tool recommended by the ICRP for reaching these decisions is collective dose or dose commitment supplemented by consideration of doses to individuals. In both these considerations the practical problem arises of whether very small doses to large numbers of people should contribute to the final decision-making process. It may be that at levels of dose which are small increments on natural background, the relationship between dose and effect is linear even though the slope may be close to zero. If so, collective dose is a meaningful concept and the calculation of total detriment for the purpose of justification could legitimately include all doses. In the calculation of collective doses for the purpose of optimisation, which involves decisions on how much money or resource should be allocated to dose reduction, it is necessary to appraise radiation detriment realistically. At low levels of dose to the individual such as those small by comparison with variations in natural background within the UK, the risk to the individual is such that his well-being will not be significantly changed by the presence or absence of the radiation dose. These small doses, which are well below the point at which an individual attaches significance, should not carry a societal significance. Societal acceptance of risk is analysed with a view to assessing a level of possible risk, and hence dose, below which resources should not in general be diverted to secure further reduction. A formulation for collective dose commitment is proposed incorporating a cut-off to exclude insignificant doses. The implications of this formulation in practical situations are discussed

  18. Total dose meter development

    International Nuclear Information System (INIS)

    Brackenbush, L.W.

    1986-09-01

    This report describes an alarming ''pocket'' monitor/dosimeter, based on a tissue-equivalent proportional counter, that measure both neutron and gamma dose and determines dose equivalent for the mixed radiation field. This report details the operation of the device and provides information on: the necessity for a device to measure dose equivalent in mixed radiation fields; the mathematical theory required to determine dose equivalent from tissue equivalent proportional; the detailed electronic circuits required; the algorithms required in the microprocessor used to calculate dose equivalent; the features of the instrument; program accomplishments and future plans

  19. Dose reader CD-02

    International Nuclear Information System (INIS)

    Jakowiuk, A.; Kaluska, I.; Machaj, B.

    2005-01-01

    Dose Reader CD-02 is designed for measurement of dose from a long narrow band of dosimetric foil used for check up and control of electron beam dose during sterilization of materials and products on conveyor belt. Irradiated foil after processing (heating) is inserted into foil driving (moving) system and when the foil is moved across focused light beam the absorbed dose is measured and displayed at the same time at computer monitor (in form of a diagram). The absorbed dose is measured on the principle of light attenuation at selected light wavelength (foil absorbance is measured). (author)

  20. Dose conversion factors

    International Nuclear Information System (INIS)

    Kocher, D.C.; Eckerman, K.F.

    1992-01-01

    The following is discussed in this report: concepts and quantities used in calculating radiation dose from internal and external exposure. Tabulations of dose conversion factor for internal and external exposure to radionuclides. Dose conversion factors give dose per unit intake (internal) or dose per unit concentration in environment (external). Intakes of radionuclides for internal exposure and concentrations of radionuclides in environment for external exposure are assumed to be known. Intakes and concentrations are obtained, e.g., from analyses of environmental transport and exposure pathways. differences between dosimetry methods for radionuclides and hazardous chemicals are highlighted

  1. Enjebi Island dose assessment

    International Nuclear Information System (INIS)

    Robison, W.L.; Conrado, C.L.; Phillips, W.A.

    1987-07-01

    We have updeated the radiological dose assessment for Enjebi Island at Enewetak Atoll using data derived from analysis of food crops grown on Enjebi. This is a much more precise assessment of potential doses to people resettling Enjebi Island than the 1980 assessment in which there were no data available from food crops on Enjebi. Details of the methods and data used to evaluate each exposure pathway are presented. The terrestrial food chain is the most significant potential exposure pathway and 137 Cs is the radionuclide responsible for most of the estimated dose over the next 50 y. The doses are calculated assuming a resettlement date of 1990. The average wholebody maximum annual estimated dose equivalent derived using our diet model is 166 mremy;the effective dose equivalent is 169 mremy. The estimated 30-, 50-, and 70-y integral whole-body dose equivalents are 3.5 rem, 5.1 rem, and 6.2 rem, respectively. Bone-marrow dose equivalents are only slightly higher than the whole-body estimates in each case. The bone-surface cells (endosteal cells) receive the highest dose, but they are a less sensitive cell population and are less sensitive to fatal cancer induction than whole body and bone marrow. The effective dose equivalents for 30, 50, and 70 y are 3.6 rem, 5.3 rem, and 6.6 rem, respectively. 79 refs., 17 figs., 24 tabs

  2. Dose measurements in mammography

    International Nuclear Information System (INIS)

    Kainberger, F.; Kallinger, W.

    1977-01-01

    Dose measurements at the mamma during mammography were carried out in the form of direct measurement with thermoluminescent dosimetry. Measurement was done for the in- and outcoming doses at the mamma, the dose exposure of the sternal region and the scattered rays above the symphysis, the latter as parameter for the genetic radiation exposure. As expected, the dose of the smooth radiation used for mammography showed a strong decrease at the outcome point in comparison with the income point. Surprisingly high was the scattered radiation in the sternal region. A corresponding protection by lead plates could be taken into consideration. Extremely low is the scattered radiation above the symphysis. Even measurements with the very sensitive calcium fluoride dosimeters did not reveal any practically important dose in the symphysis region. Most measurement values remained below the determinable dose of 0.3mR. Some maximal values varied in the range of 3-1 mR. (orig.) [de

  3. Registration of radiation doses

    International Nuclear Information System (INIS)

    2000-02-01

    In Finland the Radiation and Nuclear Safety Authority (STUK) is maintaining the register (called Dose Register) of the radiation exposure of occupationally exposed workers in order to ensure compliance with the principles of optimisation and individual protection. The guide contains a description of the Dose Register and specifies the responsibilities of the party running a radiation practice to report the relevant information to the Dose Register

  4. Paediatric dose display

    International Nuclear Information System (INIS)

    Griffin, D.W.; Derges, S.; Hesslewood, S.

    1984-01-01

    A compact, inexpensive unit, based on an 8085 microprocessor, has been designed for calculating doses of intravenous radioactive injections for children. It has been used successfully for over a year. The dose is calculated from the body surface area and the result displayed in MBq. The operator can obtain the required dose on a twelve character alphanumeric display by entering the age of the patient and the adult dose using a hexadecimal keyboard. Circuit description, memory map and input/output, and firmware are dealt with. (U.K.)

  5. An environmental dose experiment

    Science.gov (United States)

    Peralta, Luis

    2017-11-01

    Several radiation sources worldwide contribute to the delivered dose to the human population. This radiation also acts as a natural background when detecting radiation, for instance from radioactive sources. In this work a medium-sized plastic scintillation detector is used to evaluate the dose delivered by natural radiation sources. Calibration of the detector involved the use of radioactive sources and Monte Carlo simulation of the energy deposition per disintegration. A measurement of the annual dose due to background radiation to the body was then estimated. A dose value compatible with the value reported by the United Nations Scientific Committee on the Effects of Atomic Radiation was obtained.

  6. An environmental dose experiment

    International Nuclear Information System (INIS)

    Peralta, Luis

    2017-01-01

    Several radiation sources worldwide contribute to the delivered dose to the human population. This radiation also acts as a natural background when detecting radiation, for instance from radioactive sources. In this work a medium-sized plastic scintillation detector is used to evaluate the dose delivered by natural radiation sources. Calibration of the detector involved the use of radioactive sources and Monte Carlo simulation of the energy deposition per disintegration. A measurement of the annual dose due to background radiation to the body was then estimated. A dose value compatible with the value reported by the United Nations Scientific Committee on the Effects of Atomic Radiation was obtained. (paper)

  7. Doses from portable gauges

    International Nuclear Information System (INIS)

    Linauskas, S.H.

    1988-08-01

    Field studies to measure actual radiation exposures of operators of commercial moisture-density gauges were undertaken in several regions of Canada. Newly developed bubble detector dosimeter technology and conventional dosimetry such as thermoluminescent dosimeters (TLDs), integrating electronic dosimeters (DRDs), and CR-39 neutron track-etch detectors were used to estimate the doses received by 23 moisture-density gauge operators and maintenance staff. These radiation dose estimates were supported by mapping radiation fields and accounting for the time an operator was near a gauge. Major findings indicate that gauge maintenance and servicing workers were more likely than gauge operators to receive exposures above the level of 5 mSv, and that neutron doses were roughly the same as gamma doses. Gauge operators receive approximately 75% of their dose when transporting and carrying the gauge. Dose to their hands is similar to the dose to their trunks, but the dose to their feet area is 6 to 30 times higher. Gamma radiation is the primary source of radiation contributing to operator dose

  8. Radiation dose in vertebroplasty

    International Nuclear Information System (INIS)

    Mehdizade, A.; Lovblad, K.O.; Wilhelm, K.E.; Somon, T.; Wetzel, S.G.; Kelekis, A.D.; Yilmaz, H.; Abdo, G.; Martin, J.B.; Viera, J.M.; Ruefenacht, D.A.

    2004-01-01

    We wished to measure the absorbed radiation dose during fluoroscopically controlled vertebroplasty and to assess the possibility of deterministic radiation effects to the operator. The dose was measured in 11 consecutive procedures using thermoluminescent ring dosimeters on the hand of the operator and electronic dosimeters inside and outside of the operator's lead apron. We found doses of 0.022-3.256 mGy outside and 0.01-0.47 mGy inside the lead apron. Doses on the hand were higher, 0.5-8.5 mGy. This preliminary study indicates greater exposure to the operator's hands than expected from traditional apron measurements. (orig.)

  9. Effective dose equivalent

    International Nuclear Information System (INIS)

    Huyskens, C.J.; Passchier, W.F.

    1988-01-01

    The effective dose equivalent is a quantity which is used in the daily practice of radiation protection as well as in the radiation hygienic rules as measure for the health risks. In this contribution it is worked out upon which assumptions this quantity is based and in which cases the effective dose equivalent can be used more or less well. (H.W.)

  10. Doses from radiation exposure

    International Nuclear Information System (INIS)

    Menzel, H-G.; Harrison, J.D.

    2012-01-01

    Practical implementation of the International Commission on Radiological Protection’s (ICRP) system of protection requires the availability of appropriate methods and data. The work of Committee 2 is concerned with the development of reference data and methods for the assessment of internal and external radiation exposure of workers and members of the public. This involves the development of reference biokinetic and dosimetric models, reference anatomical models of the human body, and reference anatomical and physiological data. Following ICRP’s 2007 Recommendations, Committee 2 has focused on the provision of new reference dose coefficients for external and internal exposure. As well as specifying changes to the radiation and tissue weighting factors used in the calculation of protection quantities, the 2007 Recommendations introduced the use of reference anatomical phantoms based on medical imaging data, requiring explicit sex averaging of male and female organ-equivalent doses in the calculation of effective dose. In preparation for the calculation of new dose coefficients, Committee 2 and its task groups have provided updated nuclear decay data (ICRP Publication 107) and adult reference computational phantoms (ICRP Publication 110). New dose coefficients for external exposures of workers are complete (ICRP Publication 116), and work is in progress on a series of reports on internal dose coefficients to workers from inhaled and ingested radionuclides. Reference phantoms for children will also be provided and used in the calculation of dose coefficients for public exposures. Committee 2 also has task groups on exposures to radiation in space and on the use of effective dose.

  11. Gonad dose in cineurethrocystography

    International Nuclear Information System (INIS)

    Ardran, G.M.; Dixon-Brown, A.; Fursdon, P.S.

    1978-01-01

    The technical factors used for cineurethrocystography for the true lateral projection in females are given. The mid-line radiation dose has been measured with LiF TLD inserted into the vagina in 19 examinations. The average dose recorded was 148 mrad, the range being 50 to 306 mrad, the average number of cine frames exposed was 96. Data obtained using a Rando phantom indicated that the average ovary dose would be 30% greater than the mid-line dose since the near ovary receives a higher dose than the more distant one. The technique used for men is also given, the average gonad dose in six men being 123 mrad, range 56 to 243 mrad when simple lead foil gonad protection was used; the average number of cine frames was 107. The dose in one man without gonad protection was 1575 mrad for 112 cine frames. The results for both sexes compare favourably with those of others reported in the literature and with gonad doses recorded in typical IVP examinations. (author)

  12. Internal dose estimates

    International Nuclear Information System (INIS)

    Wrenn, M.E.

    1977-01-01

    Internal doses, the procedures for making them and their significance has been reviewed. Effects of uranium, radium, lead-210, polonium-210, thorium in man are analysed based on data from tables and plots. Dosimetry of some ingested nuclides and inhalation dose due to radon-222, radon-220 and their daugther products are discussed [pt

  13. Occupational dose constraint

    International Nuclear Information System (INIS)

    Heilbron Filho, Paulo Fernando Lavalle; Xavier, Ana Maria

    2005-01-01

    The revision process of the international radiological protection regulations has resulted in the adoption of new concepts, such as practice, intervention, avoidable and restriction of dose (dose constraint). The latter deserving of special mention since it may involve reducing a priori of the dose limits established both for the public and to individuals occupationally exposed, values that can be further reduced, depending on the application of the principle of optimization. This article aims to present, with clarity, from the criteria adopted to define dose constraint values to the public, a methodology to establish the dose constraint values for occupationally exposed individuals, as well as an example of the application of this methodology to the practice of industrial radiography

  14. Dose response relationship at low doses

    International Nuclear Information System (INIS)

    Schull, W.J.

    1992-01-01

    The data that have accrued in Hiroshima and Nagasaki on the effects of ionizing radiation on the developing human brain are reviewed. Effects considered are severe mental retardation, lowered IQ scores, decline in school performance, seizures, other neuropsychological effects, and small head size. All these factors may be related to radiation doses received by the mother during pregnancy. (L.L.) 3 figs., tab., 7 refs

  15. Synchronized dynamic dose reconstruction

    International Nuclear Information System (INIS)

    Litzenberg, Dale W.; Hadley, Scott W.; Tyagi, Neelam; Balter, James M.; Ten Haken, Randall K.; Chetty, Indrin J.

    2007-01-01

    Variations in target volume position between and during treatment fractions can lead to measurable differences in the dose distribution delivered to each patient. Current methods to estimate the ongoing cumulative delivered dose distribution make idealized assumptions about individual patient motion based on average motions observed in a population of patients. In the delivery of intensity modulated radiation therapy (IMRT) with a multi-leaf collimator (MLC), errors are introduced in both the implementation and delivery processes. In addition, target motion and MLC motion can lead to dosimetric errors from interplay effects. All of these effects may be of clinical importance. Here we present a method to compute delivered dose distributions for each treatment beam and fraction, which explicitly incorporates synchronized real-time patient motion data and real-time fluence and machine configuration data. This synchronized dynamic dose reconstruction method properly accounts for the two primary classes of errors that arise from delivering IMRT with an MLC: (a) Interplay errors between target volume motion and MLC motion, and (b) Implementation errors, such as dropped segments, dose over/under shoot, faulty leaf motors, tongue-and-groove effect, rounded leaf ends, and communications delays. These reconstructed dose fractions can then be combined to produce high-quality determinations of the dose distribution actually received to date, from which individualized adaptive treatment strategies can be determined

  16. Doxiciclina em pacientes com linfangioleiomiomatose: segurança e eficácia no bloqueio de metaloproteinases Doxycycline use in patients with lymphangioleiomyomatosis: safety and efficacy in metalloproteinase blockade

    Directory of Open Access Journals (Sweden)

    Suzana Pinheiro Pimenta

    2011-08-01

    Full Text Available OBJETIVO: A linfangioleiomiomatose (LAM é caracterizada pela presença de cistos pulmonares, cuja formação está associada à hiperreatividade de metaloproteinases de matriz (MMP, principalmente MMP-2 e MMP-9. Objetivamos comparar os níveis dessas MMPs entre pacientes com LAM e controles saudáveis, assim como avaliar, nas pacientes com LAM, a segurança e a eficácia do tratamento com doxiciclina, um potente inibidor de MMPs. MÉTODOS: Estudo clínico prospectivo no qual as pacientes com LAM receberam doxiciclina (100 mg/dia por seis meses, coletando-se amostras de urina e sangue para a dosagem de MMP-2 e MMP-9 antes e ao final do período. Foram ainda obtidas amostras de 10 mulheres saudáveis. RESULTADOS: De 41 pacientes com LAM que iniciaram o tratamento, 34 concluíram o protocolo. Os níveis de MMP-9 sérica e urinária foram significativamente inferiores no grupo controle (p OBJECTIVE: Lymphangioleiomyomatosis (LAM is characterized by lung cysts, whose development is associated with matrix metalloproteinase (MMP hyperactivity, principally that of MMP-2 and MMP-9. Our objective was to compare LAM patients and controls in terms of the levels of these MMPs, as well as to determine the safety and efficacy of treatment with doxycycline, a potent MMP inhibitor. METHODS: Prospective clinical study involving female LAM patients who received doxycycline (100 mg/day for six months. Urine and blood samples were collected for the quantification of MMP-2 and MMP-9 before and after the treatment period. Samples from 10 healthy women were also collected. RESULTS:Of the 41 LAM patients who started the treatment, 34 completed the protocol. Serum and urinary MMP-9 levels were significantly lower in the controls than in the LAM patients (p < 0.0001. Comparing pre- and post-treatment values, we found that the median level of MMP-9 in serum decreased from 919 ng/mL to 871 ng/mL (p = 0.05, whereas that of MMP-9 in urine decreased from 11,558 pg/mL to 7

  17. Low doses effects

    International Nuclear Information System (INIS)

    Tubiana, M.

    1997-01-01

    In this article is asked the question about a possible carcinogens effect of low dose irradiation. With epidemiological data, knowledge about the carcinogenesis, the professor Tubiana explains that in spite of experiments made on thousand or hundred of thousands animals it has not been possible to bring to the fore a carcinogens effect for low doses and then it is not reasonable to believe and let the population believe that low dose irradiation could lead to an increase of neoplasms and from this point of view any hardening of radiation protection standards could in fact, increase anguish about ionizing radiations. (N.C.)

  18. Doses from radioactive methane

    International Nuclear Information System (INIS)

    Phipps, A.W.; Kendall, G.M.; Fell, T.P.; Harrison, J.D.

    1990-01-01

    A possible radiation hazard arises from exposure to methane labelled with either a 3 H or a 14 C nuclide. This radioactive methane could be released from a variety of sources, e.g. land burial sites containing radioactive waste. Standard assumptions adopted for vapours would not apply to an inert alkane like methane. This paper discusses mechanisms by which radioactive methane would irradiate tissues and provides estimates of doses. Data on skin thickness and metabolism of methane are discussed with reference to these mechanisms. It is found that doses are dominated by dose from the small fraction of methane which is inhaled and metabolised. This component of dose has been calculated under rather conservative assumptions. (author)

  19. Controllable dose; Dosis controlable

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez R, J T; Anaya M, R A [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2004-07-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  20. Acetaminophen dosing for children

    Science.gov (United States)

    ... your child, call your provider. Proper Dosing of Suppositories If your child is vomiting or will not take oral medicine, you can use suppositories. Suppositories are placed in the anus to deliver ...

  1. Radiation dose electrophysiology procedures

    International Nuclear Information System (INIS)

    Hernandez-Armas, J.; Rodriguez, A.; Catalan, A.; Hernandez Armas, O.; Luque Japon, L.; Moral, S.; Barroso, L.; Rfuez-Hdez, R.

    2006-01-01

    The aim of this paper has been to measure and analyse some of the parameters which are directly related with the doses given to patients in two electrophysiology procedures: diagnosis and ablation with radiofrequency. 16 patients were considered in this study. 13 them had an ablation with radiofrequency at the Unit of Electrophysiology at the University Hospital of the Canaries, La Laguna., Tenerife. The results of skin doses, in the ablation cases, were higher than 2 Gy (threshold of some deterministic effects). The average value was 1.1 Gy. The personal doses, measured under the lead apron, for physician and nurses were 4 and 3 micro Sievert. These results emphasised the necessity of radiation protection measures in order to reduce, ad much as possible, the doses to patients. (Author)

  2. Dose in conventional radiography

    International Nuclear Information System (INIS)

    Acuna D, E.; Padilla R, Z. P.; Escareno J, E.; Vega C, H. R.

    2011-10-01

    It has been pointed out that medical exposures are the most significant sources of exposure to ionizing radiation for the general population. Inside the medical exposures the most important is the X-ray use for diagnosis, which is by far the largest contribution to the average dose received by the population. From all studies performed in radiology the chest radiography is the most abundant. In an X-ray machine, voltage and current are combined to obtain a good image and a reduce dose, however due to the workload in a radiology service individual dose is not monitored. In order to evaluate the dose due to chest radiography in this work a plate phantom was built according to the ISO recommendations using methylmethacrylate walls and water. The phantom was used in the Imaging department of the Zacatecas General Hospital as a radiology patient asking for a chest study; using thermoluminescent dosimeters, TLD 100 the kerma at the surface entrance was determined. (Author)

  3. Maximum permissible dose

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    This chapter presents a historic overview of the establishment of radiation guidelines by various national and international agencies. The use of maximum permissible dose and maximum permissible body burden limits to derive working standards is discussed

  4. Irradiation dose of cosmonauts

    International Nuclear Information System (INIS)

    Makra, Zs.

    1978-01-01

    The results obtained by determining the irradiation dose during the spaceflights of Apollo as well as the Sojouz-3 and Sojouz-9 spacecrafts have been compared in the form of tables. In case of Apollo astronauts the irradiation dose was determined by two methods and its sources were also pointed out, in tables. During Sojouz spacetravels the cosmonauts were exposed to a negligible dose. In spite of this fact the radiation danger is considerable. The small irradiation doses noticed so far are due to the fact that during the spaceflights there was no big proturberance. However, during the future long-range spacetravels a better radiation shielding than the one used up to now will be necessary. (P.J.)

  5. Ibuprofen dosing for children

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000772.htm Ibuprofen dosing for children To use the sharing features ... much of this medicine can be harmful. How Ibuprofen can Help Your Child Ibuprofen is a type ...

  6. Effects of low doses

    International Nuclear Information System (INIS)

    Le Guen, B.

    2001-01-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  7. Gonadal doses from radiotherapy

    International Nuclear Information System (INIS)

    Solomon, S.B.; Morris, N.D.

    1980-06-01

    The method of calculation of gonadal doses arising from different radiotherapeutic procedures is described. The measurement of scatter factors to the gonads from superficial and deep therapy is detailed and the analytic fits to the experimental data, as a function of field position, field size and beam energy are given. The data used to calculate the gonadal doses from treatments using linear accelerators, teletherapy and sealed sources are described and the analytic fits to the data given

  8. Doxycycline-regulated 3T3-L1 preadipocyte cell line with inducible, stable expression of adenoviral E4orf1 gene: a cell model to study insulin-independent glucose disposal.

    Science.gov (United States)

    Krishnapuram, Rashmi; Dhurandhar, Emily J; Dubuisson, Olga; Hegde, Vijay; Dhurandhar, Nikhil V

    2013-01-01

    Impaired glycemic control and excessive adiposity are major risk factors for Type 2 Diabetes mellitus. In rodent models, Ad36, a human adenovirus, improves glycemic control, independent of dietary fat intake or adiposity. It is impractical to use Ad36 for therapeutic action. Instead, we identified that E4orf1 protein of Ad36, mediates its anti-hyperglycemic action independent of insulin signaling. To further evaluate the therapeutic potential of E4orf1 to improve glycemic control, we established a stable 3T3-L1 cell system in which E4orf1 expression can be regulated. The development and characterization of this cell line is described here. Full-length adenoviral-36 E4orf1 cDNA obtained by PCR was cloned into a tetracycline responsive element containing vector (pTRE-Tight-E4orf1). Upon screening dozens of pTRE-Tight-E4orf1 clones, we identified the one with the highest expression of E4orf1 in response to doxycycline treatment. Furthermore, using this inducible system we characterized the ability of E4orf1 to improve glucose disposal in a time dependent manner. This stable cell line offers a valuable resource to carefully study the novel signaling pathways E4orf1 uses to enhance cellular glucose disposal independent of insulin.

  9. Doxycycline-regulated 3T3-L1 preadipocyte cell line with inducible, stable expression of adenoviral E4orf1 gene: a cell model to study insulin-independent glucose disposal.

    Directory of Open Access Journals (Sweden)

    Rashmi Krishnapuram

    Full Text Available Impaired glycemic control and excessive adiposity are major risk factors for Type 2 Diabetes mellitus. In rodent models, Ad36, a human adenovirus, improves glycemic control, independent of dietary fat intake or adiposity. It is impractical to use Ad36 for therapeutic action. Instead, we identified that E4orf1 protein of Ad36, mediates its anti-hyperglycemic action independent of insulin signaling. To further evaluate the therapeutic potential of E4orf1 to improve glycemic control, we established a stable 3T3-L1 cell system in which E4orf1 expression can be regulated. The development and characterization of this cell line is described here. Full-length adenoviral-36 E4orf1 cDNA obtained by PCR was cloned into a tetracycline responsive element containing vector (pTRE-Tight-E4orf1. Upon screening dozens of pTRE-Tight-E4orf1 clones, we identified the one with the highest expression of E4orf1 in response to doxycycline treatment. Furthermore, using this inducible system we characterized the ability of E4orf1 to improve glucose disposal in a time dependent manner. This stable cell line offers a valuable resource to carefully study the novel signaling pathways E4orf1 uses to enhance cellular glucose disposal independent of insulin.

  10. Assessment of internal doses

    CERN Document Server

    Rahola, T; Falk, R; Isaksson, M; Skuterud, L

    2002-01-01

    There is a definite need for training in dose calculation. Our first course was successful and was followed by a second, both courses were fully booked. An example of new tools for software products for bioassay analysis and internal dose assessment is the Integrated Modules for Bioassay Analysis (IMBA) were demonstrated at the second course. This suite of quality assured code modules have been adopted in the UK as the standard for regulatory assessment purposes. The intercomparison measurements are an important part of the Quality Assurance work. In what is known as the sup O utside workers ' directive it is stated that the internal dose measurements shall be included in the European Unions supervision system for radiation protection. The emergency preparedness regarding internal contamination was much improved by the training with and calibration of handheld instruments from participants' laboratories. More improvement will be gained with the handbook giving practical instructions on what to do in case of e...

  11. Mean inactivation dose (D)

    International Nuclear Information System (INIS)

    Vijayakumar, S.; Ng, T.C.; Raudkivi, U.; Meaney, T.J.

    1990-01-01

    By predicting treatment outcome to radiotherapy from in vitro radiobiological parameters, not only individual patient treatments can be tailored, but also new promising treatment protocols can be tried in patients in whom unfavorable outcome is predicted. In this respect, choosing the right parameter can be very important. Unlike D 0 and N which provide information of the distal part of the survival curve, mean inactivation dose (D) estimates overall radiosensitivity. However, the parameters reflecting the response at the clinically relevant low-dose region are neglected in the literature. In a literature survey of 98 papers in which survival curves or D 0 /N were used, only in 2 D was used. In 21 papers the D 0 /n values were important in drawing conclusions. By calculating D in 3 of these 21 papers, we show that the conclusion drawn may be altered with the use of D. The importance of ''low-dose-region-parameters'' is reviewed. (orig.)

  12. Dose Reduction Techniques

    International Nuclear Information System (INIS)

    WAGGONER, L.O.

    2000-01-01

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program

  13. CT dose management

    International Nuclear Information System (INIS)

    Zasheva, Ts.; Georgiev, E.; Kirova, G.

    2013-01-01

    Full text: Introduction: In recent decades Computed Tomography established itself as one of the most common study with a very wide range of applications and techniques of scanning. Best diagnostic value of the method resist to the risks of ionizing radiation, as statistics show that CT is one of the main sources of continuously increasing dose to the population. What you will learn: The physical parameters of the X-ray tube and the principles of image reconstruction; The relationship between variables parameters and the received dose; The ratio between the force and voltage of the current to the image quality, Influence of the used contrast medium to the physical properties of the image, The ratio of patient BMI to image processing, Effective use of knowledge for the optimal CT protocol. Discussions: The goal to reduce the dose received by the patient during a CT scan while keeping the diagnostic quality of the image puts to the test as handset X-ray producers and technicians who need to master the technique of study protocol forming as well as to balance the harm - benefit ratio. Among the most popular techniques are these of dose modulation, low-dose computed tomography at the expense of a reduction of the current or voltage intensity, and control of the number of post-processing algorithms for the image reconstruction. Conclusion: The training of radiologists and X-ray technicians plays a major role in optimizing of technical parameters in view of the reduction of the dose for the patient, while maintaining the diagnostic quality of the image

  14. Dose Reduction Techniques

    Energy Technology Data Exchange (ETDEWEB)

    WAGGONER, L.O.

    2000-05-16

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program.

  15. Radioactive cloud dose calculations

    International Nuclear Information System (INIS)

    Healy, J.W.

    1984-01-01

    Radiological dosage principles, as well as methods for calculating external and internal dose rates, following dispersion and deposition of radioactive materials in the atmosphere are described. Emphasis has been placed on analytical solutions that are appropriate for hand calculations. In addition, the methods for calculating dose rates from ingestion are discussed. A brief description of several computer programs are included for information on radionuclides. There has been no attempt to be comprehensive, and only a sampling of programs has been selected to illustrate the variety available

  16. Fertilizer micro-dosing

    International Development Research Centre (IDRC) Digital Library (Canada)

    Localized application of small quantities of fertilizer (micro-dosing), combined with improved planting pits for rainwater harvesting, has generated greater profits and food security for women farmers in the Sahel. • Women are 25% more likely to use combined applications, and have expanded areas of food crops (cowpea,.

  17. Weldon Spring dose calculations

    International Nuclear Information System (INIS)

    Dickson, H.W.; Hill, G.S.; Perdue, P.T.

    1978-09-01

    In response to a request by the Oak Ridge Operations (ORO) Office of the Department of Energy (DOE) for assistance to the Department of the Army (DA) on the decommissioning of the Weldon Spring Chemical Plant, the Health and Safety Research Division of the Oak Ridge National Laboratory (ORNL) performed limited dose assessment calculations for that site. Based upon radiological measurements from a number of soil samples analyzed by ORNL and from previously acquired radiological data for the Weldon Spring site, source terms were derived to calculate radiation doses for three specific site scenarios. These three hypothetical scenarios are: a wildlife refuge for hunting, fishing, and general outdoor recreation; a school with 40 hr per week occupancy by students and a custodian; and a truck farm producing fruits, vegetables, meat, and dairy products which may be consumed on site. Radiation doses are reported for each of these scenarios both for measured uranium daughter equilibrium ratios and for assumed secular equilibrium. Doses are lower for the nonequilibrium case

  18. Low dose epidemiologic studies

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    In this chapter the BEIR committee has reviewed low-dose irradiation studies since the BEIR III report. They have considered the carcinogenic effectiveness of low-LET in populations exposed to radiation from a number of different sources: diagnostic radiography; fallout from nuclear weapons testing; nuclear installations; radiation in the workplace and high levels of natural background radiation

  19. Radiation doses to Finns

    International Nuclear Information System (INIS)

    Rantalainen, L.

    1996-01-01

    The estimated annual radiation doses to Finns have been reduced in the recent years without any change in the actual radiation environment. This is because the radiation types have been changed. The risk factors will probably be changed again in the future, because recent studies show discrepancies in the neutron dosimetry concerning the city of Hiroshima. Neutron dosimetry discrepancy has been found between the predicted and estimated neutron radiation. The prediction of neutron radiation is calculated by Monte Carlo simulations, which have also been used when designing recommendations for the limits of radiation doses (ICRP60). Estimation of the neutron radiation is made on the basis of measured neutron activation of materials in the city. The estimated neutron dose beyond 1 km is two to ten, or more, times as high as the predicted dose. This discrepancy is important, because the most relevant distances with respect to radiation risk evaluation are between 1 and 2 km. Because of this discrepancy, the present radiation risk factors for gamma and neutron radiation, which rely on the Monte Carlo calculations, are false, too. The recommendations of ICRP60 have been adopted in a few countries, including Finland, and they affect the planned common limits of the EU. It is questionable whether happiness is increased by adopting false limits, even if they are common. (orig.) (2 figs., 1 tab.)

  20. Dose Reduction Techniques

    CERN Document Server

    Waggoner, L O

    2000-01-01

    As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the sm...

  1. Dose tracking and dose auditing in a comprehensive computed tomography dose-reduction program.

    Science.gov (United States)

    Duong, Phuong-Anh; Little, Brent P

    2014-08-01

    Implementation of a comprehensive computed tomography (CT) radiation dose-reduction program is a complex undertaking, requiring an assessment of baseline doses, an understanding of dose-saving techniques, and an ongoing appraisal of results. We describe the role of dose tracking in planning and executing a dose-reduction program and discuss the use of the American College of Radiology CT Dose Index Registry at our institution. We review the basics of dose-related CT scan parameters, the components of the dose report, and the dose-reduction techniques, showing how an understanding of each technique is important in effective auditing of "outlier" doses identified by dose tracking. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. When is a dose not a dose?

    International Nuclear Information System (INIS)

    Bond, V.P.

    1991-01-01

    Although an enormous amount of progress has been made in the fields of radiation protection and risk assessment, a number of significant problems remain. The one problem which transcends all the rest, and which has been subject to considerable misunderstanding, involves what has come to be known as the 'linear non-threshold hypothesis', or 'linear hypothesis'. Particularly troublesome has been the interpretation that any amount of radiation can cause an increase in the excess incidence of cancer. The linear hypothesis has dominated radiation protection philosophy for more than three decades, with enormous financial, societal and political impacts and has engendered an almost morbid fear of low-level exposure to ionizing radiation in large segments of the population. This document presents a different interpretation of the linear hypothesis. The basis for this view lies in the evolution of dose-response functions, particularly with respect to their use initially in the context of early acute effects, and then for the late effects, carcinogenesis and mutagenesis. 11 refs., 4 figs

  3. Dose specification for radiation therapy: dose to water or dose to medium?

    International Nuclear Information System (INIS)

    Ma, C-M; Li Jinsheng

    2011-01-01

    The Monte Carlo method enables accurate dose calculation for radiation therapy treatment planning and has been implemented in some commercial treatment planning systems. Unlike conventional dose calculation algorithms that provide patient dose information in terms of dose to water with variable electron density, the Monte Carlo method calculates the energy deposition in different media and expresses dose to a medium. This paper discusses the differences in dose calculated using water with different electron densities and that calculated for different biological media and the clinical issues on dose specification including dose prescription and plan evaluation using dose to water and dose to medium. We will demonstrate that conventional photon dose calculation algorithms compute doses similar to those simulated by Monte Carlo using water with different electron densities, which are close (<4% differences) to doses to media but significantly different (up to 11%) from doses to water converted from doses to media following American Association of Physicists in Medicine (AAPM) Task Group 105 recommendations. Our results suggest that for consistency with previous radiation therapy experience Monte Carlo photon algorithms report dose to medium for radiotherapy dose prescription, treatment plan evaluation and treatment outcome analysis.

  4. Tumor significant dose

    International Nuclear Information System (INIS)

    Supe, S.J.; Nagalaxmi, K.V.; Meenakshi, L.

    1983-01-01

    In the practice of radiotherapy, various concepts like NSD, CRE, TDF, and BIR are being used to evaluate the biological effectiveness of the treatment schedules on the normal tissues. This has been accepted as the tolerance of the normal tissue is the limiting factor in the treatment of cancers. At present when various schedules are tried, attention is therefore paid to the biological damage of the normal tissues only and it is expected that the damage to the cancerous tissues would be extensive enough to control the cancer. Attempt is made in the present work to evaluate the concent of tumor significant dose (TSD) which will represent the damage to the cancerous tissue. Strandquist in the analysis of a large number of cases of squamous cell carcinoma found that for the 5 fraction/week treatment, the total dose required to bring about the same damage for the cancerous tissue is proportional to T/sup -0.22/, where T is the overall time over which the dose is delivered. Using this finding the TSD was defined as DxN/sup -p/xT/sup -q/, where D is the total dose, N the number of fractions, T the overall time p and q are the exponents to be suitably chosen. The values of p and q are adjusted such that p+q< or =0.24, and p varies from 0.0 to 0.24 and q varies from 0.0 to 0.22. Cases of cancer of cervix uteri treated between 1978 and 1980 in the V. N. Cancer Centre, Kuppuswamy Naidu Memorial Hospital, Coimbatore, India were analyzed on the basis of these formulations. These data, coupled with the clinical experience, were used for choice of a formula for the TSD. Further, the dose schedules used in the British Institute of Radiology fraction- ation studies were also used to propose that the tumor significant dose is represented by DxN/sup -0.18/xT/sup -0.06/

  5. [Evaluation of Organ Dose Estimation from Indices of CT Dose Using Dose Index Registry].

    Science.gov (United States)

    Iriuchijima, Akiko; Fukushima, Yasuhiro; Ogura, Akio

    Direct measurement of each patient organ dose from computed tomography (CT) is not possible. Most methods to estimate patient organ dose is using Monte Carlo simulation with dedicated software. However, dedicated software is too expensive for small scale hospitals. Not every hospital can estimate organ dose with dedicated software. The purpose of this study was to evaluate the simple method of organ dose estimation using some common indices of CT dose. The Monte Carlo simulation software Radimetrics (Bayer) was used for calculating organ dose and analysis relationship between indices of CT dose and organ dose. Multidetector CT scanners were compared with those from two manufactures (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare). Using stored patient data from Radimetrics, the relationships between indices of CT dose and organ dose were indicated as each formula for estimating organ dose. The accuracy of estimation method of organ dose was compared with the results of Monte Carlo simulation using the Bland-Altman plots. In the results, SSDE was the feasible index for estimation organ dose in almost organs because it reflected each patient size. The differences of organ dose between estimation and simulation were within 23%. In conclusion, our estimation method of organ dose using indices of CT dose is convenient for clinical with accuracy.

  6. Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice

    International Nuclear Information System (INIS)

    Ware, J.H.; Rusek, A.; Sanzari, J.; Avery, S.; Sayers, C.; Krigsfeld, G.; Nuth, M.; Wan, X.S.; Kennedy, A.R.

    2010-01-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

  7. Effects of proton radiation dose, dose rate and dose fractionation on hematopoietic cells in mice.

    Science.gov (United States)

    Ware, J H; Sanzari, J; Avery, S; Sayers, C; Krigsfeld, G; Nuth, M; Wan, X S; Rusek, A; Kennedy, A R

    2010-09-01

    The present study evaluated the acute effects of radiation dose, dose rate and fractionation as well as the energy of protons in hematopoietic cells of irradiated mice. The mice were irradiated with a single dose of 51.24 MeV protons at a dose of 2 Gy and a dose rate of 0.05-0.07 Gy/min or 1 GeV protons at doses of 0.1, 0.2, 0.5, 1, 1.5 and 2 Gy delivered in a single dose at dose rates of 0.05 or 0.5 Gy/min or in five daily dose fractions at a dose rate of 0.05 Gy/min. Sham-irradiated animals were used as controls. The results demonstrate a dose-dependent loss of white blood cells (WBCs) and lymphocytes by up to 61% and 72%, respectively, in mice irradiated with protons at doses up to 2 Gy. The results also demonstrate that the dose rate, fractionation pattern and energy of the proton radiation did not have significant effects on WBC and lymphocyte counts in the irradiated animals. These results suggest that the acute effects of proton radiation on WBC and lymphocyte counts are determined mainly by the radiation dose, with very little contribution from the dose rate (over the range of dose rates evaluated), fractionation and energy of the protons.

  8. Occupational dose assessment and national dose registry system in Iran

    International Nuclear Information System (INIS)

    Jafari-Zadeh, M.; Nazeri, F.; Hosseini-Pooya, S. M.; Taheri, M.; Gheshlaghi, F.; Kardan, M. R.; Babakhani, A.; Rastkhah, N.; Yousefi-Nejad, F.; Darabi, M.; Oruji, T.; Gholamali-Zadeh, Z.; Karimi-Diba, J.; Kazemi-Movahed, A. A.; Dashti-Pour, M. R.; Enferadi, A.; Jahanbakhshian, M. H.; Sadegh-Khani, M. R.

    2011-01-01

    This report presents status of external and internal dose assessment of workers and introducing the structure of National Dose Registry System of Iran (NDRSI). As well as types of individual dosemeters in use, techniques for internal dose assessment are presented. Results obtained from the International Atomic Energy Agency intercomparison programme on measurement of personal dose equivalent H p (10) and consistency of the measured doses with the delivered doses are shown. Also, implementation of dosimetry standards, establishment of quality management system, authorisation and approval procedure of dosimetry service providers are discussed. (authors)

  9. Doses from radiation exposure

    CERN Document Server

    Menzel, H G

    2012-01-01

    Practical implementation of the International Commission on Radiological Protection's (ICRP) system of protection requires the availability of appropriate methods and data. The work of Committee 2 is concerned with the development of reference data and methods for the assessment of internal and external radiation exposure of workers and members of the public. This involves the development of reference biokinetic and dosimetric models, reference anatomical models of the human body, and reference anatomical and physiological data. Following ICRP's 2007 Recommendations, Committee 2 has focused on the provision of new reference dose coefficients for external and internal exposure. As well as specifying changes to the radiation and tissue weighting factors used in the calculation of protection quantities, the 2007 Recommendations introduced the use of reference anatomical phantoms based on medical imaging data, requiring explicit sex averaging of male and female organ-equivalent doses in the calculation of effecti...

  10. Radiation dose rate meter

    International Nuclear Information System (INIS)

    Kronenberg, S.; Siebentritt, C.R.

    1981-01-01

    A combined dose rate meter and charger unit therefor which does not require the use of batteries but on the other hand produces a charging potential by means of a piezoelectric cylinder which is struck by a manually triggered hammer mechanism. A tubular type electrometer is mounted in a portable housing which additionally includes a geiger-muller (Gm) counter tube and electronic circuitry coupled to the electrometer for providing multi-mode operation. In one mode of operation, an rc circuit of predetermined time constant is connected to a storage capacitor which serves as a timed power source for the gm tube, providing a measurement in terms of dose rate which is indicated by the electrometer. In another mode, the electrometer indicates individual counts

  11. Small dose... big poison.

    Science.gov (United States)

    Braitberg, George; Oakley, Ed

    2010-11-01

    It is not possible to identify all toxic substances in a single journal article. However, there are some exposures that in small doses are potentially fatal. Many of these exposures are particularly toxic to children. Using data from poison control centres, it is possible to recognise this group of exposures. This article provides information to assist the general practitioner to identify potential toxic substance exposures in children. In this article the authors report the signs and symptoms of toxic exposures and identify the time of onset. Where clear recommendations on the period of observation and known fatal dose are available, these are provided. We do not discuss management or disposition, and advise readers to contact the Poison Information Service or a toxicologist for this advice.

  12. Radiation dose measurements

    International Nuclear Information System (INIS)

    1960-01-01

    About 200 scientists from 28 countries and 5 international organizations met at a symposium on radiation dosimetry held by the International Atomic Energy Agency in June 1960. The aim of the symposium was not so much the description of a large number of measuring instruments as a discussion of the methods used, with special emphasis on those problems which had become important in the context of recent developments, such as the measurement of mixed or very large doses

  13. Low dose epidemiology

    International Nuclear Information System (INIS)

    Tirmarche, M.; Hubert, P.

    1992-01-01

    Actually, epidemiological studies have to establish if the assessment of cancer risk can be verified at low chronic radiation doses. The population surveillance must be very long, the side effects and cancers of such radiation appearing much later. In France, this epidemiological study on nuclear workers have been decided recently. Before describing the experiment and french projects in epidemiology of nuclear workers, the authors present the main english and american studies

  14. Time-dose modifications

    International Nuclear Information System (INIS)

    Kian Ang, K.

    1987-01-01

    Changes in fractionation schedule can be made by various approaches. However, from the first principle, it is anticipated that strategies of hyperfractionation and/or accelerated fractionation offer the most promised in improving the therapeutic ratio. Hyperfractionation is defined as a treatment schedule in which a large number of significantly reduced dose fractions (--1.2 Gy/fraction) is used to give a greater total dose in a conventional overall time period. The results of the pilot studies testing the efficacy of hyperfractionation have been encouraging. The most valid clinical trial of pure hyperfractionation, however, is that conducted by the EORTC. This study compared 70 Gy in 35 fractions or 80.5 Gy in 70 fractions over 7 weeks in the treatment of patients with oropharyngeal carcinomas. The local tumor control was significantly improved in the hyperfractionated arm without increasing the morbidity. Accelerated fractionation is defined as a schedule in which the overall time of treatment is reduced without significant changes in the total dose and fraction size. The strategy has been used to treat patients with malignant gliomas, melanomas and Head and Neck cancers. The data in Head and Neck Cancers seem to be promising

  15. Dose calculation for electrons

    International Nuclear Information System (INIS)

    Hirayama, Hideo

    1995-01-01

    The joint working group of ICRP/ICRU is advancing the works of reviewing the ICRP publication 51 by investigating the data related to radiation protection. In order to introduce the 1990 recommendation, it has been demanded to carry out calculation for neutrons, photons and electrons. As for electrons, EURADOS WG4 (Numerical Dosimetry) rearranged the data to be calculated at the meeting held in PTB Braunschweig in June, 1992, and the question and request were presented by Dr. J.L. Chartier, the responsible person, to the researchers who are likely to undertake electron transport Monte Carlo calculation. The author also has carried out the requested calculation as it was the good chance to do the mutual comparison among various computation codes regarding electron transport calculation. The content that the WG requested to calculate was the absorbed dose at depth d mm when parallel electron beam enters at angle α into flat plate phantoms of PMMA, water and ICRU4-element tissue, which were placed in vacuum. The calculation was carried out by the versatile electron-photon shower computation Monte Carlo code, EGS4. As the results, depth dose curves and the dependence of absorbed dose on electron energy, incident angle and material are reported. The subjects to be investigated are pointed out. (K.I.)

  16. Dose reduction in evacuation proctography

    International Nuclear Information System (INIS)

    Hare, C.; Halligan, S.; Bartram, C.I.; Gupta, R.; Walker, A.E.; Renfrew, I.

    2001-01-01

    The goal of this study was to reduce the patient radiation dose from evacuation proctography. Ninety-eight consecutive adult patients referred for proctography to investigate difficult rectal evacuation were studied using a digital imaging system with either a standard digital program for barium examinations, a reduced dose digital program (both with and without additional copper filtration), or Video fluoroscopy. Dose-area products were recorded for each examination and the groups were compared. All four protocols produced technically acceptable examinations. The low-dose program with copper filtration (median dose 382 cGy cm 2 ) and Video fluoroscopy (median dose 705 cGy cm 2 ) were associated with significantly less dose than other groups (p < 0.0001). Patient dose during evacuation proctography can be reduced significantly without compromising the diagnostic quality of the examination. A digital program with added copper filtration conveyed the lowest dose. (orig.)

  17. Optimized dose distribution of a high dose rate vaginal cylinder

    International Nuclear Information System (INIS)

    Li Zuofeng; Liu, Chihray; Palta, Jatinder R.

    1998-01-01

    Purpose: To present a comparison of optimized dose distributions for a set of high-dose-rate (HDR) vaginal cylinders calculated by a commercial treatment-planning system with benchmark calculations using Monte-Carlo-calculated dosimetry data. Methods and Materials: Optimized dose distributions using both an isotropic and an anisotropic dose calculation model were obtained for a set of HDR vaginal cylinders. Mathematical optimization techniques available in the computer treatment-planning system were used to calculate dwell times and positions. These dose distributions were compared with benchmark calculations with TG43 formalism and using Monte-Carlo-calculated data. The same dwell times and positions were used for a quantitative comparison of dose calculated with three dose models. Results: The isotropic dose calculation model can result in discrepancies as high as 50%. The anisotropic dose calculation model compared better with benchmark calculations. The differences were more significant at the apex of the vaginal cylinder, which is typically used as the prescription point. Conclusion: Dose calculation models available in a computer treatment-planning system must be evaluated carefully to ensure their correct application. It should also be noted that when optimized dose distribution at a distance from the cylinder surface is calculated using an accurate dose calculation model, the vaginal mucosa dose becomes significantly higher, and therefore should be carefully monitored

  18. Dose gradient curve: A new tool for evaluating dose gradient.

    Science.gov (United States)

    Sung, KiHoon; Choi, Young Eun

    2018-01-01

    Stereotactic radiotherapy, which delivers an ablative high radiation dose to a target volume for maximum local tumor control, requires a rapid dose fall-off outside the target volume to prevent extensive damage to nearby normal tissue. Currently, there is no tool to comprehensively evaluate the dose gradient near the target volume. We propose the dose gradient curve (DGC) as a new tool to evaluate the quality of a treatment plan with respect to the dose fall-off characteristics. The average distance between two isodose surfaces was represented by the dose gradient index (DGI) estimated by a simple equation using the volume and surface area of isodose levels. The surface area was calculated by mesh generation and surface triangulation. The DGC was defined as a plot of the DGI of each dose interval as a function of the dose. Two types of DGCs, differential and cumulative, were generated. The performance of the DGC was evaluated using stereotactic radiosurgery plans for virtual targets. Over the range of dose distributions, the dose gradient of each dose interval was well-characterized by the DGC in an easily understandable graph format. Significant changes in the DGC were observed reflecting the differences in planning situations and various prescription doses. The DGC is a rational method for visualizing the dose gradient as the average distance between two isodose surfaces; the shorter the distance, the steeper the dose gradient. By combining the DGC with the dose-volume histogram (DVH) in a single plot, the DGC can be utilized to evaluate not only the dose gradient but also the target coverage in routine clinical practice.

  19. Determination of organ doses and effective doses in radiooncology

    International Nuclear Information System (INIS)

    Roth, J.; Martinez, A.E.

    2007-01-01

    Background and Purpose: With an increasing chance of success in radiooncology, it is necessary to estimate the risk from radiation scatter to areas outside the target volume. The cancer risk from a radiation treatment can be estimated from the organ doses, allowing a somewhat limited effective dose to be estimated and compared. Material and Methods: The doses of the radiation-sensitive organs outside the target volume can be estimated with the aid of the PC program PERIDOSE developed by van der Giessen. The effective doses are determined according to the concept of ICRP, whereby the target volume and the associated organs related to it are not taken into consideration. Results: Organ doses outside the target volume are generally < 1% of the dose in the target volume. In some cases, however, they can be as high as 3%. The effective doses during radiotherapy are between 60 and 900 mSv, depending upon the specific target volume, the applied treatment technique, and the given dose in the ICRU point. Conclusion: For the estimation of the radiation risk, organ doses in radiooncology can be calculated with the aid of the PC program PERIDOSE. While evaluating the radiation risk after ICRP, for the calculation of the effective dose, the advanced age of many patients has to be considered to prevent that, e.g., the high gonad doses do not overestimate the effective dose. (orig.)

  20. Intercomparison On Depth Dose Measurement

    International Nuclear Information System (INIS)

    Rohmah, N; Akhadi, M

    1996-01-01

    Intercomparation on personal dose evaluation system has been carried out between CSRSR-NAEA of Indonesia toward Standard Laboratory of JAERI (Japan) and ARL (Australia). The intercomparison was in 10 amm depth dose measurement , Hp (10), from the intercomparison result could be stated that personal depth dose measurement conducted by CSRSR was sufficiently good. Deviation of dose measurement result using personal dosemeter of TLD BG-1 type which were used by CSRSR in the intercomparison and routine photon personal dose monitoring was still in internationally agreed limit. Maximum deviation of reported doses by CSRSR compared to delivered doses for dosemeter irradiation by JAERI was -10.0 percent and by ARL was +29 percent. Maximum deviation permitted in personal dose monitoring is ± 50 percent

  1. Dose-to-man studies

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Dose-to-Man Studies focused on developing computer data handling and computer modules which permit easy, rapid assessment of the dose to southeastern United States populations from routine or accidental releases of radionuclides to atmospheric and stream systems

  2. Dose monitoring in nuclear emergency

    International Nuclear Information System (INIS)

    Nan Hongjie; Yang Zhongping; Lei Xin

    2012-01-01

    In order to protect people from irradiation sickness and rebuild the radiation filed in nuclear emergency, personal and environmental dose need to be monitored. The application of TLD in dose monitoring is discussed in this paper. (authors)

  3. A review of radiology staff doses and dose monitoring requirements

    International Nuclear Information System (INIS)

    Martin, C. J.

    2009-01-01

    Studies of radiation doses received during X-ray procedures by radiology, cardiology and other clinical staff have been reviewed. Data for effective dose (E), and doses to the eyes, thyroid, hands and legs have been analysed. These data have been supplemented with local measurements to determine the most exposed part of the hand for monitoring purposes. There are ranges of 60-100 in doses to individual tissues reported in the literature for similar procedures at different centres. While ranges in the doses per unit dose-area product (DAP) are between 10 and 25, large variations in dose result from differences in the sensitivity of the X-ray equipment, the type of procedure and the operator technique, but protection factors are important in maintaining dose levels as low as possible. The influence of shielding devices is significant for determining the dose to the eyes and thyroid, and the position of the operator, which depends on the procedure, is the most significant factor determining doses to the hands. A second body dosemeter worn at the level of the collar is recommended for operators with high workloads for use in assessment of effective dose and the dose to the eye. It is proposed that the third quartile values from the distributions of dose per unit DAP identified in the review might be employed in predicting the orders of magnitude of doses to the eye, thyroid and hands, based on interventional operator workloads. Such dose estimates could be employed in risk assessments when reviewing protection and monitoring requirements. A dosemeter worn on the little finger of the hand nearest to the X-ray tube is recommended for monitoring the hand. (authors)

  4. Dose. Detriment. Limit assessment

    International Nuclear Information System (INIS)

    Breckow, J.

    2015-01-01

    One goal of radiation protection is the limitation of stochastic effects due to radiation exposure. The probability of occurrence of a radiation induced stochastic effect, however, is only one of several other parameters which determine the radiation detriment. Though the ICRP-concept of detriment is a quantitative definition, the kind of detriment weighting includes somewhat subjective elements. In this sense, the detriment-concept of ICRP represents already at the stage of effective dose a kind of assessment. Thus, by comparing radiation protection standards and concepts interconvertible or with those of environment or occupational protection one should be aware of the possibly different principles of detriment assessment.

  5. Radon dose and aerosols

    International Nuclear Information System (INIS)

    Planinic, J.; Radolic, V.; Faj, Z.; Vukovic, B.

    2000-01-01

    The equilibrium factor value (F) was measured in the NRPB radon chamber and the corresponding track density ratio (r = D/D 0 ) of bare (D) and diffusion (D 0 ) LR-115 nuclear track detectors was determined, as well as the regression equation F(r). Experiments with LR-115 nuclear track detectors and aerosol sources (burning candle and cigarette) were carried out in the Osijek University radon chamber and afterwards an empirical relationship between the equilibrium factor and aerosol concentration was derived. For the purpose of radon dose equivalent assessment, procedures for determining the unattached fraction of radon progeny were introduced using two nuclear track detectors. (author)

  6. Hanford Environmental Dose Reconstruction Project

    International Nuclear Information System (INIS)

    Cannon, S.D.; Finch, S.M.

    1992-10-01

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates):Source Terms, Environmental Transport, Environmental Monitoring Data, Demography, Food Consumption, and Agriculture, and Environmental Pathways and Dose Estimates

  7. Effective dose and dose to crystalline lens during angiographic procedures

    International Nuclear Information System (INIS)

    Pages, J.

    1998-01-01

    The highest radiation doses levels received by radiologists are observed during interventional procedures. Doses to forehead and neck received by a radiologist executing angiographic examinations at the department of radiology at the academic hospital (AZ-VUB) have been measured for a group of 34 examinations. The doses to crystalline lens and the effective doses for a period of one year have been estimated. For the crystalline lens the maximum dose approaches the ICRP limit, that indicates the necessity for the radiologist to use leaded glasses. (N.C.)

  8. Dose planning and dose delivery in radiation therapy

    International Nuclear Information System (INIS)

    Knoeoes, T.

    1991-01-01

    A method has been developed for calibration of CT-numbers to volumetric electron density distributions using tissue substitutes of known elemental composition and experimentally determined electron density. This information have been used in a dose calculation method based on photon and electron interaction processes. The method utilizes a convolution integral between the photon fluence matrix and dose distribution kernels. Inhomogeneous media are accounted for using the theorems of Fano and O'Connor for scaling dose distribution kernels in proportion to electron density. For clinical application of a calculated dose plan, a method for prediction of accelerator output have been developed. The methods gives the number of monitor units that has to be given to obtain a certain absorbed dose to a point inside an irregular, inhomogeneous object. The method for verification of dose distributions outlined in this study makes it possible to exclude the treatment related variance contributions, making an objective evaluation of dose calculations with experiments feasible. The methods for electron density determination, dose calculation and prediction of accelerator output discussed in this study will all contribute to an increased accuracy in the mean absorbed dose to the target volume. However, a substantial gain in the accuracy for the spatial absorbed dose distribution will also follow, especially using CT for mapping of electron density together with the dose calculation algorithm. (au)

  9. Normal tissue dose-effect models in biological dose optimisation

    International Nuclear Information System (INIS)

    Alber, M.

    2008-01-01

    Sophisticated radiotherapy techniques like intensity modulated radiotherapy with photons and protons rely on numerical dose optimisation. The evaluation of normal tissue dose distributions that deviate significantly from the common clinical routine and also the mathematical expression of desirable properties of a dose distribution is difficult. In essence, a dose evaluation model for normal tissues has to express the tissue specific volume effect. A formalism of local dose effect measures is presented, which can be applied to serial and parallel responding tissues as well as target volumes and physical dose penalties. These models allow a transparent description of the volume effect and an efficient control over the optimum dose distribution. They can be linked to normal tissue complication probability models and the equivalent uniform dose concept. In clinical applications, they provide a means to standardize normal tissue doses in the face of inevitable anatomical differences between patients and a vastly increased freedom to shape the dose, without being overly limiting like sets of dose-volume constraints. (orig.)

  10. Absorbed dose in CT. Comparison by CT dose index

    International Nuclear Information System (INIS)

    Yamamoto, Kenji; Akazawa, Hiroshi; Andou, Takashi

    2002-01-01

    Few reports have discussed the absorbed dose on CT units with increased scanning capacity even with the current widespread adoption of multi-slice CT units. To compare and investigate the dose indexes among CT units, we measured the absorbed dose on CT units operating in Nagano Prefecture Japan. The measurements showed proportionality between phantom absorbed dose and the exposured mAs values in conventional scanning operation. Further, the measurements showed that the absorbed dose in the center of the phantom differed by about 2.1-fold between the highest and lowest levels on individual CT units. Within a single company, multi-slice CT units of the same company gave absorbed doses of about 1.3 to 1.5 times those of conventional single-slice CT units under the same exposured conditions of conventional scanning. When the scanning pitch was reduced in helical scanning, the absorbed dose at the center of the phantom increased. (author)

  11. New recommendations for dose equivalent

    International Nuclear Information System (INIS)

    Bengtsson, G.

    1985-01-01

    In its report 39, the International Commission on Radiation Units and Measurements (ICRU), has defined four new quantities for the determination of dose equivalents from external sources: the ambient dose equivalent, the directional dose equivalent, the individual dose equivalent, penetrating and the individual dose equivalent, superficial. The rationale behind these concepts and their practical application are discussed. Reference is made to numerical values of these quantities which will be the subject of a coming publication from the International Commission on Radiological Protection, ICRP. (Author)

  12. Integral dose conservation in radiotherapy

    International Nuclear Information System (INIS)

    Reese, Adam S.; Das, Shiva K.; Curle, Charles; Marks, Lawrence B.

    2009-01-01

    Treatment planners frequently modify beam arrangements and use IMRT to improve target dose coverage while satisfying dose constraints on normal tissues. The authors herein analyze the limitations of these strategies and quantitatively assess the extent to which dose can be redistributed within the patient volume. Specifically, the authors hypothesize that (1) the normalized integral dose is constant across concentric shells of normal tissue surrounding the target (normalized to the average integral shell dose), (2) the normalized integral shell dose is constant across plans with different numbers and orientations of beams, and (3) the normalized integral shell dose is constant across plans when reducing the dose to a critical structure. Using the images of seven patients previously irradiated for cancer of brain or prostate cancer and one idealized scenario, competing three-dimensional conformal and IMRT plans were generated using different beam configurations. Within a given plan and for competing plans with a constant mean target dose, the normalized integral doses within concentric ''shells'' of surrounding normal tissue were quantitatively compared. Within each patient, the normalized integral dose to shells of normal tissue surrounding the target was relatively constant (1). Similarly, for each clinical scenario, the normalized integral dose for a given shell was also relatively constant regardless of the number and orientation of beams (2) or degree of sparing of a critical structure (3). 3D and IMRT planning tools can redistribute, rather than eliminate dose to the surrounding normal tissues (intuitively known by planners). More specifically, dose cannot be moved between shells surrounding the target but only within a shell. This implies that there are limitations in the extent to which a critical structure can be spared based on the location and geometry of the critical structure relative to the target.

  13. Patient dose measurement and dose reduction in East Anglia (UK)

    International Nuclear Information System (INIS)

    Wade, J.P.; Goldstone, K.E.; Dendy, P.P.

    1995-01-01

    At the end of 1990 a programme of patient dose measurements was introduced as part of the quality assurance service already provided for X ray departments throughout the East Anglian Health Region (UK). Thermoluminescence dosemeters (TLDs) were used to measure over 1200 skin entrance surface doses for four common radiographic views in 33 hospitals in both the NHS and private sector. The four views were chosen to cover a wide range of equipment and techniques. The data collected have enabled Regional reference doses to be set which, for all views considered, fall below the National Radiological Protection Board (NRPB) Reference levels. In departments which exceeded reference levels, techniques were reviewed, improvements suggested and doses re-measured, in accordance with the recommended procedure for patient dose audit. A significant finding was that, given appropriate controls, X ray departments in the private sector could achieve the same acceptably low doses as NHS departments. (Author)

  14. In defence of collective dose

    International Nuclear Information System (INIS)

    Fairlie, I.; Sumner, D.

    2000-01-01

    Recent proposals for a new scheme of radiation protection leave little room for collective dose estimations. This article discusses the history and present use of collective doses for occupational, ALARA, EIS and other purposes with reference to practical industry papers and government reports. The linear no-threshold (LNT) hypothesis suggests that collective doses which consist of very small doses added together should be used. Moral and ethical questions are discussed, particularly the emphasis on individual doses to the exclusion of societal risks, uncertainty over effects into the distant future and hesitation over calculating collective detriments. It is concluded that for moral, practical and legal reasons, collective dose is a valid parameter which should continue to be used. (author)

  15. Fast in vivo volume dose reconstruction via reference dose perturbation

    International Nuclear Information System (INIS)

    Lu, Weiguo; Chen, Mingli; Mo, Xiaohu; Parnell, Donald; Olivera, Gustavo; Galmarini, Daniel

    2014-01-01

    Purpose: Accurate on-line reconstruction of in-vivo volume dose that accounts for both machine and patient discrepancy is not clinically available. We present a simple reference-dose-perturbation algorithm that reconstructs in-vivo volume dose fast and accurately. Methods: We modelled the volume dose as a function of the fluence map and density image. Machine (output variation, jaw/leaf position errors, etc.) and patient (setup error, weight loss, etc.) discrepancies between the plan and delivery were modelled as perturbation of the fluence map and density image, respectively. Delivered dose is modelled as perturbation of the reference dose due to change of the fluence map and density image. We used both simulated and clinical data to validate the algorithm. The planned dose was used as the reference. The reconstruction was perturbed from the reference and accounted for output-variations and the registered daily image. The reconstruction was compared with the ground truth via isodose lines and the Gamma Index. Results: For various plans and geometries, the volume doses were reconstructed in few seconds. The reconstruction generally matched well with the ground truth. For the 3%/3mm criteria, the Gamma pass rates were 98% for simulations and 95% for clinical data. The differences mainly appeared on the surface of the phantom/patient. Conclusions: A novel reference-dose-perturbation dose reconstruction model is presented. The model accounts for machine and patient discrepancy from planning. The algorithm is simple, fast, yet accurate, which makes online in-vivo 3D dose reconstruction clinically feasible.

  16. Experimental evaluation of neutron dose in radiotherapy patients: Which dose?

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Expósito, M., E-mail: mariateresa.romero@uab.cat; Domingo, C.; Ortega-Gelabert, O.; Gallego, S. [Grup de Recerca en Radiacions Ionizants (GRRI), Departament de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); Sánchez-Doblado, F. [Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009 (Spain); Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41009 (Spain)

    2016-01-15

    Purpose: The evaluation of peripheral dose has become a relevant issue recently, in particular, the contribution of secondary neutrons. However, after the revision of the Recommendations of the International Commission on Radiological Protection, there has been a lack of experimental procedure for its evaluation. Specifically, the problem comes from the replacement of organ dose equivalent by the organ-equivalent dose, being the latter “immeasurable” by definition. Therefore, dose equivalent has to be still used although it needs the calculation of the radiation quality factor Q, which depends on the unrestricted linear energy transfer, for the specific neutron irradiation conditions. On the other hand, equivalent dose is computed through the radiation weighting factor w{sub R}, which can be easily calculated using the continuous function provided by the recommendations. The aim of the paper is to compare the dose equivalent evaluated following the definition, that is, using Q, with the values obtained by replacing the quality factor with w{sub R}. Methods: Dose equivalents were estimated in selected points inside a phantom. Two types of medical environments were chosen for the irradiations: a photon- and a proton-therapy facility. For the estimation of dose equivalent, a poly-allyl-diglicol-carbonate-based neutron dosimeter was used for neutron fluence measurements and, additionally, Monte Carlo simulations were performed to obtain the energy spectrum of the fluence in each point. Results: The main contribution to dose equivalent comes from neutrons with energy higher than 0.1 MeV, even when they represent the smallest contribution in fluence. For this range of energy, the radiation quality factor and the radiation weighting factor are approximately equal. Then, dose equivalents evaluated using both factors are compatible, with differences below 12%. Conclusions: Quality factor can be replaced by the radiation weighting factor in the evaluation of dose

  17. Angular dependence of shallow dose

    International Nuclear Information System (INIS)

    Alvarez, J.L.

    1986-01-01

    The theoretical response of a detector is discussed and compared to measurements of shallow dose with tissue and phantom response detectors. A definite energy dependent angular response of dose and measurement was observed which could not be explained by simple trigonometric arguments. The response is back scatter dependent and must be considered in detector design and dose measurements. It is not possible for standard detectors to follow this response

  18. Full dose CHOP chemotherapy

    International Nuclear Information System (INIS)

    Tominaga, Shinichi; Kondo, Makoto; Ando, Yutaka; Yamashita, Shoji; Uematsu, Minoru; Shigematsu, Naoyuki; Nishiguchi, Iku; Hashimoto, Shozo

    1985-01-01

    Since 1982, we have performed 125 courses of CHOP chemotherapy for 27 patients of malignancy, adhering to the original regimen as strictly as possible. CHOP chemotherapy consisted of Cyclophosphamide 750 mg/m 2 , iv, on day 1; Adriamycin 50 mg/m 2 , iv, on day 1; Vincristine 1.4 mg/m 2 , iv, on day 1 (maximum single dose 2.0 mg) and Prednisolone 50 mg/m 2 , po, day 1 through 5. The cycle was repeated every 21 days. As side effects, myelosuppression, hair loss, fever, nausea, vomiting, liver dysfunction, stomatitis, neuropathy, herpes zoster, arrhythmia and hemorrhagic cystitis were seen. Due to myelosuppression, twenty patients experienced febrile episodes at each nadir of WBC counts on 40 courses. However, any febrile patient did not have life threatening infection. Other side effects were also reversible. The radiotherapy of most patients was carried out as initially scheduled, except for 3 patients in whom irradiation was interrupted due to severe stomatitis or herpes zoster. We consider that CHOP chemotherapy is excellent in feasibility even when combined with radiotherapy. (author)

  19. Radiation dose in dental radiology

    International Nuclear Information System (INIS)

    Cohnen, M.; Kemper, J.; Moedder, U.; Moebes, O.; Pawelzik, J.

    2002-01-01

    The aim of this study was to compare radiation exposure in panoramic radiography (PR), dental CT, and digital volume tomography (DVT). An anthropomorphic Alderson-Rando phantom and two anatomical head phantoms with thermoluminescent dosimeters fixed at appropriate locations were exposed as in a dental examination. In PR and DVT, standard parameters were used while variables in CT included mA, pitch, and rotation time. Image noise was assessed in dental CT and DVT. Radiation doses to the skin and internal organs within the primary beam and resulting from scatter radiation were measured and expressed as maximum doses in mGy. For PR, DVT, and CT, these maximum doses were 0.65, 4.2, and 23 mGy. In dose-reduced CT protocols, radiation doses ranged from 10.9 to 6.1 mGy. Effective doses calculated on this basis showed values below 0.1 mSv for PR, DVT, and dose-reduced CT. Image noise was similar in DVT and low-dose CT. As radiation exposure and image noise of DVT is similar to low-dose CT, this imaging technique cannot be recommended as a general alternative to replace PR in dental radiology. (orig.)

  20. Hanford Environmental Dose Reconstruction Project

    International Nuclear Information System (INIS)

    Finch, S.M.; McMakin, A.H.

    1991-04-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Pacific Northwest Laboratory (PNL) under the direction of an independent Technical Steering Panel (TSP). The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from released to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demographics, agriculture, food habits; and, environmental pathways and dose estimates

  1. Occupational dose trends in Tanzania

    International Nuclear Information System (INIS)

    Muhogora, W.E.; Nyanda, A.M.; Ngaile, J.E.; Lema, U.S.

    1998-01-01

    This paper describes the present status of occupational radiation exposure of monitored workers in Tanzania from 1986 to 1997. The analysis of dose records observes over this period, a fluctuating trend both in the individual and collective doses. The trend is more related to the fluctuations of the number of radiation workers than to the possible radiation safety changes of the working conditions. It has been found that, the maximum annual dose for the worker in all work categories was about 18 mSv y -1 . This suggests that the occupational radiation exposure in all practices satisfies the current dose limitation system. The national exposure summary shows that, the highest collective dose of 12.8 man-Sv which is 90% of the total collective dose, was due to medical applications. The applications in industry and research had a contribution of nearly 0.8 and 0.7 man-Sv respectively. From the professional point of view, the medical diagnostic radiographers received the highest collective dose of 11.2 man-Sv. Although the medical physicists recorded the minimum collective dose of nearly 0.07 man-Sv, the data shows that this profession received the highest mean dose of about 33 mSv in 12 years. Some achievements of the personnel monitoring services and suggestions for future improvement are pointed out. (author)

  2. Prenatal radiation doses from radiopharmaceuticals

    International Nuclear Information System (INIS)

    Rojo, A.M.; Gomez Parada, I.M.; Di Trano, J.L.

    1998-01-01

    The radiopharmaceutical administration with diagnostic or therapeutic purpose during pregnancy implies a prenatal radiation dose. The dose assessment and the evaluation of the radiological risks become relevant due to the great radiosensitivity of the fetal tissues in development. This paper is a revision of the available data for estimating fetal doses in the cases of the more frequently used radiopharmaceuticals in nuclear medicine, taking into account recent investigation in placental crossover. The more frequent diagnostic and therapeutic procedures were analyzed according to the radiation doses implied. (author) [es

  3. Hanford Environmental Dose Reconstruction Project

    International Nuclear Information System (INIS)

    Finch, S.M.; McMakin, A.H.

    1992-06-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Battelle Pacific Northwest Laboratories under contract with the Centers for Disease Control. The independent Technical Steering Panel (TSP) provides technical direction. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms; environmental transport; environmental monitoring data; demography, food consumption, and agriculture; environmental pathways and dose estimates

  4. Radiation doses in interventional neuroradiology

    International Nuclear Information System (INIS)

    Theodorakou, C.; Butler, P.; Horrocks, J.A.

    2001-01-01

    Patient radiation doses during interventional radiology (IR) procedures may reach the thresholds for radiation-induced skin and eye lens injuries. This study investigates the radiation doses received by patients undergoing cerebral embolization. Measurements were conducted using thermoluminescent dosimeters. Radiotherapy verification films were used in order to visualise the radiation field. For each procedure the fluoroscopic and digital dose-area product, the fluoroscopic time, the total number of acquired images and entrance-skin dose calculated by the angiographic unit were recorded. In this paper, the skin, eye and thyroid glands doses on a sample of patients are presented. From a preliminary study of 13 patients having undergone cerebral embolization, it was deduced that six of them have received a dose above 1 Gy. Detailed dose data from patients undergoing IR procedures will be collected in the future with the aim of developing a model to allow estimation of the dose prior to the procedure as well as to look at techniques of dose reduction. (author)

  5. Gamma dosimetry of high doses

    International Nuclear Information System (INIS)

    Martinez C, T.; Galvan G, A.; Canizal, G.

    1991-01-01

    The gamma dosimetry of high doses is problematic in almost all the classic dosemeters either based on the thermoluminescence, electric, chemical properties, etc., because they are saturated to very high dose and they are no longer useful. This work carries out an investigation in the interval of high doses. The solid system of heptahydrate ferrous sulfate, can be used as solid dosemeter of routine for high doses of radiation. The proposed method is simple, cheap and it doesn't require sophisticated spectrophotometers or spectrometers but expensive and not common in some laboratories

  6. Spiral CT and radiation dose

    International Nuclear Information System (INIS)

    Imhof, H.; Schibany, N.; Ba-Ssalamah, A.; Czerny, C.; Hojreh, A.; Kainberger, F.; Krestan, C.; Kudler, H.; Noebauer, I.; Nowotny, R.

    2003-01-01

    Recent studies in the USA and Europe state that computed tomography (CT) scans compromise only 3-5% of all radiological exams, but they contribute 35-45% of total radiation dose to the patient population. These studies lead to concern by several public authorities. Basis of CT-dose measurements is the computed tomography dose index (CTDI), which was established 1981. Nowadays there are several modifications of the CTDI values, which may lead to confusion. It is suggested to use the standardized CTDI-100 w. value together with the dose length product in all CT-examinations. These values should be printed on all CT-images and allows an evaluation of the individualized patient dose. Nowadays, radiologist's aim must be to work at the lowest maximal diagnostic acceptable signal to noise ratio. To decrease radiation dose radiologist should use low kV and mA, but high pitches. Newly developed CT-dose-reduction soft-wares and filters should be installed in all CT-machines. We should critically compare the average dose used for a specific examination with the reference dose used in this country and/or Europe. Greater differences should caution the radiologist. Finally, we as radiologists must check very carefully all indications and recommend alternative imaging methods. But we have also to teach our customers--patients and medical doctors who are non-radiologists--that a 'good' image is not that which show all possible information, but that which visualize 'only' the diagnostic necessary information

  7. Low doses effects and gamma radiations low dose rates

    International Nuclear Information System (INIS)

    Averbeck, D.

    1999-01-01

    This expose wishes for bringing some definitions and base facts relative to the problematics of low doses effects and low dose rates effects. It shows some already used methods and some actual experimental approaches by focusing on the effects of ionizing radiations with a low linear energy transfer. (N.C.)

  8. Do dose area product meter measurements reflect radiation doses ...

    African Journals Online (AJOL)

    Enrique

    SA JOURNAL OF RADIOLOGY • August 2004. Abstract. This study determined the correlation between radiation doses absorbed by health care workers and dose area product meter (DAP) measurements at Universitas Hospital, Bloemfontein. The DAP is an instrument which accurately measures the radiation emitted from ...

  9. Do dose area product meter measurements reflect radiation doses ...

    African Journals Online (AJOL)

    This study determined the correlation between radiation doses absorbed by health care workers and dose area product meter (DAP) measurements at Universitas Hospital, Bloemfontein. The DAP is an instrument which accurately measures the radiation emitted from the source. The study included the interventional ...

  10. Pharmacoeconomic Evaluation Of Doxycycline And Tetracycline In ...

    African Journals Online (AJOL)

    recommendations for inclusion of economic evaluation of drug therapies in health policy formulations and decision making. Methods: Cost effectiveness analysis was carried out retrospectively for prescribed/dispensed antibacterials to out-patients with chlamydial implicated non-gonococcal urethritis among other infectious ...

  11. 21 CFR 522.778 - Doxycycline hyclate.

    Science.gov (United States)

    2010-04-01

    ...] (d) Conditions of use—(1) Dogs—(i) Amount. Apply subgingivally to periodontal pocket(s) of affected teeth. (ii) Indications for use. For treatment and control of periodontal disease. (iii) Limitations. Do not use in dogs less than 1-year old. Use of tetracyclines during tooth development has been...

  12. A dose error evaluation study for 4D dose calculations

    Science.gov (United States)

    Milz, Stefan; Wilkens, Jan J.; Ullrich, Wolfgang

    2014-10-01

    Previous studies have shown that respiration induced motion is not negligible for Stereotactic Body Radiation Therapy. The intrafractional breathing induced motion influences the delivered dose distribution on the underlying patient geometry such as the lung or the abdomen. If a static geometry is used, a planning process for these indications does not represent the entire dynamic process. The quality of a full 4D dose calculation approach depends on the dose coordinate transformation process between deformable geometries. This article provides an evaluation study that introduces an advanced method to verify the quality of numerical dose transformation generated by four different algorithms. The used transformation metric value is based on the deviation of the dose mass histogram (DMH) and the mean dose throughout dose transformation. The study compares the results of four algorithms. In general, two elementary approaches are used: dose mapping and energy transformation. Dose interpolation (DIM) and an advanced concept, so called divergent dose mapping model (dDMM), are used for dose mapping. The algorithms are compared to the basic energy transformation model (bETM) and the energy mass congruent mapping (EMCM). For evaluation 900 small sample regions of interest (ROI) are generated inside an exemplary lung geometry (4DCT). A homogeneous fluence distribution is assumed for dose calculation inside the ROIs. The dose transformations are performed with the four different algorithms. The study investigates the DMH-metric and the mean dose metric for different scenarios (voxel sizes: 8 mm, 4 mm, 2 mm, 1 mm 9 different breathing phases). dDMM achieves the best transformation accuracy in all measured test cases with 3-5% lower errors than the other models. The results of dDMM are reasonable and most efficient in this study, although the model is simple and easy to implement. The EMCM model also achieved suitable results, but the approach requires a more complex

  13. The patient dose survey and dose reduction in diagnostic radiology

    International Nuclear Information System (INIS)

    Dang Thanh Luong; Duong Van Vinh; Ha Ngoc Thach

    2000-01-01

    This paper presented the results of the patient dose survey in some hospitals in Hanoi from 1995 to 1997. The main investigated types of the X-ray examination were: Chest PA, LAT; Skull PA/AP, LAT; Lumbar spine AP, LAT; and Pelvis AP. The fluctuation of the entrance surface doses (ESD) was too large, even in the same type of X-ray examination and X-ray facility. It was found that the ratio of maximum and minimum ESD were ranged from 1.5 to 18. The mean values of ESD for chest and skull were higher than CEC recommended values, while the mean values of lumbar spine and pelvis were smaller than that of CEC recommended values. The result of dose intercomparison was also reported. Some methods of dose reduction were applied for improving the patient dose in X-ray departments such as a high kV technique, high sensitive screen-film combination. (author)

  14. Time and dose in carcinogenesis

    International Nuclear Information System (INIS)

    Mayneord, W.V.; Clarke, R.H.

    1978-05-01

    Previous work on the implications of different forms of dose response relationships is extended to include time as a variable, not only in time of irradiation but also in the time of appearance of effects following irradiation. The forms of relationships for time distribution of tumours revealed experimentally for both radiation and chemical carcinogens are first considered. It appears that much data may be correlated in terms of a log-normal distribution of tumour yield following the insult. Further, it is noted, that there is evidence that the median time of tumour appearance may be a function of total dose received or even of dose rate for protracted exposure. Using numerical values of these parameters derived from the biological literature speculative studies have been made of the effects on dose response relationships of using a time distribution of tumour yield, considering both uniform irradiation and point sources. In addition the effects of using dose rate rather than dose to define the log-normal distribution to tumour appearance have been investigated. It is assumed that biological response is directly proportional to dose but that effect is distributed in time. From this linear assumption the appearance of non-linear dose response relationships and apparent thresholds are continually seen. Finally, both the importance of attempting analyses of biological data in terms of stochastic concepts and the need for biological data to test our hypotheses is emphasised. (author)

  15. EPA's Benchmark Dose Modeling Software

    Science.gov (United States)

    The EPA developed the Benchmark Dose Software (BMDS) as a tool to help Agency risk assessors facilitate applying benchmark dose (BMD) method’s to EPA’s human health risk assessment (HHRA) documents. The application of BMD methods overcomes many well know limitations ...

  16. Microbeams, microdosimetry and specific dose

    International Nuclear Information System (INIS)

    Randers-Pehrson, H.

    2002-01-01

    Dose and its usefulness as a single parameter to describe the amount of radiation absorbed are well established for most situations. The conditions where the concept of dose starts to break down are well known, mostly from the study of microdosimetry. For low doses of high LET radiation it is noted that the process of taking the limiting value of the energy absorbed within a test volume divided by the mass within that volume yields either zero or a relatively large value. The problem is further exacerbated with microbeam irradiations where the uniformity of the energy deposition is experimentally manipulated on the spatial scale of cells being irradiated. Booz introduced a quantity to deal with these problems: the unfortunately named 'mean specific energy in affected volumes'. This quantity multiplied by the probability that a test volume has received an energy deposit is equal to dose (in situations where dose can be defined). I propose that Booz's quantity be renamed 'specific dose', that is the mean energy deposited divided by the mass within a specified volume. If we believe for instance that the nucleus of a cell is the critical volume for biological effects, we can refer to the nuclear specific dose. A microbeam experiment wherein 10 per cent of the cell nuclei were targeted with 10 alpha particles would be described as delivering a nuclear specific dose of 1.6 Gy to 10 per cent of the population. (author)

  17. Radiation absorbed doses in cephalography

    International Nuclear Information System (INIS)

    Eliasson, S.; Julin, P.; Richter, S.; Stenstroem, B.

    1984-01-01

    Radiation absorbed doses to different organs in the head and neck region in lateral (LAT) and postero-anterior (PA) cephalography were investigated. The doses were measured by thermoluminescence dosimeters (TLD) on a tissue equivalent phantom head. Lanthanide screens in speed group 4 were used at 90 and 85 k Vp. A near-focus aluminium dodger was used and the radiation beam was collimated strictly to the face. The maximum entrance dose from LAT was 0.25 mGy and 0.42 mGy from a PA exposure. The doses to the salivary glands ranged between 0.2 and 0.02 mGy at LAT and between 0.15 and 0.04 mGy at PA exposures. The average thyroid gland dose without any shielding was 0.11 mGy (LAT) and 0.06 mGy (PA). When a dodger was used the dose was reduced to 0.07 mGy (LAT). If the thyroid gland was sheilded off, the dose was further reduced to 0.01 mGy and if the thyroid region was collimated out of the primary radiation field the dose was reduced to only 0.005 mGy. (authors)

  18. Central index of dose information

    International Nuclear Information System (INIS)

    1991-01-01

    The Central Index of Dose Information (CIDI) is a national database of occupational exposure to radiation operated by the NRPB as agent for the Health and Safety Executive. It receives summarised information on the radiation doses to classified persons in Great Britain annually from Approved Dosimetry Services. This document is the first annual CIDI summary of the data, giving statistics for 1986. (UK)

  19. Dose optimisation in computed radiography

    International Nuclear Information System (INIS)

    Schreiner-Karoussou, A.

    2005-01-01

    After the installation of computed radiography (CR) systems in three hospitals in Luxembourg a patient dose survey was carried out for three radiographic examinations, thorax, pelvis and lumbar spine. It was found that the patient doses had changed in comparison with the patient doses measured for conventional radiography in the same three hospitals. A close collaboration between the manufacturers of the X-ray installations, the CR imaging systems and the medical physicists led to the discovery that the speed class with which each radiographic examination was to be performed, had been ignored, during installation of the digital imaging systems. A number of procedures were carried out in order to calibrate and program the X-ray installations in conjunction with the CR systems. Following this optimisation procedure, a new patient dose survey was carried out for the three radiographic examinations. It was found that patient doses for the three hospitals were reduced. (authors)

  20. Evolution of radon dose evaluation

    Directory of Open Access Journals (Sweden)

    Fujimoto Kenzo

    2004-01-01

    Full Text Available The historical change of radon dose evaluation is reviewed based on the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR reports. Since 1955, radon has been recognized as one of the important sources of exposure of the general public. However, it was not really understood that radon is the largest dose contributor until 1977 when a new concept of effective dose equivalent was introduced by International Commission on Radiological Protection. In 1982, the dose concept was also adapted by UNSCEAR and evaluated per caput dose from natural radiation. Many researches have been carried out since then. However, lots of questions have remained open in radon problems, such as the radiation weighting factor of 20 for alpha rays and the large discrepancy of risk estimation among dosimetric and epidemiological approaches.

  1. Bone and marrow dose modeling

    International Nuclear Information System (INIS)

    Stabin, Michael G.

    2004-01-01

    Nuclear medicine therapy is being used increasingly in the treatment of cancer (thyroid, leukemia/lymphoma with RIT, primary and secondary bone malignancies, and neuroblastomas). In all cases it is marrow toxicity that limits the amount of treatment that can be administered safely. Marrow dose calculations are more difficult than for many major organs because of the intricate association of bone and soft tissue elements. In RIT, there appears to be no consensus on how to calculate that dose accurately, or of individual patients ability to tolerate planned therapy. Available dose models are designed after an idealized average, healthy individual. Patient-specific methods are applied in evaluation of biokinetic data, and need to be developed for treatment of the physical data (dose conversion factors) as well: age, prior patient therapy, disease status. Contributors to marrow dose: electrons and photons

  2. Radiation dose during angiographic procedures

    International Nuclear Information System (INIS)

    Lavoie, Ch.; Rasuli, P.

    2001-01-01

    The use of angiographic procedures is becoming more prevalent as new techniques and equipment are developed. There have been concerns in the scientific community about the level of radiation doses received by patients, and indirectly by staff, during some of these radiological procedures. The purpose of this study was to assess the level of radiation dose from angiographic procedures to patient at the Ottawa Hospital, General Campus. Radiation dose measurements, using Thermo-Luminescent Dosimeters (TLDs), were performed on more than 100 patients on various procedures. The results show that while the patient dose from the great majority of angiographic procedures is less than 2 Gy, a significant number of procedures, especially interventional procedures may have doses greater than 2 Gy and may lead to deterministic effects. (author)

  3. Labour cost of radiation dose

    International Nuclear Information System (INIS)

    Cook, A.; Lockett, L.E.

    1978-01-01

    In order to optimise capital expenditure on measures to protect workers against radiation it would be useful to have a means to measure radiation dose in money terms. Because labour has to be employed to perform radiation work there must be some relationship between the wages paid and the doses received. Where the next increment of radiation dose requires additional labour to be recruited the cost will at least equal the cost of the extra labour employed. This paper examines some of the factors which affect the variability of the labour cost of radiation dose and notes that for 'in-plant' exposures the current cost per rem appears to be significantly higher than values quoted in ICRP Publication 22. An example is given showing how this concept may be used to determine the capital it is worth spending on installed plant to prevent regular increments of radiation dose to workers. (author)

  4. Patient dose measurement and dose reduction in chest radiography

    Directory of Open Access Journals (Sweden)

    Milatović Aleksandra A.

    2014-01-01

    Full Text Available Investigations presented in this paper represent the first estimation of patient doses in chest radiography in Montenegro. In the initial stage of our study, we measured the entrance surface air kerma and kerma area product for chest radiography in five major health institutions in the country. A total of 214 patients were observed. We reported the mean value, minimum and third quartile values, as well as maximum values of surface air kerma and kerma area product of patient doses. In the second stage, the possibilities for dose reduction were investigated. Mean kerma area product values were 0.8 ± 0.5 Gycm2 for the posterior-anterior projection and 1.6 ± 0.9 Gycm2 for the lateral projection. The max/min ratio for the entrance surface air kerma was found to be 53 for the posterior-anterior projection and 88 for the lateral projection. Comparing the results obtained in Montenegro with results from other countries, we concluded that patient doses in our medical centres are significantly higher. Changes in exposure parameters and increased filtration contributed to a dose reduction of up to 36% for posterior-anterior chest examinations. The variability of the estimated dose values points to a significant space for dose reduction throughout the process of radiological practice optimisation.

  5. Establishment Of Dose Correlation During Dose Mapping On Medical Devices

    International Nuclear Information System (INIS)

    Ruzalina Baharin; Hasan Sham; Ahsanulkhaliqin Abdul Wahab

    2014-01-01

    This paper explains the work done during product dose mapping in order to get the correlation between doses at MINTec-Sinagama plant. Product used was medical devices in aluminium tubes packaged in cardboard kegs packaging with average weight of 12 kg per carton. 12 cartons were loaded in every one tote to give 0.2 g/ cm 3 of density. Ceric cerous dosimeters were placed at specific locations as indicated in SP14: Product Dose Mapping, QMS of MINTec-Sinagama around three planes. Three processes were made at different days as a three replicates to show the reproducibility of measurements. (author)

  6. Dosimetric systems of high dose, dose rate and dose uniformity in food and medical products

    International Nuclear Information System (INIS)

    Vargas, J.; Vivanco, M.; Castro, E.

    2014-08-01

    In the Instituto Peruano de Energia Nuclear (IPEN) we use the chemical dosimetry Astm-E-1026 Fricke as a standard dosimetric system of reference and different routine dosimetric systems of high doses, according to the applied doses to obtain the desired effects in the treated products and the doses range determined for each type of dosimeter. Fricke dosimetry is a chemical dosimeter in aqueous solution indicating the absorbed dose by means an increase in absorbance at a specific wavelength. A calibrated spectrophotometer with controlled temperature is used to measure absorbance. The adsorbed dose range should cover from 20 to 400 Gy, the Fricke solution is extremely sensitive to organic impurities, to traces of metal ions, in preparing chemical products of reactive grade must be used and the water purity is very important. Using the referential standard dosimetric system Fricke, was determined to March 5, 2013, using the referential standard dosimetric system Astm-1026 Fricke, were irradiated in triplicate Fricke dosimeters, to 5 irradiation times (20; 30; 40; 50 and 60 seconds) and by linear regression, the dose rate of 5.400648 kGy /h was determined in the central point of the irradiation chamber (irradiator Gamma cell 220 Excel), applying the decay formula, was compared with the obtained results by manufacturers by means the same dosimetric system in the year of its manufacture, being this to the date 5.44691 kGy /h, with an error rate of 0.85. After considering that the dosimetric solution responds to the results, we proceeded to the irradiation of a sample of 200 g of cereal instant food, 2 dosimeters were placed at the lateral ends of the central position to maximum dose and 2 dosimeters in upper and lower ends as minimum dose, they were applied same irradiation times; for statistical analysis, the maximum dose rate was 6.1006 kGy /h and the minimum dose rate of 5.2185 kGy /h; with a dose uniformity of 1.16. In medical material of micro pulverized bone for

  7. Standardization of high-dose measurement of electron and gamma ray absorbed doses and dose rates

    International Nuclear Information System (INIS)

    McLaughlin, W.L.

    1985-01-01

    Intense electron beams and gamma radiation fields are used for sterilizing medical devices, treating municipal wastes, processing industrial goods, controlling parasites and pathogens, and extending the shelf-life of foods. Quality control of such radiation processes depends largely on maintaining measurement quality assurance through sound dosimetry procedures in the research leading to each process, in the commissioning of that process, and in the routine dose monitoring practices. This affords documentation as to whether satisfactory dose uniformity is maintained throughout the product and throughout the process. Therefore, dosimetry at high doses and dose rates must in many radiation processes be standardized carefully, so that 'dosimetry release' of a product is verified. This standardization is initiated through preliminary dosimetry intercomparison studies such as those sponsored recently by the IAEA. This is followed by establishing periodic exercises in traceability to national or international standards of absorbed dose and dose rate. Traceability is achieved by careful selection of dosimetry methods and proven reference dosimeters capable of giving sufficiently accurate and precise 'transfer' dose assessments: (1) they must be calibrated or have well-established radiation-yield indices; (2) their radiation response characteristics must be reproducible and cover the dose range of interest; (3) they must withstand the rigours of back-and-forth mailing between a central standardizing laboratory and radiation processing facilities, without excessive errors arising due to instabilities, dosimeter batch non-uniformities, and environmental and handling stresses. (author)

  8. Radiation dose estimates for radiopharmaceuticals

    International Nuclear Information System (INIS)

    Stabin, M.G.; Stubbs, J.B.; Toohey, R.E.

    1996-04-01

    Tables of radiation dose estimates based on the Cristy-Eckerman adult male phantom are provided for a number of radiopharmaceuticals commonly used in nuclear medicine. Radiation dose estimates are listed for all major source organs, and several other organs of interest. The dose estimates were calculated using the MIRD Technique as implemented in the MIRDOSE3 computer code, developed by the Oak Ridge Institute for Science and Education, Radiation Internal Dose Information Center. In this code, residence times for source organs are used with decay data from the MIRD Radionuclide Data and Decay Schemes to produce estimates of radiation dose to organs of standardized phantoms representing individuals of different ages. The adult male phantom of the Cristy-Eckerman phantom series is different from the MIRD 5, or Reference Man phantom in several aspects, the most important of which is the difference in the masses and absorbed fractions for the active (red) marrow. The absorbed fractions for flow energy photons striking the marrow are also different. Other minor differences exist, but are not likely to significantly affect dose estimates calculated with the two phantoms. Assumptions which support each of the dose estimates appears at the bottom of the table of estimates for a given radiopharmaceutical. In most cases, the model kinetics or organ residence times are explicitly given. The results presented here can easily be extended to include other radiopharmaceuticals or phantoms

  9. Effects of small radiation doses

    International Nuclear Information System (INIS)

    Fuchs, G.

    1986-01-01

    The term 'small radiation dosis' means doses of about (1 rem), fractions of one rem as well as doses of a few rem. Doses like these are encountered in various practical fields, e.g. in X-ray diagnosis, in the environment and in radiation protection rules. The knowledge about small doses is derived from the same two forces, on which the radiobiology of human beings nearly is based: interpretation of the Hiroshima and Nagasaki data, as well as the experience from radiotherapy. Careful interpretation of Hiroshima dates do not provide any evidence that small doses can induce cancer, fetal malformations or genetic damage. Yet in radiotherapy of various diseases, e.g. inflammations, doses of about 1 Gy (100 rad) do no harm to the patients. According to a widespread hypothesis even very small doses may induce some types of radiation damage ('no threshold'). Nevertheless an alternative view is justified. At present no decision can be made between these two alternatives, but the usefullness of radiology is definitely better established than any damage calculated by theories or extrapolations. Based on experience any exaggerated fear of radiations can be met. (author)

  10. Patient dose in neonatal units

    International Nuclear Information System (INIS)

    Smans, K.; Struelens, L.; Smet, M.; Bosmans, H.; Vanhavere, F.

    2008-01-01

    Lung disease represents one of the most life-threatening conditions in prematurely born children. In the evaluation of the neonatal chest, the primary and most important diagnostic study is therefore the chest radiograph. Since prematurely born children are very sensitive to radiation, those radiographs may lead to a significant radiation detriment. Hence, knowledge of the patient dose is necessary to justify the exposures. A study to assess the patient doses was started at the neonatal intensive care unit (NICU) of the Univ. Hospital in Leuven. Between September 2004 and September 2005, prematurely born babies underwent on average 10 X-ray examinations in the NICU. In this sample, the maximum was 78 X-ray examinations. For chest radiographs, the median entrance skin dose was 34 μGy and the median dose area product was 7.1 mGy.cm 2 . By means of conversion coefficients, the measured values were converted to organ doses. Organ doses were calculated for three different weight classes: extremely low birth weight infants ( 2500 g). The doses to the lungs for a single chest radiograph for infants with extremely low birth weights, low birth weights and normal birth weights were 24, 25 and 32 μGy, respectively. (authors)

  11. CT dose reduction in children

    International Nuclear Information System (INIS)

    Vock, Peter

    2005-01-01

    World wide, the number of CT studies in children and the radiation exposure by CT increases. The same energy dose has a greater biological impact in children than in adults, and scan parameters have to be adapted to the smaller diameter of the juvenile body. Based on seven rules, a practical approach to paediatric CT is shown: Justification and patient preparation are important steps before scanning, and they differ from the preparation of adult patients. The subsequent choice of scan parameters aims at obtaining the minimal signal-to-noise ratio and volume coverage needed in a specific medical situation; exposure can be divided in two aspects: the CT dose index determining energy deposition per rotation and the dose-length product (DLP) determining the volume dose. DLP closely parallels the effective dose, the best parameter of the biological impact. Modern scanners offer dose modulation to locally minimise exposure while maintaining image quality. Beyond the selection of the physical parameters, the dose can be kept low by scanning the minimal length of the body and by avoiding any non-qualified repeated scanning of parts of the body. Following these rules, paediatric CT examinations of good quality can be obtained at a reasonable cost of radiation exposure. (orig.)

  12. Plutonium dose-effect relationship

    International Nuclear Information System (INIS)

    Matsuoka, Osamu

    1976-01-01

    Dose in internal exposure to Pu was investigated, and dose-effect relationship was discussed. Dose-effect relationship in internal exposure was investigated by means of two methods, which were relationship between dose and its effect (relationship between μ Ci/Kg and its effect), and exposure dose and its effects (rad-effect), and merits and demerits of two methods were mentioned. Problems in a indication method such as mean dose were discussed with respect to the dose in skeleton, the liver and the lung. Pu-induced osteosarcoma in mice rats, and beagles was described, and differences in its induction between animals were discussed. Pulmonary neoplasma induced by 239 PuO 2 inhalation in beagles was reported, and description was made as to differences in induction of lung cancer between animals when Pu was inhaled and was taken into the lung. A theoretical and experimental study of a extrapolation of the results of the animal experiment using Pu to human cases is necessary. (Serizawa, K.)

  13. Dose concentration and dose verification for radiotherapy of cancer

    International Nuclear Information System (INIS)

    Maruyama, Koichi

    2005-01-01

    The number of cancer treatments using radiation therapy is increasing. The background of this increase is the accumulated fact that the number of successful cases is comparative to or even better than surgery for some types of cancer due to the improvement in irradiation technology and radiation planning technology. This review describes the principles and technology of radiation therapy, its characteristics, particle therapy that improves the dose concentration, its historical background, the importance of dose concentration, present situation and future possibilities. There are serious problems that hinder the superior dose concentration of particle therapy. Recent programs and our efforts to solve these problems are described. A new concept is required to satisfy the notion of evidence based medicine, i.e., one has to develop a method of dose verification, which is not yet available. This review is for researchers, medical doctors and radiation technologists who are developing this field. (author)

  14. Pharmacokinetically guided dosing of (high-dose) chemotherapeutic agents

    NARCIS (Netherlands)

    Attema-de Jonge, M.E. (Milly Ellen)

    2004-01-01

    Due to variation in drug distribution, metabolism and elimination processes between patients, systemic exposure to chemotherapeutic agents may be highly variable from patient to patient after administration of similar doses. This pharmacokinetic variability may explain in part the large variability

  15. Superficial dose evaluation of four dose calculation algorithms

    Science.gov (United States)

    Cao, Ying; Yang, Xiaoyu; Yang, Zhen; Qiu, Xiaoping; Lv, Zhiping; Lei, Mingjun; Liu, Gui; Zhang, Zijian; Hu, Yongmei

    2017-08-01

    Accurate superficial dose calculation is of major importance because of the skin toxicity in radiotherapy, especially within the initial 2 mm depth being considered more clinically relevant. The aim of this study is to evaluate superficial dose calculation accuracy of four commonly used algorithms in commercially available treatment planning systems (TPS) by Monte Carlo (MC) simulation and film measurements. The superficial dose in a simple geometrical phantom with size of 30 cm×30 cm×30 cm was calculated by PBC (Pencil Beam Convolution), AAA (Analytical Anisotropic Algorithm), AXB (Acuros XB) in Eclipse system and CCC (Collapsed Cone Convolution) in Raystation system under the conditions of source to surface distance (SSD) of 100 cm and field size (FS) of 10×10 cm2. EGSnrc (BEAMnrc/DOSXYZnrc) program was performed to simulate the central axis dose distribution of Varian Trilogy accelerator, combined with measurements of superficial dose distribution by an extrapolation method of multilayer radiochromic films, to estimate the dose calculation accuracy of four algorithms in the superficial region which was recommended in detail by the ICRU (International Commission on Radiation Units and Measurement) and the ICRP (International Commission on Radiological Protection). In superficial region, good agreement was achieved between MC simulation and film extrapolation method, with the mean differences less than 1%, 2% and 5% for 0°, 30° and 60°, respectively. The relative skin dose errors were 0.84%, 1.88% and 3.90%; the mean dose discrepancies (0°, 30° and 60°) between each of four algorithms and MC simulation were (2.41±1.55%, 3.11±2.40%, and 1.53±1.05%), (3.09±3.00%, 3.10±3.01%, and 3.77±3.59%), (3.16±1.50%, 8.70±2.84%, and 18.20±4.10%) and (14.45±4.66%, 10.74±4.54%, and 3.34±3.26%) for AXB, CCC, AAA and PBC respectively. Monte Carlo simulation verified the feasibility of the superficial dose measurements by multilayer Gafchromic films. And the rank

  16. Effective doses in paediatric radiology

    International Nuclear Information System (INIS)

    Iacob, Olga; Diaconescu, Cornelia; Roca, Antoaneta

    2001-01-01

    Because of their longer life expectancy, the risk of late manifestations of detrimental radiation effects is greater in children than in adults and, consequently, paediatric radiology gives ground for more concern regarding radiation protection than radiology of adults. The purpose of our study is to assess in terms of effective doses the magnitude of paediatric patient exposure during conventional X-ray examinations, selected for their high frequency or their relatively high doses to the patient. Effective doses have been derived from measurements of dose-area product (DAP) carried out on over 900 patients undergoing X-ray examinations, in five paediatric units. The conversion coefficients for estimating effective doses are those calculated by the NRPB using Monte-Carlo technique on a series of 5 mathematical phantoms representing 0, 1, 5, 10 and 15 year old children. The annual frequency of X-ray examinations necessary for collective dose calculation are those reported in our last national study on medical exposure, conducted in 1995. The annual effective doses from all medical examinations for the average paediatric patient are as follows: 1.05 mSv for 0 year old, 0.98 mSv for 1 year old, 0.53 mSv for 5 year old, 0.65 mSv for 10 year old and 0.70 mSv for 15 year old. The resulting annual collective effective dose was evaluated at 625 man Sv with the largest contribution of pelvis and hip examinations (34%). The annual collective effective associated with paediatric radiology in Romania represent 5% of the annual value resulting from all diagnostic radiology. Examination of the chest is by far the most frequent procedure for children, accounting for about 60 per cent of all annually performed X-ray conventional examinations. Knowledge of real level of patient dose is an essential component of quality assurance programs in paediatric radiology. (authors)

  17. Late effects of low doses and dose rates

    International Nuclear Information System (INIS)

    Paretzke, H.G.

    1980-01-01

    This paper outlines the spectrum of problems and approaches used in work on the derivation of quantitative prognoses of late effects in man of low doses and dose rates. The origins of principal problems encountered in radiation risks assessments, definitions and explanations of useful quantities, methods of deriving risk factors from biological and epidemiological data, and concepts of risk evaluation and problems of acceptance are individually discussed

  18. Effects of low doses; Effet des faibles doses

    Energy Technology Data Exchange (ETDEWEB)

    Le Guen, B. [Electricite de France (EDF-LAM-SCAST), 93 - Saint-Denis (France)

    2001-07-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  19. Savannah River Site dose control

    International Nuclear Information System (INIS)

    Smith, L.S.

    1992-01-01

    Health physicists from the Brookhaven National Laboratory (BNL) visited the Savannah River Site (SRS) as one of 12 facilities operated by the Department of Energy (DOE) contractors with annual collective dose equivalents greater than 100 person-rem (100 person-cSv). Their charter was to review, evaluate and summarize as low as reasonably achievable (ALARA) techniques, methods and practices as implemented. This presentation gives an overview of the two selected ALARA practices implemented at the SRS: Administrative Exposure Limits and Goal Setting. These dose control methods are used to assure that individual and collective occupational doses are ALARA and within regulatory limits

  20. Are low radiation doses Dangerous?

    International Nuclear Information System (INIS)

    Garcia Lima, O.; Cornejo, N.

    1996-01-01

    In the last few years the answers to this questions has been affirmative as well as negative from a radiation protection point of view low doses of ionizing radiation potentially constitute an agent causing stochasting effects. A lineal relation without threshold is assumed between dose and probability of occurrence of these effects . Arguments against the danger of probability of occurrence of these effects. Arguments again the danger of low dose radiation are reflected in concepts such as Hormesis and adaptive response, which are phenomena that being studied at present

  1. What is correct: equivalent dose or dose equivalent

    International Nuclear Information System (INIS)

    Franic, Z.

    1994-01-01

    In Croatian language some physical quantities in radiation protection dosimetry have not precise names. Consequently, in practice either terms in English or mathematical formulas are used. The situation is even worse since the Croatian language only a limited number of textbooks, reference books and other papers are available. This paper compares the concept of ''dose equivalent'' as outlined in International Commission on Radiological Protection (ICRP) recommendations No. 26 and newest, conceptually different concept of ''equivalent dose'' which is introduced in ICRP 60. It was found out that Croatian terminology is both not uniform and unprecise. For the term ''dose equivalent'' was, under influence of Russian and Serbian languages, often used as term ''equivalent dose'' even from the point of view of ICRP 26 recommendations, which was not justified. Unfortunately, even now, in Croatia the legal unit still ''dose equivalent'' defined as in ICRP 26, but the term used for it is ''equivalent dose''. Therefore, in Croatian legislation a modified set of quantities introduced in ICRP 60, should be incorporated as soon as possible

  2. Health effect of low dose/low dose rate radiation

    International Nuclear Information System (INIS)

    Kodama, Seiji

    2012-01-01

    The clarified and non-clarified scientific knowledge is discussed to consider the cause of confusion of explanation of the title subject. The low dose is defined roughly lower than 200 mGy and low dose rate, 0.05 mGy/min. The health effect is evaluated from 2 aspects of clinical symptom/radiation hazard protection. In the clinical aspect, the effect is classified in physical (early and late) and genetic ones, and is classified in stochastic (no threshold value, TV) and deterministic (with TV) ones from the radioprotection aspect. Although the absence of TV in the carcinogenic and genetic effects has not been proved, ICRP employs the stochastic standpoint from the safety aspect for radioprotection. The lowest human TV known now is 100 mGy, meaning that human deterministic effect would not be generated below this dose. Genetic deterministic effect can be observable only in animal experiments. These facts suggest that the practical risk of exposure to <100 mGy in human is the carcinogenesis. The relationship between carcinogenic risk in A-bomb survivors and their exposed dose are found fitted to the linear no TV model, but the epidemiologic data, because of restriction of subject number analyzed, do not always mean that the model is applicable even below the dose <100 mGy. This would be one of confusing causes in explanation: no carcinogenic risk at <100 mGy or risk linear to dose even at <100 mGy, neither of which is scientifically conclusive at present. Also mentioned is the scarce risk of cancer in residents living in the high background radiation regions in the world in comparison with that in the A-bomb survivors exposed to the chronic or acute low dose/dose rate. Molecular events are explained for the low-dose radiation-induced DNA damage and its repair, gene mutation and chromosome aberration, hypothesis of carcinogenesis by mutation, and non-targeting effect of radiation (bystander effect and gene instability). Further researches to elucidate the low dose

  3. Dose determination in computed tomography

    International Nuclear Information System (INIS)

    Descamps, C.; Garrigo, E.; Venencia, D.; Gonzalez, M.; Germanier, A.

    2011-10-01

    In the last years the methodologies to determine the dose in computed tomography have been revised. In this work was realized a dosimetric study about the exploration protocols used for simulation of radiotherapy treatments. The methodology described in the Report No. 111 of the American Association of Medical Physiques on a computed tomograph of two cuts was applied. A cylindrical phantom of water was used with dimensions: 30 cm of diameter and 50 cm of longitude that simulates the absorption and dispersion conditions of a mature body of size average. The doses were determined with ionization chamber and thermoluminescent dosimetry. The results indicate that the dose information that provides the tomograph underestimates the dose between 32 and 35%.

  4. Hanford Environmental Dose Reconstruction Project

    International Nuclear Information System (INIS)

    McMakin, A.H.; Cannon, S.D.; Finch, S.M.

    1992-07-01

    The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed technical members representing the states of Oregon, Washington, and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates): Source terms, environmental transport, environmental monitoring data, demography, food consumption, and agriculture, and environmental pathways and dose estimates. Progress is discussed

  5. Dose from drinking water Finland

    International Nuclear Information System (INIS)

    Maekelaeinen, Ilona; Salonen, Laina; Huikuri, Pia; Arvela, Hannu

    1999-01-01

    The dose from drinking water originates almost totally from naturally occurring radionuclides in the uranium-238 series, the most important nuclide being radon-222. Second comes lead-210, and third polonium-210. The mean age-group-weighted dose received by ingestion of drinking water is 0.14 mSv per year. More than half of the total cumulative dose of 750 manSv is received by the users of private wells, forming 13% of the population. The most exposed group comprises the users of wells drilled in bedrock, who receive 320 manSv while comprising only 4% of the population. The calculated number of annual cancer incidences due to drinking water is very sensitive to the dose-conversion factors of ingested radon used, as well as to the estimated lung cancer incidences caused by radon released from water into indoor air. (au)

  6. Doses from Medical Radiation Sources

    Science.gov (United States)

    ... Medical Radiation Sources Michael G. Stabin, PhD, CHP Introduction Radiation exposures from diagnostic medical examinations are generally ... of exposure annually to natural background radiation. Plain Film X Rays Single Radiographs Effective Dose, mSv Skull ( ...

  7. Gamma Radiation Doses In Sweden

    International Nuclear Information System (INIS)

    Almgren, Sara; Isaksson, Mats; Barregaard, Lars

    2008-01-01

    Gamma dose rate measurements were performed in one urban and one rural area using thermoluminescence dosimeters (TLD) worn by 46 participants and placed in their dwellings. The personal effective dose rates were 0.096±0.019(1 SD) and 0.092±0.016(1 SD)μSv/h in the urban and rural area, respectively. The corresponding dose rates in the dwellings were 0.11±0.042(1 SD) and 0.091±0.026(1 SD)μSv/h. However, the differences between the areas were not significant. The values were higher in buildings made of concrete than of wood and higher in apartments than in detached houses. Also, 222 Rn measurements were performed in each dwelling, which showed no correlation with the gamma dose rates in the dwellings

  8. Extremity doses to interventional radiologists

    International Nuclear Information System (INIS)

    Wihtby, M.; Martin, C. J.

    2002-01-01

    Radiologists performing interventional procedures are often required to stand close to the patient's side when carrying out manipulations under fluoroscopic control. This can result in their extremities receiving a high radiation dose, due to scattered radiation. These doses are sometimes high enough to warrant that the radiologist in question be designated a classified radiation worker. Classification in the UK is a result of any worker receiving or likely to receive in the course of their duties in excess of 3/10ths of any annual dose limit (500mSv to extremities, skin). The doses to the legs of radiologists have received less attention than those to the hands, however the doses may be high, due to the proximity of the legs and feet to scattered radiation. The legs can be exposed to a relatively high level of scattered radiation as the radiation in produced from scatter of the un attenuated beam from the bottom of the patient couch. The routine monitoring of extremity doses in interventional radiology is difficult due to several factors. Firstly a wide range of interventional procedures in undertaken in every radiology department, and these procedures require many different techniques, equipment and skills. This means that the position the radiologist adopts in relation to scattering medium and therefore their exposure, depends heavily on the type of procedure. As the hands which manipulate the catheters within the patient are often located close to the patients side and to the area under irradiation, the distribution of dose across the hands can be variable, with very high localised doses, making routine monitoring difficult. The purpose of this study was to determine the magnitude and distribution of dose to the hands and legs of interventional radiologists carrying out a wide range of both diagnostic and therapeutic interventional procedures. To ascertain the most effective method of monitoring the highest dose in accordance with the Basic safety standards

  9. Dose Distribution of Gamma Irradiators

    International Nuclear Information System (INIS)

    Park, Seung Woo; Shin, Sang Hun; Son, Ki Hong; Lee, Chang Yeol; Kim, Kum Bae; Jung, Hai Jo; Ji, Young Hoon

    2010-01-01

    Gamma irradiator using Cs-137 have been widely utilized to the irradiation of cell, blood, and animal, and the dose measurement and education. The Gamma cell 3000 Elan (Nordion International, Kanata, Ontario, Canada) irradiator was installed in 2003 with Cs-137 and dose rate of 3.2 Gy/min. And the BioBeam 8000 (Gamma-Service Medical GmbH, Leipzig, Germany) irradiator was installed in 2008 with Cs-137 and dose rate of 3.5 Gy/min. Our purpose was to evaluate the practical dosimetric problems associated with inhomogeneous dose distribution within the irradiated volume in open air state using glass dosimeter and Gafchromic EBT film dosimeter for routine Gamma irradiator dosimetry applications at the KIRAMS and the measurements were compared with each other. In addition, an user guideline for useful utilization of the device based on practical dosimetry will be prepared. The measurement results of uniformity of delivered dose within the device showed variation more than 14% between middle point and the lowest position at central axis. Therefore, to maintain dose variation within 10%, the criteria of useful dose distribution, for research radiation effects, the irradiated specimen located at central axis of the container should be placed within 30 mm from top and bottom surface, respectively. In addition, for measurements using the film, the variations of dose distribution were more then 50% for the case of less than 10 second irradiation, mostly within 20% for the case of more than 20 second irradiation, respectively. Therefore, the irradiation experiments using the BioBeam 8000 irradiator are recommended to be used for specimen required at least more than 20 second irradiation time.

  10. Calculating radiation exposure and dose

    International Nuclear Information System (INIS)

    Hondros, J.

    1987-01-01

    This paper discusses the methods and procedures used to calculate the radiation exposures and radiation doses to designated employees of the Olympic Dam Project. Each of the three major exposure pathways are examined. These are: gamma irradiation, radon daughter inhalation and radioactive dust inhalation. A further section presents ICRP methodology for combining individual pathway exposures to give a total dose figure. Computer programs used for calculations and data storage are also presented briefly

  11. Dose assessment at Bikini Atoll

    International Nuclear Information System (INIS)

    Robison, W.L.; Phillips, W.A.; Colsher, C.S.

    1977-01-01

    Bikini Atoll is one of two sites in the northern Marshall Islands that was used by the United States as testing grounds for the nuclear weapons program from 1946 to 1958. In 1969 a general cleanup began at Bikini Atoll. Subsistence crops, coconut and Pandanus fruit, were planted on Bikini and Eneu Islands, and housing was constructed on Bikini Island. A second phase of housing was planned for the interior of Bikini Island. Preliminary data indicated that external gamma doses in the interior of the island might be higher than in other parts of the island. Therefore, to select a second site for housing on the island with minimum external exposure, a survey of Bikini Atoll was conducted in June 1975. External gamma measurements were made on Bikini and Eneu Islands, and soil and vegetations samples collected to evaluate the potential doses via terrestrial food chains and inhalation. Estimates of potential dose via the marine food chain were based upon data collected on previous trips to the atoll. The terrestrial pathway contributes the greater percentage, external gamma exposure contributes the next highest, and inhalation and marine pathways contribute minor fractions of the total whole body and bone marrow doses. The radionuclides contributing the major fraction of the dose are 90 Sr and 137 Cs. All living patterns involving Bikini Island exceed federal guidelines for 30-yr population doses. The Eneu Island living pattern leads to doses that are slightly less than federal guidelines. All patterns evaluated for Bikini Atoll lead to higher doses than those on the southern islands at Enewetak Atoll

  12. Personnel external dose monitoring system

    International Nuclear Information System (INIS)

    Zhao Hengyuan

    1989-01-01

    The status and trend of personnel external dose monitoring system are introduced briefly. Their characteristics, functions and TLD bedges of some commercially available automatic TLD system, including UD-710A (Matsushita, Japan), Harshaw-2271, 2276 (Harshaw, USA), Harshaw-8000 (Harshaw/Filtrol), Studsvik-1313 (Sweden) and Pitman-800 (UK) were depicted in detail. Finally, personnel dose management and record keeping system were presented and two examples were given

  13. Weldon Spring historical dose estimate

    International Nuclear Information System (INIS)

    Meshkov, N.; Benioff, P.; Wang, J.; Yuan, Y.

    1986-07-01

    This study was conducted to determine the estimated radiation doses that individuals in five nearby population groups and the general population in the surrounding area may have received as a consequence of activities at a uranium processing plant in Weldon Spring, Missouri. The study is retrospective and encompasses plant operations (1957-1966), cleanup (1967-1969), and maintenance (1969-1982). The dose estimates for members of the nearby population groups are as follows. Of the three periods considered, the largest doses to the general population in the surrounding area would have occurred during the plant operations period (1957-1966). Dose estimates for the cleanup (1967-1969) and maintenance (1969-1982) periods are negligible in comparison. Based on the monitoring data, if there was a person residing continually in a dwelling 1.2 km (0.75 mi) north of the plant, this person is estimated to have received an average of about 96 mrem/yr (ranging from 50 to 160 mrem/yr) above background during plant operations, whereas the dose to a nearby resident during later years is estimated to have been about 0.4 mrem/yr during cleanup and about 0.2 mrem/yr during the maintenance period. These values may be compared with the background dose in Missouri of 120 mrem/yr

  14. Technical basis for dose reconstruction

    International Nuclear Information System (INIS)

    Anspaugh, L.R.

    1996-01-01

    The purpose of this paper is to consider two general topics: Technical considerations of why dose-reconstruction studies should or should not be performed and methods of dose reconstruction. The first topic is of general and growing interest as the number of dose-reconstruction studies increases, and one asks the question whether it is necessary to perform a dose reconstruction for virtually every site at which, for example, the Department of Energy (DOE) has operated a nuclear-related facility. And there is the broader question of how one might logically draw the line at performing or not performing dose-reconstruction (radiological and chemical) studies for virtually every industrial complex in the entire country. The second question is also of general interest. There is no single correct way to perform a dose-reconstruction study, and it is important not to follow blindly a single method to the point that cheaper, faster, more accurate, and more transparent methods might not be developed and applied. 90 refs., 4 tabs

  15. Weldon Spring historical dose estimate

    Energy Technology Data Exchange (ETDEWEB)

    Meshkov, N.; Benioff, P.; Wang, J.; Yuan, Y.

    1986-07-01

    This study was conducted to determine the estimated radiation doses that individuals in five nearby population groups and the general population in the surrounding area may have received as a consequence of activities at a uranium processing plant in Weldon Spring, Missouri. The study is retrospective and encompasses plant operations (1957-1966), cleanup (1967-1969), and maintenance (1969-1982). The dose estimates for members of the nearby population groups are as follows. Of the three periods considered, the largest doses to the general population in the surrounding area would have occurred during the plant operations period (1957-1966). Dose estimates for the cleanup (1967-1969) and maintenance (1969-1982) periods are negligible in comparison. Based on the monitoring data, if there was a person residing continually in a dwelling 1.2 km (0.75 mi) north of the plant, this person is estimated to have received an average of about 96 mrem/yr (ranging from 50 to 160 mrem/yr) above background during plant operations, whereas the dose to a nearby resident during later years is estimated to have been about 0.4 mrem/yr during cleanup and about 0.2 mrem/yr during the maintenance period. These values may be compared with the background dose in Missouri of 120 mrem/yr.

  16. Technical basis for dose reconstruction

    International Nuclear Information System (INIS)

    Anspaugh, L.R.

    1996-01-01

    The purpose of this paper is to consider two general topics: technical considerations of why dose-reconstruction studies should or should not be performed and methods of dose reconstruction. The first topic is of general and growing interest as the number of dose-reconstruction studies increases, and one asks the question whether it is necessary to perform a dose reconstruction for virtually every site at which, for example, the Department of Energy (DOE) has operated a nuclear-related facility. And there is the broader question of how one might logically draw the line at performing or not performing dose-reconstruction (radiological and chemical) studies for virtually every industrial complex in the entire country. The second question is also of general interest. There is no single correct way to perform a dose-reconstruction study, and it is important not to follow blindly a single method to the point that cheaper, faster, more accurate, and more transparent methods might not be developed and applied

  17. Dose assessments for SFR 1

    International Nuclear Information System (INIS)

    Bergstroem, Ulla; Avila, Rodolfo; Ekstroem, Per-Anders; Cruz, Idalmis de la

    2008-05-01

    Following a review by the Swedish regulatory authorities of the safety analysis of the SFR 1 disposal facility for low and intermediate level waste, SKB has prepared an updated safety analysis, SAR-08. This report presents estimations of annual doses to the most exposed groups from potential radionuclide releases from the SFR 1 repository for a number of calculation cases, selected using a systematic approach for identifying relevant scenarios for the safety analysis. The dose estimates can be used for demonstrating that the long term safety of the repository is in compliance with the regulatory requirements. In particular, the mean values of the annual doses can be used to estimate the expected risks to the most exposed individuals, which can then be compared with the regulatory risk criteria for human health. The conversion from doses to risks is performed in the main report. For one scenario however, where the effects of an earthquake taking place close to the repository are analysed, risk calculations are presented in this report. In addition, prediction of concentrations of radionuclides in environmental media, such as water and soil, are compared with concentration limits suggested by the Erica-project as a base for estimating potential effects on the environment. The assessment of the impact on non-human biota showed that the potential impact is negligible. Committed collective dose for an integration period of 10,000 years for releases occurring during the first thousand years after closure are also calculated. The collective dose commitment was estimated to be 8 manSv. The dose calculations were carried out for a period of 100,000 years, which was sufficient to observe peak doses in all scenarios considered. Releases to the landscape and to a well were considered. The peaks of the mean annual doses from releases to the landscape are associated with C-14 releases to a future lake around year 5,000 AD. In the case of releases to a well, the peak annual doses

  18. Dose assessments for SFR 1

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, Ulla (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Avila, Rodolfo; Ekstroem, Per-Anders; Cruz, Idalmis de la (Facilia AB, Bromma (Sweden))

    2008-06-15

    Following a review by the Swedish regulatory authorities of the safety analysis of the SFR 1 disposal facility for low and intermediate level waste, SKB has prepared an updated safety analysis, SAR-08. This report presents estimations of annual doses to the most exposed groups from potential radionuclide releases from the SFR 1 repository for a number of calculation cases, selected using a systematic approach for identifying relevant scenarios for the safety analysis. The dose estimates can be used for demonstrating that the long term safety of the repository is in compliance with the regulatory requirements. In particular, the mean values of the annual doses can be used to estimate the expected risks to the most exposed individuals, which can then be compared with the regulatory risk criteria for human health. The conversion from doses to risks is performed in the main report. For one scenario however, where the effects of an earthquake taking place close to the repository are analysed, risk calculations are presented in this report. In addition, prediction of concentrations of radionuclides in environmental media, such as water and soil, are compared with concentration limits suggested by the Erica-project as a base for estimating potential effects on the environment. The assessment of the impact on non-human biota showed that the potential impact is negligible. Committed collective dose for an integration period of 10,000 years for releases occurring during the first thousand years after closure are also calculated. The collective dose commitment was estimated to be 8 manSv. The dose calculations were carried out for a period of 100,000 years, which was sufficient to observe peak doses in all scenarios considered. Releases to the landscape and to a well were considered. The peaks of the mean annual doses from releases to the landscape are associated with C-14 releases to a future lake around year 5,000 AD. In the case of releases to a well, the peak annual doses

  19. Radiation dose monitoring in the clinical routine

    Energy Technology Data Exchange (ETDEWEB)

    Guberina, Nika [UK Essen (Germany). Radiology

    2017-04-15

    Here we describe the first clinical experiences regarding the use of an automated radiation dose management software to monitor the radiation dose of patients during routine examinations. Many software solutions for monitoring radiation dose have emerged in the last decade. The continuous progress in radiological techniques, new scan features, scanner generations and protocols are the primary challenge for radiation dose monitoring software systems. To simulate valid dose calculations, radiation dose monitoring systems have to follow current trends and stay constantly up-to-date. The dose management software is connected to all devices at our institute and conducts automatic data acquisition and radiation dose calculation. The system incorporates 18 virtual phantoms based on the Cristy phantom family, estimating doses in newborns to adults. Dose calculation relies on a Monte Carlo simulation engine. Our first practical experiences demonstrate that the software is capable of dose estimation in the clinical routine. Its implementation and use have some limitations that can be overcome. The software is promising and allows assessment of radiation doses, like organ and effective doses according to ICRP 60 and ICRP 103, patient radiation dose history and cumulative radiation doses. Furthermore, we are able to determine local diagnostic reference doses. The radiation dose monitoring software systems can facilitate networking between hospitals and radiological departments, thus refining radiation doses and implementing reference doses at substantially lower levels.

  20. Low-dose dental CT

    International Nuclear Information System (INIS)

    Rustemeyer, P.; Eich, H.T.; John-Mikolajewski, V.; Mueller, R.D.

    1999-01-01

    Purpose: The intention of this study was to reduce patient dose during dental CT in the planning for osseointegrated implants. Methods and Materials: Dental CTs were performed with a spiral CT (Somatom Plus 4, Siemens) and a dental software package. Use of the usual dental CT technique (120 kVp; 165 mA, 1 s rotation time, 165 mAs; pitch factor 1) was compared with a new protocol (120 kVp; 50 mA; 0.7 s rotation time; 35 mAs; pitch factor 2) which delivered the best image quality at the lowest possible radiation dose, as tested in a preceding study. Image quality was analysed using a human anatomic head preparation. Four radiologists analysed the images independently. A Wilcoxon rank pair-test was used for statistic evaluation. The doses to the thyroid gland, the active bone marrow, the salivary glands, and the eye lens were determined in a tissue-equivalent phantom (Alderson-Rando Phantom) with lithium fluoride thermoluminescent dosimeters at the appropriate locations. Results: By mAs reduction from 165 to 35 and using a pitch factor of 2, the radiation dose could be reduced by a factor of nine (max.) (e.g., the bone marrow dose could be reduced from 23.6 mSv to 2.9 mSv, eye lens from 0.5 mSv to 0.3 mSv, thyroid gland from 2.5 mSv to 0.5 mSv, parotid glands from 2.3 mSv to 0.4 mSv). The dose reduction did not lead to an actual loss of image quality or diagnostic information. Conclusion: A considerable dose reduction without loss of diagnostic information is achievable in dental CT. Dosereducing examination protocols like the one presented may further expand the use of preoperative dental CT. (orig.) [de

  1. Patient and staff doses in interventional neuroradiology

    International Nuclear Information System (INIS)

    Bor, D.; Cekirge, S.; Tuerkay, T.; Turan, O.; Guelay, M.; Oenal, E.; Cil, B.

    2005-01-01

    Radiation doses for interventional examinations are generally high and therefore necessitate dose monitoring for patients and staff. Relating the staff dose to a patient dose index, such as dose-area product (DAP), could be quite useful for dose comparisons. In this study, DAP and skin doses of 57 patients, who underwent neuro-interventional examinations, were measured simultaneously with staff doses. Although skin doses were comparable with the literature data, higher DAP values of 215 and 188.6 Gy cm 2 were measured for the therapeutical cerebral and carotid examinations, respectively, owing to the use of biplane system and complexity of the procedure. Mean staff doses for eye, finger and thyroid were measured as 80.6, 77.6 and 28.8 μGy per procedure. The mean effective dose per procedure for the radiologists was 32 μSv. In order to allow better comparisons to be made, DAP normalised doses were also presented. (authors)

  2. Repair and dose-response at low doses

    International Nuclear Information System (INIS)

    Totter, J.R.; Weinberg, A.M.

    1977-04-01

    The DNA of each individual is subject to formation of some 2-4 x 10 14 ion pairs during the first 30 years of life from background radiation. If a single hit is sufficient to cause cancer, as is implicit in the linear, no-threshold theories, it is unclear why all individuals do not succumb to cancer, unless repair mechanisms operate to remove the damage. We describe a simple model in which the exposed population displays a distribution of repair thresholds. The dose-response at low dose is shown to depend on the shape of the threshold distribution at low thresholds. If the probability of zero threshold is zero, the response at low dose is quadratic. The model is used to resolve a longstanding discrepancy between observed incidence of leukemia at Nagasaki and the predictions of the usual linear hypothesis

  3. Notes on the effect of dose uncertainty

    International Nuclear Information System (INIS)

    Morris, M.D.

    1987-01-01

    The apparent dose-response relationship between amount of exposure to acute radiation and level of mortality in humans is affected by uncertainties in the dose values. It is apparent that one of the greatest concerns regarding the human data from Hiroshima and Nagasaki is the unexpectedly shallow slope of the dose response curve. This may be partially explained by uncertainty in the dose estimates. Some potential effects of dose uncertainty on the apparent dose-response relationship are demonstrated

  4. Trends in population dose and examples of occupational dose reduction

    International Nuclear Information System (INIS)

    Shaw, K.B.; Hughes, J.S.; McDonough, L.; Gelder, R.

    1989-01-01

    The recent review by NRPB of the exposure of the UK population shows the average annual dose to the population from all sources of radiation to be 2.5 mSv(1). Natural radiation gives rise to 87% of this with radon daughters accounting for the largest single contribution of 1.2 mSv. Medical irradiation remains the most significant contributor to the dose from man-made sources: the current estimate for all diagnostic uses is 0.3 mSv per annum. (author)

  5. Peripheral doses from pediatric IMRT

    International Nuclear Information System (INIS)

    Klein, Eric E.; Maserang, Beth; Wood, Roy; Mansur, David

    2006-01-01

    Peripheral dose (PD) data exist for conventional fields (≥10 cm) and intensity-modulated radiotherapy (IMRT) delivery to standard adult-sized phantoms. Pediatric peripheral dose reports are limited to conventional therapy and are model based. Our goal was to ascertain whether data acquired from full phantom studies and/or pediatric models, with IMRT treatment times, could predict Organ at Risk (OAR) dose for pediatric IMRT. As monitor units (MUs) are greater for IMRT, it is expected IMRT PD will be higher; potentially compounded by decreased patient size (absorption). Baseline slab phantom peripheral dose measurements were conducted for very small field sizes (from 2 to 10 cm). Data were collected at distances ranging from 5 to 72 cm away from the field edges. Collimation was either with the collimating jaws or the multileaf collimator (MLC) oriented either perpendicular or along the peripheral dose measurement plane. For the clinical tests, five patients with intracranial or base of skull lesions were chosen. IMRT and conventional three-dimensional (3D) plans for the same patient/target/dose (180 cGy), were optimized without limitation to the number of fields or wedge use. Six MV, 120-leaf MLC Varian axial beams were used. A phantom mimicking a 3-year-old was configured per Center for Disease Control data. Micro (0.125 cc) and cylindrical (0.6 cc) ionization chambers were appropriated for the thyroid, breast, ovaries, and testes. The PD was recorded by electrometers set to the 10 -10 scale. Each system set was uniquely calibrated. For the slab phantom studies, close peripheral points were found to have a higher dose for low energy and larger field size and when MLC was not deployed. For points more distant from the field edge, the PD was higher for high-energy beams. MLC orientation was found to be inconsequential for the small fields tested. The thyroid dose was lower for IMRT delivery than that predicted for conventional (ratio of IMRT/cnventional ranged from

  6. Tissue dose in thorotrast patients

    International Nuclear Information System (INIS)

    Kaul, A.; Noffz, W.

    1978-01-01

    Absorbed doses to the liver, spleen, red marrow, lungs, kidneys, and to various parts of bone tissue were calculated for long-term burdens of intravascularly injected Thorotrast. The estimates were performed for typical injection levels of 10, 30, 50 and 100 ml, based upon best estimates of 232 Th tissue distribution, and steady state activity ratios between the subsequent daughters. Correcting for the α-particle self absorption within Thorotrast aggregates, the mean α-dose to a standard 70-kg man at 30 yr after the injection 0f 25 ml of Thorotrast is 750 rad to the liver, 2100 rad to the spleen, 270 rad to the red marrow, 60-620 rad in various parts of the lung, and 13 rad to the kidneys. Dose rates to various parts of bone tissue (bone surface, compact, and cancellous bone) were estimated by applying the ICRP model on alkaline earth metabolism to the continuous translocation of thorium daughters to bone and to the formation of thorium daughters by decay within bone tissue. The average dose to calcified bone from translocated 224 Ra with its daughters is 18 rad at 30 yr after the injection of 25 ml of Thorotrast. Considering the Spiess-Mays risk coefficient of 0.9-1.7% bone sarcoma/ 100 rad of average skeletal dose from 224 Ra and its daughters, the induction of 1.6-3.1 bone sarcomas per 1000 Thorotrast patients is predicted. (author)

  7. AGING FACILITY WORKER DOSE ASSESSMENT

    International Nuclear Information System (INIS)

    R.L. Thacker

    2005-01-01

    The purpose of this calculation is to estimate radiation doses received by personnel working in the Aging Facility performing operations to transfer aging casks to the aging pads for thermal and logistical management, stage empty aging casks, and retrieve aging casks from the aging pads for further processing in other site facilities. Doses received by workers due to aging cask surveillance and maintenance operations are also included. The specific scope of work contained in this calculation covers both collective doses and individual worker group doses on an annual basis, and includes the contributions due to external and internal radiation from normal operation. There are no Category 1 event sequences associated with the Aging Facility (BSC 2004 [DIRS 167268], Section 7.2.1). The results of this calculation will be used to support the design of the Aging Facility and to provide occupational dose estimates for the License Application. The calculations contained in this document were developed by Environmental and Nuclear Engineering of the Design and Engineering Organization and are intended solely for the use of the Design and Engineering Organization in its work regarding facility operation. Yucca Mountain Project personnel from the Environmental and Nuclear Engineering should be consulted before use of the calculations for purposes other than those stated herein or use by individuals other than authorized personnel in Environmental and Nuclear Engineering

  8. Radiation Dose from Reentrant Electrons

    Science.gov (United States)

    Badhwar, G.D.; Cleghorn, T. E.; Watts, J.

    2003-01-01

    In estimating the crew exposures during an EVA, the contribution of reentrant electrons has always been neglected. Although the flux of these electrons is small compared to the flux of trapped electrons, their energy spectrum extends to several GeV compared to about 7 MeV for trapped electrons. This is also true of splash electrons. Using the measured reentrant electron energy spectra, it is shown that the dose contribution of these electrons to the blood forming organs (BFO) is more than 10 times greater than that from the trapped electrons. The calculations also show that the dose-depth response is a very slowly changing function of depth, and thus adding reasonable amounts of additional shielding would not significantly lower the dose to BFO.

  9. Dose reconstruction using mobile phones

    International Nuclear Information System (INIS)

    Beerten, K.; Reekmans, F.; Schroeyers, W.; Lievens, L.; Vanhavere, F.

    2011-01-01

    Electronic components inside mobile phones are regarded as useful tools for accident and retrospective dosimetry using optically stimulated luminescence (OSL) and thermoluminescence. Components inside the devices with suitable properties for luminescence dosimetry include, amongst others, ceramic substrates in resistors, capacitors, transistors and antenna switches. Checking the performance of such devices in dosimetric experiments is a crucial step towards developing a reliable dosimetry system for emergency situations using personal belongings. Here, the results of dose assessment experiments using irradiated mobile phones are reported. It will be shown that simple regenerative dose estimates, derived from various types of components removed from different mobile phone models, are consistent with the given dose, after applying an average fading correction factor. (authors)

  10. Parameterization of solar flare dose

    International Nuclear Information System (INIS)

    Lamarche, A.H.; Poston, J.W.

    1996-01-01

    A critical aspect of missions to the moon or Mars will be the safety and health of the crew. Radiation in space is a hazard for astronauts, especially high-energy radiation following certain types of solar flares. A solar flare event can be very dangerous if astronauts are not adequately shielded because flares can deliver a very high dose in a short period of time. The goal of this research was to parameterize solar flare dose as a function of time to see if it was possible to predict solar flare occurrence, thus providing a warning time. This would allow astronauts to take corrective action and avoid receiving a dose greater than the recommended limit set by the National Council on Radiation Protection and Measurements (NCRP)

  11. Consultative exercise on dose assessments.

    Science.gov (United States)

    Bridges, B A; Parker, T; Simmonds, J R; Sumner, D

    2001-06-01

    A summary is given of a meeting held at Sussex University, UK, in October 2000, which allowed the exchange of ideas on methods of assessment of dose to the public arising from potential authorised radioactive discharges from nuclear sites in the UK. Representatives of groups with an interest in dose assessments were invited, and hence the meeting was called the Consultative Exercise on Dose Assessments (CEDA). Although initiated and funded by the Food Standards Agency, its organisation, and the writing of the report, were overseen by an independent Chairman and Steering Group. The report contains recommendations for improvement in co-ordination between different agencies involved in assessments, on method development and on the presentation of data on assessments. These have been prepared by the Steering Group, and will be taken forward by the Food Standards Agency and other agencies in the UK. The recommendations are included in this memorandum.

  12. The Effect of Low‑Dose Ketamine (Preemptive Dose) on ...

    African Journals Online (AJOL)

    Average dosage of diclofenac suppository and mean time for taking the first dosage of opioids have not statistical difference too (respectively; P = 0.76, P = 0.87). Average dose of pethidine was lesser than placebo statistically. It means, the case group did not take pethidine but this amount was 6 (20%) in the control one (P ...

  13. Carcinogenesis in mice after low doses and dose rates

    International Nuclear Information System (INIS)

    Ullrich, R.L.

    1979-01-01

    The results from the experimental systems reported here indicate that the dose-response curves for tumor induction in various tissues cannot be described by a single model. Furthermore, although the understanding of the mechanisms involved in different systems is incomplete, it is clear that very different mechanisms for induction are involved. For some tumors the mechanism of carcinogenesis may be mainly a result of direct effects on the target cell, perhaps involving one or more mutations. While induction may occur, in many instances, through such direct effects, the eventual expression of the tumor can be influenced by a variety of host factors including endocrine status, competence of the immune system, and kinetics of target and interacting cell populations. In other tumors, indirect effects may play a major role in the initiation or expression of tumors. Some of the hormone-modulated tumors would fall into this class. Despite the complexities of the experimental systems and the lack of understanding of the types of mechanisms involved, in nearly every example the tumorigenic effectiveness per rad of low-LET radiation tends to decrease with decreasing dose rate. For some tumor types the differences may be small or may appear only with very low dose rates, while for others the dose-rate effects may be large

  14. Stereotactic intracranial radiotherapy: Dose prescription

    International Nuclear Information System (INIS)

    Schlienger, M.; Lartigau, E.; Nataf, F.; Mornex, F.; Latorzeff, I.; Lisbona, A.; Mahe, M.

    2012-01-01

    The aim of this article was the study of the successive steps permitting the prescription of dose in stereotactic intracranial radiotherapy, which includes radiosurgery and fractionated stereotactic radiotherapy. The successive steps studied are: the choice of stereotactic intracranial radiotherapy among the therapeutic options, based on curative or palliative treatment intent, then the selection of lesions according to size/volume, pathological type and their number permitting the choice between radiosurgery or fractionated stereotactic radiotherapy, which have the same methodological basis. Clinical experience has determined the level of dose to treat the lesions and limit the irradiation of healthy adjacent tissues and organs at risk structures. The last step is the optimization of the different parameters to obtain a safe compromise between the lesion dose and healthy adjacent structures. Study of dose-volume histograms, coverage indices and 3D imaging permit the optimization of irradiation. For lesions close to or included in a critical area, the prescribed dose is planned using the inverse planing method. Implementation of the successively described steps is mandatory to insure the prescription of an optimized dose. The whole procedure is based on the delineation of the lesion and adjacent healthy tissues. There are sometimes difficulties to assess the delineation and the volume of the target, however improvement of local control rates and reduction of secondary effects are the proof that the totality of the successive procedures are progressively improved. In practice, stereotactic intracranial radiotherapy is a continually improved treatment method, which constantly benefits from improvements in the choice of indications, imaging, techniques of irradiation, planing/optimization methodology and irradiation technique and from data collected from prolonged follow-up. (authors)

  15. Performance standard for dose Calibrator

    CERN Document Server

    Darmawati, S

    2002-01-01

    Dose calibrator is an instrument used in hospitals to determine the activity of radionuclide for nuclear medicine purposes. International Electrotechnical Commission (IEC) has published IEC 1303:1994 standard that can be used as guidance to test the performance of the instrument. This paper briefly describes content of the document,as well as explains the assessment that had been carried out to test the instrument accuracy in Indonesia through intercomparison measurement.Its is suggested that hospitals acquire a medical physicist to perform the test for its dose calibrator. The need for performance standard in the form of Indonesia Standard is also touched.

  16. Dose budget for exposure control

    International Nuclear Information System (INIS)

    Nair, P.S.

    1999-01-01

    Dose budget is an important management tool to effectively control the collective dose incurred in a nuclear facility. The budget represents a set of yardsticks or guidelines for use in controlling the internal activities, involving radiation exposure in the organisation. The management, through budget can evaluate the radiation protection performance at every level of the organisation where a number of independent functional groups work on routine and non-routine jobs. The discrepancy between the plan and the actual performance is high lighted through the budgets. The organisation may have to change the course of its operation in a particular area or revise its plan with due focus on appropriate protective measures. (author)

  17. Natural radiation dose to Gammarus

    International Nuclear Information System (INIS)

    Paschoa, A.S.; Wrenn, M.E.; Eisenbud, M.

    1975-01-01

    The natural radiation dose rate to whole body and components of the Gammarus species (i.e., G. Tigrinus, G. Fasciatus and G. Daiberi) that occurs in the Hudson River is evaluated and the results compared with the upper limits of dose rates from man made sources to the whole body of the organisms. Methods were developed to study the distribution of alpha emitters from 226 Ra plus daughter products in Gammarus using autoradiographic techniques, taking into account the amount of radon that escapes from the organisms. This methodology may be adapted to study the distribution of alpha emitters in contaminated tissues of plants and animals

  18. Confectionery-based dose forms.

    Science.gov (United States)

    Tangso, Kristian J; Ho, Quy Phuong; Boyd, Ben J

    2015-01-01

    Conventional dosage forms such as tablets, capsules and syrups are prescribed in the normal course of practice. However, concerns about patient preferences and market demands have given rise to the exploration of novel unconventional dosage forms. Among these, confectionery-based dose forms have strong potential to overcome compliance problems. This report will review the availability of these unconventional dose forms used in treating the oral cavity and for systemic drug delivery, with a focus on medicated chewing gums, medicated lollipops, and oral bioadhesive devices. The aim is to stimulate increased interest in the opportunities for innovative new products that are available to formulators in this field, particularly for atypical patient populations.

  19. Statistical and low dose response

    International Nuclear Information System (INIS)

    Thorson, M.R.; Endres, G.W.R.

    1981-01-01

    The low dose response and the lower limit of detection of the Hanford dosimeter depend upon may factors, including the energy of the radiation, whether the exposure is to be a single radiation or mixed fields, annealing cycles, environmental factors, and how well various batches of TLD materials are matched in the system. A careful statistical study and sensitivity analysis were performed to determine how these factors influence the response of the dosimeter system. Estimates have been included in this study of the standard deviation of calculated dose for various mixed field exposures from 0 to 1000 mrem

  20. Comparison of Nordic dose models

    International Nuclear Information System (INIS)

    Thykier-Nielsen, S.

    1978-04-01

    A comparison is made between the models used in the four Nordic countries, Finland, Norway, Sweden and Denmark, for calculation of concentrations and doses from releases of radioactive material to the atmosphere. The comparison is limited to the near-zone models, i.e. the models for calculation of concentrations and doses within 50 km from the release point, and it comprises the following types of calculation: a. Concentrations of airborne material, b. External gamma doses from a plume, c. External gamma doses from radioactive material deposited on the ground. All models are based on the gaussian dispersion model (the gaussian plume model). Unit releases of specific isotopes under specific meteorological conditions are assumed. On the basis of the calculation results from the models, it is concluded that there are no essential differences. The difference between the calculation results only exceeds a factor of 3 in special cases. It thus lies within the known limits of uncertainty for the gaussian plume model. (author)

  1. The cost of occupational dose

    International Nuclear Information System (INIS)

    Fleishman, A.B.; Clark, M.J.

    1980-01-01

    The optimization of radiological protection will routinely involve the balancing of public and occupational exposure, particularly within the nuclear fuel cycle. For example the reduction of public exposure from an effluent stream could lead to increases in occupational exposure from treatment, storage and disposal operations. A methodology is propased for the estimation of the cost of occupational exposure in the UK (Pound man-Sv -1 ) based on valuations of changes in risk. A variable value for the cost of the occupational man-Sv is obtained depending on per caput dose levels. The values at particular per caput dose levels are different for occupational workers and the general public, because of different demography and assumptions on risk perception and aversion. They are however approximately the same when the per caput doses are expressed as percentages of the dose limits for workers and the general public respectively. An example of the application of the derived cost of the occupational man-Sv to an optimisation problem is given. (author)

  2. Dose response relationship and Alara

    International Nuclear Information System (INIS)

    Hubert, P.

    1986-09-01

    In this paper, it will be shown how dose-response relationships allow to give quantitative figures for the detriment of irradiation. At this stage, the detriment is expressed directly as a certain number of health effects, whose valuation is not dealt with here. The present tools for quantifying, their weaknesses and their strenghts, and their scientific basis will be developed

  3. Model of organ dose combination

    International Nuclear Information System (INIS)

    Valley, J.-F.; Lerch, P.

    1977-01-01

    The ICRP recommendations are based on the limitation of the dose to each organ. In the application and for a unique source the critical organ concept allows to limit the calculation and represents the irradiation status of an individuum. When several sources of radiation are involved the derivation of the dose contribution of each source to each organ is necessary. In order to represent the irradiation status a new parameter is to be defined. Propositions have been made by some authors, in particular by Jacobi introducing at this level biological parameters like the incidence rate of detriment and its severity. The new concept is certainly richer than a simple dose notion. However, in the actual situation of knowledge about radiation effects an intermediate parameter, using only physical concepts and the maximum permissible doses to the organs, seems more appropriate. The model, which is a generalization of the critical organ concept and shall be extended in the future to take the biological effects into account, will be presented [fr

  4. Dose reduction - the radiologist's view

    International Nuclear Information System (INIS)

    Russell, J.G.B.

    1984-01-01

    The magnitude of the exposure to ionising radiation dominates radiological practice in only three fields, i.e. foetal radiography, mammography and computed tomography. The balance between risk and benefit are briefly examined. The types of hazard considered are carcinogenesis, genetic injury and organogenesis. Ways of achieving a reduction of the dose to the patient are also briefly discussed. (U.K.)

  5. Compliance with public dose limits

    International Nuclear Information System (INIS)

    Mason, G.C.

    1991-01-01

    Radiation, in various forms, is ubiquitous in the environment. Natural background radiation leads to an average radiation exposure for the general population of about 2 mSv per year. The mining and milling of radioactive ores - uranium and mineral sands - may cause a small increase in radiation exposure for some members of the public. Because any such increment in exposure is small compared with a natural exposure that is variable and difficult to quantify accurately, it is not easy to determine what proportion of the total dose received by a member of the public can be attributed to mining and milling activities. Consequently, because public dose limits apply and to those doses caused by human activity, such as mining and milling, the task of demonstrating compliance can be hampered by uncertainty. Some strategies for handling this situation are discussed. While the discussion concentrates on public dose limits, much of it may also be applicable, or adaptable, to occupational exposure. 4 refs., 2 figs

  6. Dose modeling in ultraviolet phototherapy

    International Nuclear Information System (INIS)

    Grimes, David Robert; Robbins, Chris; O'Hare, Neil John

    2010-01-01

    Purpose: Ultraviolet phototherapy is widely used in the treatment of numerous skin conditions. This treatment is well established and largely beneficial to patients on both physical and psychological levels; however, overexposure to ultraviolet radiation (UVR) can have detrimental effects, such as erythemal responses and ocular damage in addition to the potentially carcinogenic nature of UVR. For these reasons, it is essential to control and quantify the radiation dose incident upon the patient to ensure that it is both biologically effective and has the minimal possible impact on the surrounding unaffected tissue. Methods: To date, there has been little work on dose modeling, and the output of artificial UVR sources is an area where research has been recommended. This work characterizes these sources by formalizing an approach from first principles and experimentally examining this model. Results: An implementation of a line source model is found to give impressive accuracy and quantifies the output radiation well. Conclusions: This method could potentially serve as a basis for a full computational dose model for quantifying patient dose.

  7. The dose-rate effect

    International Nuclear Information System (INIS)

    Steel, G.G.

    1989-01-01

    This paper presents calculations that illustrate two conclusions; for any particular cell type there will be a critical radius at which tumor control breaks down, and the radius at which this occurs is strongly dependent upon the low-dose-rate radiosensitivity of the cells

  8. Dose limits for ionising radiation

    International Nuclear Information System (INIS)

    Gifford, D.

    1989-01-01

    Dose limits for exposure to ionising radiation are assessed to see if they give sufficient protection both for the occupationally exposed and for the general public. It is concluded that current limits give a level of safety that satisfies the necessary criteria in the light of present knowledge and further reductions would be unlikely to improve standards of safety. (author)

  9. Calculation of dose conversion factors for doses in the fingernails to organ doses at external gamma irradiation in air

    International Nuclear Information System (INIS)

    Khailov, A.M.; Ivannikov, A.I.; Skvortsov, V.G.; Stepanenko, V.F.; Orlenko, S.P.; Flood, A.B.; Williams, B.B.; Swartz, H.M.

    2015-01-01

    Absorbed doses to fingernails and organs were calculated for a set of homogenous external gamma-ray irradiation geometries in air. The doses were obtained by stochastic modeling of the ionizing particle transport (Monte Carlo method) for a mathematical human phantom with arms and hands placed loosely along the sides of the body. The resulting dose conversion factors for absorbed doses in fingernails can be used to assess the dose distribution and magnitude in practical dose reconstruction problems. For purposes of estimating dose in a large population exposed to radiation in order to triage people for treatment of acute radiation syndrome, the calculated data for a range of energies having a width of from 0.05 to 3.5 MeV were used to convert absorbed doses in fingernails to corresponding doses in organs and the whole body as well as the effective dose. Doses were assessed based on assumed rates of radioactive fallout at different time periods following a nuclear explosion. - Highlights: • Elemental composition and density of nails were determined. • MIRD-type mathematical human phantom with arms and hands was created. • Organ doses and doses to nails were calculated for external photon exposure in air. • Effective dose and nail doses values are close for rotational and soil surface exposures.

  10. Dose due to 40K

    International Nuclear Information System (INIS)

    Escareno J, E.; Vega C, H. R.

    2011-10-01

    The dose due to 40 K has been estimated. Potassium is one of the most abundant elements in nature, being approximately 2% of the Earth's crust. Potassium has three isotopes 39 K, 40 K and 41 K, two are stable while 40 K is radioactive with a half life of 1.2x10 9 years; there is 0.0117% 40 K-to-K ratio. Potassium plays an important role in plants, animals and humans growth and reproduction. Due to the fact that K is an essential element for humans, 40 K is the most abundant radioisotope in human body. In order to keep good health conditions K must be intake at daily basis trough food and beverages, however when K in ingested above the requirements produce adverse health effects in persons with renal, cardiac and hypertension problems or suffering diabetes. In 89.3% 40 K decays to 40 C through β-decay, in 10.3% decays through electronic capture and emitting 1.46 MeV γ-ray. K is abundant in soil, construction materials, sand thus γ-rays produced during 40 K decay contribute to external dose. For K in the body practically all 40 K decaying energy is absorbed by the body; thus 40 K contributes to total dose in humans and it is important to evaluate its contribution. In this work a set of 40 K sources were prepared using different amounts of KCl salt, a γ-ray spectrometer with a NaI(Tl) was characterized to standardized the sources in order to evaluate the dose due to 40 K. Using thermoluminescent dosemeters the dose due to 40 K was measured and related to the amount of 40 K γ-ray activity. (Author)

  11. Collective dose, conceptual basis and practical applications

    International Nuclear Information System (INIS)

    Bonka, H.

    1985-01-01

    In the ICRP Publications no. 22(1973) and no. 26(1977), the ICRP recommends that the maximum permissible whole-body dose by kept below the dose limits corresponding to the sum of all effective dose equivalents of the persons concerned, i.e. the collective dose. The effective dose equivalent is recommended by the ICRP for use as a new quantity for evaluating the stochastic radiation dose for individual persons. Examples are given by the author explaining cost-benefit analyses according to ICRP recommendations, especially discussing the definition of optimum local dose limits with regard to shielding design in nuclear installations. (DG) [de

  12. Tank Z-361 dose rate calculations

    International Nuclear Information System (INIS)

    Richard, R.F.

    1998-01-01

    Neutron and gamma ray dose rates were calculated above and around the 6-inch riser of tank Z-361 located at the Plutonium Finishing Plant. Dose rates were also determined off of one side of the tank. The largest dose rate 0.029 mrem/h was a gamma ray dose and occurred 76.2 cm (30 in.) directly above the open riser. All other dose rates were negligible. The ANSI/ANS 1991 flux to dose conversion factor for neutrons and photons were used in this analysis. Dose rates are reported in units of mrem/h with the calculated uncertainty shown within the parentheses

  13. Mixed field dose equivalent measuring instruments

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; McDonald, J.C.; Endres, G.W.R.; Quam, W.

    1985-01-01

    In the past, separate instruments have been used to monitor dose equivalent from neutrons and gamma rays. It has been demonstrated that it is now possible to measure simultaneously neutron and gamma dose with a single instrument, the tissue equivalent proportional counter (TEPC). With appropriate algorithms dose equivalent can also be determined from the TEPC. A simple ''pocket rem meter'' for measuring neutron dose equivalent has already been developed. Improved algorithms for determining dose equivalent for mixed fields are presented. (author)

  14. Organ or tissue doses, effective dose and collective effective dose from X-ray diagnosis, in Japan

    International Nuclear Information System (INIS)

    Murayama, Takashi; Nishizawa, Kanae; Noda, Yutaka; Kumamoto, Yoshikazu; Iwai, Kazuo.

    1996-01-01

    Effective doses and collective effective doses from X-ray diagnostic examinations were calculated on the basis of the frequency of examinations estimated by a nationwide survey and the organ or tissue doses experimentally determined. The average organ or tissue doses were determined with thermoluminescence dosimeters put at various sites of organs or tissues in an adult and a child phantom. Effective doses (effective dose equivalents) were calculated as the sum of the weighted equivalent doses in all the organs or tissues of the body. As the examples of results, the effective doses per radiographic examination were approximately 7 mGy for male, and 9 mGy for female angiocardiography, and about 3 mGy for barium meal. Annual collective effective dose from X-ray diagnostic examinations in 1986 were about 104 x 10 3 person Sv from radiography and 118 x 10 3 person Sv from fluoroscopy, with the total of 222 x 10 3 person Sv. (author)

  15. Update on pediatric resuscitation drugs: high dose, low dose, or no dose at all.

    Science.gov (United States)

    Sorrentino, Annalise

    2005-04-01

    Pediatric resuscitation has been a topic of discussion for years. It is difficult to keep abreast of changing recommendations, especially for busy pediatricians who do not regularly use these skills. This review will focus on the most recent guidelines for resuscitation drugs. Three specific questions will be discussed: standard dose versus high-dose epinephrine, amiodarone use, and the future of vasopressin in pediatric resuscitation. The issue of using high-dose epinephrine for cardiopulmonary resuscitation refractory to standard dose epinephrine has been a topic of debate for many years. Recently, a prospective, double-blinded study was performed to help settle the debate. These results will be reviewed and compared with previous studies. Amiodarone is a medication that was added to the pediatric resuscitation algorithms with the most recent recommendations from the American Heart Association in 2000. Its use and safety will also be discussed. Another topic that is resurfacing in resuscitation is the use of vasopressin. Its mechanism and comparisons to other agents will be highlighted, although its use in the pediatric patient has not been thoroughly studied. Pediatric resuscitation is a constantly evolving subject that is on the mind of anyone taking care of sick children. Clinicians are continually searching for the most effective methods to resuscitate children in terms of short- and long-term outcomes. It is important to be familiar with not only the agents being used but also the optimal way to use them.

  16. Evaluation of the dose uniformity for double-plane high dose rate interstitial breast implants with the use of dose reference points and dose non-uniformity ratio

    International Nuclear Information System (INIS)

    MAjor, T.; Polgar, C.; Somogyi, A.; Nemeth, G.

    2000-01-01

    This study investigated the influence of dwell time optimizations on dose uniformity characterized by dose values in dose points and dose non-uniformity ratio (DNR) and analyzed which implant parameters have influence on the DNR. Double-plane breast implants with catheters arranged in triangular pattern were used for the calculations. At a typical breast implant, dose values in dose reference points inside the target volume and volumes enclosed by given isodose surfaces were calculated and compared for non-optimized and optimized implants. The same 6-cm treatment length was used for the comparisons. Using different optimizations plots of dose non-uniformity ratio as a function of catheter separation, source step size, number of catheters, length of active sections were drawn and the minimum DNR values were determined. Optimization resulted in less variation in dose values over dose points through the whole volume and in the central plane only compared to the non-optimized case. At implant configurations consisting of seven catheters with 15-mm separation, 5-mm source step size and various active lengths adapted according to the type of optimization, the no optimization, geometrical (volume mode) and dose point (on dose points and geometry) optimization resulted in similar treatment volumes, but an increased high dose volume was observed due to the optimization. The dose non-uniformity ratio always had the minimum at average dose over dose normalization points, defined in the midpoints between the catheters through the implant volume. The minimum value of DNR depended on catheter separation, source step size, active length and number of catheters. The optimization had only a small influence on DNR. In addition to the reference points in the central plane only, dose points positioned in the whole implant volume can be used for evaluating the dose uniformity of interstitial implants. The dose optimization increases not only the dose uniformity within the implant but

  17. Dose apportionment for BARC facilities

    International Nuclear Information System (INIS)

    Preetha, J.; Sundar, D.; Munshi, S.K.; Pradeepkumar, K.S.

    2017-01-01

    One of the important responsibilities of BARC Safety Council (BSC) is to ensure that appropriate measures are in place to protect the members of the public and the environment from the undue effects of radioactive releases from the facilities regulated by BSC. It is with this aim in mind that a Standing Committee for Dose Apportionment (DAC) was constituted by BSC in 2005, to ensure that the limits are set by the regulatory body for release of low-level gaseous and liquid effluents into the environment from BARC facilities. There are three Committees for dose apportionment constituted by the Chairman, BSC, viz, DAC-TK for Tarapur and Kalpakkam facilities, DAC-TV for Trombay and DACSF for specific faculties

  18. Dose assessment in radiological accidents

    International Nuclear Information System (INIS)

    Donkor, S.

    2013-04-01

    The applications of ionizing radiation bring many benefits to humankind, ranging from power generation to uses in medicine, industry and agriculture. Facilities that use radiation source require special care in the design and operation of equipment to prevent radiation injury to workers or to the public. Despite considerable development of radiation safety, radiation accidents do happen. The purpose of this study is therefore to discuss how to assess doses to people who will be exposed to a range of internal and external radiation sources in the event of radiological accidents. This will go a long way to complement their medical assessment thereby helping to plan their treatment. Three radiological accidents were reviewed to learn about the causes of those accidents and the recommendations that were put in place to prevent recurrence of such accidents. Various types of dose assessment methods were discussed.(au)

  19. Atmospheric radiation flight dose rates

    Science.gov (United States)

    Tobiska, W. K.

    2015-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. Of the domains that are affected by space weather, the coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has been conducting space weather observations of the atmospheric radiation environment at aviation altitudes that will eventually be transitioned into air traffic management operations. The Automated Radiation Measurements for Aerospace Safety (ARMAS) system and Upper-atmospheric Space and Earth Weather eXperiment (USEWX) both are providing dose rate measurements. Both activities are under the ARMAS goal of providing the "weather" of the radiation environment to improve aircraft crew and passenger safety. Over 5-dozen ARMAS and USEWX flights have successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. Flight altitudes now exceed 60,000 ft. and extend above commercial aviation altitudes into the stratosphere. In this presentation we describe recent ARMAS and USEWX results.

  20. Dose to patient in tomosynthesis

    International Nuclear Information System (INIS)

    Minambres Moro, A.; Fernandez Leton, P.; Garcia Rui-Zorrilla, J.; Perez Moreno, J. M.; Zucca Aparicio, D.

    2013-01-01

    They are beginning to implement digital mammography with the possibility of acquiring in tomosynthesis, whose biggest advantage is to distinguish structures without overlapping through of pseudotridimensionals images. With these modified mammograms can acquire a planar mammography, with fixed x-ray tube, or a tomosynthesis with tube by turning. For acquire tomosynthesis is necessary a detector of high efficiency together with tungsten white tubes. The objective of this study is to know the dose received by the patient with this new imaging. (Author)

  1. Radiation dose from cigarette tobacco

    International Nuclear Information System (INIS)

    Papastefanou, Constantin

    2008-01-01

    The radioactivity in tobacco leaves collected from 15 different regions of Greece before cigarette production was studied in order to estimate the effective dose from cigarette tobacco due to the naturally occurring primordial radionuclides, such as 226 Ra and 210 Pb of the uranium series and 228 Ra of the thorium series and or man-made produced radionuclides, such as 137 Cs of Chernobyl origin. Gamma-ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the annual effective dose due to inhalation for adults (smokers) for 226 Ra varied from 42.5 to 178.6 μSv y -1 (average 79.7 μSv y -1 ), while for 228 Ra from 19.3 to 116.0 μSv y -1 (average 67.1 μSv y -1 ) and for 210 Pb from 47.0 to 134.9 μSv y -1 (average 104.7 μSv y -1 ), that is the same order of magnitude for each radionuclide. The sum of the effective dose of the three natural radionuclides varied from 151.9 to 401.3 μSv y -1 (average 251.5 μSv y -1 ). The annual effective dose from 137 Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4 μSv y -1 (average 199.3 μSv y -1 ). (author)

  2. Urban contamination and dose model

    International Nuclear Information System (INIS)

    Robertson, E.; Barry, P.J.

    1995-10-01

    Nuclear power reactors and other nuclear facilities are being built near or even within urban centres. Accidental releases of radionuclides to the atmosphere in built-up areas result in radiological exposure pathways that differ from those caused by releases in rural environments. Other than inhalation, exposure pathways involve external radiation from the plume while it passes and from radioactivity deposited onto the many and varied surfaces after it has passed. Radiation fields inside buildings are attenuated but many people are potentially exposed so while individual doses may be relatively low, population integrated doses may be high enough to cause concern. It is important, therefore, to assess the potential exposures and to estimate the cost-effectiveness of dose reduction measures in urban environments. This report describes a model developed to carry out such assessments. The model draws heavily on experience gained in European cities after their contamination fallout from the Chernobyl accident. Input is time integrated concentrations of specific radionuclides in urban air, obtained either by direct measurement or by prediction using an atmospheric dispersion model. The code includes default values for site specific variables and transfer parameters but the user is invited if desired to enter other values from the keyboard. Output is the time integrated dose rates for individuals selected because of the characteristic living, working and recreational habits. An accompanying manual documents the technical background on which the model is based and leads a first-time suer through various steps and operations encountered while the model is running. (author). 60 refs., 10 tabs., 1 fig

  3. Prenatal radiation exposure. Dose calculation

    International Nuclear Information System (INIS)

    Scharwaechter, C.; Schwartz, C.A.; Haage, P.; Roeser, A.

    2015-01-01

    The unborn child requires special protection. In this context, the indication for an X-ray examination is to be checked critically. If thereupon radiation of the lower abdomen including the uterus cannot be avoided, the examination should be postponed until the end of pregnancy or alternative examination techniques should be considered. Under certain circumstances, either accidental or in unavoidable cases after a thorough risk assessment, radiation exposure of the unborn may take place. In some of these cases an expert radiation hygiene consultation may be required. This consultation should comprise the expected risks for the unborn while not perturbing the mother or the involved medical staff. For the risk assessment in case of an in-utero X-ray exposition deterministic damages with a defined threshold dose are distinguished from stochastic damages without a definable threshold dose. The occurrence of deterministic damages depends on the dose and the developmental stage of the unborn at the time of radiation. To calculate the risks of an in-utero radiation exposure a three-stage concept is commonly applied. Depending on the amount of radiation, the radiation dose is either estimated, roughly calculated using standard tables or, in critical cases, accurately calculated based on the individual event. The complexity of the calculation thereby increases from stage to stage. An estimation based on stage one is easily feasible whereas calculations based on stages two and especially three are more complex and often necessitate execution by specialists. This article demonstrates in detail the risks for the unborn child pertaining to its developmental phase and explains the three-stage concept as an evaluation scheme. It should be noted, that all risk estimations are subject to considerable uncertainties.

  4. Dose assessment models. Annex A

    International Nuclear Information System (INIS)

    1982-01-01

    The models presented in this chapter have been separated into 2 general categories: environmental transport models which describe the movement of radioactive materials through all sectors of the environment after their release, and dosimetric models to calculate the absorbed dose following an intake of radioactive materials or exposure to external irradiation. Various sections of this chapter also deal with atmospheric transport models, terrestrial models, and aquatic models.

  5. Tolerance doses for treatment planning

    International Nuclear Information System (INIS)

    Lyman, J.T.

    1985-10-01

    Data for the tolerance of normal tissues or organs to (low-LET) radiation has been compiled from a number of sources which are referenced at the end of this document. This tolerance dose data are ostensibly for uniform irradiation of all or part of an organ, and are for either 5% (TD 5 ) or 50% (TD 50 ) complication probability. The ''size'' of the irradiated organ is variously stated in terms of the absolute volume or the fraction of the organ volume irradiated, or the area or the length of the treatment field. The accuracy of these data is questionable. Much of the data represents doses that one or several experienced therapists have estimated could be safely given rather than quantitative analyses of clinical observations. Because these data have been obtained from multiple sources with possible different criteria for the definition of a complication, there are sometimes different values for what is apparently the same endpoint. The data from some sources shows a tendancy to be quantized in 5 Gy increments. This reflects the size of possible round off errors. It is believed that all these data have been accumulated without the benefit of 3-D dose distributions and therefore the estimates of the size of the volume and/or the uniformity of the irradiation may be less accurate than is now possible. 19 refs., 4 figs

  6. Gamma dose rate effect on JFET transistors

    International Nuclear Information System (INIS)

    Assaf, J.

    2011-04-01

    The effect of Gamma dose rate on JFET transistors is presented. The irradiation was accomplished at the following available dose rates: 1, 2.38, 5, 10 , 17 and 19 kGy/h at a constant dose of 600 kGy. A non proportional relationship between the noise and dose rate in the medium range (between 2.38 and 5 kGy/h) was observed. While in the low and high ranges, the noise was proportional to the dose rate as the case of the dose effect. This may be explained as follows: the obtained result is considered as the yield of a competition between many reactions and events which are dependent on the dose rate. At a given values of that events parameters, a proportional or a non proportional dose rate effects are generated. No dependence effects between the dose rate and thermal annealing recovery after irradiation was observed . (author)

  7. Calculation methods for determining dose equivalent

    International Nuclear Information System (INIS)

    Endres, G.W.R.; Tanner, J.E.; Scherpelz, R.I.; Hadlock, D.E.

    1987-11-01

    A series of calculations of neutron fluence as a function of energy in an anthropomorphic phantom was performed to develop a system for determining effective dose equivalent for external radiation sources. Critical organ dose equivalents are calculated and effective dose equivalents are determined using ICRP-26 [1] methods. Quality factors based on both present definitions and ICRP-40 definitions are used in the analysis. The results of these calculations are presented and discussed. The effective dose equivalent determined using ICRP-26 methods is significantly smaller than the dose equivalent determined by traditional methods. No existing personnel dosimeter or health physics instrument can determine effective dose equivalent. At the present time, the conversion of dosimeter response to dose equivalent is based on calculations for maximal or ''cap'' values using homogeneous spherical or cylindrical phantoms. The evaluated dose equivalent is, therefore, a poor approximation of the effective dose equivalent as defined by ICRP Publication 26. 3 refs., 2 figs., 1 tab

  8. Field measurement and interpretation of beta doses and dose rates

    International Nuclear Information System (INIS)

    Selby, J.M.; Swinth, K.L.; Hooker, C.D.; Kenoyer, J.L.

    1983-01-01

    A wide variety of portable survey instruments employing GM, ionization chamber and scintillation detectors exist for the measurement of gamma exposure rates. Often these same survey instruments are used for monitoring beta fields. This is done by making measurements with and without a removable shield which is intended to shield out the non-penetrating component (beta) of the radiation field. The difference does not correspond to an absorbed dose rate for the beta field due to a variety of factors. Among these factors are the dependence on beta energy, source-detector geometries, mixed fields and variable ambient conditions. Attempting to use such measurements directly can lead to errors as high as a factor of 100. In many instances correction factors have been derived, that if properly applied, can reduce these errors substantially. However, this requires some knowledge of the beta spectra, calibration techniques and source geometry. This paper discusses some aspects of the proper use of instruments for beta measurements including the application of appropriate correction factors. Ionization type instruments are commonly used to measure beta dose rates. Through design and calibration these instruments will give an accurate reading only for uniform irradiation of the detection volume. Often in the field it is not feasible to meet these conditions. Large area uniform distributions of activity are not generally encountered and it is not possible to use large source-to-detector distances due to beta particle absorption in air. An example of correction factors required for various point sources is presented when a cutie pie ionization chamber is employed. The instrument reading is multiplied by the appropriate correction factor to obtain the dose rate at the window. When a different detector is used or for other geometries, a different set of correction factors must be used

  9. Editorial: New operational dose equivalent quantities

    International Nuclear Information System (INIS)

    Harvey, J.R.

    1985-01-01

    The ICRU Report 39 entitled ''Determination of Dose Equivalents Resulting from External Radiation Sources'' is briefly discussed. Four new operational dose equivalent quantities have been recommended in ICRU 39. The 'ambient dose equivalent' and the 'directional dose equivalent' are applicable to environmental monitoring and the 'individual dose equivalent, penetrating' and the 'individual dose equivalent, superficial' are applicable to individual monitoring. The quantities should meet the needs of day-to-day operational practice, while being acceptable to those concerned with metrological precision, and at the same time be used to give effective control consistent with current perceptions of the risks associated with exposure to ionizing radiations. (U.K.)

  10. The MIRD method of estimating absorbed dose

    International Nuclear Information System (INIS)

    Weber, D.A.

    1991-01-01

    The estimate of absorbed radiation dose from internal emitters provides the information required to assess the radiation risk associated with the administration of radiopharmaceuticals for medical applications. The MIRD (Medical Internal Radiation Dose) system of dose calculation provides a systematic approach to combining the biologic distribution data and clearance data of radiopharmaceuticals and the physical properties of radionuclides to obtain dose estimates. This tutorial presents a review of the MIRD schema, the derivation of the equations used to calculate absorbed dose, and shows how the MIRD schema can be applied to estimate dose from radiopharmaceuticals used in nuclear medicine

  11. Collective dose commitments from nuclear power programmes

    International Nuclear Information System (INIS)

    Beninson, D.

    1977-01-01

    The concepts of collective dose and collective dose commitment are discussed, particularly regarding their use to compare the relative importance of the exposure from several radiation sources and to predict future annual doses from a continuing practice. The collective dose commitment contributions from occupational exposure and population exposure due to the different components of the nuclear power fuel cycle are evaluated. A special discussion is devoted to exposures delivered over a very long time by released radionuclides of long half-lives and to the use of the incomplete collective dose commitment. The maximum future annual ''per caput'' doses from present and projected nuclear power programmes are estimated

  12. Radiation doses from residual radioactivity

    International Nuclear Information System (INIS)

    Okajima, Shunzo; Fujita, Shoichiro; Harley, John H.

    1987-01-01

    requires knowing the location of the person to within about 200 m from the time of the explosion to a few weeks afterwards. This is an effort that might be comparable to the present shielding study for survivors. The sizes of the four exposed groups are relatively small; however, the number has been estimated only for those exposed to fallout in the Nishiyama district of Nagasaki. Okajima listed the population of Nishiyama as about 600 at the time of the bomb. No figures are available for the other three groups. The individual exposures from residual radiation may not be significant compared with the direct radiation at the time of the bomb. On the other hand, individuals with potential exposure from these sources are dubious candidates for inclusion in a cohort that was presumably not exposed. For comparison with organ doses estimated in other parts of this program, the exposure estimates are converted to absorbed dose in tissue. The first conversion of exposure to absorbed dose in air uses the factor rad in air 0.87 x exposure in R. UNSCEAR uses an average combined factor of 0.7 to convert absorbed dose in air to absorbed dose in tissue for the whole body. This factor accounts for the change in material (air to tissue) and for backscatter and the shielding afforded by other tissues of the body. No allowance for shielding by buildings has been included here. The cumulative fallout exposures given above become absorbed doses in tissue of 12 to 24 rad for Nagasaki and 0.6 to 2 rad for Hiroshima. The cumulative exposures from induced radioactivity become absorbed doses in tissue of 18 to 24 rad for Nagasaki and about 50 rad for Hiroshima. (author)

  13. Analysis of Cumulative Dose to Implanted Pacemaker According to Various IMRT Delivery Methods: Optimal Dose Delivery Versus Dose Reduction Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Woo; Hong, Se Mie [Dept. of Radiation Oncology, Konkuk University Medical Center, Seoul (Korea, Republic of)

    2011-11-15

    Cancer patients with implanted cardiac pacemaker occasionally require radiotherapy. Pacemaker may be damaged or malfunction during radiotherapy due to ionizing radiation or electromagnetic interference. Although radiotherapy should be planned to keep the dose to pacemaker as low as possible not to malfunction ideally, current radiation treatment planning (RTP) system does not accurately calculate deposited dose to adjacent field border or area beyond irradiated fields. In terms of beam delivery techniques using multiple intensity modulated fields, dosimetric effect of scattered radiation in high energy photon beams is required to be detailed analyzed based on measurement data. The aim of this study is to evaluate dose discrepancies of pacemaker in a RTP system as compared to measured doses. We also designed dose reduction strategy limited value of 2 Gy for radiation treatment patients with cardiac implanted pacemaker. Total accumulated dose of 145 cGy based on in-vivo dosimetry was satisfied with the recommendation criteria to prevent malfunction of pacemaker in SS technique. However, the 2 mm lead shielder enabled the scattered doses to reduce up to 60% and 40% in the patient and the phantom, respectively. The SS technique with the lead shielding could reduce the accumulated scattered doses less than 100 cGy. Calculated and measured doses were not greatly affected by the beam delivery techniques. In-vivo and measured doses on pacemaker position showed critical dose discrepancies reaching up to 4 times as compared to planned doses in RTP. The current SS technique could deliver lower scattered doses than recommendation criteria, but use of 2 mm lead shielder contributed to reduce scattered doses by 60%. The tertiary lead shielder can be useful to prevent malfunction or electrical damage of implanted pacemakers during radiotherapy. It is required to estimate more accurate scattered doses of the patient or medical device in RTP to design proper dose reduction strategy.

  14. Analysis of Cumulative Dose to Implanted Pacemaker According to Various IMRT Delivery Methods: Optimal Dose Delivery Versus Dose Reduction Strategy

    International Nuclear Information System (INIS)

    Lee, Jeong Woo; Hong, Se Mie

    2011-01-01

    Cancer patients with implanted cardiac pacemaker occasionally require radiotherapy. Pacemaker may be damaged or malfunction during radiotherapy due to ionizing radiation or electromagnetic interference. Although radiotherapy should be planned to keep the dose to pacemaker as low as possible not to malfunction ideally, current radiation treatment planning (RTP) system does not accurately calculate deposited dose to adjacent field border or area beyond irradiated fields. In terms of beam delivery techniques using multiple intensity modulated fields, dosimetric effect of scattered radiation in high energy photon beams is required to be detailed analyzed based on measurement data. The aim of this study is to evaluate dose discrepancies of pacemaker in a RTP system as compared to measured doses. We also designed dose reduction strategy limited value of 2 Gy for radiation treatment patients with cardiac implanted pacemaker. Total accumulated dose of 145 cGy based on in-vivo dosimetry was satisfied with the recommendation criteria to prevent malfunction of pacemaker in SS technique. However, the 2 mm lead shielder enabled the scattered doses to reduce up to 60% and 40% in the patient and the phantom, respectively. The SS technique with the lead shielding could reduce the accumulated scattered doses less than 100 cGy. Calculated and measured doses were not greatly affected by the beam delivery techniques. In-vivo and measured doses on pacemaker position showed critical dose discrepancies reaching up to 4 times as compared to planned doses in RTP. The current SS technique could deliver lower scattered doses than recommendation criteria, but use of 2 mm lead shielder contributed to reduce scattered doses by 60%. The tertiary lead shielder can be useful to prevent malfunction or electrical damage of implanted pacemakers during radiotherapy. It is required to estimate more accurate scattered doses of the patient or medical device in RTP to design proper dose reduction strategy.

  15. Dose indices: everybody wants a number

    International Nuclear Information System (INIS)

    Strauss, Keith J.

    2014-01-01

    This paper discusses the merits and weaknesses of the standard terms that have been developed to quantify CT dose: CT dose indices (CTDI), dose length product (DLP) and effective dose. The difference between the measured CTDI vol and the CTDI vol displayed on the CT scanner illustrates a clinical dilemma. Displayed CTDI vol represents the radiation dose delivered to a plastic phantom, which is significantly different from the dose delivered to the patient, depending on the size of the patient. Although effective dose is simple to calculate for an individual patient, it was never intended for this purpose. The need for a simple, appropriate method to estimate pediatric patient doses led to the development of the size-specific dose estimate (SSDE), the newest CT dose index. Here I compare SSDE and its merits to the use of effective dose to estimate patient dose. The discussion concludes with a few sample calculations and basic clinical applications of SSDE to better quantify pediatric patient dose from CT scans. (orig.)

  16. Dose-mapping distribution around MNSR

    CERN Document Server

    Jamal, M H

    2002-01-01

    The aim of this study is to establish the dose-rate map through the determination of radiological dose-rate levels in reactor hall, adjacent rooms, and outside the MNSR facility. Controlling dose rate to reactor operating personnel , dose map was established. The map covers time and distances in the reactor hall, during reactor operation at nominal power. Different measurement of dose rates in other areas of the reactor buildings was established. The maximum dose rate, during normal operation of the MNSR was 40 and 21 Sv/hr on the top of the reactor and near the pool fence, respectively. Whereas, gamma and neutron doses have not exceeded natural background in all rooms adjacent to the reactor hall or nearly buildings. The relation between the dose rate for gamma rays and neutron flux at the top of cover of reactor pool was studied as well. It was found that this relation is linear.

  17. Dose-mapping distribution around MNSR

    International Nuclear Information System (INIS)

    Jamal, M. H.; Khamis, I.

    2002-12-01

    The aim of this study is to establish the dose-rate map through the determination of radiological dose-rate levels in reactor hall, adjacent rooms, and outside the MNSR facility. Controlling dose rate to reactor operating personnel , dose map was established. The map covers time and distances in the reactor hall, during reactor operation at nominal power. Different measurement of dose rates in other areas of the reactor buildings was established. The maximum dose rate, during normal operation of the MNSR was 40 and 21 Sv/hr on the top of the reactor and near the pool fence, respectively. Whereas, gamma and neutron doses have not exceeded natural background in all rooms adjacent to the reactor hall or nearly buildings. The relation between the dose rate for gamma rays and neutron flux at the top of cover of reactor pool was studied as well. It was found that this relation is linear. (author)

  18. Simplified dose calculation method for mantle technique

    International Nuclear Information System (INIS)

    Scaff, L.A.M.

    1984-01-01

    A simplified dose calculation method for mantle technique is described. In the routine treatment of lymphom as using this technique, the daily doses at the midpoints at five anatomical regions are different because the thicknesses are not equal. (Author) [pt

  19. Organ doses from computerized tomography examinations

    Energy Technology Data Exchange (ETDEWEB)

    Janeczek, J.

    1995-12-31

    Estimates of mean organs doses from five typical computerized tomography (CT) examinations were obtained. Measurements were done using Rando-Alderson anthropomorphic phantom and thermoluminescent dosemeters (TLD). Radiation dose distributions within a phantom has been measured for each examination and results were used for organ dose calculation. Doses to organs specified by ICPR 60 Recommendations were measured for five CT scanners (CT/T8800, CT 9800, CT MAX - made by General Electric; CT 1200 SX - made by Picker; SOMATOM 2 - made by Siemens). Dose distributions from scattered radiation were measured and indicate that scattered radiation dose to thyroid and eye lens can be reduced by proper examination limits setting. The lowest mean organ doses were obtained from CT/T8800 scanner. More advanced scanners using high intensity continuous radiation were giving higher organ doses. (author). 23 refs, 6 figs, 13 tabs.

  20. Organ doses from computerized tomography examinations

    International Nuclear Information System (INIS)

    Janeczek, J.

    1995-01-01

    Estimates of mean organs doses from five typical computerized tomography (CT) examinations were obtained. Measurements were done using Rando-Alderson anthropomorphic phantom and thermoluminescent dosemeters (TLD). Radiation dose distributions within a phantom has been measured for each examination and results were used for organ dose calculation. Doses to organs specified by ICPR 60 Recommendations were measured for five CT scanners (CT/T8800, CT 9800, CT MAX - made by General Electric; CT 1200 SX - made by Picker; SOMATOM 2 - made by Siemens). Dose distributions from scattered radiation were measured and indicate that scattered radiation dose to thyroid and eye lens can be reduced by proper examination limits setting. The lowest mean organ doses were obtained from CT/T8800 scanner. More advanced scanners using high intensity continuous radiation were giving higher organ doses. (author). 23 refs, 6 figs, 13 tabs

  1. Calibration of dose meters used in radiotherapy

    International Nuclear Information System (INIS)

    1979-01-01

    This manual is a practical guide, not a comprehensive textbook, to the instrumentation and procedures necessary to calibrate a radiation dose meter used in clinical practice against a secondary standard dose meter

  2. Bayesian estimation of dose rate effectiveness

    International Nuclear Information System (INIS)

    Arnish, J.J.; Groer, P.G.

    2000-01-01

    A Bayesian statistical method was used to quantify the effectiveness of high dose rate 137 Cs gamma radiation at inducing fatal mammary tumours and increasing the overall mortality rate in BALB/c female mice. The Bayesian approach considers both the temporal and dose dependence of radiation carcinogenesis and total mortality. This paper provides the first direct estimation of dose rate effectiveness using Bayesian statistics. This statistical approach provides a quantitative description of the uncertainty of the factor characterising the dose rate in terms of a probability density function. The results show that a fixed dose from 137 Cs gamma radiation delivered at a high dose rate is more effective at inducing fatal mammary tumours and increasing the overall mortality rate in BALB/c female mice than the same dose delivered at a low dose rate. (author)

  3. Dose-rate dependence of thermoluminescence response

    International Nuclear Information System (INIS)

    McKeever, S.W.S.; Chen, R.; Groom, P.J.; Durrani, S.A.

    1980-01-01

    The previously observed dose-rate effect of thermoluminescence in quartz at high dose-rates is given at theoretical formulation. Computer calculations simulating the experimental conditions yield similar results to the experimental ones. (orig.)

  4. Dose estimation by biological methods

    International Nuclear Information System (INIS)

    Guerrero C, C.; David C, L.; Serment G, J.; Brena V, M.

    1997-01-01

    The human being is exposed to strong artificial radiation sources, mainly of two forms: the first is referred to the occupationally exposed personnel (POE) and the second, to the persons that require radiological treatment. A third form less common is by accidents. In all these conditions it is very important to estimate the absorbed dose. The classical biological dosimetry is based in the dicentric analysis. The present work is part of researches to the process to validate the In situ Fluorescent hybridation (FISH) technique which allows to analyse the aberrations on the chromosomes. (Author)

  5. Internal radiation dose of Indians

    International Nuclear Information System (INIS)

    Ranganathan, S.; Nagaratnam, A.; Sharma, U.C.

    2001-01-01

    The measurement of γ-rays from 40 K by whole-body counting provides a sensitive technique to estimate the body 40 K radioactivity. In India, right from the whole body counter (WBC) of Trombay in the early 1960s to the INMAS WBC of 1970s, some limited information has been available about the internal 40 K of Indians. However, information on 40 K dose with age and sex of Indians is scanty. Therefore, a systematic study was taken up to generate this information

  6. The philosophy of dose limitation

    International Nuclear Information System (INIS)

    Recht, P.

    1981-01-01

    The evolution of concepts and terms appearing in the European Rules of 15 July 1980 is briefly described. After a period where ''tolerance doses'' represent definite limits which should be respected, appears the concept of a ''as low as possible'' and ''as low as practicable'' level. The hypothesis that any exposure represents a risk which should be avoided is taken into account in the later evolution. As a consequence one has to examine the advantages and disadvantages in other words to make a cost-benefit analysis. This evolution leads to the concepts of justification and optimization used at the present time. (author)

  7. Dose dispenser for radioactive gas

    International Nuclear Information System (INIS)

    Horwitz, N.H.; Gutkowski, R.E.

    1977-01-01

    An activity metering apparatus for metering predetermined activities of radioactive gas from a supply ampul to dose vials is described. The apparatus includes a shielded ampul housing, a fine metering valve communicating with the ampul housing chamber, a shielded vial housing and a hypodermic needle communicating with the metering valve and received through an opening in the vial housing. A Geiger-Muller tube is adjustably supported opposite an opening in the vial housing, whereby the activity of the radioactive gas dispensed to a partially evacuated vial within the vial chamber may be read directly by a standard laboratory rate meter

  8. Dose limits cause unacceptable risk

    International Nuclear Information System (INIS)

    Collier, Sylvia.

    1985-01-01

    This paper on radiation dose limits for workers and the public discusses the following: Medical Research Council report; safety standards; risk assessment; deaths from cancers; biological radiation effects; UK legislation; low-level radiation; public concern; UKAEA staff survey; Ionising Radiations Regulations; United Nations Scientific Committee on Effects of Atomic Radiation; US studies on work force in nuclear establishments; problems of extrapolation; Japanese data from Hiroshima and Nagasaki; International Commission on Radiological Protection recommendations; studies on uranium miners; UK Health and Safety Executive; UK National Radiological Protection Board. (U.K.)

  9. Optimizing lithium dosing in hemodialysis

    DEFF Research Database (Denmark)

    Bjarnason, N H; Munkner, R; Kampmann, J P

    2006-01-01

    in which we developed an algorithm based on a 2-compartment distribution without elimination. The GFR estimate led to plasma concentrations 3-4 times lower than those anticipated. In contrast, the estimates based on V(d) and the algorithm derived from pharmacokinetic modeling led to comparable loading dose...... in this patient with no residual kidney function. We did not observe adverse effects related to this regimen, which was monitored from 18 days to 8 months of therapy, and the patient experienced relief from her severe depressive disorder. In conclusion, dialysis patients may be treated with lithium administrated...

  10. Fiber optics in high dose radiation fields

    International Nuclear Information System (INIS)

    Partin, J.K.

    1985-01-01

    A review of the behavior of state-of-the-art optical fiber waveguides in high dose (greater than or equal to 10 5 rad), steady state radiation fields is presented. The influence on radiation-induced transmission loss due to experimental parameters such as dose rate, total dose, irradiation history, temperature, wavelength, and light intensity, for future work in high dose environments are given

  11. Multiple anatomy optimization of accumulated dose

    International Nuclear Information System (INIS)

    Watkins, W. Tyler; Siebers, Jeffrey V.; Moore, Joseph A.; Gordon, James; Hugo, Geoffrey D.

    2014-01-01

    Purpose: To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. Methods: MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV- and MAO-plans, target dose variations were also investigated. Results: By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. Conclusions: MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated

  12. Dose-response relationship in clinical oncology

    International Nuclear Information System (INIS)

    Gehan, E.A.

    1984-01-01

    The relationship of dose (and dose rate) to response and toxicity in clinical oncology is reviewed. The concepts expressed by some authors in dose-response studies in animal and human systems are reviewed briefly. Dose rate and tactics of conducting clinical studies are reviewed for both radiotherapy and various types of chemotherapeutic treatment. Examples are given from clinical studies in Hodgkin's disease, acute leukemia, and breast cancer that may prove useful in planning future clinical studies

  13. Multiple anatomy optimization of accumulated dose

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, W. Tyler, E-mail: watkinswt@virginia.edu; Siebers, Jeffrey V. [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Moore, Joseph A. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland 21231 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Gordon, James [Henry Ford Health System, Detroit, Michigan 48202 and Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States); Hugo, Geoffrey D. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

    2014-11-01

    Purpose: To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. Methods: MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV- and MAO-plans, target dose variations were also investigated. Results: By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. Conclusions: MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated.

  14. Multiple anatomy optimization of accumulated dose.

    Science.gov (United States)

    Watkins, W Tyler; Moore, Joseph A; Gordon, James; Hugo, Geoffrey D; Siebers, Jeffrey V

    2014-11-01

    To investigate the potential advantages of multiple anatomy optimization (MAO) for lung cancer radiation therapy compared to the internal target volume (ITV) approach. MAO aims to optimize a single fluence to be delivered under free-breathing conditions such that the accumulated dose meets the plan objectives, where accumulated dose is defined as the sum of deformably mapped doses computed on each phase of a single four dimensional computed tomography (4DCT) dataset. Phantom and patient simulation studies were carried out to investigate potential advantages of MAO compared to ITV planning. Through simulated delivery of the ITV- and MAO-plans, target dose variations were also investigated. By optimizing the accumulated dose, MAO shows the potential to ensure dose to the moving target meets plan objectives while simultaneously reducing dose to organs at risk (OARs) compared with ITV planning. While consistently superior to the ITV approach, MAO resulted in equivalent OAR dosimetry at planning objective dose levels to within 2% volume in 14/30 plans and to within 3% volume in 19/30 plans for each lung V20, esophagus V25, and heart V30. Despite large variations in per-fraction respiratory phase weights in simulated deliveries at high dose rates (e.g., treating 4/10 phases during single fraction beams) the cumulative clinical target volume (CTV) dose after 30 fractions and per-fraction dose were constant independent of planning technique. In one case considered, however, per-phase CTV dose varied from 74% to 117% of prescription implying the level of ITV-dose heterogeneity may not be appropriate with conventional, free-breathing delivery. MAO incorporates 4DCT information in an optimized dose distribution and can achieve a superior plan in terms of accumulated dose to the moving target and OAR sparing compared to ITV-plans. An appropriate level of dose heterogeneity in MAO plans must be further investigated.

  15. Concepts of collective dose in radiological protection

    International Nuclear Information System (INIS)

    Lindell, B.

    1985-01-01

    The collective dose (S) is the product of the number of individuals exposed and their average radiation dose. ''Radiation dose'' is usually taken to be the effective dose equivalent (Hsub(E)) as defined by the ICRP. The unit of the collective dose is then the man.sievert (man.Sv). The following four applications of the collective dose are the most common: (a) in the assessment of the highest per caput dose rate in the future from a continued practice which exposes some critical group or the population as a whole to radiation; (b) in the limitation of present radiation sources, if it is believed that additional sources in the future may add to the per caput dose in a population so that it might reach unacceptable levels unless all sources are controlled at an early stage; (c) as an input to justification assessments, indicating the total detriment from a certain practice; and (d) as an input to optimization assessments as the basis for costing detriment in differential cost-benefit analyses of protection arrangements. It is sometimes said that the collective dose is a useful quantity only if the assumption of a non-threshold, linear dose-response relation is valid. This assumption is not always necessary. Applications (a) and (b) are possible without any assumption on the dose-response relationship at very low doses. Only applications (c) and (d) require the assumption of a non-threshold, linear dose-response relation. Some hesitation in using the collective dose originates in distrust in the biological assumptions implied by uses (c) and (d), but also in lack of confidence in the meaningfulness of collective doses that have been derived by adding dose contributions over very long time periods. However, none of the four applications (a) - (d) is by necessity related to extreme time scales. That problem mainly arises in the assessment of radioactive waste repositories

  16. Background dose subtraction in personnel dosimetry

    International Nuclear Information System (INIS)

    Picazo, T.; Llorca, N.; Alabau, J.

    1997-01-01

    In this paper it is proposed to consider the mode of the frequency distribution of the low dose dosemeters from each clinic that uses X rays as the background environmental dose that should be subtracted from the personnel dosimetry to evaluate the doses due to practice. The problems and advantages of this indirect method to estimate the environmental background dose are discussed. The results for 60 towns are presented. (author)

  17. Cervical cancer: intracavitary dose specification and prescription

    International Nuclear Information System (INIS)

    Potish, R.A.; Gerbi, B.J.

    1987-01-01

    Dose and volume specifications for reporting intracavitary therapy were analyzed according to criteria recommended by the International Commission on Radiation Units and Measurements (ICRU). Ninety Fletcher-Suit radium applications were studied to examine the validity of the assumptions of the ICRU and the merit of their routine reporting. It was demonstrated that the reporting recommendations were inconsistent with clinical prescription systems and added little to dose specification. The distinction between dose specification and dose prescription was stressed

  18. Maternal methadone dosing schedule and fetal neurobehavior

    Science.gov (United States)

    Jansson, Lauren M.; DiPietro, Janet A.; Velez, Martha; Elko, Andrea; Knauer, Heather; Kivlighan, Katie T.

    2008-01-01

    Objective Daily methadone maintenance is the standard of care for opiate dependency during pregnancy. Previous research has indicated that single-dose maternal methadone administration significantly suppresses fetal neurobehaviors. The purpose of this study was to determine if split-dosing would have less impact on fetal neurobehavior than single-dose administration. Methods Forty methadone-maintained women were evaluated at peak and trough maternal methadone levels on single- and split-dosing schedules. Monitoring sessions occurred at 36 and 37 weeks gestation in a counterbalanced study design. Fetal measures included heart rate, variability, accelerations, motor activity and fetal movement-heart rate coupling (FM-FHR). Maternal measures included heart period, variability, skin conductance, respiration and vagal tone. Repeated measure analysis of variance was used to evaluate within-subject changes between split- and single-dosing regimens. Results All fetal neurobehavioral parameters were suppressed by maternal methadone administration, regardless of dosing regimen. Fetal parameters at peak were significantly lower during single vs. split methadone administration. FM-FHR coupling was less suppressed from trough to peak during split-dosing vs. single-dosing. Maternal physiologic parameters were generally unaffected by dosing condition. Conclusion Split- dosed fetuses displayed less neurobehavioral suppression from trough to peak maternal methadone levels as compared to single-dosed fetuses. Split-dosing may be beneficial for methadone-maintained pregnant women. PMID:19085624

  19. Failure-probability driven dose painting

    DEFF Research Database (Denmark)

    Vogelius, Ivan R; Håkansson, Katrin; Due, Anne K

    2013-01-01

    To demonstrate a data-driven dose-painting strategy based on the spatial distribution of recurrences in previously treated patients. The result is a quantitative way to define a dose prescription function, optimizing the predicted local control at constant treatment intensity. A dose planning study...

  20. A dose monitoring system for dental radiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chena; Lee, Sam Sun; Kim, Jo Eun; Huh, Kyung Hoe; Yi, Woo Jin; Heo, Min Suk; Choi, Soon Chul [Dept. of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of); Symkhampha, Khanthaly [Dept. of Oral and Maxillofacial Radiology, Department of Basic Science, Faculty of Dentistry, University of Health Sciences, Vientiane (Lao People' s Democratic Republic); Lee, Woo Jin [Dept. of Interdisciplinary Program in Radiation, Applied Life Sciences Major, College of Medicine, BK21, and Dental Research Institute, Seoul National University, Seoul (Korea, Republic of); Yeom, Heon Young [School of Computer Science Engineering, Seoul National University, Seoul (Korea, Republic of)

    2016-06-15

    The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed. An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system. The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access. A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose.

  1. A dose monitoring system for dental radiography

    International Nuclear Information System (INIS)

    Lee, Chena; Lee, Sam Sun; Kim, Jo Eun; Huh, Kyung Hoe; Yi, Woo Jin; Heo, Min Suk; Choi, Soon Chul; Symkhampha, Khanthaly; Lee, Woo Jin; Yeom, Heon Young

    2016-01-01

    The current study investigates the feasibility of a platform for a nationwide dose monitoring system for dental radiography. The essential elements for an unerring system are also assessed. An intraoral radiographic machine with 14 X-ray generators and five sensors, 45 panoramic radiographic machines, and 23 cone-beam computed tomography (CBCT) models used in Korean dental clinics were surveyed to investigate the type of dose report. A main server for storing the dose data from each radiographic machine was prepared. The dose report transfer pathways from the radiographic machine to the main sever were constructed. An effective dose calculation method was created based on the machine specifications and the exposure parameters of three intraoral radiographic machines, five panoramic radiographic machines, and four CBCTs. A viewing system was developed for both dentists and patients to view the calculated effective dose. Each procedure and the main server were integrated into one system. The dose data from each type of radiographic machine was successfully transferred to the main server and converted into an effective dose. The effective dose stored in the main server is automatically connected to a viewing program for dentist and patient access. A patient radiation dose monitoring system is feasible for dental clinics. Future research in cooperation with clinicians, industry, and radiologists is needed to ensure format convertibility for an efficient dose monitoring system to monitor unexpected radiation dose

  2. The definition of the individual dose equivalent

    International Nuclear Information System (INIS)

    Ehrlich, Margarete

    1986-01-01

    A brief note examines the choice of the present definition of the individual dose equivalent, the new operational dosimetry quantity for external exposure. The consequences of the use of the individual dose equivalent and the danger facing the individual dose equivalent, as currently defined, are briefly discussed. (UK)

  3. Practical experience of monitoring patient dose

    Energy Technology Data Exchange (ETDEWEB)

    McDonnell, C.; Shrimpton, P. (National Radiological Protection Board, Chilton (United Kingdom)); O' Mahoney, M. (National Radiological Protection Board, Leeds (United Kingdom)); Foster, J. (Nuffield Hospitals, Surbiton (United Kingdom))

    1994-05-01

    NRPB recommends the use of reference dose levels for diagnostic medical exposures as an aid to patient dose reduction, but is this approach effective This article describes the broadly encouraging experiences of one large group of hospitals in carrying out measurements of entrance surface dose on patients undergoing some common types of x-ray examination. (author).

  4. Gonadal dose in routine diagnostic examinations

    International Nuclear Information System (INIS)

    Weber, J.; Koen, J.A.; Akkermans, J.A.

    1974-01-01

    Gonadal doses caused by stray radiation produced during radiodiagnostic investigations were measured with thermoluminescent dosemeters in various hospitals in the Netherlands. Significantly different gonadal doses were measured depending upon the hospital where the investigations were carried out. The mean dose of an examination type in one country can only be determined with any accuracy if measurements in a large number of hospitals are performed

  5. Endorectal high dose rate brachytherapy quality assurance

    International Nuclear Information System (INIS)

    Devic, S.; Vuong, T.; Evans, M.; Podgorsak, E.

    2008-01-01

    We describe our quality assurance method for preoperative high dose rate (HDR) brachytherapy of endorectal tumours. Reproduction of the treatment planning dose distribution on a daily basis is crucial for treatment success. Due to the cylindrical symmetry, two types of adjustments are necessary: applicator rotation and dose distribution shift along the applicator axis. (author)

  6. Dose mapping role in gamma irradiation industry

    International Nuclear Information System (INIS)

    Noriah Mod Ali; John Konsoh Sangau; Mazni Abd Latif

    2002-01-01

    In this studies, the role of dosimetry activity in gamma irradiator was discussed. Dose distribution in the irradiator, which is a main needs in irradiator or chamber commissioning. This distribution data were used to confirm the dosimetry parameters i.e. exposure time, maximum and minimum dose map/points, and dose distribution - in which were used as guidelines for optimum product irradiation. (Author)

  7. Dose/dose-rate responses of shrimp larvae to UV-B radiation

    International Nuclear Information System (INIS)

    Damkaer, D.M.

    1981-01-01

    Previous work indicated dose-rate thresholds in the effects of UV-B on the near-surface larvae of three shrimp species. Additional observations suggest that the total dose response varies with dose-rate. Below 0.002 Wm -2 sub([DNA]) irradiance no significant effect is noted in activity, development, or survival. Beyond that dose-rate threshold, shrimp larvae are significantly affected if the total dose exceeds about 85 Jm -2 sub([DNA]). Predictions cannot be made without both the dose-rate and the dose. These dose/dose-rate thresholds are compared to four-year mean dose/dose-rate solar UV-B irradiances at the experimental site, measured at the surface and calculated for 1 m depth. The probability that the shrimp larvae would receive lethal irradiance is low for the first half of the season of surface occurrence, even with a 44% increase in damaging UV radiation. (orig.)

  8. Estimation of exposed dose, 1

    International Nuclear Information System (INIS)

    Okajima, Shunzo

    1976-01-01

    Radioactive atomic fallouts in Nishiyama district of Nagasaki Prefecture are reported on the basis of the survey since 1969. In 1969, the amount of 137 Cs in the body of 50 inhabitants in Nishiyama district was measured using human counter, and was compared with that of non-exposured group. The average value of 137 Cs (pCi/kg) was higher in inhabitants in Nishiyama district (38.5 in men and 24.9 in females) than in the controls (25.5 in men and 14.9 in females). The resurvey in 1971 showed that the amount of 137 Cs was decreased to 76% in men and 60% in females. When the amount of 137 Cs in the body was calculated from the chemical analysis of urine, it was 29.0 +- 8.2 in men and 29.4 +- 26.2 in females in Nishiyama district, and 29.9 +- 8.2 in men and 29.4 +- 11.7 in females in the controls. The content of 137 Cs in soils and crops (potato etc.) was higher in Nishiyama district than in the controls. When the internal exposure dose per year was calculated from the amount of 137 Cs in the body in 1969, it was 0.29 mrad/year in men and 0.19 mrad/year in females. Finally, the internal exposure dose immediately after the explosion was estimated. (Serizawa, K.)

  9. Patient doses in interventional cardiology

    International Nuclear Information System (INIS)

    Carrera, F.; Ojeda, C.; Ruiz-Cruces, R.; Francisco Diaz, J.; Sanchez, A.; Tort, I.

    2001-01-01

    Cardiovascular diseases are the first cause of death in Spain. The most usual procedures in interventional cardiology are coronariography and PTCA. The first is a diagnostic technique, and the second one is interventional. Our goal has been to study procedures made during the first six months in the Interventional Cardiology Unit of the Juan Ramon Jimenez Hospital (Huelva-Spain), taking into account radiation protection issues. We have studied 178 patients; 145 of them underwent coronariography, and 33 of the patients had PTCA too. Every case was analyzed taking into account technical and dosimetric parameters. We show parameters values gathered: Diagnostic techniques (valvular and non-valvular patients), and interventional techniques (coronariography and PTCA in different or in the same intervention). Higher doses were obtained with valvular patients, although the number of frames was similar. Attending to therapeutic procedures, the highest values were gotten with the 'double' interventions. Interventional procedures exceed in 60% doses gotten in diagnostic studies: this is because of the number of series and number of frames per series. Similar values obtained by other authors have been gotten. (author)

  10. Doses in mammography. Preliminary study

    International Nuclear Information System (INIS)

    Marquez P, F.; Acosta R, N.; Universidad Nacional Mayor de San Marcos, Lima; Benavente, T.; Universidad Nacional Mayor de San Marcos, Lima; Poma, M.

    2002-01-01

    Mammography is the most important method to detect lesions in the breast with this technique one can detect small tumours before clear clinical symptoms appear. Mammographic image of require high quality standards due that the extremely low contrast between the normal and pathological areas in the breast, eg.g., they have similar attenuation and absorption coefficient. The x-ray mammographic systems, used in this study are Senographe 500t and Senographe DMR, a detector with a RadCal ionization chambers calibrated to the qualities of mammographic x-ray beams, and a breast simulator that is a phantoms of polymethylmethacrylate (PMMA) of several thicknesses with the equivalence of 50% of the glandular tissue. The results obtained indicate that the values of doses at the entrance surface of a breast (DES) are greater the reference value 20 mGy to 5,0 cm of PMMA and the values of the mean glandular dose (MGD) exceed the reference value of 2,1 mGy for 5,1 cm of compressed thick breast. We consider that the values high of the EDS and MGD are due that the x-ray systems no meeting in good condition or for used of x-ray spectra no suitable, so is recommendable be carried out test of quality control to the x-ray systems and also realize studies, or characterize the of x-ray mammographic spectra

  11. Patient dose in digital mammography

    International Nuclear Information System (INIS)

    Chevalier, Margarita; Moran, Pilar; Ten, Jose I.; Fernandez Soto, Jose M.; Cepeda, T.; Vano, Eliseo

    2004-01-01

    In the present investigation, we analyze the dose of 5034 patients (20 137 images) who underwent mammographic examinations with a full-field digital mammography system. Also, we evaluate the system calibration by analyzing the exposure factors as a function of breast thickness. The information relevant to this study has been extracted from the image DICOM header and stored in a database during a 3-year period (March 2001-October 2003). Patient data included age, breast thickness, kVp, mAs, target/filter combination, and nominal dose values. Entrance surface air kerma (ESAK) without backscatter was calculated from the tube output as measured for each voltage used under clinical conditions and from the tube loading (mAs) included in the DICOM header. Mean values for the patient age and compressed breast thickness were 56 years (SD: 11) and 52 mm (SD: 13), respectively. The majority of the images was acquired using the STD (for standard) automatic mode (98%). The most frequent target/filter combination automatically selected for breast smaller than 35 mm was Mo/Mo (75%); for intermediate thicknesses between 35 and 65 mm, the combinations were Mo/Rh (54%) and Rh/Rh (38.5%); Rh/Rh was the combination selected for 91% of the cases for breasts thicker than 65 mm. A wide kVp range was observed for each target/filter combination. The most frequent values were 28 kVp for Mo/Mo, 29 kVp for Mo/Rh, and 29 and 30 kV for Rh/Rh. Exposure times ranged from 0.2 to 4.2 s with a mean value of 1.1 s. Average glandular doses (AGD) per exposure were calculated by multiplying the ESAK values by the conversion factors tabulated by Dance for women in the age groups 50 to 64 and 40 to 49. This approach is based on the dependence of breast glandularity on breast thickness and age. The total mean average glandular dose (AGD T ) was calculated by summing the values associated with the pre-exposure and with the main exposure. Mean AGD T per exposure was 1.88 mGy (CI 0.01) and the mean AGD T per

  12. Field measurement and interpretation of beta doses and dose rates

    International Nuclear Information System (INIS)

    Selby, J.M.; Swinth, K.L.; Hooker, C.D.; Kenoyer, J.L.

    1983-01-01

    A large number of portable survey instruments employing G.M., ionization chamber, and scintillation detectors used for gamma measurements are also used for monitoring in beta fields by using removable shields to separate the beta and gamma components of the radiation field. The difference does not correspond to an absorbed dose rate for the beta field due to a variety of factors. Among these factors are the dependence on beta energy, source-detector geometries, mixed fields and variable ambient conditions. Attempting to use such measurements directly can lead to errors as high as a factor of 100. Appropriate calibrations and correction factors can be used to reduce the errors in beta measurements to a tolerable level

  13. Isobio software: biological dose distribution and biological dose volume histogram from physical dose conversion using linear-quadratic-linear model.

    Science.gov (United States)

    Jaikuna, Tanwiwat; Khadsiri, Phatchareewan; Chawapun, Nisa; Saekho, Suwit; Tharavichitkul, Ekkasit

    2017-02-01

    To develop an in-house software program that is able to calculate and generate the biological dose distribution and biological dose volume histogram by physical dose conversion using the linear-quadratic-linear (LQL) model. The Isobio software was developed using MATLAB version 2014b to calculate and generate the biological dose distribution and biological dose volume histograms. The physical dose from each voxel in treatment planning was extracted through Computational Environment for Radiotherapy Research (CERR), and the accuracy was verified by the differentiation between the dose volume histogram from CERR and the treatment planning system. An equivalent dose in 2 Gy fraction (EQD 2 ) was calculated using biological effective dose (BED) based on the LQL model. The software calculation and the manual calculation were compared for EQD 2 verification with pair t -test statistical analysis using IBM SPSS Statistics version 22 (64-bit). Two and three-dimensional biological dose distribution and biological dose volume histogram were displayed correctly by the Isobio software. Different physical doses were found between CERR and treatment planning system (TPS) in Oncentra, with 3.33% in high-risk clinical target volume (HR-CTV) determined by D 90% , 0.56% in the bladder, 1.74% in the rectum when determined by D 2cc , and less than 1% in Pinnacle. The difference in the EQD 2 between the software calculation and the manual calculation was not significantly different with 0.00% at p -values 0.820, 0.095, and 0.593 for external beam radiation therapy (EBRT) and 0.240, 0.320, and 0.849 for brachytherapy (BT) in HR-CTV, bladder, and rectum, respectively. The Isobio software is a feasible tool to generate the biological dose distribution and biological dose volume histogram for treatment plan evaluation in both EBRT and BT.

  14. Dose rate visualization of radioisotope thermoelectric generators

    International Nuclear Information System (INIS)

    Schwarz, R.A.; Kessler, S.F.; Tomaszewski, T.A.

    1995-09-01

    Advanced visualization techniques can be used to investigate gamma ray and neutron dose rates around complex dose rate intensive operations. A method has been developed where thousands of dose points are calculated using the MCNP(Monte Carlo N-Particle) computer code and then displayed to create color contour plots of the dose rate for complex geometries. Once these contour plots are created, they are sequenced together creating an animation to dynamically show how the dose rate changes with changes in the geometry or source over time

  15. Discuss on luminescence dose data analysis technology

    International Nuclear Information System (INIS)

    Ma Xinhua; Xiao Wuyun; Ai Xianyun; Shi Zhilan; Liu Ying

    2009-01-01

    This article describes the development of luminescence dose data measurement and processing technology. General design planning of luminescence dose data measurement and processing technology is put forward with the diverse demands. The emphasis is focused on dose data processing method, luminescence curve analysis method, using of network, mechanics of communication among computers, data base management system of individual dose in this paper. The main methods and skills used in this technology as well as their advantages are also discussed. And it offers general design references for development luminescence dose data processing software. (authors)

  16. Patient radiation doses from enteroclysis examinations

    International Nuclear Information System (INIS)

    Hart, D.; Wall, B.F.; Haggett, P.J.; Boardman, P.; Nolan, D.J.

    1994-01-01

    Data relating to patient dose have been acquired for enteroclysis examinations (small bowel enemas) performed at the John Radcliffe Hospital, Oxford, on 23 adult patients. Dose-area products, fluoroscopy times and the number of radiographs taken are used to compare the examination procedure at the Hospital with enteroclysis and barium follow-throughs performed elsewhere. The mean dose-area product for the 23 examinations was 6.8 Gy cm 2 and the mean effective dose was estimated to be 1.5 mSv. These doses are intermediate between those arising from barium meals and barium enemas performed in the same room. (author)

  17. Dose rate visualization of radioisotope thermoelectric generators

    International Nuclear Information System (INIS)

    Schwarz, R.A.; Kessler, S.F.; Tomaszewski, T.A.

    1996-01-01

    Advanced visualization techniques can be used to investigate gamma ray and neutron dose rates around complex dose rate intensive operations. A method has been developed where thousands of dose points are calculated using the MCNP (Monte Carlo N-Particle) computer code (Briesmeister 1993) and then displayed to create color contour plots of the dose rate for complex geometries. Once these contour plots are created, they are sequenced together creating an animation to dynamically show how the dose rate changes with changes in the geometry or source over time. copyright 1996 American Institute of Physics

  18. Dose Rate Effects in Linear Bipolar Transistors

    Science.gov (United States)

    Johnston, Allan; Swimm, Randall; Harris, R. D.; Thorbourn, Dennis

    2011-01-01

    Dose rate effects are examined in linear bipolar transistors at high and low dose rates. At high dose rates, approximately 50% of the damage anneals at room temperature, even though these devices exhibit enhanced damage at low dose rate. The unexpected recovery of a significant fraction of the damage after tests at high dose rate requires changes in existing test standards. Tests at low temperature with a one-second radiation pulse width show that damage continues to increase for more than 3000 seconds afterward, consistent with predictions of the CTRW model for oxides with a thickness of 700 nm.

  19. Entrance and peripheral dose measurements during radiotherapy

    International Nuclear Information System (INIS)

    Sulieman, A.; Kappas, K.; Theodorou, K.

    2008-01-01

    In vivo dosimetry of entrance dose was performed using thermoluminescent dosimeters (TLD) in order to evaluate the clinical application of the build up caps in patient dose measurements and for different treatment techniques. Peripheral dose (thyroid and skin) was measured for patients during breast radiotherapy to evaluate the probability of secondary cancer induction. TLD-100 chips were used with different Copper build up caps (for 6 MV and 15 MV photon beams from two linear accelerators. Entrance doses were measured for patients during radiotherapy course for breast, head and neck, abdomen and pelvis malignancies. The measured entrance dose for the different patients for 6 MV beams is found to be within the ±2.6% compared to the dose derived from theoretical estimation (normalized dose at D max ). The same measurements for 15 MV beams are found to be ±3 %. The perturbation value can reach up to 20% of the D max , which acts as a limitation for entrance dose measurements. An average thyroid skin dose of 3.7% of the prescribed dose was measured per treatment session while the mean skin dose breast treatment session is estimated to be 42% of D max , for both internal and external fields. These results are comparable in those of the in vivo of reported in literature. The risk of fatality due to thyroid cancer per treatment course is 3x10 -3

  20. On uncertainties in definition of dose equivalent

    International Nuclear Information System (INIS)

    Oda, Keiji

    1995-01-01

    The author has entertained always the doubt that in a neutron field, if the measured value of the absorbed dose with a tissue equivalent ionization chamber is 1.02±0.01 mGy, may the dose equivalent be taken as 10.2±0.1 mSv. Should it be 10.2 or 11, but the author considers it is 10 or 20. Even if effort is exerted for the precision measurement of absorbed dose, if the coefficient being multiplied to it is not precise, it is meaningless. [Absorbed dose] x [Radiation quality fctor] = [Dose equivalent] seems peculiar. How accurately can dose equivalent be evaluated ? The descriptions related to uncertainties in the publications of ICRU and ICRP are introduced, which are related to radiation quality factor, the accuracy of measuring dose equivalent and so on. Dose equivalent shows the criterion for the degree of risk, or it is considered only as a controlling quantity. The description in the ICRU report 1973 related to dose equivalent and its unit is cited. It was concluded that dose equivalent can be considered only as the absorbed dose being multiplied by a dimensionless factor. The author presented the questions. (K.I.)

  1. Guidance levels, achievable doses and expectation levels

    International Nuclear Information System (INIS)

    Li, Lianbo; Meng, Bing

    2002-01-01

    The National Radiological Protection Board (NRPB), the International Atomic Energy Agency (IAEA) and the Commission of the European Communities (CEC) published their guidance levels and reference doses for typical X-ray examination and nuclear medicine in their documents in 1993, 1994 and 1996 respectively. From then on, the concept of guidance levels or reference doses have been applied to different examinations in the field of radiology and proved to be effective for reduction of patient doses. But the guidance levels or reference doses are likely to have some shortcomings and can do little to make further reduction of patient dose in the radiology departments where patient dose are already below them. For this reason, the National Radiological Protection Board (NRPB) proposed a concept named achievable doses which are based on the mean dose observed for a selected sample of radiology departments. This paper will review and discuss the concept of guidance levels and achievable doses, and propose a new concept referred to as Expectation Levels that will encourage the radiology departments where patient dose are already below the guidance levels to keep patient dose as low as reasonably achievable. Some examples of the expectation levels based on the data published by a few countries are also illustrated in this paper

  2. Considering job-related doses in Europe

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    As part of its role of safeguarding nuclear workers the Commission of the European Community has created a European data bank on job-related doses. The data bank is intended to correlate jobs and workers doses and is a useful instrument to observe the collected doses of workers in nuclear power plants. Set up in 1980, the database covers doses in PWRs and BWRs. To create it a questionnaire is distributed to plant operators. The database responses provide information on (i) Trends in total collective doses, including those for some ancillary jobs. It is possible to see trends by calendar year and by fuel cycle number. (ii) Other trends such as dose in terms of installed power or dose in terms of power station design. (iii) Dose differences between power stations, normalized against the differences in dose rates. This is only possible for PWRs that monitor dose rates using the EPRI standard monitoring programme. (vi) The relative dose rate in each plant for a defined job. The questionnaire is not perfectly adapted to all the working criteria in nuclear power stations but it is an effective tool for implementing radiation protection. (author)

  3. Peripheral dose outside applicators in electron beams

    International Nuclear Information System (INIS)

    Chow, James C L; Grigorov, Grigor N

    2006-01-01

    The peripheral dose outside the applicators in electron beams was studied using a Varian 21 EX linear accelerator. To measure the peripheral dose profiles and point doses for the applicator, a solid water phantom was used with calibrated Kodak TL films. Peak dose spot was observed in the 4 MeV beam outside the applicator. The peripheral dose peak was very small in the 6 MeV beam and was ignorable at higher energies. Using the 10 x 10 cm 2 cutout and applicator, the dose peak for the 4 MeV beam was about 12 cm away from the field central beam axis (CAX) and the peripheral dose profiles did not change with depths measured at 0.2, 0.5 and 1 cm. The peripheral doses and profiles were further measured by varying the angle of obliquity, cutout and applicator size for the 4 MeV beam. The local peak dose was increased with about 3% per degree angle of obliquity, and was about 1% of the prescribed dose (angle of obliquity equals zero) at 1 cm depth in the phantom using the 10 x 10 cm 2 cutout and applicator. The peak dose position was also shifted 7 mm towards the CAX when the angle of obliquity was increased from 0 to 15 deg. (note)

  4. Cytogenetic effects of low-dose radiation

    International Nuclear Information System (INIS)

    Metalli, P.

    1983-01-01

    The effects of ionizing radiation on chromosomes have been known for several decades and dose-effect relationships are also fairly well established in the mid- and high-dose and dose-rate range for chromosomes of mammalian cells. In the range of low doses and dose rates of different types of radiation few data are available for direct analysis of the dose-effect relationships, and extrapolation from high to low doses is still the unavoidable approach in many cases of interest for risk assessment. A review is presented of the data actually available and of the attempts that have been made to obtain possible generalizations. Attention is focused on some specific chromosomal anomalies experimentally induced by radiation (such as reciprocal translocations and aneuploidies in germinal cells) and on their relevance for the human situation. (author)

  5. Dose evaluation in diagnostic for computerized tomography

    International Nuclear Information System (INIS)

    Flores, W.; Borges, J.C.; Mota, H.

    1998-01-01

    The patients which are subjected to computerized tomography tests are exposed to relatively high doses given as result doses on organs that are not matter to test. It was realized a dose levels raising in patients subjected to tests by T C, utilizing to measure this magnitude, TLD-100 thermoluminescent dosemeters which were put directly on the patient, in eye regions, thyroid, breast and navel; founding doses fluctuating between 29.10-49.39 mGy in organs examined and dose values between 0.21-29.10 mGy for organs that no matter to test. The applications of ionizing radiations in medicine do not have dose limits, but paying attention to the radiological protection optimization principle, it is recommended the use of clothes to anti-rays protection for zones not examined, getting with this to reduce the level doses as low as possible, without this to diminish the test quality. (Author)

  6. The concept of the effective dose

    International Nuclear Information System (INIS)

    Jacobi, W.

    1975-01-01

    Irradiation of the human body by external or internal sources leads mostly to a simultaneous exposure of several organs. However, so far no clear and consistent recommendations for the combination of organ doses and the assessment of an exposure limit under such irradiation conditions are available. Following a proposal described in ICRP-publication 14 one possible concept for the combination of organ doses is discussed in this paper. This concept is based on the assumption that at low doses the total radiation detriment to the exposed person is given by the sum of radiation detriments to the single organs. Taking into account a linear dose-risk relationship, the sum of weighted organ doses leads to the definition of an 'Effective Dose'. The applicability and consequences of this 'Effective Dose Concept' are discussed especially with regard to the assessment of the maximum permissible intake of radionuclides into the human body and the combination of external and internal exposure. (orig.) [de

  7. Salivary gland doses from dental radiographic exposures

    International Nuclear Information System (INIS)

    Hoshi, Masaharu; Kato, Kazuo; Wada, Takuro; Antoku, Shigetoshi; Russell, W.J.

    1989-01-01

    Salivary gland doses incurred during dental radiography were measured by phantom dosimetry, and these dose data and data obtained during a two-week survey of Hiroshima and Nagasaki dental hospitals and clinics were used to estimate the respective doses to members of the populations of the two cities. The results obtained were used to supplement previously determined doses to the thyroid gland, lens, and pituitary gland from dental radiography. No significant differences in doses were observed by age, sex or city. Doses to the salivary glands during dental radiography are probably not sufficiently large to cause bias in assessments of atomic bomb survivors for late radiation effects. However, the steadily increasing use of dental radiography underscores the need for continued monitoring of dental radiography doses in the interests of these assessments. (author)

  8. Routine monitoring of eye dose; and reply

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, K; Jeans, S P; Faulkner, K; Bardsley, R A; Love, H G

    1985-12-01

    This letter briefly reports the assessment at Papworth Hospital of the feasibility of monitoring eye doses of staff using a film badge worn on the shoulder in addition to the badge worn under the lead apron. For three consecutive months hand and eye (forehead) dose were monitored using TLDs, while shoulder and body dose, recorded under the lead apron, were measured with film badges. For the four doctors monitored, (two radiologists and two cardiologists) the shoulder badge somewhat overestimated the eye dose. In the case of nurses, the dose recorded by the shoulder badge was of a similar order to the TLD-recorded eye dose. The reply from the Christie Hospital at Manchester comments on the use of the shoulder badge and contends that the use of forehead dosemeters to measure eye dose is to be preferred whenever possible.

  9. Hand Dose in Nuclear Medicine Staff Members

    International Nuclear Information System (INIS)

    Taha, T.M.; Shahein, A.Y.; Hassan, R.

    2009-01-01

    Measurement of the hand dose during preparation and injection of radiopharmaceuticals is useful in the assessment of the extremity doses received by nuclear medicine personnel. Hand radiation doses to the occupational workers that handling 99m Tc-labeled compounds, 131 I for diagnostic in nuclear medicine were measured by thermoluminescence dosimetry. A convenient method is to use a TLD ring dosimeter for measuring doses of the diagnostic units of different nuclear medicine facilities . Their doses were reported in millisieverts that accumulated in 4 weeks. The radiation doses to the hands of nuclear medicine staff at the hospitals under study were measured. The maximum expected annual dose to the extremities appeared to be less than the annual limit (500 mSv/y) because all of these workers are on rotation and do not constantly handle radioactivity throughout the year

  10. Maintaining occupational dose ALARA through work management

    International Nuclear Information System (INIS)

    Khan, A. H.

    1999-01-01

    Canadian philosophy in keeping occupational dose ALARA has been to train staff in radiation safety so that they can be fully responsible for participating in minimizing the risks associated with the hazardous work. Senior managers actively promote high standards of performance in dose reduction techniques as a means for integrating ALARA into the operation and maintenance of the station by all personnel. Minimizing radiation dose is accomplished by applying cost effective work management techniques such as Job Safety Analysis, pre-job briefings and establishing and achieving radiation dose goals. Radiation dose goals are used as a management tool for involving all work groups in reducing doses as well as providing a means of assessing the effectiveness of dose reduction actions. ALARA, along with conventional safety, is used as a lever to raise the standard of quality of work and to overall build a safety culture. (author). 4 figs

  11. MONTEC, an interactive fortran program to simulate radiation dose and dose-rate responses of populations

    International Nuclear Information System (INIS)

    Perry, K.A.; Szekely, J.G.

    1983-09-01

    The computer program MONTEC was written to simulate the distribution of responses in a population whose members are exposed to multiple radiation doses at variable dose rates. These doses and dose rates are randomly selected from lognormal distributions. The individual radiation responses are calculated from three equations, which include dose and dose-rate terms. Other response-dose/rate relationships or distributions can be incorporated by the user as the need arises. The purpose of this documentation is to provide a complete operating manual for the program. This version is written in FORTRAN-10 for the DEC system PDP-10

  12. Experimental data and dose-response models

    International Nuclear Information System (INIS)

    Ullrich, R.L.

    1985-01-01

    Dose-response relationships for radiation carcinogenesis have been of interest to biologists, modelers, and statisticians for many years. Despite his interest there are few instances in which there are sufficient experimental data to allow the fitting of various dose-response models. In those experimental systems for which data are available the dose-response curves for tumor induction for the various systems cannot be described by a single model. Dose-response models which have been observed following acute exposures to gamma rays include threshold, quadratic, and linear models. Data on sex, age, and environmental influences of dose suggest a strong role of host factors on the dose response. With decreasing dose rate the effectiveness of gamma ray irradiation tends to decrease in essentially every instance. In those cases in which the high dose rate dose response could be described by a quadratic model, the effect of dose rate is consistent with predictions based on radiation effects on the induction of initial events. Whether the underlying reasons for the observed dose-rate effect is a result of effects on the induction of initial events or is due to effects on the subsequent steps in the carcinogenic process is unknown. Information on the dose response for tumor induction for high LET (linear energy transfer) radiations such as neutrons is even more limited. The observed dose and dose rate data for tumor induction following neutron exposure are complex and do not appear to be consistent with predictions based on models for the induction of initial events

  13. Patient Dose From Megavoltage Computed Tomography Imaging

    International Nuclear Information System (INIS)

    Shah, Amish P.; Langen, Katja M.; Ruchala, Kenneth J.; Cox, Andrea; Kupelian, Patrick A.; Meeks, Sanford L.

    2008-01-01

    Purpose: Megavoltage computed tomography (MVCT) can be used daily for imaging with a helical tomotherapy unit for patient alignment before treatment delivery. The purpose of this investigation was to show that the MVCT dose can be computed in phantoms, and further, that the dose can be reported for actual patients from MVCT on a helical tomotherapy unit. Methods and Materials: An MVCT beam model was commissioned and verified through a series of absorbed dose measurements in phantoms. This model was then used to retrospectively calculate the imaging doses to the patients. The MVCT dose was computed for five clinical cases: prostate, breast, head/neck, lung, and craniospinal axis. Results: Validation measurements in phantoms verified that the computed dose can be reported to within 5% of the measured dose delivered at the helical tomotherapy unit. The imaging dose scaled inversely with changes to the CT pitch. Relative to a normal pitch of 2.0, the organ dose can be scaled by 0.67 and 2.0 for scans done with a pitch of 3.0 and 1.0, respectively. Typical doses were in the range of 1.0-2.0 cGy, if imaged with a normal pitch. The maximal organ dose calculated was 3.6 cGy in the neck region of the craniospinal patient, if imaged with a pitch of 1.0. Conclusion: Calculation of the MVCT dose has shown that the typical imaging dose is approximately 1.5 cGy per image. The uniform MVCT dose delivered using helical tomotherapy is greatest when the anatomic thickness is the smallest and the pitch is set to the lowest value

  14. Conventional radiology and genetic dose

    International Nuclear Information System (INIS)

    Gonzalez-Vila, V.; Fernandez, A.; Rivera, F.; Martinez, M.; Gomez, A.; Luis, J.

    1992-01-01

    A research project was established in 1984 to evaluate the expected genetic abnormalities due to radiation received by the population attending the Outpatient Radiological Service due to medical radiological practices. The study was conducted in 1985 (12 weeks chosen by random). The equivalent gonadal dose was the chosen parameter, representing the social cost of the radiology. Samples of 2945 men and 2929 women were considered in the study. The number of genetic abnormalities, in relation to the mean age of reproduction (a generation every 30 years), was 2.13 cases per million in the first generation and 15.97 cases per million at equilibrium. The authors interpretation is that both the method and the expected genetic detriment are suitable procedures for the characterisation of the Radiological Service as a radiation source. (author)

  15. Quality control for dose calibrators

    International Nuclear Information System (INIS)

    Mendes, L.C.G.

    1984-01-01

    Nuclear medicine laboratories are required to assay samples of radioactivity to be administered to patients. Almost universally, these assays are accomplished by use of a well ionization chamber isotope calibrator. The Instituto de Radioprotecao e Dosimetria (Institute for Radiological Protection and Dosimetry) of the Comissao Nacional de Energia Nuclear (National Commission for Nuclear Energy) is carrying out a National Quality Control Programme in Nuclear Medicine, supported by the International Atomic Energy Agency. The assessment of the current needs and practices of quality control in the entire country of Brazil includes Dose Calibrators and Scintillation Cameras, but this manual is restricted to the former. Quality Control Procedures for these Instruments are described in this document together with specific recommendations and assessment of its accuracy. (author)

  16. Method of preparing radionuclide doses

    International Nuclear Information System (INIS)

    Kuperus, J.H.

    1987-01-01

    A method is described of preparing aliquot dosea of a tracer material useful in diagnostic nuclear medicine comprising: storing discrete quantities of a lyophilized radionuclide carrier in separate tubular containers from which air and moisture is excluded, selecting from the tubular containers a container in which is stored a carrier appropriate for a nuclear diagnostic test to be performed, interposing the selected container between the needle and the barrel of a hypodermic syringe, and drawing a predetermined amount of a liquid containing a radionuclide tracer in known concentration into the hypodermic syringe barrel through the hypodermic needle and through the selected container to dissolve the discrete quantity of lyophilized carrier therein to combine the carrier with the radionuclide tracer to form an aliquot dose of nuclear diagnostic tracer material, as needed

  17. Radiation dose rate measuring device

    International Nuclear Information System (INIS)

    Sorber, R.

    1987-01-01

    A portable device is described for in-field usage for measuring the dose rate of an ambient beta radiation field, comprising: a housing, substantially impervious to beta radiation, defining an ionization chamber and having an opening into the ionization chamber; beta radiation pervious electrically-conductive window means covering the opening and entrapping, within the ionization chamber, a quantity of gaseous molecules adapted to ionize upon impact with beta radiation particles; electrode means disposed within the ionization chamber and having a generally shallow concave surface terminating in a generally annular rim disposed at a substantially close spacing to the window means. It is configured to substantially conform to the window means to define a known beta radiation sensitive volume generally between the window means and the concave surface of the electrode means. The concave surface is effective to substantially fully expose the beta radiation sensitive volume to the radiation field over substantially the full ambient area faced by the window means

  18. Optimizing lithium dosing in hemodialysis

    DEFF Research Database (Denmark)

    Bjarnason, N H; Munkner, R; Kampmann, J P

    2006-01-01

    We studied a 62-year-old female hemodialysis patient during initiation and maintenance of lithium carbonate therapy. Three different methods were applied to estimate the regimen: a scenario based on volume of distribution (V(d)), a scenario based on glomerular filtration rate (GFR), and a scenario...... estimates. Furthermore, the maintenance dose estimated from the central compartment (V1) led to plasma concentrations within the therapeutic range. Thus, a regimen where 12.2 mmol lithium was given after each hemodialysis session resulted in stable between-dialysis plasma lithium concentrations...... in this patient with no residual kidney function. We did not observe adverse effects related to this regimen, which was monitored from 18 days to 8 months of therapy, and the patient experienced relief from her severe depressive disorder. In conclusion, dialysis patients may be treated with lithium administrated...

  19. Determination of Entrance Skin Doses and Organ Doses for Medical X Ray Examinations

    International Nuclear Information System (INIS)

    Tung, C.J.; Cheng, C.Y.; Chao, T.C.; Tsai, H.Y.

    1999-01-01

    A national survey of patient doses for diagnostic X ray radiographs is planned in Taiwan. Entrance skin doses and organ doses for all installed X ray machines will be investigated. A pilot study has been carried out for the national survey to develop a protocol for the dose assessment. Entrance skin doses and organ doses were measured by thermoluminescence dosemeters and calculated by Monte Carlo simulations for several X ray examinations. The conversion factor from free air entrance absorbed dose to entrance skin dose was derived. A formula for the computation of entrance skin doses from inputs of kV p , mA.s, source to skin distance, aluminium filtration, and generator rectifying was constructed. Organ doses were measured using a RANDO phantom and calculated using a mathematical phantom. All data will be passed to the Atomic Energy Council for developing a programme of national survey and regulatory controls for diagnostic X ray examinations. (author)

  20. Quality control of 192Ir high dose rate after loading brachytherapy dose veracity

    International Nuclear Information System (INIS)

    Feng Zhongsu; Xu Xiao; Liu Fen

    2008-01-01

    Recently, 192 Ir high dose rate (HDR) afterloading are widely used in brachytherapy. The advantage of using HDR systems over low dose rate systems are shorter treatment time and higher fraction dose. To guarantee the veracity of the delivery dose, several quality control methods are deseribed in this work. With these we can improve the position precision, time precision and dose precision of the brachytherapy. (authors)

  1. Prediction of midline dose from entrance ad exit dose using OSLD measurements for total irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Heon; Park, Jong Min; Park, So Yeon; Chun, Min Soo; Han, Ji Hye; Cho, Jin Dong; Kim, Jung In [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2017-06-15

    This study aims to predict the midline dose based on the entrance and exit doses from optically stimulated luminescence detector (OSLD) measurements for total body irradiation (TBI). For TBI treatment, beam data sets were measured for 6 MV and 15 MV beams. To evaluate the tissue lateral effect of various thicknesses, the midline dose and peak dose were measured using a solid water phantom (SWP) and ion chamber. The entrance and exit doses were measured using OSLDs. OSLDs were attached onto the central beam axis at the entrance and exit surfaces of the phantom. The predicted midline dose was evaluated as the sum of the entrance and exit doses by OSLD measurement. The ratio of the entrance dose to the exit dose was evaluated at various thicknesses. The ratio of the peak dose to the midline dose was 1.12 for a 30 cm thick SWP at both energies. When the patient thickness is greater than 30 cm, the 15 MV should be used to ensure dose homogeneity. The ratio of the entrance dose to the exit dose was less than 1.0 for thicknesses of less than 30 cm and 40 cm at 6 MV and 15 MV, respectively. Therefore, the predicted midline dose can be underestimated for thinner body. At 15 MV, the ratios were approximately 1.06 for a thickness of 50 cm. In cases where adult patients are treated with the 15 MV photon beam, it is possible for the predicted midline dose to be overestimated for parts of the body with a thickness of 50 cm or greater. The predicted midline dose and OSLD-measured midline dose depend on the phantom thickness. For in-vivo dosimetry of TBI, the measurement dose should be corrected in order to accurately predict the midline dose.

  2. Skin dose variation: influence of energy

    International Nuclear Information System (INIS)

    Cheung, T.; Yu, P.K.N.; Butson, M.J.; Cancer Services, Wollongong, NSW

    2004-01-01

    Full text: This research aimed to quantitatively evaluate the differences in percentage dose of maximum for 6MV and 18MV x-ray beams within the first lcm of interactions. Thus provide quantitative information regarding the basal, dermal and subcutaneous dose differences achievable with these two types of high-energy x-ray beams. Percentage dose of maximum build up curves are measured for most clinical field sizes using 6MV and 18MV x-ray beams. Calculations are performed to produce quantitative results highlighting the percentage dose of maximum differences delivered to various depths within the skin and subcutaneous tissue region by these two beams Results have shown that basal cell layer doses are not significantly different for 6MV and 18Mv x-ray beams At depths beyond the surface and basal cell layer there is a measurable and significant difference in delivered dose. This variation increases to 20% of maximum and 22% of maximum at Imm and 1cm depths respectively. The percentage variations are larger for smaller field sizes where the photon in phantom component of the delivered dose is the most significant contributor to dose By producing graphs or tables of % dose differences in the build up region we can provide quantitative information to the oncologist for consideration (if skin and subcutaneous tissue doses are of importance) during the beam energy selection process for treatment. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  3. Failure-probability driven dose painting

    International Nuclear Information System (INIS)

    Vogelius, Ivan R.; Håkansson, Katrin; Due, Anne K.; Aznar, Marianne C.; Kristensen, Claus A.; Rasmussen, Jacob; Specht, Lena; Berthelsen, Anne K.; Bentzen, Søren M.

    2013-01-01

    Purpose: To demonstrate a data-driven dose-painting strategy based on the spatial distribution of recurrences in previously treated patients. The result is a quantitative way to define a dose prescription function, optimizing the predicted local control at constant treatment intensity. A dose planning study using the optimized dose prescription in 20 patients is performed.Methods: Patients treated at our center have five tumor subvolumes from the center of the tumor (PET positive volume) and out delineated. The spatial distribution of 48 failures in patients with complete clinical response after (chemo)radiation is used to derive a model for tumor control probability (TCP). The total TCP is fixed to the clinically observed 70% actuarial TCP at five years. Additionally, the authors match the distribution of failures between the five subvolumes to the observed distribution. The steepness of the dose–response is extracted from the literature and the authors assume 30% and 20% risk of subclinical involvement in the elective volumes. The result is a five-compartment dose response model matching the observed distribution of failures. The model is used to optimize the distribution of dose in individual patients, while keeping the treatment intensity constant and the maximum prescribed dose below 85 Gy.Results: The vast majority of failures occur centrally despite the small volumes of the central regions. Thus, optimizing the dose prescription yields higher doses to the central target volumes and lower doses to the elective volumes. The dose planning study shows that the modified prescription is clinically feasible. The optimized TCP is 89% (range: 82%–91%) as compared to the observed TCP of 70%.Conclusions: The observed distribution of locoregional failures was used to derive an objective, data-driven dose prescription function. The optimized dose is predicted to result in a substantial increase in local control without increasing the predicted risk of toxicity

  4. ''Low dose'' and/or ''high dose'' in radiation protection: A need to setting criteria for dose classification

    International Nuclear Information System (INIS)

    Sohrabi, M.

    1997-01-01

    The ''low dose'' and/or ''high dose'' of ionizing radiation are common terms widely used in radiation applications, radiation protection and radiobiology, and natural radiation environment. Reading the title, the papers of this interesting and highly important conference and the related literature, one can simply raise the question; ''What are the levels and/or criteria for defining a low dose or a high dose of ionizing radiation?''. This is due to the fact that the criteria for these terms and for dose levels between these two extreme quantities have not yet been set, so that the terms relatively lower doses or higher doses are usually applied. Therefore, setting criteria for classification of radiation doses in the above mentioned areas seems a vital need. The author while realizing the existing problems to achieve this important task, has made efforts in this paper to justify this need and has proposed some criteria, in particular for the classification of natural radiation areas, based on a system of dose limitation. (author)

  5. A graphical review of radiogenic animal cancer data using the 'dose and dose-rate map'

    International Nuclear Information System (INIS)

    Yoshida, Kazuo; Hoshi, Yuko; Sakai, Kazuo

    2008-01-01

    We have been investigating the effects of low dose or low dose rate irradiation on mice, using our low dose-rate irradiation facilities. In these studies, we found that the effects were highly dependent on both total dose and dose rate. To show this visually, we proposed the 'dose/dose rate map', and plotted the results of our laboratory and our co-workers. The map demonstrated that dose/dose rate plane could be divided into three areas; 1) An area where harmful effects are observed, 2) An area where no harmful effects are observed, and 3) Another area, between previous two areas, where certain protective functions are enhanced. As this map would be a powerful tool to find some trend among the vast numbers of data relating the biological effects of ionizing radiation, we have developed a computer program which plots the collected data on the dose/dose rate map sorting by experimental conditions. In this study, we graphically reviewed and analyzed the data relating to the lifespan studies of animals with a view to determining the relationships between doses and dose rates of ionizing radiation and cancer incidence. The data contains about 800 sets of experiments, which concerns 187,000 animals exposed to gamma ray or X-ray and their 112,000 controls, and total of about 30,000 cancers in exposed animals and 14,000 cancers in controls. About 800 points of data were plotted on the dose/dose rate map. The plot showed that 1) The divided three areas in the dose/dose rate map were generally confirmed by these 800 points of data, and 2) In some particular conditions, e.g. sarcoma by X-rays, the biologically effective area is extended to relatively high dose/dose rate area. (author)

  6. Simulation of dose reduction in tomosynthesis

    International Nuclear Information System (INIS)

    Svalkvist, Angelica; Baath, Magnus

    2010-01-01

    Purpose: Methods for simulating dose reduction are valuable tools in the work of optimizing radiographic examinations. Using such methods, clinical images can be simulated to have been collected at other, lower, dose levels without the need of additional patient exposure. A recent technology introduced to healthcare that needs optimization is tomosynthesis, where a number of low-dose projection images collected at different angles is used to reconstruct section images of an imaged object. The aim of the present work was to develop a method of simulating dose reduction for digital radiographic systems, suitable for tomosynthesis. Methods: The developed method uses information about the noise power spectrum (NPS) at the original dose level and the simulated dose level to create a noise image that is added to the original image to produce an image that has the same noise properties as an image actually collected at the simulated dose level. As the detective quantum efficiency (DQE) of digital detectors operating at the low dose levels used for tomosynthesis may show a strong dependency on the dose level, it is important that a method for simulating dose reduction for tomosynthesis takes this dependency into account. By applying an experimentally determined relationship between pixel mean and pixel variance, variations in both dose and DQE in relevant dose ranges are taken into account. Results: The developed method was tested on a chest tomosynthesis system and was shown to produce NPS of simulated dose-reduced projection images that agreed well with the NPS of images actually collected at the simulated dose level. The simulated dose reduction method was also applied to tomosynthesis examinations of an anthropomorphic chest phantom, and the obtained noise in the reconstructed section images was very similar to that of an examination actually performed at the simulated dose level. Conclusions: In conclusion, the present article describes a method for simulating dose

  7. Practical applications of internal dose calculations

    International Nuclear Information System (INIS)

    Carbaugh, E.H.

    1994-06-01

    Accurate estimates of intake magnitude and internal dose are the goal for any assessment of an actual intake of radioactivity. When only one datum is available on which to base estimates, the choices for internal dose assessment become straight-forward: apply the appropriate retention or excretion function, calculate the intake, and calculate the dose. The difficulty comes when multiple data and different types of data become available. Then practical decisions must be made on how to interpret conflicting data, or how to adjust the assumptions and techniques underlying internal dose assessments to give results consistent with the data. This article describes nine types of adjustments which can be incorporated into calculations of intake and internal dose, and then offers several practical insights to dealing with some real-world internal dose puzzles

  8. Radiation doses in buildings containing coal

    International Nuclear Information System (INIS)

    Somlai, J.; Kanyar, B.; Nenyei, A.; Nemeth, Z.; Nemeth, Cs.

    2001-01-01

    Using coal-slag with high concentration of 226 Ra as building material could result excess dose of people living in these dwellings. The gamma dose rate, the radon concentration and the radionuclide concentration of built-in slags were measured in kindergartens, schools and homes of three towns (Ajka, Tatabanya, Varpalota). The absorbed dose rates exceeded significantly the world average (80 nGy/h) and the annual dose reached 3-4 mSv in some cases. The dose coming from radon is significant in the case of slags, which did not originate from power plants but from smaller stoves and furnaces because in these cases the burning temperature is lower, so the radon emanation is higher. The dose in the latter cases could reach 10-20 mSv/year. (author)

  9. The dose-area product in DSA

    International Nuclear Information System (INIS)

    Gfirtner, H.

    1995-01-01

    In DSA, the dose-area product shows a very good correlation with the maximum incidence dose. It may therefore serve as a reliable basis for the assessment of radiation doses to patients. The dose-area product is also a useful tool for the detection pf peak shifts in the radiation curves for certain investigations. In view of the considerable scatter of the values for the dose-area product these must, however, be subjected to an additional statistical analysis. Provided that this rule is observed, the dose-area product will considerably gain in importance for the monitoring of radiation exposures of patients. A very noteworthy learning effect could be achieved, if it would be made mandatory for those statistical analyses to be carried out not only on an investigation-specific but also an investigator-specific basis. The latter is particularly true of teaching hospitals. (orig./VHE) [de

  10. Patient and staff dose during hysterosalpinography

    International Nuclear Information System (INIS)

    Buls, N.; Osteaux, M.

    2001-01-01

    Hysterosalpingography (HSG) is a useful and widely employed technique which uses X-ray fluoroscopy to investigate the female genital tract. Fluoroscopy is assessed by a gynaecologist, a physician who is not always trained to work with ionising radiation. Dose-area product measurements in a group of 34 patients allowed an estimation of the median effective dose (0,83 mSv) and the median dose to the ovaries (1,63 mGy) of the patient per procedure. The dose to the staff was estimated using thermoluminescent dosimetry. The following median entrance surface doses were estimated per procedure: 0,22 mGy to the lens of the eye, 0,15 mGy to the neck at thyroid level and 0,19 mGy to the back of the hand. The annual eye dose limit could be exceeded if the gynaecologist is a member of the public. (author)

  11. Progress in high-dose radiation dosimetry

    International Nuclear Information System (INIS)

    Ettinger, K.V.; Nam, J.W.; McLaughlin, W.L.; Chadwick, K.H.

    1981-01-01

    The last decade has witnessed a deluge of new high-dose dosimetry techniques and expanded applications of methods developed earlier. Many of the principal systems are calibrated by means of calorimetry, although production of heat is not always the final radiation effect of interest. Reference systems also include a number of chemical dose meters: ferrous sulphate, ferrous-cupric sulphate, and ceric sulphate acidic aqueous solutions. Requirements for stable and reliable transfer dose meters have led to further developments of several important high-dose systems: amino acids and saccharides analysed by ESR or lyoluminescence, thermoluminescent materials, radiochromic dyes and plastics, ceric-cerous solutions analysed by potentiometry, and ethanol-chlorobenzene solutions analysed by high-frequency oscillometry. A number of other prospective dose meters are also treated in this review. In addition, an IAEA programme of high-dose standardization and intercomparison for industrial radiation processing is described. (author)

  12. Use of dose constraints in public exposure

    International Nuclear Information System (INIS)

    Tageldein, Amged

    2015-02-01

    An overview of the dose constraints in public exposures has been carried out in this project. The establishment, development and the application of the concept of dose constraints are reviewed with regards to public exposure. The role of dose constraints in the process of optimization of radiation protection was described and has been showed that the concept of the dose constraints along with many other concept of radiation protection is widely applied in the optimization of exposure to radiation. From the beginning of the establishment of dose constraints as a concept in radiation protection, the International Commission of Radiological Protection (ICRP) has published a number of documents that provides detailed application related to radiation protection and safety of public exposure from ionizing radiation. This work provides an overview of such publications and related documents with special emphasis on optimization of public exposure using dose constraints. (au)

  13. Dependence of total dose response of bipolar linear microcircuits on applied dose rate

    International Nuclear Information System (INIS)

    McClure, S.; Will, W.; Perry, G.; Pease, R.L.

    1994-01-01

    The effect of dose rate on the total dose radiation hardness of three commercial bipolar linear microcircuits is investigated. Total dose tests of linear bipolar microcircuits show larger degradation at 0.167 rad/s than at 90 rad/s even after the high dose rate test is followed by a room temperature plus a 100 C anneal. No systematic correlation could be found for degradation at low dose rate versus high dose rate and anneal. Comparison of the low dose rate with the high dose rate anneal data indicates that MIL-STD-883, method 1019.4 is not a worst-case test method when applied to bipolar microcircuits for low dose rate space applications

  14. Analysis of workers' dose records from the Greek Dose Registry Information System

    International Nuclear Information System (INIS)

    Kamenopoulou, V.; Dimitriou, P.; Proukakis, Ch.

    1995-01-01

    The object of this work is the study of the individual film badge annual dose information of classified workers in Greece, monitored and assessed by the central dosimetry service of the Greek Atomic Energy Commission. Dose summaries were recorded and processed by the Dose Registry Information System. The statistical analysis refers to the years 1989-93 and deals with the distribution of individuals in the occupational groups, the mean annual dose, the collective dose, the distribution of the dose over the different specialties and the number of workers that have exceeded any of the established dose limits. Results concerning the annual dose summaries, demonstrate a year-by-year reduction in the mean individual dose to workers in the health sector. Conversely, exposures in the industrial sector did not show any decreasing tendency during the period under consideration. (Author)

  15. Equivalent dose determination in foraminifera: analytical description of the CO2--signal dose-response curve

    International Nuclear Information System (INIS)

    Hoffmann, D.; Woda, C.; Mangini, A.

    2003-01-01

    The dose-response of the CO 2 - signal (g=2.0006) in foraminifera with ages between 19 and 300 ka is investigated. The sum of two exponential saturation functions is an adequate function to describe the dose-response curve up to an additional dose of 8000 Gy. It yields excellent dating results but requires an artificial doses of at least 5000 Gy. For small additional doses of about 500 Gy the single exponential saturation function can be used to calculate a reliable equivalent dose D E , although it does not describ the dose-response for higher doses. The CO 2 - -signal dose-response indicates that the signal has two components of which one is less stable than the other

  16. Dynamically accumulated dose and 4D accumulated dose for moving tumors

    International Nuclear Information System (INIS)

    Li Heng; Li Yupeng; Zhang Xiaodong; Li Xiaoqiang; Liu Wei; Gillin, Michael T.; Zhu, X. Ronald

    2012-01-01

    Purpose: The purpose of this work was to investigate the relationship between dynamically accumulated dose (dynamic dose) and 4D accumulated dose (4D dose) for irradiation of moving tumors, and to quantify the dose uncertainty induced by tumor motion. Methods: The authors established that regardless of treatment modality and delivery properties, the dynamic dose will converge to the 4D dose, instead of the 3D static dose, after multiple deliveries. The bounds of dynamic dose, or the maximum estimation error using 4D or static dose, were established for the 4D and static doses, respectively. Numerical simulations were performed (1) to prove the principle that for each phase, after multiple deliveries, the average number of deliveries for any given time converges to the total number of fractions (K) over the number of phases (N); (2) to investigate the dose difference between the 4D and dynamic doses as a function of the number of deliveries for deliveries of a “pulsed beam”; and (3) to investigate the dose difference between 4D dose and dynamic doses as a function of delivery time for deliveries of a “continuous beam.” A Poisson model was developed to estimate the mean dose error as a function of number of deliveries or delivered time for both pulsed beam and continuous beam. Results: The numerical simulations confirmed that the number of deliveries for each phase converges to K/N, assuming a random starting phase. Simulations for the pulsed beam and continuous beam also suggested that the dose error is a strong function of the number of deliveries and/or total deliver time and could be a function of the breathing cycle, depending on the mode of delivery. The Poisson model agrees well with the simulation. Conclusions: Dynamically accumulated dose will converge to the 4D accumulated dose after multiple deliveries, regardless of treatment modality. Bounds of the dynamic dose could be determined using quantities derived from 4D doses, and the mean dose

  17. Switching From Age-Based Stimulus Dosing to Dose Titration Protocols in Electroconvulsive Therapy: Empirical Evidence for Better Patient Outcomes With Lower Peak and Cumulative Energy Doses.

    Science.gov (United States)

    O'Neill-Kerr, Alex; Yassin, Anhar; Rogers, Stephen; Cornish, Janie

    2017-09-01

    The aim of this study was to test the proposition that adoption of a dose titration protocol may be associated with better patient outcomes, at lower treatment dose, and with comparable cumulative dose to that in patients treated using an age-based stimulus dosing protocol. This was an analysis of data assembled from archived records and based on cohorts of patients treated respectively on an age-based stimulus dosing protocol and on a dose titration protocol in the National Health Service in England. We demonstrated a significantly better response in the patient cohort treated with dose titration than with age-based stimulus dosing. Peak doses were less and the total cumulative dose was less in the dose titration group than in the age-based stimulus dosing group. Our findings are consistent with superior outcomes in patients treated using a dose titration protocol when compared with age-based stimulus dosing in a similar cohort of patients.

  18. Application of biological dose concept in dose optimization for conformal radiotherapy of prostate carcinoma

    International Nuclear Information System (INIS)

    Li Yunhai; Liao Yuan; Zhou Lijun; Pan Ziqiang; Feng Yan

    2003-01-01

    Objective: On basis of physical dose optimization, LQ model was used to investigate the difference between the curves of biological effective dose and physical isodose. The influence of applying the biological dose concept on three dimensional conformal radiotherapy of prostate carcinoma was discussed. Methods: Four treatment plannings were designed for physical dose optimization: three fields, four-box fields, five fields and six fields. Target dose uniformity and protection of the critical tissue-rectum were used as the principal standard for designing the treatment planning. Biological effective dose (BED) was calculated by LQ model. The difference between the BED curve drawn in the central layer and the physical isodose curve was studied. The difference between the adjusted physical dose (APD) and the physical dose was also studied. Results: Five field planning was the best in target dose uniformity and protection of the critical tissue-rectum. The physical dose was uniform in the target, but the biological effective doses revealed great discrepancy in the biological model. Adjusted physical dose distribution also displayed larger discrepancy than the physical dose unadjusted. Conclusions: Intensified Modulated Radiotherapy (IMRT) technique with inversion planning using biological dose concept may be much more advantageous to reach a high tumor control probability and low normal tissue complication probability

  19. Absorbed dose by a CMOS in radiotherapy

    International Nuclear Information System (INIS)

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R.; Paredes G, L. C.

    2011-10-01

    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  20. Monitoring and dose recording for the individual

    International Nuclear Information System (INIS)

    1988-01-01

    This document specifies the conditions under which monitoring of individuals is required. For workers identified as Atomic Radiation Workers, determination of dose or exposure must be made. In circumstances where personal monitoring techniques are impractical, doses and exposures may be estimated by non-personal monitoring techniques. For workers not identified as Atomic Radiation Workers, licensees must be able to demonstrate that there is no reasonable potential for accumulating radiation doses or exposures in excess of regulatory limits. (L.L.)

  1. Hanford Environmental Dose Reconstruction Project monthly report

    International Nuclear Information System (INIS)

    Finch, S.M.

    1991-10-01

    The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doeses that individuals and populations could have received from nuclear operations at Hanford since 1944. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): Source terms; environmental transport; environmental monitoring data; demographics, agriculture, food habits; environmental pathways and dose estimates

  2. Calculation methods for determining dose equivalent

    International Nuclear Information System (INIS)

    Endres, G.W.R.; Tanner, J.E.; Scherpelz, R.I.; Hadlock, D.E.

    1988-01-01

    A series of calculations of neutron fluence as a function of energy in an anthropomorphic phantom was performed to develop a system for determining effective dose equivalent for external radiation sources. critical organ dose equivalents are calculated and effective dose equivalents are determined using ICRP-26 methods. Quality factors based on both present definitions and ICRP-40 definitions are used in the analysis. The results of these calculations are presented and discussed

  3. Low-dose Dental-CT

    International Nuclear Information System (INIS)

    Gahleitner, A.; Imhof, H.; Homolka, P.; Fuerhauser, R.; Freudenthaler, J.; Watzek, G.

    2000-01-01

    Dental-CT is a relatively new, increasingly used investigation technique in dental radiology. Several authors have stated that the indication for Dental-CT has to be chosen on a strict basis, due to high dose values. This article describes the technique of performing dental-CT and calculates the effective dose based on published data and own measurements as well as the dose reduction potential to achieve an optimized protocol for Dental-CT investigations. (orig.) [de

  4. The reconstruction of thyroid dose following Chernobyl

    International Nuclear Information System (INIS)

    Stepanenko, V.; Kondrashov, A.; Yaskova, E.; Petin, D.; Skvortsov, V.; Parshkov, E.; Gavrilin, Yu.; Khrousch, V.; Shinkarev, S.; Makarenkova, I.; Volkov, V.; Zvonova, I.; Bratilova, A.; Kaidanovsky, J.; Minenko, V.; Drozdovich, V.; Ulanovsky, A.; Korneev, S.; Heinemann, K.; Pomplun, E.; Hille, R.; Bailiff, A.

    1996-01-01

    The report presents the overview of several approaches in working out the methods of thyroid internal dose reconstruction following Chernobyl. One of these approaches was developed (IBPh, Moscow; MRRC, Obninsk; IRM, Minsk) using the correlations between the mean dose calculation based on I 131 thyroid content measurements and Cs 137 contamination of territories. The available data on I 131 soil contamination were taken into account. The lack of data on I 131 soil contamination was supposed to be compensated by I 129 measurements in soil samples from contaminated territories. The semiempiric model was developed for dose reconstruction. The comparison of the results obtained by semiempiric model and empirical values are presented. The estimated values of average dose according semiempiric model were used for individual dose reconstruction. The IRH (St.-Petersburg) has developed the following method for individual dose reconstruction: correlation between the total I 131 radioiodine incorporation in thyroid and whole body Cs 137 content during first months after accident. The individual dose reconstruction is also mentioned to be performed using the data on individual milk consumption during first weeks after accident. For evaluation of average doses it is suggested to use the linear correlation: thyroid dose values based on radioiodine thyroid measurements vs Cs 137 contamination, air kerma rate, mean I 131 concentration in the milk. The method for retrospective reconstruction of thyroid dose caused by short-living iodine nuclides released after the Chernobyl accident has been developed by Research Centre, Juelich, Germany. It is based on the constant ratio that these nuclides have with the long-living I 129 . The contamination of soil samples by this nuclide can be used to assess thyroid doses. First results of I 129 contamination values and derived thyroid doses are to be presented

  5. Characteristics of repair following very low doses

    International Nuclear Information System (INIS)

    Braby, L.A.; Metting, N.F.; Nelson, J.M.

    1987-01-01

    The effects of ionizing radiation on living systems being with the physical processes of energy deposition and develop through many stages of chemical reaction and biological response. The modeling effort attempts to organize the available data and theories of all of these stages into self-consistent models that can be compared and tested. In some cases, important differences among models result in only small differences in cell survival within the ranges of dose and dose rate that are normally investigated. To overcome this limitation, new ways of irradiating cells at extremes of dose rate, or ways of evaluating the effects of very small doses, are developed. Mathematical modeling and cellular studies complement each other. It has recently been found that some mechanisms are not adequate to account for the interaction of dose and repair time as they affect the reproductive survival of plateau-phase Chinese hamster ovary (CHO) cells. Repair of radiation-induced cellular damage plays a central role in the survival of cells exposed to doses of 1 Gy or more. This repair is responsible for the dose rate, split-dose and delayed plating effect and can be evaluated. Because split-dose and dose-rate experiments involve repair during irradiation and delayed plating experiments involve repair after irradiation is completed, it was originally thought that different repair processes were involved. It is now clear that this is not necessarily the case. Appropriately designed models can account for observed effects at conventional doses (1 Gy or more) whether they assume all damage is lethal unless repaired or some damage is innocuous unless it interacts with additional damage. The fact that the survival following a plating delay is always less than the survival following immediate plating at low doses indicates that the damage produced is probably not potentially lethal

  6. Radiation dose reduction in pediatric CT

    International Nuclear Information System (INIS)

    Robinson, A.E.; Hill, E.P.; Harpen, M.D.

    1986-01-01

    The relationship between image noise and radiation dose was investigated in computed tomography (CT) images of a pediatric abdomen phantom. A protocol which provided a minimum absorbed dose consistent with acceptable image noise criteria was determined for a fourth generation CT scanner. It was found that pediatric abdominal CT scans could maintain diagnostic quality with at least a 50% reduction in dose from the manufacturers' suggested protocol. (orig.)

  7. Patient doses in interventional cardiology procedures

    International Nuclear Information System (INIS)

    Domienik, J.; Papierz, S.; Jankowski, J.; Peruga, J.Z.

    2008-01-01

    In most countries of European Union legislation requires the determination of the total skin dose to patient resulting from interventional procedures to assess the risk of deterministic effect. To this end, various dose indicators like dose area product (DAP), cumulative dose (CD) and entrance dose at the patient plane (EFD) are used in clinical practice. The study aims at relating those dose indicators with doses ascribe to the most irradiated areas of the patient skin usually expressed in terms of local maximal skin dose (MSD). For the study the local MSD and related to their areas are investigated and compared for coronary angiography CA and intervention (PCI). Two methods implying radiographic films Kodak EDR2 and matrixes of thermoluminescent dosimeters (TLDs) are applied for direct measurements of dose distribution for selected procedures. Both methods are compared. Additionally, for patient dosimetry the following data: MSD, CD, EFD, fluoroscopy time (FT), number of acquired images, total DAP, fluoro-DAP and record-DAP were collected for randomly selected procedure. The statistical quantities like: median, 3 rd quartile, mean and standard deviation for all dosimetric parameters are determined. Preliminary study showed that the values of data collected for coronary procedures are in the ranges 0,7 - 27,3 min for fluoroscopy time, 50 - 350 Gy cm 2 for total DAP, 300 - 2000 mGy for CD, 140 - 2000 mGy for EFD and 100 - 1500 mGy for local maximal skin dose. For interventions the ranges are, accordingly 3,0 - 43,6 min , 25 - 450 Gy cm 2 , 270 - 6600 mGy, 80 - 2600 mGy and 80 - 1500 mGy. As a result of the study the correlations between dose indicators and local MSD are analyzed. The concentration of dose on irradiated films are going to be investigated in some detail as well. (author)

  8. Dose mapping for documentation of radiation sterilization

    DEFF Research Database (Denmark)

    Miller, A.

    1999-01-01

    The radiation sterilization standards EN 552 and ISO 11137 require that dose mapping in real or simulated product be carried in connection with the process qualification. This paper reviews the recommendations given in the standards and discusses the difficulties and limitations of practical dose...... mapping. The paper further gives recommendations for effective dose mapping including traceable dosimetry, documented procedures for placement of dosimeters, and evaluation of measurement uncertainties. (C) 1999 Elsevier Science Ltd. All rights reserved....

  9. Cosmic radiation dose in the aircraft

    International Nuclear Information System (INIS)

    Vukovic, B.; Radolic, V.; Varga, M.; Planinic, J.; Vekic, B.

    2006-01-01

    When primary particles from space, mainly protons, enter the atmosphere, they produce interactions with air nuclei, and cosmic-ray showers are induced. The radiation field at aircraft altitude is complex, with different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. The non-neutron component of cosmic radiation dose aboard A 320 and ATR 42 aircraft was measured with TLD-100 (LiF:Mg,Ti) detectors and the Mini 6100 semiconductor dosimeter; the neutron dose was measured with the neutron dosimeter consisted of LR-115 track detector and boron foil BN-1 or 10B converter. The estimated occupational effective dose for the aircraft crew (A320) working 500 h per year was 1.64 mSv. Another experiment was performed at the flights Zagreb - Paris - Buenos Aires and reversely, when one measured cosmic radiation dose; for 26.7 h of flight, the MINI 6100 dosimeter gave an average dose rate of 2.3 μSv/h and the TLD dosimeter registered the total dose of 75 μSv or the average dose rate of 2.7 μSv/h; the neutron dosimeter gave the dose rate of 2.4 μSv/h. In the same month, February 2005, a traveling to the Japan (24 hours-flight: Zagreb - Frankfurt - Tokyo and reversely) and the TLD-100 measurement showed the average dose rate of 2.4 μSv/h; the neutron dosimeter gave the dose rate of 2.5 μSv/h. Comparing dose rates of the non-neutron component (low LET) and the neutron one (high LET) of the radiation field at the aircraft flight level, we could conclude the neutron component curried about 50% of the total dose, that was near other known data. (author)

  10. Individual dose control of workers

    International Nuclear Information System (INIS)

    Keverling Buisman, A.S.

    1990-01-01

    This publication has the character of a set of recommendations towards in practice working radiation protection specialists who are involved within their company or institute with the organization and performance of measurements in order to control the individual radiation burden caused by external exposition and internal contamination in applying radioactive materials and radiation apparatus. This publication gives information about the practical performance of personnel dosimetry at external exposure with a personnel dosimeter, which is carried on the body. The individual control of internal contamination is a much more complicated task. This publication assumes, with regard to this part, that people who are involved with it have been schooled as a radiation specialist level-3. For this part this publication contains numerical information needed for assessing of the individual effective follow-dose equivalence in occurring cases. A list with data of much used radionuclides is included. Also dosimetric data are presented which may be useful in case of contamination of skin and wounds. (author). 14 refs.; 2 figs.; 17 tabs

  11. Control instrument for dose ratemeters

    International Nuclear Information System (INIS)

    Rutzki, B.

    1974-01-01

    The testing apparatus for the dose ratemeter has safety locking mechanisms for protection of the operating personnel allowing the apparatus to be opened only if the nuclear radiation source is shielded. For this purpose, the apparatus consists of a casing with an opening to be locked. The lock may be in the shape of a hollow cylinder matching with the likewise cylindrical wall of the casing through a ball bearing. The hollow-cylindrical part has an internal flange with a recess in which a shielding body in the shape of a roller is supported. The shielding body has a flattening on the jacket surface and penetrations for the nuclear radiation filled with absorbing material. Because of the eccentric bearing of the rotating shielding body with respect to the flange resp. the recess, the door connot be opened. Only after removal of the shielding block from the recess whereby the movement is caused from outside the casing by means of a knurling wheel, can the door be opened. Now, however, the shielding block is in the way of the beam from the nuclear radiation source and is shielding the door completely from it. (DG) [de

  12. Concentration - dose - risk computer code

    International Nuclear Information System (INIS)

    Frujinoiu, C.; Preda, M.

    1997-01-01

    Generally, the society is less willing in promoting remedial actions in case of low level chronic exposure situations. Radon in dwellings and workplaces is a case connected to chronic exposure. Apart from radon, the solely source on which the international community agreed for setting action levels, there are other numerous sources technically modified by man that can generate chronic exposure. Even if the nuclear installations are the most relevant, we are surrounded by 'man-made radioactivity' such as: mining industry, coal-fired power plants and fertilizer industry. The operating of an installation even within 'normal limits' could generate chronic exposure due to accumulation of the pollutants after a definite time. This asymptotic proclivity to a constant level define a steady-state concentration that represents a characteristic of the source's presence in the environment. The paper presents a methodology and a code package that derives sequentially the steady-state concentration, doses, detriments, as well as the costs of the effects of installation operation in a given environment. (authors)

  13. A dose of HLW reality

    International Nuclear Information System (INIS)

    Payne, J.

    1993-01-01

    What many people were sure they knew, and some others were fairly confident they knew, was acknowledged by the US Department of Energy in December: A monitored retrievable storage (MRS) facility will not be ready to accept spent fuel by January 31, 1998. A dose of reality has thus been added to the US high-level radioactive waste scene. Perhaps as important as the new reality is the practical, businesslike nature of the DOE's plan. The Department's proposal has the quality of a plan aimed at genuinely solving a problem rather just going through the motions. (In contrast, some readers are familiar with New York State's procedures for siting and licensing a low-level waste facility - procedures so labyrinthine that they are much more likely to protect political careers in that state than they are to achieve an LLW site). The DOE has received a lot of criticism - some justified, some not - about its handling of the HLW program. In this instance, it is proposing what many in the industry might have recommended: Make available storage capacity for spent nuclear fuel at existing federal government sites

  14. Neutrons in active proton therapy. Parameterization of dose and dose equivalent

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Uwe; Haelg, Roger A. [Univ. of Zurich (Switzerland). Dept. of Physics; Radiotherapy Hirslanden AG, Aarau (Switzerland); Lomax, Tony [Paul Scherrer Institute, Villigen (Switzerland). Center for Proton Therapy

    2017-08-01

    One of the essential elements of an epidemiological study to decide if proton therapy may be associated with increased or decreased subsequent malignancies compared to photon therapy is an ability to estimate all doses to non-target tissues, including neutron dose. This work therefore aims to predict for patients using proton pencil beam scanning the spatially localized neutron doses and dose equivalents. The proton pencil beam of Gantry 1 at the Paul Scherrer Institute (PSI) was Monte Carlo simulated using GEANT. Based on the simulated neutron dose and neutron spectra an analytical mechanistic dose model was developed. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed model in order to calculate the neutron component of the delivered dose distribution for each treated patient. The neutron dose was estimated for two patient example cases. The analytical neutron dose model represents the three-dimensional Monte Carlo simulated dose distribution up to 85 cm from the proton pencil beam with a satisfying precision. The root mean square error between Monte Carlo simulation and model is largest for 138 MeV protons and is 19% and 20% for dose and dose equivalent, respectively. The model was successfully integrated into the PSI treatment planning system. In average the neutron dose is increased by 10% or 65% when using 160 MeV or 177 MeV instead of 138 MeV. For the neutron dose equivalent the increase is 8% and 57%. The presented neutron dose calculations allow for estimates of dose that can be used in subsequent epidemiological studies or, should the need arise, to estimate the neutron dose at any point where a subsequent secondary tumour may occur. It was found that the neutron dose to the patient is heavily increased with proton energy.

  15. Radon Exposure and the Definition of Low Doses-The Problem of Spatial Dose Distribution.

    Science.gov (United States)

    Madas, Balázs G

    2016-07-01

    Investigating the health effects of low doses of ionizing radiation is considered to be one of the most important fields in radiological protection research. Although the definition of low dose given by a dose range seems to be clear, it leaves some open questions. For example, the time frame and the target volume in which absorbed dose is measured have to be defined. While dose rate is considered in the current system of radiological protection, the same cancer risk is associated with all exposures, resulting in a given amount of energy absorbed by a single target cell or distributed among all the target cells of a given organ. However, the biological effects and so the health consequences of these extreme exposure scenarios are unlikely to be the same. Due to the heterogeneous deposition of radon progeny within the lungs, heterogeneous radiation exposure becomes a practical issue in radiological protection. While the macroscopic dose is still within the low dose range, local tissue doses on the order of Grays can be reached in the most exposed parts of the bronchial airways. It can be concluded that progress in low dose research needs not only low dose but also high dose experiments where small parts of a biological sample receive doses on the order of Grays, while the average dose over the whole sample remains low. A narrow interpretation of low dose research might exclude investigations with high relevance to radiological protection. Therefore, studies important to radiological protection should be performed in the frame of low dose research even if the applied doses do not fit in the dose range used for the definition of low doses.

  16. Electron and bremsstrahlung penetration and dose calculation

    Science.gov (United States)

    Watts, J. W., Jr.; Burrell, M. O.

    1972-01-01

    Various techniques for the calculation of electron and bremsstrahlung dose deposition are described. Energy deposition, transmission, and reflection coefficients for electrons incident on plane slabs are presented, and methods for their use in electron dose calculations were developed. A method using the straight-ahead approximation was also developed, and the various methods were compared and found to be in good agreement. Both accurate and approximate methods of calculating bremsstrahlung dose were derived and compared. Approximation is found to give a good estimate of dose where the electron spectrum falls off exponentially with energy.

  17. Dosimetry in Interventional Radiology - Effective Dose Estimation

    International Nuclear Information System (INIS)

    Miljanic, S.; Buls, N.; Clerinx, P.; Jarvinen, H.; Nikodemova, D.; Ranogajec-Komor, M; D'Errico, F.

    2008-01-01

    Interventional radiological procedures can lead to significant radiation doses to patients and to staff members. In order to evaluate the personal doses with respect to the regulatory dose limits, doses measured by dosimeters have to be converted to effective doses (E). Measurement of personal dose equivalent Hp(10) using a single unshielded dosimeter above the lead apron can lead to significant overestimation of the effective dose, while the measurement with dosimeter under the apron can lead to underestimation. To improve the accuracy, measurements with two dosimeters, one above and the other under the apron have been suggested ( d ouble dosimetry ) . The ICRP has recommended that interventional radiology departments develop a policy that staff should wear two dosimeters. The aim of this study was to review the double dosimetry algorithms for the calculation of effective dose in high dose interventional radiology procedures. The results will be used to develop general guidelines for personal dosimetry in interventional radiology procedures. This work has been carried out by Working Group 9 (Radiation protection dosimetry of medical staff) of the CONRAD project, which is a Coordination Action supported by the European Commission within its 6th Framework Program.(author)

  18. Nuclear Electric's central dose record service

    International Nuclear Information System (INIS)

    Goldfinch, E.P.; Mullarkey, D.T.; McWhan, A.W.; Risk, G.; Vaughan, L.

    1991-01-01

    This paper describes the conception, development and operation of the Nuclear Electric Central Dose Record Service, including the initial philosophy considered necessary for a database for a large multi-site organisation, the setting up of the data and current routine operation. Lessons learned are briefly described. CDRS holds 35,000 records in a high security environment. The database includes records of radiation doses received by contractor's employees working at Nuclear Electric sites as well as dose records and dose histories for classified and non classified Nuclear Electric employees. (Author)

  19. Dose reconstruction modeling for medical radiation workers

    International Nuclear Information System (INIS)

    Choi, Yeong Chull; Cha, Eun Shil; Lee, Won Jin

    2017-01-01

    Exposure information is a crucial element for the assessment of health risk due to radiation. Radiation doses received by medical radiation workers have been collected and maintained by public registry since 1996. Since exposure levels in the remote past are greater concern, it is essential to reconstruct unmeasured doses in the past using known information. We developed retrodiction models for different groups of medical radiation workers and estimate individual past doses before 1996. Reconstruction models for past radiation doses received by medical radiation workers were developed, and the past doses were estimated. Using these estimates, organ doses should be calculated which, in turn, will be used to explore a wide range of health risks of medical occupational radiation exposure. Reconstruction models for past radiation doses received by medical radiation workers were developed, and the past doses were estimated. Using these estimates, organ doses should be calculated which, in turn, will be used to explore a wide range of health risks of medical occupational radiation exposure.

  20. Skin dose measurement with MICROSPEC-2 trademark

    International Nuclear Information System (INIS)

    Hsu, H.H.

    1997-01-01

    For many years, the Eberline HP-260 trademark beta detectors were used for skin dose measurements at Los Alamos National Laboratory. This detector does not measure the beta spectrum and the skin dose can only be determined if the contaminating radioactive isotope is known. A new product MICROSPEC-2 trademark, has been developed which consists of a small portable computer with a multichannel analyzer and a beta probe consisting of a phoswich detector. The system measures the beta spectrum and automatically folds in the beta fluence-to-dose conversion function to yield the skin dose