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Sample records for patient skin dose

  1. Measured Head CT/CTA Skin Dose and Intensive Care Unit Patient Cumulative Exposure.

    PubMed

    Nawfel, R D; Young, G S

    2017-03-01

    Estimates of cumulative CT/CTA radiation dose based on volumetric CT dose index have raised concern that neurological intensive care unit patient exposures may reach thresholds for deterministic skin injury. Because the accuracy of volumetric CT dose index for this purpose in unknown, we set out to directly measure head CT and CTA peak skin dose, assess the relationship of volumetric CT dose index to measured peak skin dose, and determine whether multiple CT/CTA exposures in typical patients in the neurological intensive care unit produce cumulative doses approaching or exceeding single-dose deterministic thresholds for skin injury. In a prospective study from 2011-2013, nanoDot optical stimulated luminescence dosimeters were used to measure head CT/CTA peak skin dose in 52 patients (28 female, 24 male; mean age, 63 years) divided equally between 2 CT scanners. Volumetric CT dose index and dose-length product were recorded for each examination. Peak skin dose was also measured on an acrylic skull phantom in each scanner. A 2-tailed, unpaired t test was used to compare mean patient skin doses between the 2 scanners. The measured peak skin doses were then used to calculate cumulative peak skin dose in 4 typical patients in intensive care units who received multiple CT/CTA scans. Head CT/CTA peak skin dose agreed between scanners in patients and phantoms: (scanner 1 CT/CTA: patients, 39.2 ± 3.7 mGy and 98.9 ± 5.3 mGy, respectively, versus phantom, 40.0 mGy and 105.4 mGy, respectively; scanner 2 CT/CTA: patients, 42.9 ± 9.4 mGy and 98.8 ± 7.4 mGy, respectively, versus phantom, 37.6 mGy and 95.2 mGy, respectively). Volumetric CT dose index overestimated peak skin dose by a factor of 1.4-1.9 depending on examination and CT scanner. Cumulative doses in 4 patients in the intensive care unit estimated from measured CT/CTA peak skin dose ranged from 1.9-4.5 Gy. Directly measured radiation skin doses from head CT/CTA patient examinations are substantially lower than

  2. Does digital acquisition reduce patients' skin dose in cardiac interventional procedures? An experimental study.

    PubMed

    Chida, Koichi; Saito, Haruo; Zuguchi, Masayuki; Shirotori, Kazutoshi; Kumagai, Shinsaku; Nakayama, Hiromi; Matsubara, Kana; Kohzuki, Masahiro

    2004-10-01

    It is necessary to reduce the exposure doses from both fluoroscopy and angiocardiography. Pulsed fluoroscopy clearly reduces patients' exposure. By contrast, whether digital acquisition reduces patients' exposure is not clear. This study simulated the skin radiation doses of patients in cardiac catheterization laboratories with various radiography systems used in percutaneous transluminal coronary angioplasty to determine whether digital acquisition reduces patient exposure as compared with cine film recording. The entrance surface doses with cineangiography and fluoroscopy of acrylic phantoms were compared for 11 radiography systems at seven facilities; each performs more than 100 cardiac intervention procedures per year. The entrance surface dose for an acrylic plate (20 cm thick) was measured using a skin-dose monitor. The maximum dose exceeded the minimum dose by 6.44 times for cineangiography and by 3.42 times for fluoroscopy. The entrance surface dose with acrylic plate was lower with digital-only acquisition (mean +/- SD, 3.07 +/- 0.84 mGy/sec) than with film recording (6.00 +/- 3.04 mGy/sec). By contrast, the entrance surface frame dose, after correction for the cine frame rate, tended to be higher with digital acquisition than with film recording (0.210 +/- 0.053 vs 0.179 +/- 0.058 mGy/frame, respectively). CONCLUSION. The entrance surface dose was approximately 50% less with digital-only acquisition than with film recording. However, after correcting the dose for cine frame rate, filmless acquisition did not in itself reduce the exposure. For the surface dose to be reduced for cardiac interventional radiography, even with digital filmless radiography systems, a low recording speed is necessary for angiocardiography.

  3. Changing Default Fluoroscopy Equipment Settings Decreases Entrance Skin Dose in Patients.

    PubMed

    Canales, Benjamin K; Sinclair, Lindsay; Kang, Diana; Mench, Anna M; Arreola, Manuel; Bird, Vincent G

    2016-04-01

    Proper fluoroscopic education and protocols may reduce the patient radiation dose but few prospective studies in urology have been performed. Using optically stimulated luminescent dosimeters we tested whether fluoroscopy time and/or entrance skin dose would decrease after educational and radiation reduction protocols. At default manufacturer settings fluoroscopy time and entrance skin dose were prospectively measured using optically stimulated luminescent dosimeters in patients undergoing ureteroscopy, retrograde pyelogram/stent or percutaneous nephrolithotomy with access for stone disease. A validated radiation safety competency test was administered to urology faculty and residents before and after web based, hands-on fluoroscopy training. Default fluoroscopy settings were changed from continuous to intermittent pulse rate and from standard to half-dose output. Fluoroscopy time and entrance skin dose were then measured again. The cohorts of 44 pre-protocol and 50 post-protocol patients with stones were similarly matched. The change in mean fluoroscopy time and entrance skin dose from pre-protocol to post-protocol was -0.6 minutes and -11.6 mGy (33%) for percutaneous nephrolithotomy (p = 0.62 and <0.001), 0.5 minutes and -0.1 mGy (34%) for ureteroscopy (p = 0.42 and 0.31), and 0.1 minute and -0.1 mGy (29%) for retrograde pyelogram/stent (p = 0.85 and 0.49, respectively). Urologist post-training test scores increased 30% from pretraining scores (p = 0.1). Radiation safety training protocols improved clinical knowledge but did not significantly alter fluoroscopy time. Changing equipment default settings to intermittent pulse rate (12 frames per second) and half-dose lowered the entrance skin dose by 30% across all endourology patients but most significantly during percutaneous nephrolithotomy. To limit patient radiation exposure fluoroscopy default settings should be decreased before all endourology procedures and image equipment manufacturers should consider

  4. Main clinical, therapeutic and technical factors related to patient's maximum skin dose in interventional cardiology procedures

    PubMed Central

    Journy, N; Sinno-Tellier, S; Maccia, C; Le Tertre, A; Pirard, P; Pagès, P; Eilstein, D; Donadieu, J; Bar, O

    2012-01-01

    Objective The study aimed to characterise the factors related to the X-ray dose delivered to the patient's skin during interventional cardiology procedures. Methods We studied 177 coronary angiographies (CAs) and/or percutaneous transluminal coronary angioplasties (PTCAs) carried out in a French clinic on the same radiography table. The clinical and therapeutic characteristics, and the technical parameters of the procedures, were collected. The dose area product (DAP) and the maximum skin dose (MSD) were measured by an ionisation chamber (Diamentor; Philips, Amsterdam, The Netherlands) and radiosensitive film (Gafchromic; International Specialty Products Advanced Materials Group, Wayne, NJ). Multivariate analyses were used to assess the effects of the factors of interest on dose. Results The mean MSD and DAP were respectively 389 mGy and 65 Gy cm−2 for CAs, and 916 mGy and 69 Gy cm−2 for PTCAs. For 8% of the procedures, the MSD exceeded 2 Gy. Although a linear relationship between the MSD and the DAP was observed for CAs (r=0.93), a simple extrapolation of such a model to PTCAs would lead to an inadequate assessment of the risk, especially for the highest dose values. For PTCAs, the body mass index, the therapeutic complexity, the fluoroscopy time and the number of cine frames were independent explanatory factors of the MSD, whoever the practitioner was. Moreover, the effect of technical factors such as collimation, cinematography settings and X-ray tube orientations on the DAP was shown. Conclusion Optimising the technical options for interventional procedures and training staff on radiation protection might notably reduce the dose and ultimately avoid patient skin lesions. PMID:22457404

  5. Direct measurement of a patient's entrance skin dose during pediatric cardiac catheterization

    PubMed Central

    Sun, Lue; Mizuno, Yusuke; Iwamoto, Mari; Goto, Takahisa; Koguchi, Yasuhiro; Miyamoto, Yuka; Tsuboi, Koji; Chida, Koichi; Moritake, Takashi

    2014-01-01

    Children with complex congenital heart diseases often require repeated cardiac catheterization; however, children are more radiosensitive than adults. Therefore, radiation-induced carcinogenesis is an important consideration for children who undergo those procedures. We measured entrance skin doses (ESDs) using radio-photoluminescence dosimeter (RPLD) chips during cardiac catheterization for 15 pediatric patients (median age, 1.92 years; males, n = 9; females, n = 6) with cardiac diseases. Four RPLD chips were placed on the patient's posterior and right side of the chest. Correlations between maximum ESD and dose–area products (DAP), total number of frames, total fluoroscopic time, number of cine runs, cumulative dose at the interventional reference point (IRP), body weight, chest thickness, and height were analyzed. The maximum ESD was 80 ± 59 (mean ± standard deviation) mGy. Maximum ESD closely correlated with both DAP (r = 0.78) and cumulative dose at the IRP (r = 0.82). Maximum ESD for coiling and ballooning tended to be higher than that for ablation, balloon atrial septostomy, and diagnostic procedures. In conclusion, we directly measured ESD using RPLD chips and found that maximum ESD could be estimated in real-time using angiographic parameters, such as DAP and cumulative dose at the IRP. Children requiring repeated catheterizations would be exposed to high radiation levels throughout their lives, although treatment influences radiation dose. Therefore, the radiation dose associated with individual cardiac catheterizations should be analyzed, and the effects of radiation throughout the lives of such patients should be followed. PMID:24968708

  6. Patient skin dose during neuroembolization by multiple-point measurement using a radiosensitive indicator.

    PubMed

    Suzuki, S; Furui, S; Matsumaru, Y; Nobuyuki, S; Ebara, M; Abe, T; Itoh, D

    2008-06-01

    Although neuroembolization has recently spread quickly, sufficient attention has not been focused on the associated radiation exposure. The purpose of this research was to evaluate the patient's entrance skin dose (ESD) during neuroembolizations in 6 institutions. This study was approved by all of the 6 institutional review boards, and all of the patients gave informed consent. This study included a total of 103 consecutive neuroembolizations in the 6 institutions. Patient ESDs during the procedures were evaluated by using caps that had 44 radiosensitive indicators adherent to the surface. The patient ESDs were calculated from the color difference of the indicators. To check for effects on the scalp, clinical follow-up was performed at 1-2 days, 2 weeks, and 3 months after the procedure. The averages of total fluoroscopic time, total number of digital subtraction angiography frames, and dose area product were 67.1 +/- 41.6 minutes, 883 +/- 626, and 257 +/- 150 Gy x cm(2), respectively. The average maximum ESD for each patient was 1.9 +/- 1.1 Gy (range, 0.4-5.6 Gy; median, 1.5 Gy). The average maximum ESDs of each institution ranged from 1.0 to 2.4 Gy. Epilation was observed in 6 patients. The maximum ESDs during neuroembolizations exceed the thresholds for radiation skin injuries in some cases.

  7. Direct measurement of patient's entrance skin dose during neurointerventional procedure to avoid further radiation-induced skin injuries.

    PubMed

    Hayakawa, Mikito; Moritake, Takashi; Kataoka, Fumikatsu; Takigawa, Tomoji; Koguchi, Yasuhiro; Miyamoto, Yuka; Akahane, Keiichi; Matsumaru, Yuji

    2010-07-01

    Although several cases of radiation-induced skin injury (RSI) have been reported in association with neurointerventional procedures such as endovascular embolization for cerebral aneurysm, cerebral arteriovenous malformation, and dural arteriovenous fistula, in most cases the absorbed doses are not measured directly; therefore, we built the first direct measurement system that enables the ideal dosimetry for entrance skin dose (ESD) during neurointerventional procedures to be easily determined. This system was then applied to a 55-year-old man who underwent two transvenous embolizations with a 2-month interval, for a right cavernous sinus dural arteriovenous fistula, to establish the efficacy of precise mapping of ESDs. Throughout the procedures, the patient wore a fitted dosimetry cap that contained 60 radiophotoluminescence glass dosimeter (RPLGD) chips. After the first procedure, temporary epilation occurred in the occipital region. Precise mapping of ESDs revealed that this region was exposed to 4.2Gy. In the first procedure, the X-ray tube was generally positioned straight for an optimal posterior-anterior view; however, in the second procedure we intermittently used the second-best position to prevent further RSI. In this position, the maximum ESD was 1.0Gy in the right posterior-temporal region and the epilation site was exposed to patient did not develop any further epilation. We conclude that direct dosimetry using multiple RPLGDs can accurately reveal the maximum ESD and that precise information regarding ESD can prevent further RSIs from subsequent procedures. Copyright 2010 Elsevier B.V. All rights reserved.

  8. Updates in the real-time Dose Tracking System (DTS) to improve the accuracy in calculating the radiation dose to the patients skin during fluoroscopic procedures.

    PubMed

    Rana, Vijay K; Rudin, Stephen; Bednarek, Daniel R

    2013-03-06

    We have developed a dose-tracking system (DTS) to manage the risk of deterministic skin effects to the patient during fluoroscopic image-guided interventional cardiac procedures. The DTS calculates the radiation dose to the patient's skin in real-time by acquiring exposure parameters and imaging-system geometry from the digital bus on a Toshiba C-arm unit and displays the cumulative dose values as a color map on a 3D graphic of the patient for immediate feedback to the interventionalist. Several recent updates have been made to the software to improve its function and performance. Whereas the older system needed manual input of pulse rate for dose-rate calculation and used the CPU clock with its potential latency to monitor exposure duration, each x-ray pulse is now individually processed to determine the skin-dose increment and to automatically measure the pulse rate. We also added a correction for the table pad which was found to reduce the beam intensity to the patient for under-table projections by an additional 5-12% over that of the table alone at 80 kVp for the x-ray filters on the Toshiba system. Furthermore, mismatch between the DTS graphic and the patient skin can result in inaccuracies in dose calculation because of inaccurate inverse-square-distance calculation. Therefore, a means for quantitative adjustment of the patient-graphic-model position and a parameterized patient-graphic library have been developed to allow the graphic to more closely match the patient. These changes provide more accurate estimation of the skin-dose which is critical for managing patient radiation risk.

  9. Updates in the real-time Dose Tracking System (DTS) to improve the accuracy in calculating the radiation dose to the patients skin during fluoroscopic procedures

    PubMed Central

    Rana, Vijay K.; Rudin, Stephen; Bednarek, Daniel R.

    2013-01-01

    We have developed a dose-tracking system (DTS) to manage the risk of deterministic skin effects to the patient during fluoroscopic image-guided interventional cardiac procedures. The DTS calculates the radiation dose to the patient’s skin in real-time by acquiring exposure parameters and imaging-system geometry from the digital bus on a Toshiba C-arm unit and displays the cumulative dose values as a color map on a 3D graphic of the patient for immediate feedback to the interventionalist. Several recent updates have been made to the software to improve its function and performance. Whereas the older system needed manual input of pulse rate for dose-rate calculation and used the CPU clock with its potential latency to monitor exposure duration, each x-ray pulse is now individually processed to determine the skin-dose increment and to automatically measure the pulse rate. We also added a correction for the table pad which was found to reduce the beam intensity to the patient for under-table projections by an additional 5–12% over that of the table alone at 80 kVp for the x-ray filters on the Toshiba system. Furthermore, mismatch between the DTS graphic and the patient skin can result in inaccuracies in dose calculation because of inaccurate inverse-square-distance calculation. Therefore, a means for quantitative adjustment of the patient-graphic-model position and a parameterized patient-graphic library have been developed to allow the graphic to more closely match the patient. These changes provide more accurate estimation of the skin-dose which is critical for managing patient radiation risk. PMID:24817801

  10. In vivo evaluating skin doses for lung cancer patients undergoing volumetric modulated arc therapy treatment.

    PubMed

    Tseng, Hsien-Chun; Pan, Lung-Kang; Chen, Hsin-Yu; Liu, Wen-Shan; Hsu, Chang-Chieh; Chen, Chien-Yi

    2015-01-01

    This study is the first to use 10- to 90-kg tissue-equivalent phantoms as patient surrogates to measure peripheral skin doses (Dskin) in lung cancer treatment through Volumetric Modulated Arc Therapy of the Axesse linac. Five tissue-equivalent and Rando phantoms were used to simulate lung cancer patients using the thermoluminescent dosimetry (TLD-100H) approach. TLD-100H was calibrated using 6 MV photons coming from the Axesse linac. Then it was inserted into phantom positions that closely corresponded with the position of the represented organs and tissues. TLDs were measured using the Harshaw 3500 TLD reader. The ICRP 60 evaluated the mean Dskin to the lung cancer for 1 fraction (7 Gy) undergoing VMAT. The Dskin of these phantoms ranged from 0.51±0.08 (10-kg) to 0.22±0.03 (90-kg) mSv/Gy. Each experiment examined the relationship between the Dskin and the distance from the treatment field. These revealed strong variations in positions close to the tumor center. The correlation between Dskin and body weight was Dskin (mSv) = -0.0034x + 0.5296, where x was phantom's weight in kg. R2 is equal to 0.9788. This equation can be used to derive an equation for lung cancer in males. Finally, the results are compared to other published research. These findings are pertinent to patients, physicians, radiologists, and the public.

  11. Skin dose mapping for fluoroscopically guided interventions

    SciTech Connect

    Johnson, Perry B.; Borrego, David; Balter, Stephen; Johnson, Kevin; Siragusa, Daniel; Bolch, Wesley E.

    2011-10-15

    Purpose: To introduce a new skin dose mapping software system for interventional fluoroscopy dose assessment and to analyze the benefits and limitations of patient-phantom matching. Methods: In this study, a new software system was developed for visualizing patient skin dose during interventional fluoroscopy procedures. The system works by translating the reference point air kerma to the location of the patient's skin, which is represented by a computational model. In order to orient the model with the x-ray source, geometric parameters found within the radiation dose structured report (RDSR) are used along with a limited number of in-clinic measurements. The output of the system is a visual indication of skin dose mapped onto an anthropomorphic model at a resolution of 5 mm. In order to determine if patient-dependent and patient-sculpted models increase accuracy, peak skin dose was calculated for each of 26 patient-specific models and compared with doses calculated using an elliptical stylized model, a reference hybrid model, a matched patient-dependent model and one patient-sculpted model. Results were analyzed in terms of a percent difference using the doses calculated using the patient-specific model as the true standard. Results: Anthropometric matching, including the use of both patient-dependent and patient-sculpted phantoms, was shown most beneficial for left lateral and anterior-posterior projections. In these cases, the percent difference using a reference model was between 8 and 20%, using a patient-dependent model between 7 and 15%, and using a patient-sculpted model between 3 and 7%. Under the table tube configurations produced errors less than 5% in most situations due to the flattening affects of the table and pad, and the fact that table height is the main determination of source-to-skin distance for these configurations. In addition to these results, several skin dose maps were produced and a prototype display system was placed on the in

  12. Skin dose mapping for fluoroscopically guided interventions

    PubMed Central

    Johnson, Perry B.; Borrego, David; Balter, Stephen; Johnson, Kevin; Siragusa, Daniel; Bolch, Wesley E.

    2011-01-01

    Purpose: To introduce a new skin dose mapping software system for interventional fluoroscopy dose assessment and to analyze the benefits and limitations of patient-phantom matching. Methods: In this study, a new software system was developed for visualizing patient skin dose during interventional fluoroscopy procedures. The system works by translating the reference point air kerma to the location of the patient’s skin, which is represented by a computational model. In order to orient the model with the x-ray source, geometric parameters found within the radiation dose structured report (RDSR) are used along with a limited number of in-clinic measurements. The output of the system is a visual indication of skin dose mapped onto an anthropomorphic model at a resolution of 5 mm. In order to determine if patient-dependent and patient-sculpted models increase accuracy, peak skin dose was calculated for each of 26 patient-specific models and compared with doses calculated using an elliptical stylized model, a reference hybrid model, a matched patient-dependent model and one patient-sculpted model. Results were analyzed in terms of a percent difference using the doses calculated using the patient-specific model as the true standard. Results: Anthropometric matching, including the use of both patient-dependent and patient-sculpted phantoms, was shown most beneficial for left lateral and anterior–posterior projections. In these cases, the percent difference using a reference model was between 8 and 20%, using a patient-dependent model between 7 and 15%, and using a patient-sculpted model between 3 and 7%. Under the table tube configurations produced errors less than 5% in most situations due to the flattening affects of the table and pad, and the fact that table height is the main determination of source-to-skin distance for these configurations. In addition to these results, several skin dose maps were produced and a prototype display system was placed on the in

  13. Dose-surface analysis for prediction of severe acute radio-induced skin toxicity in breast cancer patients.

    PubMed

    Pastore, Francesco; Conson, Manuel; D'Avino, Vittoria; Palma, Giuseppe; Liuzzi, Raffaele; Solla, Raffaele; Farella, Antonio; Salvatore, Marco; Cella, Laura; Pacelli, Roberto

    2016-01-01

    Severe acute radiation-induced skin toxicity (RIST) after breast irradiation is a side effect impacting the quality of life in breast cancer (BC) patients. The aim of the present study was to develop normal tissue complication probability (NTCP) models of severe acute RIST in BC patients. We evaluated 140 consecutive BC patients undergoing conventional three-dimensional conformal radiotherapy (3D-CRT) after breast conserving surgery in a prospective study assessing acute RIST. The acute RIST was classified according to the RTOG scoring system. Dose-surface histograms (DSHs) of the body structure in the breast region were extracted as representative of skin irradiation. Patient, disease, and treatment-related characteristics were analyzed along with DSHs. NTCP modeling by Lyman-Kutcher-Burman (LKB) and by multivariate logistic regression using bootstrap resampling techniques was performed. Models were evaluated by Spearman's Rs coefficient and ROC area. By the end of radiotherapy, 139 (99%) patients developed any degree of acute RIST. G3 RIST was found in 11 of 140 (8%) patients. Mild-moderate (G1-G2) RIST was still present at 40 days after treatment in six (4%) patients. Using DSHs for LKB modeling of acute RIST severity (RTOG G3 vs. G0-2), parameter estimates were TD50=39 Gy, n=0.38 and m=0.14 [Rs = 0.25, area under the curve (AUC) = 0.77, p = 0.003]. On multivariate analysis, the most predictive model of acute RIST severity was a two-variable model including the skin receiving ≥30 Gy (S30) and psoriasis [Rs = 0.32, AUC = 0.84, p < 0.001]. Using body DSH as representative of skin dose, the LKB n parameter was consistent with a surface effect for the skin. A good prediction performance was obtained using a data-driven multivariate model including S30 and a pre-existing skin disease (psoriasis) as a clinical factor.

  14. A tracking system to calculate patient skin dose in real-time during neurointerventional procedures using a biplane x-ray imaging system.

    PubMed

    Rana, V K; Rudin, S; Bednarek, D R

    2016-09-01

    Neurovascular interventional procedures using biplane fluoroscopic imaging systems can lead to increased risk of radiation-induced skin injuries. The authors developed a biplane dose tracking system (Biplane-DTS) to calculate the cumulative skin dose distribution from the frontal and lateral x-ray tubes and display it in real-time as a color-coded map on a 3D graphic of the patient for immediate feedback to the physician. The agreement of the calculated values with the dose measured on phantoms was evaluated. The Biplane-DTS consists of multiple components including 3D graphic models of the imaging system and patient, an interactive graphical user interface, a data acquisition module to collect geometry and exposure parameters, the computer graphics processing unit, and functions for determining which parts of the patient graphic skin surface are within the beam and for calculating dose. The dose is calculated to individual points on the patient graphic using premeasured calibration files of entrance skin dose per mAs including backscatter; corrections are applied for field area, distance from the focal spot and patient table and pad attenuation when appropriate. The agreement of the calculated patient skin dose and its spatial distribution with measured values was evaluated in 2D and 3D for simulated procedure conditions using a PMMA block phantom and an SK-150 head phantom, respectively. Dose values calculated by the Biplane-DTS were compared to the measurements made on the phantom surface with radiochromic film and a calibrated ionization chamber, which was also used to calibrate the DTS. The agreement with measurements was specifically evaluated with variation in kVp, gantry angle, and field size. The dose tracking system that was developed is able to acquire data from the two x-ray gantries on a biplane imaging system and calculate the skin dose for each exposure pulse to those vertices of a patient graphic that are determined to be in the beam. The

  15. SYSTEM UPGRADE ON PHILIPS ALLURA FD20 ANGIOGRAPHY SYSTEMS: EFFECTS ON PATIENT SKIN DOSE AND STATIC IMAGE QUALITY.

    PubMed

    Ryckx, Nick; Sans-Merce, Marta; Meuli, Reto; Zerlauth, Jean-Baptiste; Verdun, Francis R

    2016-06-01

    Fluoroscopically guided procedures might be highly irradiating for patients, possibly leading to skin injuries. In such a context, every effort should be done to lower patient exposure as much as possible. Moreover, patient dose reduction does not only benefit to the patient but also allows reducing staff exposure. In this framework, Philips Healthcare recently introduced a system upgrade for their angiography units, called 'AlluraClarity'. The authors performed air kerma rate measurements for all available fluoroscopy modes and air kerma per frame measurements for the digital subtraction angiography protocols, along with subjective spatial resolution and low-contrast detectability assessments using a standard QA phantom. Air kerma reductions ranging from 25.5 to 84.4 % were found, with no significant change in image quality when switching from a standard operating mode to an upgraded version. These results are confirmed by the comparison of actual patient exposures for similar procedures.

  16. In vivo skin dose measurement in breast conformal radiotherapy

    PubMed Central

    Soleymanifard, Shokouhozaman; Noghreiyan, Atefeh Vejdani; Ghorbani, Mahdi; Jamali, Farideh; Davenport, David

    2016-01-01

    Aim of the study Accurate skin dose assessment is necessary during breast radiotherapy to assure that the skin dose is below the tolerance level and is sufficient to prevent tumour recurrence. The aim of the current study is to measure the skin dose and to evaluate the geometrical/anatomical parameters that affect it. Material and methods Forty patients were simulated by TIGRT treatment planning system and treated with two tangential fields of 6 MV photon beam. Wedge filters were used to homogenise dose distribution for 11 patients. Skin dose was measured by thermoluminescent dosimeters (TLD-100) and the effects of beam incident angle, thickness of irradiated region, and beam entry separation on the skin dose were analysed. Results Average skin dose in treatment course of 50 Gy to the clinical target volume (CTV) was 36.65 Gy. The corresponding dose values for patients who were treated with and without wedge filter were 35.65 and 37.20 Gy, respectively. It was determined that the beam angle affected the average skin dose while the thickness of the irradiated region and the beam entry separation did not affect dose. Since the skin dose measured in this study was lower than the amount required to prevent tumour recurrence, application of bolus material in part of the treatment course is suggested for post-mastectomy advanced breast radiotherapy. It is more important when wedge filters are applied to homogenize dose distribution. PMID:27358592

  17. Influence of a Commercial Lead Apron on Patient Skin Dose Delivered During Oral and Maxillofacial Examinations under Cone Beam Computed Tomography (CBCT).

    PubMed

    Schulze, Ralf Kurt Willy; Sazgar, Mahssa; Karle, Heiko; de Las Heras Gala, Hugo

    2017-08-01

    The purpose of this paper is to investigate the impact of a commercial lead apron on patient skin dose delivered during maxillofacial CBCT in five critical regions by means of solid-state-dosimetry. Five anatomical regions (thyroid gland, left and right breast, gonads, back of the phantom torso) in an adult female anthropomorphic phantom were selected for dose measurement by means of the highly sensitive solid-state dosimeter QUART didoSVM. Ten repeated single exposures were assessed for each patient body region for a total of five commercial CBCT devices with and without a lead apron present. Shielded and non-shielded exposures were compared under the paired Wilcoxon test, with absolute and relative differences computed. Reproducibility was expressed as the coefficient of variation (CV) between the 10 repeated assessments. The highest doses observed at skin level were found at the thyroid (mean shielded ± SD: 450.5 ± 346.7 μGy; non-shielded: 339.2 ± 348.8 μGy, p = 0.4922). Shielding resulted in a highly significant (p < 0.001) 93% dose reduction in skin dose in the female breast region with a mean non-shielded dose of approximately 35 μGy. Dose reduction was also significantly lower for the back-region (mean: -65%, p < 0.0001) as well as for the gonad-region (mean: -98%, p < 0.0001) in the shielded situation. Reproducibility was inversely correlated to skin dose (Rspearman = -0.748, p < 0.0001) with a mean CV of 10.45% (SD: 24.53 %). Skin dose in the thyroid region of the simulated patient was relatively high and not influenced by the lead apron, which did not shield this region. Dose reduction by means of a commercial lead apron was significant in all other regions, particularly in the region of the female breast.

  18. Characteristics of dosemeter types for skin dose measurements in practice.

    PubMed

    Van Dam, J; Bosmans, H; Marchal, G; Wambersie, A

    2005-01-01

    A growing number of papers report deterministic effects in the skin of patients who have undergone interventional radiological procedures. Dose measurements, and especially skin dose measurements, are therefore increasingly important. Methods and acceptable dosemeters are, however, not clearly defined. This paper is the result of a literature overview with regard to assessing the entrance skin dose during radiological examinations by putting a dosemeter on the patient's skin. The relevant intrinsic characteristics, as well as some examples of clinical use of the different detector types, are presented. In this respect, thermoluminescence, scintillation, semiconductor and film dosemeters are discussed and compared with respect to their practical use.

  19. A tracking system to calculate patient skin dose in real-time during neurointerventional procedures using a biplane x-ray imaging system

    PubMed Central

    Rana, V. K.; Rudin, S.; Bednarek, D. R.

    2016-01-01

    Purpose: Neurovascular interventional procedures using biplane fluoroscopic imaging systems can lead to increased risk of radiation-induced skin injuries. The authors developed a biplane dose tracking system (Biplane-DTS) to calculate the cumulative skin dose distribution from the frontal and lateral x-ray tubes and display it in real-time as a color-coded map on a 3D graphic of the patient for immediate feedback to the physician. The agreement of the calculated values with the dose measured on phantoms was evaluated. Methods: The Biplane-DTS consists of multiple components including 3D graphic models of the imaging system and patient, an interactive graphical user interface, a data acquisition module to collect geometry and exposure parameters, the computer graphics processing unit, and functions for determining which parts of the patient graphic skin surface are within the beam and for calculating dose. The dose is calculated to individual points on the patient graphic using premeasured calibration files of entrance skin dose per mAs including backscatter; corrections are applied for field area, distance from the focal spot and patient table and pad attenuation when appropriate. The agreement of the calculated patient skin dose and its spatial distribution with measured values was evaluated in 2D and 3D for simulated procedure conditions using a PMMA block phantom and an SK-150 head phantom, respectively. Dose values calculated by the Biplane-DTS were compared to the measurements made on the phantom surface with radiochromic film and a calibrated ionization chamber, which was also used to calibrate the DTS. The agreement with measurements was specifically evaluated with variation in kVp, gantry angle, and field size. Results: The dose tracking system that was developed is able to acquire data from the two x-ray gantries on a biplane imaging system and calculate the skin dose for each exposure pulse to those vertices of a patient graphic that are determined to be

  20. Calibration of Kodak EDR2 film for patient skin dose assessment in cardiac catheterization procedures

    NASA Astrophysics Data System (ADS)

    Morrell, Rachel E.; Rogers, Andy

    2004-12-01

    Kodak EDR2 film has been calibrated across the range of exposure conditions encountered in our cardiac catheterization laboratory. Its dose-response function has been successfully modelled, up to the saturation point of 1 Gy. The most important factor affecting film sensitivity is the use of beam filtration. Spectral filtration and kVp together account for a variation in dose per optical density of -10% to +25%, at 160 mGy. The use of a dynamic wedge filter may cause doses to be underestimated by up to 6%. The film is relatively insensitive to variations in batch, field size, exposure rate, time to processing and day-to-day fluctuations in processor performance. Overall uncertainty in the calibration is estimated to be -20% to +40%, at 160 mGy. However, the uncertainty increases at higher doses, as the curve saturates. Artefacts were seen on a number of films, due to faults in the light-proofing of the film packets.

  1. Skin dose measurement with MICROSPEC-2{trademark}

    SciTech Connect

    Hsu, H.H.; Chen, J.; Ing, H.; Clifford, E.T.H.; McLean, T.

    1997-10-01

    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.

  2. Use of a graphics processing unit (GPU) to facilitate real-time 3D graphic presentation of the patient skin-dose distribution during fluoroscopic interventional procedures.

    PubMed

    Rana, Vijay; Rudin, Stephen; Bednarek, Daniel R

    2012-02-23

    We have developed a dose-tracking system (DTS) that calculates the radiation dose to the patient's skin in real-time by acquiring exposure parameters and imaging-system-geometry from the digital bus on a Toshiba Infinix C-arm unit. The cumulative dose values are then displayed as a color map on an OpenGL-based 3D graphic of the patient for immediate feedback to the interventionalist. Determination of those elements on the surface of the patient 3D-graphic that intersect the beam and calculation of the dose for these elements in real time demands fast computation. Reducing the size of the elements results in more computation load on the computer processor and therefore a tradeoff occurs between the resolution of the patient graphic and the real-time performance of the DTS. The speed of the DTS for calculating dose to the skin is limited by the central processing unit (CPU) and can be improved by using the parallel processing power of a graphics processing unit (GPU). Here, we compare the performance speed of GPU-based DTS software to that of the current CPU-based software as a function of the resolution of the patient graphics. Results show a tremendous improvement in speed using the GPU. While an increase in the spatial resolution of the patient graphics resulted in slowing down the computational speed of the DTS on the CPU, the speed of the GPU-based DTS was hardly affected. This GPU-based DTS can be a powerful tool for providing accurate, real-time feedback about patient skin-dose to physicians while performing interventional procedures.

  3. Use of a graphics processing unit (GPU) to facilitate real-time 3D graphic presentation of the patient skin-dose distribution during fluoroscopic interventional procedures

    NASA Astrophysics Data System (ADS)

    Rana, Vijay; Rudin, Stephen; Bednarek, Daniel R.

    2012-03-01

    We have developed a dose-tracking system (DTS) that calculates the radiation dose to the patient's skin in realtime by acquiring exposure parameters and imaging-system-geometry from the digital bus on a Toshiba Infinix C-arm unit. The cumulative dose values are then displayed as a color map on an OpenGL-based 3D graphic of the patient for immediate feedback to the interventionalist. Determination of those elements on the surface of the patient 3D-graphic that intersect the beam and calculation of the dose for these elements in real time demands fast computation. Reducing the size of the elements results in more computation load on the computer processor and therefore a tradeoff occurs between the resolution of the patient graphic and the real-time performance of the DTS. The speed of the DTS for calculating dose to the skin is limited by the central processing unit (CPU) and can be improved by using the parallel processing power of a graphics processing unit (GPU). Here, we compare the performance speed of GPU-based DTS software to that of the current CPU-based software as a function of the resolution of the patient graphics. Results show a tremendous improvement in speed using the GPU. While an increase in the spatial resolution of the patient graphics resulted in slowing down the computational speed of the DTS on the CPU, the speed of the GPU-based DTS was hardly affected. This GPU-based DTS can be a powerful tool for providing accurate, real-time feedback about patient skin-dose to physicians while performing interventional procedures.

  4. Use of a graphics processing unit (GPU) to facilitate real-time 3D graphic presentation of the patient skin-dose distribution during fluoroscopic interventional procedures

    PubMed Central

    Rana, Vijay; Rudin, Stephen; Bednarek, Daniel R.

    2012-01-01

    We have developed a dose-tracking system (DTS) that calculates the radiation dose to the patient’s skin in real-time by acquiring exposure parameters and imaging-system-geometry from the digital bus on a Toshiba Infinix C-arm unit. The cumulative dose values are then displayed as a color map on an OpenGL-based 3D graphic of the patient for immediate feedback to the interventionalist. Determination of those elements on the surface of the patient 3D-graphic that intersect the beam and calculation of the dose for these elements in real time demands fast computation. Reducing the size of the elements results in more computation load on the computer processor and therefore a tradeoff occurs between the resolution of the patient graphic and the real-time performance of the DTS. The speed of the DTS for calculating dose to the skin is limited by the central processing unit (CPU) and can be improved by using the parallel processing power of a graphics processing unit (GPU). Here, we compare the performance speed of GPU-based DTS software to that of the current CPU-based software as a function of the resolution of the patient graphics. Results show a tremendous improvement in speed using the GPU. While an increase in the spatial resolution of the patient graphics resulted in slowing down the computational speed of the DTS on the CPU, the speed of the GPU-based DTS was hardly affected. This GPU-based DTS can be a powerful tool for providing accurate, real-time feedback about patient skin-dose to physicians while performing interventional procedures. PMID:24027616

  5. SU-E-I-28: Development of Graphic Patient Models for a Real-Time Skin Dose Tracking System (DTS) for Fluoroscopic Interventional Procedures.

    PubMed

    Rana, V; Bednarek, D; Wu, J; Rudin, S

    2012-06-01

    To develop a library of graphic human models that closely match patients undergoing interventional fluoroscopic procedures in order to obtain an accurate estimate of their skin dose. A dose tracking system (DTS) has been developed that calculates the dose to the patient's skin in real time during fluoroscopic procedures based on a graphical simulation of the x-ray system and the patient. The calculation is performed using a lookup table containing values of mGy per mAs at a reference point and inverse-square correction using the distance from the source to individual points on the skin. For proper inverse-square correction, the external shape of the graphic should closely match that of the patient. We are in the process of developing a library of 3D human graphic models categorized as a function of basic body type, sex, height and weight. Two different open- source software applications are being used to develop graphic models with varying weights and heights, to 'morph' the shapes for body type and to 'pose' them for proper positioning on the table. The DTS software is being designed such that the most appropriate body graphic can be automatically selected based on input of several basic patient dimensional metrics. A series of male and female body graphic models have been developed which vary in weight and height. Matching pairs have been constructed with arms at the side and over the head to simulate the usual placement in cardiac procedures. The error in skin dose calculation due to inverse-square correction is expected to be below 5% if the graphic can match the position of the patient's skin surface within 1 cm. A library of categorized body shapes should allow close matching of the graphic to the patient shape allowing more accurate determination of skin dose with the DTS. Support for this work was provided in part by NIH grants R43FD0158401, R44FD0158402, R01EB002873 and R01EB008425, and by Toshiba Medical Systems Corporation. © 2012 American Association

  6. SU-E-I-55: The Contribution to Skin Dose Due to Scatter From the Patient Table and the Head Holder During Fluoroscopy

    SciTech Connect

    Islam, N; Xiong, Z; Vijayan, S; Rudin, S; Bednarek, D

    2015-06-15

    Purpose: To determine contributions to skin dose due to scatter from the table and head holder used during fluoroscopy, and also to explore alternative design material to reduce the scatter dose. Methods: Measurements were made of the primary and scatter components of the xray beam exiting the patient table and a cylindrical head holder used on a Toshiba Infinix c-arm unit as a function of kVp for the various beam filters on the machine and for various field sizes. The primary component of the beam was measured in air with the object placed close to the x-ray tube with an air gap between it and a 6 cc parallel-plate ionization chamber and with the beam collimated to a size just larger than the chamber. The primary plus scatter radiation components were measured with the object moved to a position in the beam next to the chamber for larger field sizes. Both sets of measurements were preformed while keeping the source-to-chamber distance fixed. The scatter fraction was estimated by taking the ratio of the difference between the two measurements and the reading that included both primary and scatter. Similar measurements were also made for a 2.3 cm thick Styrofoam block which could substitute for the patient support. Results: The measured scatter fractions indicate that the patient table as well as the head holder contributes an additional 10–16% to the patient entrance dose depending on field size. Forward scatter was reduced with the Styrofoam block so that the scatter fraction was about 4–5%. Conclusion: The results of this investigation demonstrated that scatter from the table and head holder used in clinical fluoroscopy contribute substantially to the skin dose. The lower contribution of scatter from Styrofoam suggests that there is an opportunity to redesign patient support accessories to reduce the skin dose. Partial support from NIH grant R01EB002873 and Toshiba Medical Systems Corporation Equipment Grant.

  7. High-dose vitamin D3 supplementation is a requisite for modulation of skin-homing markers on regulatory T cells in HIV-infected patients.

    PubMed

    Khoo, Ai-Leng; Koenen, Hans J P M; Michels, Meta; Ooms, Sharon; Bosch, Marjolein; Netea, Mihai G; Joosten, Irma; van der Ven, André J A M

    2013-02-01

    Vitamin D(3) is known to have an effect on the immune function. We investigated the immunomodulatory capability of vitamin D(3) in HIV-infected patients and studied the expression of chemokine receptors on regulatory T cells (Treg). Vitamin D(3)-deficient HIV-1-seropositive subjects were treated with cholecalciferol (vitamin D(3)) at a dose of 800 IU daily for 3 months (n=9) or 25,000 IU weekly for 2 months (n=7). Peripheral blood mononuclear cells (PBMCs) were isolated and analyzed for skin-homing (CCR4 and CCR10) and gut-homing (CCR9 and integrin α(4)β(7)) marker expression on Treg, by flow cytometry, before and after supplementation. Serum 25(OH)D(3) and parathyroid hormone (PTH) levels were determined at baseline and after the treatment period. Weekly doses of 25,000 IU cholecalciferol effectively achieved the optimal target serum 25(OH)D(3) concentration of >75 nmol/liter (30 ng/ml) in HIV-infected patients. High-dose cholecalciferol supplementation differentially influenced skin-homing markers on Treg with an increased level of CCR10 expression and while a reduction in CCR4 expression level was observed together with a lower percentage of Treg expressing CCR4. For both dosing regimens, there were no significant differences in the expression of gut-homing markers, CCR9, and integrin α(4)β(7). High-dose vitamin D(3) supplementation is needed to reverse vitamin D(3) deficiency in HIV-infected individuals and this results in modulation of skin-homing markers but not gut-homing markers expression on Treg. At a standard dose of 800 IU/day, vitamin D(3) is not effective in achieving an optimal 25(OH)D(3) concentration in patients with an underlying T cell dysfunction and is unable to exert any immunomodulatory effects.

  8. Radiological Dose Assessment - Nonuniform Skin Dose, Radioactive Skin Contamination, and Multiple Dosimetry

    SciTech Connect

    W. C. Inkret; M. E. Schillaci

    1999-03-01

    Radioactive skin contamination with {beta}- and {gamma}-emitting radionuclides may result in biologically significant absorbed doses to the skin. A specific exposure scenario of interest is a nonuniform skin dose delivered by {beta}- and {gamma}-emissions from radioactive skin contamination. The United States Department of Energy requires a formal evaluation and reporting of nonuniform skin doses. The United States Department of Energy also requires specific, formal procedures for evaluating the results from the placement or use of multiple dosimeters. Action levels relative to potential absorbed doses for the contamination survey instrumentation in use at Los Alamos and formal procedures for evaluating nonuniform skin doses and multiple dosimeters are developed and presented here.

  9. Evaluation the consistency of location of moist desquamation and skin high dose area for breast cancer patients receiving adjuvant radiotherapy after breast conservative surgery.

    PubMed

    Sun, Li-Min; Huang, Eng-Yen; Liang, Ji-An; Meng, Fan-Yun; Chang, Gia-Hsin; Tsao, Min-Jen

    2013-03-06

    To evaluate whether the location of moist desquamation matches high dose area for breast cancer patients receiving adjuvant radiotherapy (RT) after breast conservative surgery. One hundred and nine breast cancer patients were enrolled to this study. Their highest skin dose area (the hot spot) was estimated from the treatment planning. We divided the irradiated field into breast; sternal/parasternal; axillary; and inframammary fold areas. The location for moist desquamation was recorded to see if it matches the hot spot. We also analyzed other possible risk factors which may be related to the moist desquamation. Forty-eight patients with 65 locations developed moist desquamation during the RT course. Patients with larger breast sizes and easy to sweat are two independent risk factors for moist desquamation. The distribution of moist desquamation occurred most in the axillary area. All nine patients with the hot spots located at the axillary area developed moist desquamation at the axillary area, and six out of seven patients with the hot spots located at the inframammary fold developed moist desquamation there. The majority of patients with moist desquamation over the breast or sternal/parasternal areas had the hot spots located at these areas. For a patient with moist desquamation, if a hot spot is located at the axillary or inframammary fold areas, it is very likely to have moist desquamation occur there. On the other hand, if moist desquamation occurs over the breast or sternal/parasternal areas, we can highly expect these two areas are also the hot spot locations.

  10. Skin dose in breast brachytherapy: Defining a robust metric.

    PubMed

    Hilts, Michelle; Halperin, Heather; Morton, Dan; Batchelar, Deidre; Bachand, Francois; Chowdhury, Rezwan; Crook, Juanita

    2015-01-01

    To define a simple, robust, and relevant metric for measuring skin dose in breast brachytherapy. Postoperative treatment plans (Day 0) for 15 permanent breast seed implant (PBSI) and 10 multicatheter high-dose-rate (MC-HDR) brachytherapy patients were included. Retrospectively, three skin structures were contoured: 2 mm external from the body; and subsurface layers 2 mm and 4 mm thick. Maximum point dose (Dmax), doses to small volumes (e.g., D0.2cc), and the volumes receiving a percentage of the prescription dose (V%, e.g., V66) were calculated. D0.2cc was investigated as a surrogate to the dose given to 1 cm(2) of skin (D1cm(2)). Pearson product-moment correlation (R(2)) was computed between metrics. Observed trends were consistent across brachytherapy technique. V% did not correlate well with any other metrics: median (range) R(2), 0.63 (0.43, 0.77) and 0.69 (0.3, 0.89) for PBSI and MC-HDR, respectively. Dmax was inconsistently correlated across contours and not well correlated with doses to small volumes: median (range) R(2), 0.85 (0.76, 0.93) and 0.88 (0.83, 0.93) for PBSI and MC-HDR, respectively. In contrast, doses to small volumes were consistently well correlated, even across skin layers: D0.1cc vs. D0.2cc median (range) R(2), 0.98 (0.97, 0.99) and 0.97 (0.94, 0.99) for PBSI and MC-HDR, respectively. Doses to small volumes are robust measures of breast skin dose and given skin's strong area effect, D0.2cc for a 2 mm thick skin layer, a simple surrogate of D1cm(2), is recommended for recording skin dose in any breast brachytherapy. Dmax is not robust and should be avoided. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  11. Pharmacokinetic/pharmacodynamic analysis to evaluate ceftaroline fosamil dosing regimens for the treatment of community-acquired bacterial pneumonia and complicated skin and skin-structure infections in patients with normal and impaired renal function.

    PubMed

    Canut, A; Isla, A; Rodríguez-Gascón, A

    2015-04-01

    In this study, the probability of pharmacokinetic/pharmacodynamic target attainment (PTA) of ceftaroline against clinical isolates causing community-acquired bacterial pneumonia (CABP) and complicated skin and skin-structure infection (cSSSI) in Europe was evaluated. Three dosing regimens were assessed: 600 mg every 12 h (q12 h) as a 1-h infusion (standard dose) or 600 mg every 8 h (q8 h) as a 2-h infusion in virtual patients with normal renal function; and 400 mg q12 h as a 1-h infusion in patients with moderate renal impairment. Pharmacokinetic and microbiological data were obtained from the literature. The PTA and the cumulative fraction of response (CFR) were calculated by Monte Carlo simulation. In patients with normal renal function, the ceftaroline standard dose (600 mg q12 h as a 1-h infusion) can be sufficient to treat CABP due to ceftazidime-susceptible (CAZ-S) Escherichia coli, CAZ-S Klebsiella pneumoniae, meticillin-susceptible Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis (CFR>90%). However, against meticillin-resistant S. aureus (MRSA), the CFR was 72%. In cSSSI, the CFR was also <80% for MRSA. Administration of ceftaroline 600 mg q8 h as a 2-h infusion or 400 mg q12 h as a 1-h infusion in patients with moderate renal insufficiency provided a high probability of treatment success (CFR ca. 100%) for most micro-organisms causing CABP and cSSSI, including MRSA and penicillin-non-susceptible S. pneumoniae. These results suggest that in patients with normal renal function, ceftaroline 600 mg q8 h as a 2-h infusion may be a better option than the standard dose, especially if the MRSA rate is high.

  12. In vivo skin dose measurement using MOSkin detectors in tangential breast radiotherapy.

    PubMed

    Jong, W L; Ung, N M; Wong, J H D; Ng, K H; Wan Ishak, W Z; Abdul Malik, R; Phua, V C E; Cutajar, D L; Metcalfe, P E; Rosenfeld, A B; Ho, G F

    2016-11-01

    The purpose of this study is to measure patient skin dose in tangential breast radiotherapy. Treatment planning dose calculation algorithm such as Pencil Beam Convolution (PBC) and in vivo dosimetry techniques such as radiochromic film can be used to accurately monitor radiation doses at tissue depths, but they are inaccurate for skin dose measurement. A MOSFET-based (MOSkin) detector was used to measure skin dose in this study. Tangential breast radiotherapies ("bolus" and "no bolus") were simulated on an anthropomorphic phantom and the skin doses were measured. Skin doses were also measured in 13 patients undergoing each of the techniques. In the patient study, the EBT2 measurements and PBC calculation tended to over-estimate the skin dose compared with the MOSkin detector (p<0.05) in the "no bolus radiotherapy". No significant differences were observed in the "bolus radiotherapy" (p>0.05). The results from patients were similar to that of the phantom study. This shows that the EBT2 measurement and PBC calculation, while able to predict accurate doses at tissue depths, are inaccurate in predicting doses at build-up regions. The clinical application of the MOSkin detectors showed that the average total skin doses received by patients were 1662±129cGy (medial) and 1893±199cGy (lateral) during "no bolus radiotherapy". The average total skin doses were 4030±72cGy (medial) and 4004±91cGy (lateral) for "bolus radiotherapy". In some cases, patient skin doses were shown to exceed the dose toxicity level for skin erythema. Hence, a suitable device for in vivo dosimetry is necessary to accurately determine skin dose. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  13. UV doses and skin effects during psoriasis climate therapy

    NASA Astrophysics Data System (ADS)

    Randeberg, Lise L.; Hernandez-Palacios, Julio; Lilleeng, Mila; Nilsen, Lill Tove; Krogstad, Anne-Lene

    2011-03-01

    Psoriasis is a common autoimmune disease with inflammatory symptoms affecting skin and joints. One way of dealing with psoriasis is by controlled solar UV exposure treatment. However, this treatment should be optimized to get the best possible treatment effect and to limit negative side effects such as erythema and an increased risk of skin cancer. In this study 24 patients at Valle Marina Treatment Center in Gran Canaria were monitored throughout a treatment period of three weeks starting at the beginning of November. The total UV dose to the location was monitored by UV-meters placed on the roof of the treatment centere, and the patients wore individual film dosimeters throughout the treatment period. Skin parameters were accessed by reflection spectroscopy (400-850nm). This paper presents preliminary findings from the skin measurements in the visible part of the spectrum, such as blood oxygenation, erythema and melanin indexes. Reflection spectroscopy was found to be a good tool for such treatment monitoring.

  14. Incidence of hypersensitivity skin reactions in patients on full-dose low-molecular-weight heparins during pregnancy.

    PubMed

    Schultinge, L; Knol, H M; Kluin-Nelemans, H C; Erwich, J J H M; Meijer, K

    2013-12-01

    Low-molecular-weight heparins (LMWH) are the most commonly used anticoagulants for the treatment and prophylaxis of venous thromboembolism in pregnancy. Hypersensitivity skin reactions associated with the use of LMWH are frequently seen, but are probably underreported. To evaluate the incidence of hypersensitivity skin reactions due to the use of LMWH in pregnancy, and the subsequent management of anticoagulation. From 1999 to 2009, we followed consecutive women who used therapeutic anticoagulation for venous indications. Women visited a combined obstetric/coagulation clinic and were seen by a thrombosis specialist every two months until six weeks postpartum. All women were started on nadroparin. We included 135 pregnancies in 88 women. Overall, in 52 of 135 pregnancies (39%), women switched at least once to another anticoagulant because of the development of hypersensitivity skin reactions. Switching to another preparation of LMWH was effective in 77% of the cases. In 23% of the cases skin reactions recurred and another switch had to be made. In almost half of the pregnancies, women had to switch at least once to another anticoagulant preparation due to the development of hypersensitivity skin reactions on LMWH. In most cases, skin reactions did not recur on the second preparation of LMWH used.

  15. Phase 2, Randomized, Double-Blind, Dose-Ranging Study Evaluating the Safety, Tolerability, Population Pharmacokinetics, and Efficacy of Oral Torezolid Phosphate in Patients with Complicated Skin and Skin Structure Infections▿ † ‡

    PubMed Central

    Prokocimer, P.; Bien, P.; Surber, J.; Mehra, P.; DeAnda, C.; Bulitta, J. B.; Corey, G. R.

    2011-01-01

    Torezolid (TR-700) is the active moiety of the prodrug torezolid phosphate ([TP] TR-701), a second-generation oxazolidinone with 4- to 16-fold greater potency than linezolid against Gram-positive species including methicillin-resistant Staphylococcus aureus (MRSA). A double-blind phase 2 study evaluated three levels (200, 300, or 400 mg) of oral, once-daily TP over 5 to 7 days for complicated skin and skin structure infections (cSSSI). Patients 18 to 75 years old with cSSSI caused by suspected or confirmed Gram-positive pathogens were randomized 1:1:1. Of 188 treated patients, 76.6% had abscesses, 17.6% had extensive cellulitis, and 5.9% had wound infections. S. aureus, the most common pathogen, was isolated in 90.3% of patients (139/154) with a baseline pathogen; 80.6% were MRSA. Cure rates in clinically evaluable patients were 98.2% at 200 mg, 94.4% at 300 mg, and 94.4% at 400 mg. Cure rates were consistent across diagnoses, regardless of lesion size or the presence of systemic signs of infection. Clinical cure rates in patients with S. aureus isolated at baseline were 96.6% overall and 96.8% for MRSA. TP was safe and well tolerated at all dose levels. No patients discontinued treatment due to an adverse event. Three-stage hierarchical population pharmacokinetic modeling yielded a geometric mean clearance of 8.28 liters/h (between-patient variability, 32.3%), a volume of the central compartment of 71.4 liters (24.0%), and a volume of the peripheral compartment of 27.9 liters (35.7%). Results of this study show a high degree of efficacy at all three dose levels without significant differences in the safety profile and support the continued evaluation of TP for the treatment of cSSSI in phase 3 trials. PMID:21115795

  16. Skin dose differences between intensity-modulated radiation therapy and volumetric-modulated arc therapy and between boost and integrated treatment regimens for treating head and neck and other cancer sites in patients.

    PubMed

    Penoncello, Gregory P; Ding, George X

    2016-01-01

    The purpose of this study was (1) to evaluate dose to skin between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) treatment techniques for target sites in the head and neck, pelvis, and brain and (2) to determine if the treatment dose and fractionation regimen affect the skin dose between traditional sequential boost and integrated boost regimens for patients with head and neck cancer. A total of 19 patients and 48 plans were evaluated. The Eclipse (v11) treatment planning system was used to plan therapy in 9 patients with head and neck cancer, 5 patients with prostate cancer, and 5 patients with brain cancer with VMAT and static-field IMRT. The mean skin dose and the maximum dose to a contiguous volume of 2cm(3) for head and neck plans and brain plans and a contiguous volume of 5cm(3) for pelvis plans were compared for each treatment technique. Of the 9 patients with head and neck cancer, 3 underwent an integrated boost regimen. One integrated boost plan was replanned with IMRT and VMAT using a traditional boost regimen. For target sites located in the head and neck, VMAT reduced the mean dose and contiguous hot spot most noticeably in the shoulder region by 5.6% and 5.4%, respectively. When using an integrated boost regimen, the contiguous hot spot skin dose in the shoulder was larger on average than a traditional boost pattern by 26.5% and the mean skin dose was larger by 1.7%. VMAT techniques largely decrease the contiguous hot spot in the skin in the pelvis by an average of 36% compared with IMRT. For the same target coverage, VMAT can reduce the skin dose in all the regions of the body, but more noticeably in the shoulders in patients with head and neck and pelvis cancer. We also found that using integrated boost regimens in patients with head and neck cancer leads to higher shoulder skin doses compared with traditional boost regimens.

  17. Skin dose differences between intensity-modulated radiation therapy and volumetric-modulated arc therapy and between boost and integrated treatment regimens for treating head and neck and other cancer sites in patients

    SciTech Connect

    Penoncello, Gregory P.; Ding, George X.

    2016-04-01

    The purpose of this study was (1) to evaluate dose to skin between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) treatment techniques for target sites in the head and neck, pelvis, and brain and (2) to determine if the treatment dose and fractionation regimen affect the skin dose between traditional sequential boost and integrated boost regimens for patients with head and neck cancer. A total of 19 patients and 48 plans were evaluated. The Eclipse (v11) treatment planning system was used to plan therapy in 9 patients with head and neck cancer, 5 patients with prostate cancer, and 5 patients with brain cancer with VMAT and static-field IMRT. The mean skin dose and the maximum dose to a contiguous volume of 2 cm{sup 3} for head and neck plans and brain plans and a contiguous volume of 5 cm{sup 3} for pelvis plans were compared for each treatment technique. Of the 9 patients with head and neck cancer, 3 underwent an integrated boost regimen. One integrated boost plan was replanned with IMRT and VMAT using a traditional boost regimen. For target sites located in the head and neck, VMAT reduced the mean dose and contiguous hot spot most noticeably in the shoulder region by 5.6% and 5.4%, respectively. When using an integrated boost regimen, the contiguous hot spot skin dose in the shoulder was larger on average than a traditional boost pattern by 26.5% and the mean skin dose was larger by 1.7%. VMAT techniques largely decrease the contiguous hot spot in the skin in the pelvis by an average of 36% compared with IMRT. For the same target coverage, VMAT can reduce the skin dose in all the regions of the body, but more noticeably in the shoulders in patients with head and neck and pelvis cancer. We also found that using integrated boost regimens in patients with head and neck cancer leads to higher shoulder skin doses compared with traditional boost regimens.

  18. Relationship between fluoroscopic time, dose-area product, body weight, and maximum radiation skin dose in cardiac interventional procedures.

    PubMed

    Chida, Koichi; Saito, Haruo; Otani, Hiroki; Kohzuki, Masahiro; Takahashi, Shoki; Yamada, Shogo; Shirato, Kunio; Zuguchi, Masayuki

    2006-03-01

    Real-time maximum dose monitoring of the skin is unavailable on many of the X-ray machines that are used for cardiac intervention procedures. Therefore, some reports have recommended that physicians record the fluoroscopic time for patients undergoing fluoroscopically guided intervention procedures. However, the relationship between the fluoroscopic time and the maximum radiation skin dose is not clear. This article describes the correlation between the maximum radiation skin dose and fluoroscopic time for patients undergoing cardiac intervention procedures. In addition, we examined whether the correlations between maximum radiation skin dose and body weight, fluoroscopic time, and dose-area product (DAP) were useful for estimating the maximum skin dose during cardiac intervention procedures. Two hundred consecutive cardiac intervention procedures were studied: 172 percutaneous coronary interventions and 28 cardiac radiofrequency catheter ablation (RFCA) procedures. The patient skin dose and DAP were measured using Caregraph with skin-dose-mapping software. For the RFCA procedures, we found a good correlation between the maximum radiation skin dose and fluoroscopic time (r = 0.801, p < 0.0001), whereas we found a poor correlation between the maximum radiation skin dose and fluoroscopic time for the percutaneous coronary intervention procedures (r = 0.628, p < 0.0001). There was a strong correlation between the maximum radiation skin dose and DAP in RFCA procedures (r = 0.942, p < 0.0001). There was also a significant correlation between the maximum radiation skin dose and DAP (r = 0.724, p < 0.0001) and weight-fluoroscopic time product (WFP) (r = 0.709, p < 0.0001) in percutaneous coronary intervention procedures. The correlation between the maximum radiation skin dose with DAP is more striking than that with fluoroscopic time in both RFCA and percutaneous coronary intervention procedures. We recommend that physicians record the DAP when it can be monitored and

  19. Patient dose in cardiac radiology.

    PubMed

    Stratis, Andreas I; Anthopoulos, Prodromos L; Gavaliatsis, Isidoros P; Ifantis, Georghios P; Salahas, Anastasios I; Antonellis, Ioannis P; Tavernarakis, Antonios G; Molfetas, Michael I

    2009-01-01

    In diagnostic and interventional cardiology procedures performed with the use of X-ray diagnostic imaging systems, the long fluoroscopy time and the large number of cine projections, as well as the repetition of the procedure due to the recurrence of the lesion--a common event--result in a high locally delivered skin dose, which may even lead to patient skin necrosis. The purpose of this study was to collect information in order to estimate the patient dose during coronary angiography and coronary angioplasty procedures, using the dose-area product measuring system of the X-ray angiographic machine. Dose-area product (DAP), fluoroscopy time, number of sequences and frames per sequence were collected for each of 108 coronary angiography and 101 coronary angioplasty procedures, using the dedicated X-ray machine of the hospital's haemodynamic department, where more than 3000 procedures are performed per year. The median values of DAP were 19.96 and 40.17 Gy.cm(2) for coronary angiography and angioplasty, respectively; fluoroscopy times were 7.7 and 23.4 minutes; and the numbers of frames were 457 and 641, respectively. There was a strong correlation between DAP and fluoroscopy time, the number of frames per sequence, and hence the cine recording time. The entrance skin dose delivered to the patient in the haemodynamic department was lower than that of other studies, although the mean fluoroscopy time per patient was longer. The practices in use satisfy the diagnostic reference levels as far as DAP values and number of frames per patient are concerned, but not with regard to fluoroscopy time. We did not find the correlation between doctors' experience and DAP values reported in other studies, as we did not take into account the complexity index of the lesion.

  20. Pooled analysis of single-dose oritavancin in the treatment of acute bacterial skin and skin-structure infections caused by Gram-positive pathogens, including a large patient subset with methicillin-resistant Staphylococcus aureus.

    PubMed

    Corey, G Ralph; Arhin, Francis F; Wikler, Matthew A; Sahm, Daniel F; Kreiswirth, Barry N; Mediavilla, José R; Good, Samantha; Fiset, Claude; Jiang, Hai; Moeck, Greg; Kabler, Heidi; Green, Sinikka; O'Riordan, William

    2016-11-01

    Oritavancin is a lipoglycopeptide antibiotic with bactericidal activity against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). The phase 3 studies SOLO I and SOLO II demonstrated comparable efficacy and safety of a single dose of oritavancin compared with 7-10 days of twice-daily vancomycin in adults with acute bacterial skin and skin-structure infections (ABSSSIs). The present analysis assessed clinical responses by pathogen at 48-72 h and at study days 14-24 in SOLO patients within the pooled data set. Of the 1959 patients in the pooled SOLO studies, 1067 had at least one baseline Gram-positive pathogen and 405 had MRSA. Clinical response rates were similar for oritavancin- and vancomycin-treated patients by pathogen, including Staphylococcus aureus with or without the Panton-Valentine leukocidin (pvl) gene and from different clonal complexes, and were similar for pathogens within each treatment group. Oritavancin exhibited potent in vitro activity against all baseline pathogens, with MIC90 values (minimum inhibitory concentration required to inhibit 90% of the isolates) of 0.12 µg/mL for Staphylococcus  aureus, 0.25 µg/mL for Streptococcus pyogenes and 0.06 µg/mL for Enterococcus faecalis. Whereas both oritavancin and vancomycin achieved similarly high rates of clinical response by pathogen, including methicillin-susceptible and -resistant Staphylococcus aureus, oritavancin provides a single-dose alternative to 7-10 days of twice-daily vancomycin to treat ABSSSIs.

  1. Limitations of the TG-43 formalism for skin high-dose-rate brachytherapy dose calculations

    SciTech Connect

    Granero, Domingo; Perez-Calatayud, Jose; Vijande, Javier; Ballester, Facundo; Rivard, Mark J.

    2014-02-15

    Purpose: In skin high-dose-rate (HDR) brachytherapy, sources are located outside, in contact with, or implanted at some depth below the skin surface. Most treatment planning systems use the TG-43 formalism, which is based on single-source dose superposition within an infinite water medium without accounting for the true geometry in which conditions for scattered radiation are altered by the presence of air. The purpose of this study is to evaluate the dosimetric limitations of the TG-43 formalism in HDR skin brachytherapy and the potential clinical impact. Methods: Dose rate distributions of typical configurations used in skin brachytherapy were obtained: a 5 cm × 5 cm superficial mould; a source inside a catheter located at the skin surface with and without backscatter bolus; and a typical interstitial implant consisting of an HDR source in a catheter located at a depth of 0.5 cm. Commercially available HDR{sup 60}Co and {sup 192}Ir sources and a hypothetical {sup 169}Yb source were considered. The Geant4 Monte Carlo radiation transport code was used to estimate dose rate distributions for the configurations considered. These results were then compared to those obtained with the TG-43 dose calculation formalism. In particular, the influence of adding bolus material over the implant was studied. Results: For a 5 cm × 5 cm{sup 192}Ir superficial mould and 0.5 cm prescription depth, dose differences in comparison to the TG-43 method were about −3%. When the source was positioned at the skin surface, dose differences were smaller than −1% for {sup 60}Co and {sup 192}Ir, yet −3% for {sup 169}Yb. For the interstitial implant, dose differences at the skin surface were −7% for {sup 60}Co, −0.6% for {sup 192}Ir, and −2.5% for {sup 169}Yb. Conclusions: This study indicates the following: (i) for the superficial mould, no bolus is needed; (ii) when the source is in contact with the skin surface, no bolus is needed for either {sup 60}Co and {sup 192}Ir. For

  2. Limitations of the TG-43 formalism for skin high-dose-rate brachytherapy dose calculations

    SciTech Connect

    Granero, Domingo; Perez-Calatayud, Jose; Vijande, Javier; Ballester, Facundo; Rivard, Mark J.

    2014-02-15

    Purpose: In skin high-dose-rate (HDR) brachytherapy, sources are located outside, in contact with, or implanted at some depth below the skin surface. Most treatment planning systems use the TG-43 formalism, which is based on single-source dose superposition within an infinite water medium without accounting for the true geometry in which conditions for scattered radiation are altered by the presence of air. The purpose of this study is to evaluate the dosimetric limitations of the TG-43 formalism in HDR skin brachytherapy and the potential clinical impact. Methods: Dose rate distributions of typical configurations used in skin brachytherapy were obtained: a 5 cm × 5 cm superficial mould; a source inside a catheter located at the skin surface with and without backscatter bolus; and a typical interstitial implant consisting of an HDR source in a catheter located at a depth of 0.5 cm. Commercially available HDR{sup 60}Co and {sup 192}Ir sources and a hypothetical {sup 169}Yb source were considered. The Geant4 Monte Carlo radiation transport code was used to estimate dose rate distributions for the configurations considered. These results were then compared to those obtained with the TG-43 dose calculation formalism. In particular, the influence of adding bolus material over the implant was studied. Results: For a 5 cm × 5 cm{sup 192}Ir superficial mould and 0.5 cm prescription depth, dose differences in comparison to the TG-43 method were about −3%. When the source was positioned at the skin surface, dose differences were smaller than −1% for {sup 60}Co and {sup 192}Ir, yet −3% for {sup 169}Yb. For the interstitial implant, dose differences at the skin surface were −7% for {sup 60}Co, −0.6% for {sup 192}Ir, and −2.5% for {sup 169}Yb. Conclusions: This study indicates the following: (i) for the superficial mould, no bolus is needed; (ii) when the source is in contact with the skin surface, no bolus is needed for either {sup 60}Co and {sup 192}Ir. For

  3. Verification of Calculated Skin Doses in Postmastectomy Helical Tomotherapy

    SciTech Connect

    Ito, Shima; Parker, Brent C.; Levine, Renee; Sanders, Mary Ella; Fontenot, Jonas; Gibbons, John; Hogstrom, Kenneth

    2011-10-01

    Purpose: To verify the accuracy of calculated skin doses in helical tomotherapy for postmastectomy radiation therapy (PMRT). Methods and Materials: In vivo thermoluminescent dosimeters (TLDs) were used to measure the skin dose at multiple points in each of 14 patients throughout the course of treatment on a TomoTherapy Hi.Art II system, for a total of 420 TLD measurements. Five patients were evaluated near the location of the mastectomy scar, whereas 9 patients were evaluated throughout the treatment volume. The measured dose at each location was compared with calculations from the treatment planning system. Results: The mean difference and standard error of the mean difference between measurement and calculation for the scar measurements was -1.8% {+-} 0.2% (standard deviation [SD], 4.3%; range, -11.1% to 10.6%). The mean difference and standard error of the mean difference between measurement and calculation for measurements throughout the treatment volume was -3.0% {+-} 0.4% (SD, 4.7%; range, -18.4% to 12.6%). The mean difference and standard error of the mean difference between measurement and calculation for all measurements was -2.1% {+-} 0.2% (standard deviation, 4.5%: range, -18.4% to 12.6%). The mean difference between measured and calculated TLD doses was statistically significant at two standard deviations of the mean, but was not clinically significant (i.e., was <5%). However, 23% of the measured TLD doses differed from the calculated TLD doses by more than 5%. Conclusions: The mean of the measured TLD doses agreed with TomoTherapy calculated TLD doses within our clinical criterion of 5%.

  4. Verification of calculated skin doses in postmastectomy helical tomotherapy.

    PubMed

    Ito, Shima; Parker, Brent C; Levine, Renee; Sanders, Mary Ella; Fontenot, Jonas; Gibbons, John; Hogstrom, Kenneth

    2011-10-01

    To verify the accuracy of calculated skin doses in helical tomotherapy for postmastectomy radiation therapy (PMRT). In vivo thermoluminescent dosimeters (TLDs) were used to measure the skin dose at multiple points in each of 14 patients throughout the course of treatment on a TomoTherapy Hi·Art II system, for a total of 420 TLD measurements. Five patients were evaluated near the location of the mastectomy scar, whereas 9 patients were evaluated throughout the treatment volume. The measured dose at each location was compared with calculations from the treatment planning system. The mean difference and standard error of the mean difference between measurement and calculation for the scar measurements was -1.8% ± 0.2% (standard deviation [SD], 4.3%; range, -11.1% to 10.6%). The mean difference and standard error of the mean difference between measurement and calculation for measurements throughout the treatment volume was -3.0% ± 0.4% (SD, 4.7%; range, -18.4% to 12.6%). The mean difference and standard error of the mean difference between measurement and calculation for all measurements was -2.1% ± 0.2% (standard deviation, 4.5%: range, -18.4% to 12.6%). The mean difference between measured and calculated TLD doses was statistically significant at two standard deviations of the mean, but was not clinically significant (i.e., was <5%). However, 23% of the measured TLD doses differed from the calculated TLD doses by more than 5%. The mean of the measured TLD doses agreed with TomoTherapy calculated TLD doses within our clinical criterion of 5%. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. Construction of new skin models and calculation of skin dose coefficients for electron exposures

    NASA Astrophysics Data System (ADS)

    Yeom, Yeon Soo; Kim, Chan Hyeong; Nguyen, Thang Tat; Choi, Chansoo; Han, Min Cheol; Jeong, Jong Hwi

    2016-08-01

    The voxel-type reference phantoms of the International Commission on Radiological Protection (ICRP), due to their limited voxel resolutions, cannot represent the 50- μm-thick radiosensitive target layer of the skin necessary for skin dose calculations. Alternatively, in ICRP Publication 116, the dose coefficients (DCs) for the skin were calculated approximately, averaging absorbed dose over the entire skin depth of the ICRP phantoms. This approximation is valid for highly-penetrating radiations such as photons and neutrons, but not for weakly penetrating radiations like electrons due to the high gradient in the dose distribution in the skin. To address the limitation, the present study introduces skin polygon-mesh (PM) models, which have been produced by converting the skin models of the ICRP voxel phantoms to a high-quality PM format and adding a 50- μm-thick radiosensitive target layer into the skin models. Then, the constructed skin PM models were implemented in the Geant4 Monte Carlo code to calculate the skin DCs for external exposures of electrons. The calculated values were then compared with the skin DCs of the ICRP Publication 116. The results of the present study show that for high-energy electrons (≥ 1 MeV), the ICRP-116 skin DCs are, indeed, in good agreement with the skin DCs calculated in the present study. For low-energy electrons (< 1 MeV), however, significant discrepancies were observed, and the ICRP-116 skin DCs underestimated the skin dose as much as 15 times for some energies. Besides, regardless of the small tissue weighting factor of the skin ( w T = 0.01), the discrepancies in the skin dose were found to result in significant discrepancies in the effective dose, demonstarting that the effective DCs in ICRP-116 are not reliable for external exposure to electrons.

  6. Megavoltage x-ray skin dose variation with an angle using grid carbon fibre couch tops.

    PubMed

    Butson, Martin J; Cheung, Tsang; Yu, Peter K N

    2007-10-21

    It is well known that a skin dose from high-energy x-ray radiation varies with the angle of beam incidence or the presence of a radiotherapy linear accelerator couch top material. This note investigates changes produced to the skin dose from a Varian carbon fibre grid couch top at differing angles of incidence for 6 MV x-rays as is often the case clinically. Results have shown that the skin dose can easily be measured using an EBT Gafchromic film whereby the delivered skin dose can be quantified to a high level of spatial resolution, not easily achieved with other skin dose detectors. Results have shown a significant increase in the skin dose specifically at the point of a cross-sectional carbon fibre grid. Values in % of the skin dose increased from approximately 27% (an open area within a 10 cm x 10 cm field) up to 55% (same field size) at the centre of the carbon fibre mesh strip (0 degrees incidence). This is compared to 19% of the skin dose for an open field of a 10 cm x 10 cm beam without the couch material present. At larger angles similar effects occur with values changing from 52% to 75% (60 degrees , 10 cm x 10 cm) in the open area and under the grid, respectively. This produces a wave effect for the skin dose. The average skin dose magnitude increases with the angle of incidence of the beam, ranging from 37.5% to 66% from 0 degrees to 60 degrees (10 x 10 cm), respectively. The symmetric wave nature of the skin dose profile skews to deliver an increased dose on the posterior side of the carbon fibre grid as the angle of incidence increases. Simulated fractional dose delivery on a phantom has shown that over 30 fractions the wave nature of the delivered skin dose is minimized due to the random nature of most patient positioning on the treatment couch. However, some variations are still present as the ratio of the open to grid area is approximately 4:1 and the dose spread is not necessarily completely averaged during a typical fractionated radiotherapy

  7. How accurately can the peak skin dose in fluoroscopy be determined using indirect dose metrics?

    SciTech Connect

    Jones, A. Kyle; Ensor, Joe E.; Pasciak, Alexander S.

    2014-07-15

    Purpose: Skin dosimetry is important for fluoroscopically-guided interventions, as peak skin doses (PSD) that result in skin reactions can be reached during these procedures. There is no consensus as to whether or not indirect skin dosimetry is sufficiently accurate for fluoroscopically-guided interventions. However, measuring PSD with film is difficult and the decision to do so must be madea priori. The purpose of this study was to assess the accuracy of different types of indirect dose estimates and to determine if PSD can be calculated within ±50% using indirect dose metrics for embolization procedures. Methods: PSD were measured directly using radiochromic film for 41 consecutive embolization procedures at two sites. Indirect dose metrics from the procedures were collected, including reference air kerma. Four different estimates of PSD were calculated from the indirect dose metrics and compared along with reference air kerma to the measured PSD for each case. The four indirect estimates included a standard calculation method, the use of detailed information from the radiation dose structured report, and two simplified calculation methods based on the standard method. Indirect dosimetry results were compared with direct measurements, including an analysis of uncertainty associated with film dosimetry. Factors affecting the accuracy of the different indirect estimates were examined. Results: When using the standard calculation method, calculated PSD were within ±35% for all 41 procedures studied. Calculated PSD were within ±50% for a simplified method using a single source-to-patient distance for all calculations. Reference air kerma was within ±50% for all but one procedure. Cases for which reference air kerma or calculated PSD exhibited large (±35%) differences from the measured PSD were analyzed, and two main causative factors were identified: unusually small or large source-to-patient distances and large contributions to reference air kerma from cone

  8. Association Between Maximal Skin Dose and Breast Brachytherapy Outcome: A Proposal for More Rigorous Dosimetric Constraints

    SciTech Connect

    Cuttino, Laurie W.; Heffernan, Jill; Vera, Robyn; Rosu, Mihaela; Ramakrishnan, V. Ramesh; Arthur, Douglas W.

    2011-11-01

    Purpose: Multiple investigations have used the skin distance as a surrogate for the skin dose and have shown that distances <6 mm have been associated with late toxicity after MammoSite brachytherapy. No publications have yet described the relationship between the actual maximal skin dose and the outcome. The present study analyzed the maximal skin dose delivered and the occurrence of late toxicity in a large cohort of patients with prolonged follow-up. Methods: A total of 96 patients treated with breast brachytherapy between 2000 and 2007 for whom complete planning and follow-up data were available were included in the present analysis. The median follow-up was 48 months (range, 24-111). Of the 96 patients, 40 were treated with multicatheter interstitial brachytherapy and 56 with MammoSite. A multivariate statistical analysis was performed to determine the relationship between several dosimetric parameters and patient outcome. Results: The treatment was well tolerated, with 98% of patients experiencing good to excellent cosmesis. Significant late toxicity was uncommon. The maximal dose delivered to the skin was significantly associated with the incidence of any degree of telangiectasia (p = .009) and moderate to severe fibrosis (p = .010). The incidence of late toxicity was significantly increased when the dose to the skin was >4.05 Gy/fraction. Conclusion: The initial skin dose recommendations have been based on safe use and the avoidance of significant toxicity. The results from the present study have suggested that patients might further benefit if more rigorous constraints were applied and if the skin dose were limited to 120% of the prescription dose.

  9. Maculopapular skin rashes associated with high-dose chemotherapy: prevalence and risk factors.

    PubMed

    Wright, Lynette G

    2006-11-27

    To determine the prevalence of and risk factors for maculopapular skin rashes associated with high-dose chemotherapy. Observational pilot study. A bone marrow transplant hematology-oncology unit in a private city hospital. Data were collected on 14 patients who developed maculopapular rashes out of 127 patients who received high-dose chemotherapy (purposive sampling). Observation of the distribution and nature of skin rashes in relation to chemotherapy, disease, adjuvant medications, and white blood cell counts. Diseases, chemotherapy protocols and doses, adjuvant medications, and blood counts. Skin reactions ranged from mild, scattered macular or maculopapular rashes to severe rashes. Patients newly diagnosed with acute myelogenous leukemia (AML) who received induction protocols containing cytarabine had the most rashes, affecting 6 of 11 patients (55%). No rashes were observed on patients treated with the protocol that included high-dose corticosteroids. Patients rarely had recurrence of the rash with further courses of chemotherapy. Cytarabine doses higher than 700 mg/m2 may be a cause of maculopapular skin rashes. Patients most at risk were those newly diagnosed with AML who received induction therapy. Corticosteroids may prevent the development of skin rashes. No useful nursing strategy exists to prevent, lessen the intensity of, or shorten the course of a delayed hypersensitivity rash. Knowing which patients are most at risk is useful to enable close monitoring and patient and staff education.

  10. Evaluating the consistency of location of the most severe acute skin reaction and highest skin dose measured by thermoluminescent dosimeter during radiotherapy for breast cancer.

    PubMed

    Sun, Li-Min; Huang, Chih-Jen; Chen, Hsiao-Yun; Chang, Gia-Hsin; Tsao, Min-Jen

    2016-01-01

    We conducted this prospective study to evaluate whether the location of the most severe acute skin reaction matches the highest skin dose measured by thermoluminescent dosimeter (TLD) during adjuvant radiotherapy (RT) for patients with breast cancer after breast conservative surgery. To determine whether TLD measurement can reflect the location of the most severe acute skin reaction, 80 consecutive patients were enrolled in this prospective study. We divided the irradiated field into breast, axillary, inframammary fold, and areola/nipple areas. In 1 treatment session when obvious skin reaction occurred, we placed the TLD chips onto the 4 areas and measured the skin dose. We determined whether the highest measured skin dose area is consistent with the location of the most severe skin reaction. The McNemar test revealed that the clinical skin reaction and TLD measurement are more consistent when the most severe skin reaction occurred at the axillary area, and the p = 0.0108. On the contrary, TLD measurement of skin dose is less likely consistent with clinical observation when the most severe skin reaction occurred at the inframammary fold, breast, and areola/nipple areas (all the p > 0.05). Considering the common site of severe skin reaction over the axillary area, TLD measurement may be an appropriate way to predict skin reaction during RT. Copyright © 2016 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  11. A Comparison of Skin and Chest Wall Dose Delivered With Multicatheter, Contura Multilumen Balloon, and MammoSite Breast Brachytherapy

    SciTech Connect

    Cuttino, Laurie W.; Todor, Dorin; Rosu, Mihaela; Arthur, Douglas W.

    2011-01-01

    Purpose: Skin and chest wall doses have been correlated with toxicity in patients treated with breast brachytherapy . This investigation compared the ability to control skin and chest wall doses between patients treated with multicatheter (MC), Contura multilumen balloon (CMLB), and MammoSite (MS) brachytherapy. Methods and Materials: 43 patients treated with the MC technique, 45 patients treated with the CMLB, and 83 patients treated with the MS were reviewed. The maximum doses delivered to the skin and chest wall were calculated for all patients. Results: The mean maximum skin doses for the MC, CMLB, and MS were 2.3 Gy (67% of prescription dose), 2.8 Gy (82% of prescription dose), and 3.2 Gy per fraction (94% of prescription dose), respectively. Although the skin distances were similar (p = 0.23) for the two balloon techniques, the mean skin dose with the CMLB was significantly lower than with the MS (p = 0.05). The mean maximum rib doses for the MC, CMLB, and MS were 2.3 Gy (67% of prescription dose), 2.8 Gy (82% of prescription dose), and 3.6 Gy per fraction (105% of prescription dose), respectively. Again, the mean rib dose with the CMLB was significantly lower than with the MS (p = 0.002). Conclusion: The MC and CMLB techniques are associated with significantly lower mean skin and rib doses than is the MS. Treatment with the MS was associated with significantly more patients receiving doses to the skin or rib in excess of 125% of the prescription. Treatment with the CMLB may prove to yield less normal tissue toxicity than treatment with the MS.

  12. A system to track skin dose for neuro-interventional cone-beam computed tomography (CBCT)

    NASA Astrophysics Data System (ADS)

    Vijayan, Sarath; Xiong, Zhenyu; Rudin, Stephen; Bednarek, Daniel R.

    2016-03-01

    The skin-dose tracking system (DTS) provides a color-coded illustration of the cumulative skin-dose distribution on a closely-matching 3D graphic of the patient during fluoroscopic interventions in real-time for immediate feedback to the interventionist. The skin-dose tracking utility of DTS has been extended to include cone-beam computed tomography (CBCT) of neurointerventions. While the DTS was developed to track the entrance skin dose including backscatter, a significant part of the dose in CBCT is contributed by exit primary radiation and scatter due to the many overlapping projections during the rotational scan. The variation of backscatter inside and outside the collimated beam was measured with radiochromic film and a curve was fit to obtain a scatter spread function that could be applied in the DTS. Likewise, the exit dose distribution was measured with radiochromic film for a single projection and a correction factor was determined as a function of path length through the head. Both of these sources of skin dose are added for every projection in the CBCT scan to obtain a total dose mapping over the patient graphic. Results show the backscatter to follow a sigmoidal falloff near the edge of the beam, extending outside the beam as far as 8 cm. The exit dose measured for a cylindrical CTDI phantom was nearly 10 % of the entrance peak skin dose for the central ray. The dose mapping performed by the DTS for a CBCT scan was compared to that measured with radiochromic film and a CTDI-head phantom with good agreement.

  13. Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

    NASA Astrophysics Data System (ADS)

    Lucero, J. F.; Rojas, J. I.

    2016-07-01

    Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient's entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

  14. A practical method for skin dose estimation in interventional cardiology based on fluorographic DICOM information.

    PubMed

    Matthews, Lucy; Dixon, Matthew; Rowles, Nick; Stevens, Greg

    2016-03-01

    A practical method for skin dose estimation for interventional cardiology patients has been developed to inform pre-procedure planning and post-procedure patient management. Absorbed dose to the patient skin for certain interventional radiology procedures can exceed thresholds for deterministic skin injury, requiring documentation within the patient notes and appropriate patient follow-up. The primary objective was to reduce uncertainty associated with current methods, particularly surrounding field overlap. This was achieved by considering rectangular field geometry incident on a spherical patient model in a polar coordinate system. The angular size of each field was quantified at surface of the sphere, i.e. the skin surface. Computer-assisted design software enabled the modelling of a sufficient dataset that was subsequently validated with radiochromic film. Modelled overlap was found to agree with overlap measured using film to within 2.2° ± 2.0°, showing that the overall error associated with the model was < 1 %. Mathematical comparison against exposure data extracted from procedural Digital Imaging and Communication in Medicine files was used to generate a graphical skin dose map, demonstrating the dose distribution over a sphere centred at the interventional reference point. Dosimetric accuracy of the software was measured as between 3.5 and 17 % for different variables.

  15. Radiation effect in mouse skin: Dose fractionation and wound healing

    SciTech Connect

    Gorodetsky, R.; Mou, X.D.; Fisher, D.R.; Taylor, J.M.; Withers, H.R. )

    1990-05-01

    Radiation induced dermal injury was measured by the gain in the physical strength of healing wounds in mouse skin. A sigmoid dose response for the inhibition of wound healing 14 days after surgery was found for single doses of X rays. The sparing of dermal damage from fractionation of the X-ray dose was quantified in terms of the alpha/beta ratio in the linear-quadratic (LQ) model, at a wide range of doses per fraction reaching as low as about 1 Gy. The fit and the appropriateness of the LQ model for the skin wound healing assay was examined with the use of the Fe-plot in which inverse total dose is plotted versus dose per fraction for wound strength isoeffects. The alpha/beta ratio of the skin was about 2.5 Gy (95% confidence of less than +/- 1 Gy) and was appropriate over a dose range of 1 Gy to about 8 Gy. The low alpha/beta value is typical for a late responding tissue. This assay, therefore, has the advantage of measuring and forecasting late radiation responses of the dermis within a short time after irradiation.

  16. Validation of the photon dose calculation model in the VARSKIN 4 skin dose computer code.

    PubMed

    Sherbini, Sami; Decicco, Joseph; Struckmeyer, Richard; Saba, Mohammad; Bush-Goddard, Stephanie

    2012-12-01

    An updated version of the skin dose computer code VARSKIN, namely VARSKIN 4, was examined to determine the accuracy of the photon model in calculating dose rates with different combinations of source geometry and radionuclides. The reference data for this validation were obtained by means of Monte Carlo transport calculations using MCNP5. The geometries tested included the zero volume sources point and disc, as well as the volume sources sphere and cylinder. Three geometries were tested using source directly on the skin, source off the skin with an absorber material between source and skin, and source off the skin with only an air gap between source and skin. The results of these calculations showed that the non-volume sources produced dose rates that were in very good agreement with the Monte Carlo calculations, but the volume sources resulted in overestimates of the dose rates compared with the Monte Carlo results by factors that ranged up to about 2.5. The results for the air gap showed poor agreement with Monte Carlo for all source geometries, with the dose rates overestimated in all cases. The conclusion was that, for situations where the beta dose is dominant, these results are of little significance because the photon dose in such cases is generally a very small fraction of the total dose. For situations in which the photon dose is dominant, use of the point or disc geometries should be adequate in most cases except those in which the dose approaches or exceeds an applicable limit. Such situations will often require a more accurate dose assessment and may require the use of methods such as Monte Carlo transport calculations.

  17. Dosimetric optimization of a conical breast brachytherapy applicator for improved skin dose sparing

    SciTech Connect

    Yang Yun; Rivard, Mark J.

    2010-11-15

    Purpose: Both the AccuBoost D-shaped and round applicators have been dosimetrically characterized and clinically used to treat patients with breast cancer. While the round applicators provide conformal dose coverage, under certain clinical circumstances the breast skin dose may be higher than preferred. The purpose of this study was to modify the round applicators to minimize skin dose while not substantially affecting dose uniformity within the target volume and reducing the treatment time. Methods: In order to irradiate the intended volume while sparing critical structures such as the skin, the current round applicator design has been augmented through the addition of an internal truncated cone (i.e., frustum) shield. Monte Carlo methods and clinical constraints were used to design the optimal cone applicator. With the cone applicator now defined as the entire assembly including the surrounding tungsten-alloy shell holding the HDR {sup 192}Ir source catheter, the applicator height was reduced to diminish the treatment time while minimizing skin dose. Monte Carlo simulation results were validated using both radiochromic film and ionization chamber measurements based on established techniques. Results: The optimal cone applicators diminished the maximum skin dose by 15%-32% (based on the applicator diameter and breast separation) with the tumor dose reduced by less than 3% for a constant exposure time. Furthermore, reduction in applicator height diminished the treatment time by up to 30%. Radiochromic film and ionization chamber dosimetric results in phantom agreed with Monte Carlo simulation results typically within 3%. Larger differences were outside the treatment volume in low dose regions or associated with differences between the measurement and Monte Carlo simulation environments. Conclusions: A new radiotherapy treatment device was developed and dosimetrically characterized. This set of applicators significantly reduces the skin dose and treatment time while

  18. Dosimetric optimization of a conical breast brachytherapy applicator for improved skin dose sparing.

    PubMed

    Yang, Yun; Rivard, Mark J

    2010-11-01

    Both the AccuBoost D-shaped and round applicators have been dosimetrically characterized and clinically used to treat patients with breast cancer. While the round applicators provide conformal dose coverage, under certain clinical circumstances the breast skin dose may be higher than preferred. The purpose of this study was to modify the round applicators to minimize skin dose while not substantially affecting dose uniformity within the target volume and reducing the treatment time. In order to irradiate the intended volume while sparing critical structures such as the skin, the current round applicator design has been augmented through the addition of an internal truncated cone (i.e., frustum) shield. Monte Carlo methods and clinical constraints were used to design the optimal cone applicator. With the cone applicator now defined as the entire assembly including the surrounding tungsten-alloy shell holding the HDR 192Ir source catheter, the applicator height was reduced to diminish the treatment time while minimizing skin dose. Monte Carlo simulation results were validated using both radiochromic film and ionization chamber measurements based on established techniques. The optimal cone applicators diminished the maximum skin dose by 15%-32% (based on the applicator diameter and breast separation) with the tumor dose reduced by less than 3% for a constant exposure time. Furthermore, reduction in applicator height diminished the treatment time by up to 30%. Radiochromic film and ionization chamber dosimetric results in phantom agreed with Monte Carlo simulation results typically within 3%. Larger differences were outside the treatment volume in low dose regions or associated with differences between the measurement and Monte Carlo simulation environments. A new radiotherapy treatment device was developed and dosimetrically characterized. This set of applicators significantly reduces the skin dose and treatment time while retaining uniform target dose.

  19. NOTE: Variations in skin dose associated with linac bed material at 6 MV x-ray energy

    NASA Astrophysics Data System (ADS)

    Butson, Martin J.; Cheung, Tsang; Yu, Peter K. N.; Webb, Belinda

    2002-01-01

    Treatment with radiotherapy x-rays at 6 MV energy produces a build-up effect whereby a smaller dose is delivered to the patient's skin compared to the tumour dose. With anterior fields, no material is normally placed over the patient's skin, thus providing the maximum skin sparing possible with the beam configuration used. A posterior beam normally passes through the treatment couch top and increases the dose delivered to the patient's skin. Both the Mylar sheeting and the support ribbing material produce a significant increase in skin dose. Measurements at 6 MV have shown that the basal cell layer dose can be increased by up to 51% of maximum dose with a carbon fibre/Mylar couch and by 28% for a tennis string/Mylar couch when compared to anterior beams. These values are associated with the position of the carbon fibre or tennis string ribbing. Dermal layer doses are increased by up to 30 and 24% of maximum dose for carbon fibre and tennis string, respectively. These values include a combination of dose due to the support ribbing and the Mylar sheeting. Due to the variability in patient positioning on the couch top, these increases would be spread out over the skin surface producing an average increase per unit area at the basal layer of up to 32 and 20% of the maximum, respectively, for carbon fibre and tennis string couch tops and 21 and 12% at the dermal layer compared to dose at Dmax.

  20. Radiation Dose to the Skin and to the Gonads from Diagnostic X-Ray Procedures

    PubMed Central

    Duggan, H. E.; Olde, G. L.

    1963-01-01

    The design of a study to assess the hazard to patients from radiation received during diagnostic radiological procedures is described. The long-term accumulation of data relating to the skin and gonadal doses received by patients in a large x-ray department has been initiated. This will serve as a model for any situation involving small recurrent radiation doses to a significant proportion of the population. A description is given of the basic dose measurements made and the method used in calculating and recording the skin and gonadal doses for each patient. Although no definite conclusions concerning the presence or absence of a radiation hazard have yet been made, the proposed future course of this study is discussed. ImagesFig. 3Fig. 4 PMID:14079142

  1. Automatic monitoring of localized skin dose with fluoroscopic and interventional procedures.

    PubMed

    Khodadadegan, Yasaman; Zhang, Muhong; Pavlicek, William; Paden, Robert G; Chong, Brian; Schueler, Beth A; Fetterly, Kenneth A; Langer, Steve G; Wu, Teresa

    2011-08-01

    This software tool locates and computes the intensity of radiation skin dose resulting from fluoroscopically guided interventional procedures. It is comprised of multiple modules. Using standardized body specific geometric values, a software module defines a set of male and female patients arbitarily positioned on a fluoroscopy table. Simulated X-ray angiographic (XA) equipment includes XRII and digital detectors with or without bi-plane configurations and left and right facing tables. Skin dose estimates are localized by computing the exposure to each 0.01 × 0.01 m(2) on the surface of a patient irradiated by the X-ray beam. Digital Imaging and Communications in Medicine (DICOM) Structured Report Dose data sent to a modular dosimetry database automatically extracts the 11 XA tags necessary for peak skin dose computation. Skin dose calculation software uses these tags (gantry angles, air kerma at the patient entrance reference point, etc.) and applies appropriate corrections of exposure and beam location based on each irradiation event (fluoroscopy and acquistions). A physicist screen records the initial validation of the accuracy, patient and equipment geometry, DICOM compliance, exposure output calibration, backscatter factor, and table and pad attenuation once per system. A technologist screen specifies patient positioning, patient height and weight, and physician user. Peak skin dose is computed and localized; additionally, fluoroscopy duration and kerma area product values are electronically recorded and sent to the XA database. This approach fully addresses current limitations in meeting accreditation criteria, eliminates the need for paper logs at a XA console, and provides a method where automated ALARA montoring is possible including email and pager alerts.

  2. Verification of the VARSKIN beta skin dose calculation computer code.

    PubMed

    Sherbini, Sami; DeCicco, Joseph; Gray, Anita Turner; Struckmeyer, Richard

    2008-06-01

    The computer code VARSKIN is used extensively to calculate dose to the skin resulting from contaminants on the skin or on protective clothing covering the skin. The code uses six pre-programmed source geometries, four of which are volume sources, and a wide range of user-selectable radionuclides. Some verification of this code had been carried out before the current version of the code, version 3.0, was released, but this was limited in extent and did not include all the source geometries that the code is capable of modeling. This work extends this verification to include all the source geometries that are programmed in the code over a wide range of beta radiation energies and skin depths. Verification was carried out by comparing the doses calculated using VARSKIN with the doses for similar geometries calculated using the Monte Carlo radiation transport code MCNP5. Beta end-point energies used in the calculations ranged from 0.3 MeV up to 2.3 MeV. The results showed excellent agreement between the MCNP and VARSKIN calculations, with the agreement being within a few percent for point and disc sources and within 20% for other sources with the exception of a few cases, mainly at the low end of the beta end-point energies. The accuracy of the VARSKIN results, based on the work in this paper, indicates that it is sufficiently accurate for calculation of skin doses resulting from skin contaminations, and that the uncertainties arising from the use of VARSKIN are likely to be small compared with other uncertainties that typically arise in this type of dose assessment, such as those resulting from a lack of exact information on the size, shape, and density of the contaminant, the depth of the sensitive layer of the skin at the location of the contamination, the duration of the exposure, and the possibility of the source moving over various areas of the skin during the exposure period if the contaminant is on protective clothing.

  3. Interplanetary crew doses and dose equivalents: variations among different bone marrow and skin sites

    NASA Astrophysics Data System (ADS)

    Hoff, J. L.; Townsend, L. W.; Zapp, E. N.

    2004-01-01

    Previously, calculations of bone marrow dose from the large solar particle event (SPE) of July 2000 were carried out using the BRYNTRN space radiation transport code and the computerized anatomical man (CAM) model. Results indicated that the dose for a bone marrow site in the mid-thigh might be twice as large as the dose for a site in the pelvis. These large variations may be significant for space radiation protection purposes, which traditionally use an average of many (typically 33) sites throughout the body. Other organs that cover large portions of the body, such as the skin, may also exhibit similar variations with doses differing from site to site. The skin traditionally uses an average of 32 sites throughout the body. Variations also occur from site to site among the dose equivalents, which may be important in determining stochastic effects. In this work, the magnitudes of dose and dose equivalent variations from site to site are investigated. The BRYNTRN and HZETRN transport codes and the CAM model are used to estimate bone marrow and skin doses and dose equivalents as a function of position in the body for several large solar particle events and annual galactic cosmic ray spectra from throughout the space era. These position-specific results are compared with the average values usually used for radiation protection purposes. Various thicknesses of aluminum shielding, representative of nominal spacecraft, are used in the analyses.

  4. Interplanetary Crew Doses and Dose Equivalents: Variations among Different Bone Marrow and Skin Sites

    NASA Astrophysics Data System (ADS)

    Hoff, J.; Townsend, L.; Zapp, E.

    Previously, calculations of bone marrow dose from the large solar particle event (SPE) of July 2000 were carried out using the BRYNTRN space radiation transport code and the Computerized Anatomical Man (CAM) model. Results indicated that the dose for a bone marrow site in the mid-thigh might be twice as large as the dose for a site in the pelvis. These large variations may be significant for space radiation protection purposes, which traditionally use an average of many (typically 33) sites throughout the body. Other organs that cover large portions of the body, such as the skin, may also exhibit similar variations with doses differing from site to site. The skin traditionally uses an average of 32 sites throughout the body. Variations also occur from site to site among the dose equivalents, which may be important in determining stochastic effects. In this work, the magnitudes of dose and dose equivalent variations from site to site are investigated. The BRYNTRN and HZETRN transport codes and the CAM model are used to estimate bone marrow and skin doses and dose equivalents as a function of position in the body for several large solar particle events and annual galactic cosmic ray (GCR) spectra from throughout the space era. These position-specific results are compared with the average values usually used for radiation protection purposes. Various thicknesses of aluminum shielding, representative of nominal spacecraft and SPE "storm shelter" designs, are used in the analyses.

  5. A Real-Time Skin Dose Tracking System for Biplane Neuro-Interventional Procedures

    PubMed Central

    Rana, Vijay K.; Rudin, Stephen; Bednarek, Daniel R.

    2015-01-01

    A biplane dose-tracking system (Biplane-DTS) that provides a real-time display of the skin-dose distribution on a 3D-patient graphic during neuro-interventional fluoroscopic procedures was developed. Biplane-DTS calculates patient skin dose using geometry and exposure information for the two gantries of the imaging system acquired from the digital system bus. The dose is calculated for individual points on the patient graphic surface for each exposure pulse and cumulative dose for both x-ray tubes is displayed as color maps on a split screen showing frontal and lateral projections of a 3D-humanoid graphic. Overall peak skin dose (PSD), FOV-PSD and current dose rates for the two gantries are also displayed. Biplane-DTS uses calibration files of mR/mAs for the frontal and lateral tubes measured with and without the table in the beam at the entrance surface of a 20 cm thick PMMA phantom placed 15 cm tube-side of the isocenter. For neuro-imaging, conversion factors are applied as a function of entrance field area to scale the calculated dose to that measured with a Phantom Laboratory head phantom which contains a human skull to account for differences in backscatter between PMMA and the human head. The software incorporates inverse-square correction to each point on the skin and corrects for angulation of the beam through the table. Dose calculated by Biplane DTS and values measured by a 6-cc ionization chamber placed on the head phantom at multiple points agree within a range of −3% to +7% with a standard deviation for all points of less than 3%. PMID:26430290

  6. A real-time skin dose tracking system for biplane neuro-interventional procedures

    NASA Astrophysics Data System (ADS)

    Rana, Vijay K.; Rudin, Stephen R.; Bednarek, Daniel R.

    2015-03-01

    A biplane dose-tracking system (Biplane-DTS) that provides a real-time display of the skin-dose distribution on a 3D-patient graphic during neuro-interventional fluoroscopic procedures was developed. Biplane-DTS calculates patient skin dose using geometry and exposure information for the two gantries of the imaging system acquired from the digital system bus. The dose is calculated for individual points on the patient graphic surface for each exposure pulse and cumulative dose for both x-ray tubes is displayed as color maps on a split screen showing frontal and lateral projections of a 3D-humanoid graphic. Overall peak skin dose (PSD), FOV-PSD and current dose rates for the two gantries are also displayed. Biplane- TS uses calibration files of mR/mAs for the frontal and lateral tubes measured with and without the table in the beam at the entrance surface of a 20 cm thick PMMA phantom placed 15 cm tube-side of the isocenter. For neuro-imaging, conversion factors are applied as a function of entrance field area to scale the calculated dose to that measured with a Phantom Laboratory head phantom which contains a human skull to account for differences in backscatter between PMMA and the human head. The software incorporates inverse-square correction to each point on the skin and corrects for angulation of the beam through the table. Dose calculated by Biplane DTS and values measured by a 6-cc ionization chamber placed on the head phantom at multiple points agree within a range of -3% to +7% with a standard deviation for all points of less than 3%.

  7. Clinically relevant investigation of flattening filter-free skin dose.

    PubMed

    Guy, Christopher L; Karki, Kishor; Sharma, Manju; Kim, Siyong

    2016-11-08

    As flattening filter-free (FFF) photon beams become readily available for treat-ment delivery in techniques such as SBRT, thorough investigation of skin dose from FFF photon beams is necessary under clinically relevant conditions. Using a parallel-plate PTW Markus chamber placed in a custom water-equivalent phantom, surface-dose measurements were taken at 2 × 2, 3 × 3, 4 × 4, 6 × 6, 8 × 8, 10 × 10, 20 × 20, and 30 × 30 cm2 field sizes, at 80, 90, and 100 cm source-to-surface distances (SSDs), and with fields defined by jaws and multileaf collimator (MLC) using multiple beam energies (6X, 6XFFF, 10X, and 10XFFF). The same set of measurements was repeated with the chamber at a reference depth of 10cm. Each surface measurement was normalized by its corresponding reference depth measurement for analysis. The FFF surface doses at 100 cm SSD were higher than flattened surface doses by 45% at 2 × 2 cm2 to 13% at 20 × 20 cm2 for 6MV energy. These surface dose differences varied to a greater degree as energy increased, ranging from +63% at 2 × 2 cm2 to -2% at 20 × 20 cm2 for 10 MV. At small field sizes, higher energy increased FFF surface dose relative to flattened surface dose; while at larger field sizes, relative FFF surface dose was higher for lower energies. At both energies investigated, decreasing SSD caused a decrease in the ratios of FFF-to-flattened surface dose. Variability with SSD of FFF-to-flattened surface dose differences increased with field size and ranged from 0% to 6%. The field size at which FFF and flattened beams gave the same skin dose increased with decreasing beam energy. Surface dose was higher with MLC fields compared to jaw fields under most conditions, with the difference reaching its maximum at a field size between 4 × 4 cm2 and 6 × 6 cm2 for a given energy and SSD. This study conveyed the magnitude of surface dose in a clinically meaning-ful manner by reporting results normalized to 10 cm depth dose instead of depth of dose

  8. Objective method to report planner-independent skin/rib maximal dose in balloon-based high dose rate (HDR) brachytherapy for breast cancer

    SciTech Connect

    Kim, Yongbok; Trombetta, Mark G.

    2011-04-15

    Purpose: An objective method was proposed and compared with a manual selection method to determine planner-independent skin and rib maximal dose in balloon-based high dose rate (HDR) brachytherapy planning. Methods: The maximal dose to skin and rib was objectively extracted from a dose volume histogram (DVH) of skin and rib volumes. A virtual skin volume was produced by expanding the skin surface in three dimensions (3D) external to the breast with a certain thickness in the planning computed tomography (CT) images. Therefore, the maximal dose to this volume occurs on the skin surface the same with a conventional manual selection method. The rib was also delineated in the planning CT images and its maximal dose was extracted from its DVH. The absolute (Abdiff=|D{sub max}{sup Man}-D{sub max}{sup DVH}|) and relative (Rediff[%]=100x(|D{sub max}{sup Man}-D{sub max}{sup DVH}|)/D{sub max}{sup DVH}) maximal skin and rib dose differences between the manual selection method (D{sub max}{sup Man}) and the objective method (D{sub max}{sup DVH}) were measured for 50 balloon-based HDR (25 MammoSite and 25 Contura) patients. Results: The average{+-}standard deviation of maximal dose difference was 1.67%{+-}1.69% of the prescribed dose (PD). No statistical difference was observed between MammoSite and Contura patients for both Abdiff and Rediff[%] values. However, a statistically significant difference (p value <0.0001) was observed in maximal rib dose difference compared with maximal skin dose difference for both Abdiff (2.30%{+-}1.71% vs 1.05%{+-}1.43%) and Rediff[%] (2.32%{+-}1.79% vs 1.21%{+-}1.41%). In general, rib has a more irregular contour and it is more proximally located to the balloon for 50 HDR patients. Due to the inverse square law factor, more dose difference was observed in higher dose range (D{sub max}>90%) compared with lower dose range (D{sub max}<90%): 2.16%{+-}1.93% vs 1.19%{+-}1.25% with p value of 0.0049. However, the Rediff[%] analysis eliminated the

  9. MR-guided breast radiotherapy: feasibility and magnetic-field impact on skin dose

    NASA Astrophysics Data System (ADS)

    van Heijst, Tristan C. F.; den Hartogh, Mariska D.; Lagendijk, Jan J. W.; Desirée van den Bongard, H. J. G.; van Asselen, Bram

    2013-09-01

    The UMC Utrecht MRI/linac (MRL) design provides image guidance with high soft-tissue contrast, directly during radiotherapy (RT). Breast cancer patients are a potential group to benefit from better guidance in the MRL. However, due to the electron return effect, the skin dose can be increased in presence of a magnetic field. Since large skin areas are generally involved in breast RT, the purpose of this study is to investigate the effects on the skin dose, for whole-breast irradiation (WBI) and accelerated partial-breast irradiation (APBI). In ten patients with early-stage breast cancer, targets and organs at risk (OARs) were delineated on postoperative CT scans co-registered with MRI. The OARs included the skin, comprising the first 5 mm of ipsilateral-breast tissue, plus extensions. Three intensity-modulated RT techniques were considered (2× WBI, 1× APBI). Individual beam geometries were used for all patients. Specially developed MRL treatment-planning software was used. Acceptable plans were generated for 0 T, 0.35 T and 1.5 T, using a class solution. The skin dose was augmented in WBI in the presence of a magnetic field, which is a potential drawback, whereas in APBI the induced effects were negligible. This opens possibilities for developing MR-guided partial-breast treatments in the MRL.

  10. Skin cancer in patients with chronic radiation dermatitis

    SciTech Connect

    Davis, M.M.; Hanke, C.W.; Zollinger, T.W.; Montebello, J.F.; Hornback, N.B.; Norins, A.L.

    1989-04-01

    The cases of 76 patients with chronic radiation dermatitis resulting from low-dose ionizing radiation for benign disease were reviewed retrospectively for risk factors leading to the development of neoplasia. The patients were studied with respect to original hair color, eye color, sun reactive skin type, benign disease treated, area treated, age at treatment, and age at development of first skin cancer. Analysis of data showed 37% of patients had sun-reactive skin type I, 27% had type II, and 36% had type III. Types IV through VI were not represented. There appeared to be an overrepresentation of types I and II. Increased melanin pigmentation may therefore be either directly or indirectly protective against the development of skin cancers in patients who have received low-dose superficial ionizing radiation for benign disease. The sun-reactive skin type of patients with chronic radiation dermatitis may be used as a predictor of skin cancer risk when the total dose of ionizing radiation is not known.

  11. Patient Dose in Diagnostic Radiology

    NASA Astrophysics Data System (ADS)

    Noel, Alain

    One of the basic principles, stated explicitly in Article 4 of the EC Council Directive 97/43 Euratom, is optimization. This means that all radiological examinations should be performed with a dose that is As Low As Reasonably Achievable (ALARA principle applied to the protection of the patient) in order to obtain the required diagnostic information. Therefore, dose needs to be determined with the relationship between image quality and dose always kept in mind. In this paper, radiation quantities and units to report patient doses in diagnostic radiology will be identified.

  12. Rituximab in severe skin diseases: target, disease, and dose

    PubMed Central

    Bennett, Daniel D; Ohanian, Maro; Cable, Christian T

    2010-01-01

    New clinical indications for rituximab seem to appear every day. This review will trace the use of this monoclonal antibody from lymphoid malignancy, to classic autoimmune disease, and specifically severe autoimmune skin diseases. The history leading to different dosing schema with associated pharmacokinetic data will be discussed. A case of livedoid vasculopathy (atrophie blanche) responding to rituximab will illustrate how the response to therapy can help to elucidate previously obscure pathophysiology. PMID:22291497

  13. Effects of erythropoietin in skin wound healing are dose related.

    PubMed

    Sorg, Heiko; Krueger, Christian; Schulz, Torsten; Menger, Michael D; Schmitz, Frank; Vollmar, Brigitte

    2009-09-01

    The hematopoietic growth factor erythropoietin (EPO) attracts attention due to its all-tissue-protective pleiotropic properties. We studied the effect of EPO on dermal regeneration using intravital microscopy in a model of full dermal thickness wounds in the skin-fold chamber of hairless mice. Animals received repetitive low doses or high doses of EPO (RLD-EPO or RHD-EPO) or a single high dose of EPO (SHD-EPO). SHD-EPO accelerated wound epithelialization, reduced wound cellularity, and induced maturation of newly formed microvascular networks. In contrast, RHD-EPO impaired the healing process, as indicated by delayed epithelialization, high wound cellularity, and lack of maturation of microvascular networks. Also, RHD-EPO caused an excessive erythrocyte mass and rheological malfunction, further deteriorating vessel and tissue maturation. Moreover, RHD-EPO altered fibroblast and keratinocyte migration in vitro, while both cell types exposed to RLD-EPO, and, in particular, to SHD-EPO showed accelerated wound scratch closure. In summary, our data show that a single application of a high dose of EPO accelerates and improves skin wound healing.

  14. Coronary angiography and percutaneous transluminal coronary angioplasty procedures: Evaluation of patients' maximum skin dose using Gafchromic films and a comparison of local levels with reference levels proposed in the literature.

    PubMed

    Giordano, C; D'Ercole, L; Gobbi, R; Bocchiola, M; Passerini, F

    2010-10-01

    The aim of this study was to evaluate the maximum skin dose (MSD) in patients undergoing interventional cardiology procedures, obtaining local reference levels and comparing these with the reference levels proposed in the literature. The patients' MSD was measured using Gafchromic XR type R films. In order to evaluate reference levels, the number of images acquired, the fluoroscopy times and the KAP(TOTAL) were recorded for each procedure. For the evaluation of the MSD, 8 coronary angiography (CA) and 16 percutaneous transluminal coronary angioplasty (PTCA) procedures, carried out in the period from May to June 2008, were analyzed. For the CA procedures the MSD values were below 0.5 Gy. For the PTCA procedures, we found a fairly good correlation between fluoroscopy time and MSD (r = 0.80, p = 0.0002) and between MSD and WFP (r = 0.863, p < 0.0001); there was a strong correlation between KAP(TOTAL) and MSD (r = 0.904, p <0.0001). Since the correlation between KAP(TOTAL) and MSD is more striking than that with fluoroscopic time and the WFP, KAP measurements are suitable for online skin dosimetry and may, therefore, be used to avoid radiation-induced skin injuries. A MSD greater than 3 Gy occurred in only one procedure. For calculus of the local reference levels, we extended the data-gathering to 30 procedure CA and to 40 PTCA: we compared local practice with that in other centers using the guidance levels proposed by Balter et al. Our median KAP values were below these proposed guidance levels; our mean KAP values were above these proposed action levels. From a first application of the proposed reference levels, it appears that, according to the recommendations of Balter et al. an investigation into local practice is not necessary. Copyright © 2010 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  15. Dose evaluation for skin and organ in hepatocellular carcinoma during angiographic procedure

    PubMed Central

    2013-01-01

    Purpose The purpose of this study is to evaluate the radiation dose in patients undergoing liver angiographic procedure and verify the usefulness of different dose measurements to prevent deterministic effects. Gafchromic film, MicroMOSFET data and DIAMENTOR device of the X-ray system were used to characterize the examined interventional radiology (IR) procedure. Materials and methods A liver embolization procedure, the SIRT (Selective Internal Radiation Therapy), was investigated. The exposure parameters from the DIAMENTOR as well as patient and geometrical data were registered. Entrance skin dose map obtained using Gafchromic film (ESDGAF) in a standard phantom as well as in 12 patients were used to calculate the maximum skin dose (MSDGAF). MicroMOSFETs were used to assess ESD in relevant points/areas. Moreover, the maximum value of five MicroMOSFETs array, due to the extension of treated area and to the relative distance of 2–3 cm of two adjacent MicroMOSFETs, was useful to predict the MSD without interfering with the clinical practice. PCXMC vers.1.5 was used to calculate effective dose (E) and equivalent dose (H). Results The mean dose-area product (DAPDIAMENTOR) for SIRT procedures was 166 Gycm2, although a wide range was observed. The mean MSDGAF for SIRT procedures was 1090 mGy, although a wide range was experienced. A correlation was found between the MSDGAF measured on a patient and the DAPDIAMENTOR value for liver embolizations. MOSFET and Gafchromic data were in agreement within 5% in homogeneous area and within 20% in high dose gradient regions. The mean equivalent dose in critical organs was 89.8 mSv for kidneys, 22.9 mSv for pancreas, 20.2 mSv for small intestine and 21.0 mSv for spleen. Whereas the mean E was 3.7 mSv (range: 0.5-13.7). Conclusions Gafchromic films result useful to study patient exposure and determine localization and amplitude of high dose skin areas to better predict the skin injuries. Then, DAPDIAMENTOR or MOSFET data

  16. Guideline implementation: preoperative patient skin antisepsis.

    PubMed

    Cowperthwaite, Liz; Holm, Rebecca L

    2015-01-01

    Performing preoperative skin antisepsis to remove soil and microorganisms at the surgical site may help prevent patients from developing a surgical site infection. The updated AORN "Guideline for preoperative skin antisepsis" addresses the topics of preoperative patient bathing and hair removal, selection and application of skin antiseptics, and safe handling, storage, and disposal of skin antiseptics. This article focuses on key points of the guideline to help perioperative personnel develop protocols for patient skin antisepsis. The key points include the need for the patient to take a preoperative bath or shower and the need for perioperative personnel to manage hair at the surgical site, select a safe and effective antiseptic for the individual patient, perform a safe preoperative surgical site prep, and appropriately store skin antiseptics. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures.

  17. Using a thermoluminescent dosimeter to evaluate the location reliability of the highest–skin dose area detected by treatment planning in radiotherapy for breast cancer

    SciTech Connect

    Sun, Li-Min; Huang, Chih-Jen; Chen, Hsiao-Yun; Meng, Fan-Yun; Lu, Tsung-Hsien; Tsao, Min-Jen

    2014-01-01

    Acute skin reaction during adjuvant radiotherapy for breast cancer is an inevitable process, and its severity is related to the skin dose. A high–skin dose area can be speculated based on the isodose distribution shown on a treatment planning. To determine whether treatment planning can reflect high–skin dose location, 80 patients were collected and their skin doses in different areas were measured using a thermoluminescent dosimeter to locate the highest–skin dose area in each patient. We determined whether the skin dose is consistent with the highest-dose area estimated by the treatment planning of the same patient. The χ{sup 2} and Fisher exact tests revealed that these 2 methods yielded more consistent results when the highest-dose spots were located in the axillary and breast areas but not in the inframammary area. We suggest that skin doses shown on the treatment planning might be a reliable and simple alternative method for estimating the highest skin doses in some areas.

  18. Using a thermoluminescent dosimeter to evaluate the location reliability of the highest-skin dose area detected by treatment planning in radiotherapy for breast cancer.

    PubMed

    Sun, Li-Min; Huang, Chih-Jen; Chen, Hsiao-Yun; Meng, Fan-Yun; Lu, Tsung-Hsien; Tsao, Min-Jen

    2014-01-01

    Acute skin reaction during adjuvant radiotherapy for breast cancer is an inevitable process, and its severity is related to the skin dose. A high-skin dose area can be speculated based on the isodose distribution shown on a treatment planning. To determine whether treatment planning can reflect high-skin dose location, 80 patients were collected and their skin doses in different areas were measured using a thermoluminescent dosimeter to locate the highest-skin dose area in each patient. We determined whether the skin dose is consistent with the highest-dose area estimated by the treatment planning of the same patient. The χ(2) and Fisher exact tests revealed that these 2 methods yielded more consistent results when the highest-dose spots were located in the axillary and breast areas but not in the inframammary area. We suggest that skin doses shown on the treatment planning might be a reliable and simple alternative method for estimating the highest skin doses in some areas. Copyright © 2014 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  19. A Prospective, Open-Label Study of Low-Dose Total Skin Electron Beam Therapy in Mycosis Fungoides

    SciTech Connect

    Kamstrup, Maria R.; Specht, Lena; Skovgaard, Gunhild L.; Gniadecki, Robert

    2008-07-15

    Purpose: To determine the effect of low-dose (4 Gy) total skin electron beam therapy as a second-line treatment of Stage IB-II mycosis fungoides in a prospective, open-label study. Methods and Materials: Ten patients (6 men, 4 women, average age 68.7 years [range, 55-82 years]) with histopathologically confirmed mycosis fungoides T2-T4 N0-N1 M0 who did not achieve complete remission or relapsed within 4 months after treatment with psoralen plus ultraviolet-A were included. Treatment consisted of low-dose total skin electron beam therapy administered at a total skin dose of 4 Gy given in 4 fractions over 4 successive days. Results: Two patients had a complete clinical response but relapsed after 3.5 months. Six patients had partial clinical responses, with a mean duration of 2.0 months. One patient had no clinical response. Median time to relapse was 2.7 months. One patient died of unrelated causes and did not complete treatment. Acute side effects included desquamation, xerosis, and erythema of the skin. No severe side effects were observed. Conclusion: Low-dose total skin electron beam therapy can induce complete and partial responses in Stage IB-II mycosis fungoides; however, the duration of remission is short. Low-dose total skin electron beam therapy may find application in palliative treatment of mycosis fungoides because of limited toxicity and the possibility of repeating treatments for long-term disease control.

  20. Skin Dose Impact from Vacuum Immobilization Device and Carbon Fiber Couch in Intensity Modulated Radiation Therapy for Prostate Cancer

    SciTech Connect

    Lee, K.-W.; Wu, J.-K.; Jeng, S.-C.; Hsueh Liu Yen-Wan; Cheng, Jason Chia-Hsien

    2009-10-01

    To investigate the unexpected skin dose increase from intensity-modulated radiation therapy (IMRT) on vacuum cushions and carbon-fiber couches and then to modify the dosimetric plan accordingly. Eleven prostate cancer patients undergoing IMRT were treated in prone position with a vacuum cushion. Two under-couch beams scattered the radiation from the vacuum cushion and carbon-fiber couch. The IMRT plans with both devices contoured were compared with the plans not contouring them. The skin doses were measured using thermoluminescent dosimeters (TLDs) placed on the inguinal regions in a single IMRT fraction. Tissue equivalent thickness was transformed for both devices with the relative densities. The TLD-measured skin doses (59.5 {+-} 9.5 cGy and 55.6 {+-} 5.9 cGy at left and right inguinal regions, respectively) were significantly higher than the calculated doses (28.7 {+-} 4.7 cGy; p = 2.2 x 10{sup -5} and 26.2 {+-} 4.3 cGy; p = 1.5 x 10{sup -5}) not contouring the vacuum cushion and carbon-fiber couch. The calculated skin doses with both devices contoured (59.1 {+-} 8.8 cGy and 55.5 {+-} 5.7 cGy) were similar to the TLD-measured doses. In addition, the calculated skin doses using the vacuum cushion and a converted thickness of the simulator couch were no different from the TLD-measured doses. The recalculated doses of rectum and bladder did not change significantly. The dose that covered 95% of target volume was less than the prescribed dose in 4 of 11 patients, and this problem was solved after re-optimization applying the corrected contours. The vacuum cushion and carbon-fiber couch contributed to increased skin doses. The tissue-equivalent-thickness method served as an effective way to correct the dose variations.

  1. Skin dose impact from vacuum immobilization device and carbon fiber couch in intensity modulated radiation therapy for prostate cancer.

    PubMed

    Lee, Kuo-Wei; Wu, Jian-Kuen; Jeng, Shiu-Chen; Hsueh Liu, Yen-Wan; Cheng, Jason Chia-Hsien

    2009-01-01

    To investigate the unexpected skin dose increase from intensity-modulated radiation therapy (IMRT) on vacuum cushions and carbon-fiber couches and then to modify the dosimetric plan accordingly. Eleven prostate cancer patients undergoing IMRT were treated in prone position with a vacuum cushion. Two under-couch beams scattered the radiation from the vacuum cushion and carbon-fiber couch. The IMRT plans with both devices contoured were compared with the plans not contouring them. The skin doses were measured using thermoluminescent dosimeters (TLDs) placed on the inguinal regions in a single IMRT fraction. Tissue equivalent thickness was transformed for both devices with the relative densities. The TLD-measured skin doses (59.5 +/- 9.5 cGy and 55.6 +/- 5.9 cGy at left and right inguinal regions, respectively) were significantly higher than the calculated doses (28.7 +/- 4.7 cGy; p = 2.2 x 10(-5) and 26.2 +/- 4.3 cGy; p = 1.5 x 10(-5)) not contouring the vacuum cushion and carbon-fiber couch. The calculated skin doses with both devices contoured (59.1 +/- 8.8 cGy and 55.5 +/- 5.7 cGy) were similar to the TLD-measured doses. In addition, the calculated skin doses using the vacuum cushion and a converted thickness of the simulator couch were no different from the TLD-measured doses. The recalculated doses of rectum and bladder did not change significantly. The dose that covered 95% of target volume was less than the prescribed dose in 4 of 11 patients, and this problem was solved after re-optimization applying the corrected contours. The vacuum cushion and carbon-fiber couch contributed to increased skin doses. The tissue-equivalent-thickness method served as an effective way to correct the dose variations.

  2. The use of Monte Carlo technique to optimize the dose distribution in total skin irradiation

    NASA Astrophysics Data System (ADS)

    Poli, M. E. R.; Pereira, S. A.; Yoriyaz, H.

    2001-06-01

    Cutaneous T-cell lymphoma (mycosis fungoides) is an indolent disease with a low percentage of cure. Total skin irradiation using an electron beam has become an efficient treatment of mycosis fungoides with curative intention, with success in almost 40% of the patients. In this work, we propose the use of a Monte Carlo technique to simulate the dose distribution in the patients during total skin irradiation treatments. Use was made of MCNP-4B, a well known and established code used to simulate transport of electrons, photons and neutrons through matter, especially in the area of reactor physics, and also finding increasing utility in medical physics. The goal of our work is to simulate different angles between each beam with a fixed treatment distance in order to obtain a uniform dose distribution in the patient.

  3. Characterization of a MOSkin detector for in vivo skin dose measurements during interventional radiology procedures

    SciTech Connect

    Safari, M. J.; Wong, J. H. D.; Ng, K. H.; Jong, W. L.; Cutajar, D. L.; Rosenfeld, A. B.

    2015-05-15

    Purpose: The MOSkin is a MOSFET detector designed especially for skin dose measurements. This detector has been characterized for various factors affecting its response for megavoltage photon beams and has been used for patient dose measurements during radiotherapy procedures. However, the characteristics of this detector in kilovoltage photon beams and low dose ranges have not been studied. The purpose of this study was to characterize the MOSkin detector to determine its suitability for in vivo entrance skin dose measurements during interventional radiology procedures. Methods: The calibration and reproducibility of the MOSkin detector and its dependency on different radiation beam qualities were carried out using RQR standard radiation qualities in free-in-air geometry. Studies of the other characterization parameters, such as the dose linearity and dependency on exposure angle, field size, frame rate, depth-dose, and source-to-surface distance (SSD), were carried out using a solid water phantom under a clinical x-ray unit. Results: The MOSkin detector showed good reproducibility (94%) and dose linearity (99%) for the dose range of 2 to 213 cGy. The sensitivity did not significantly change with the variation of SSD (±1%), field size (±1%), frame rate (±3%), or beam energy (±5%). The detector angular dependence was within ±5% over 360° and the dose recorded by the MOSkin detector in different depths of a solid water phantom was in good agreement with the Markus parallel plate ionization chamber to within ±3%. Conclusions: The MOSkin detector proved to be reliable when exposed to different field sizes, SSDs, depths in solid water, dose rates, frame rates, and radiation incident angles within a clinical x-ray beam. The MOSkin detector with water equivalent depth equal to 0.07 mm is a suitable detector for in vivo skin dosimetry during interventional radiology procedures.

  4. High-dose immunosuppressant alters the immunological status of New Zealand white rabbits following skin transplantation.

    PubMed

    Cheng, Peilun; Zhong, Liming; Jiang, Zesheng; Wang, Yan; Pan, Mingxin; Gao, Y I

    2015-09-01

    The aim of this study was to investigate the effect of an immunosuppressant on the immunological status of New Zealand white rabbits after skin grafting, and to evaluate a method for monitoring the immunological status of subjects with skin transplants. The rabbits were randomly divided into allograft rejection, autograft tolerance, nontransplant, allograft low-dose immunosuppressant and allograft high-dose immunosuppressant groups. The rabbits in the low- and high-dose immunosuppressant groups were treated with cyclosporine A intravenously 8 h prior to skin transplantation and once daily following transplantation at doses of 2 and 25 mg/kg, respectively. At 12 days after skin transplantation, the spleens of donor (female) rabbits and recipient (male) rabbits were harvested for the preparation of single-cell suspensions. The splenocytes from recipient and donor rabbits were labeled with 0.3 or 6 µM carboxy fluorescein diacetate succinimidyl ester, respectively, and a mixed cell suspension was prepared. The final preparation was intravenously injected into recipient New Zealand white rabbits. The ratio of the two fluorescently labeled cell populations in the peripheral blood was measured using flow cytometry at 1, 2, 4 and 8 h after the injection, and the cell death rate was calculated. Histological analysis was also performed on samples collected at the time of splenectomy. The cell death rates of the allograft rejection and low-dose immunosuppressant groups reached their highest levels 8 h after the injection of spleen cell suspension. Allogeneic spleen cells from donor male rabbits were almost completely removed within 8 h of injection. The cell death rate increased slowly in the nontransplant, autograft and high-dose immunosuppressant groups without specificity. This study provides a specific method for the in vivo monitoring of the immunological status of patients after skin grafting. This method can quickly and accurately detect the immunological status of

  5. Skin dosimetry of patients during interventional cardiology procedures in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Sukupova, Lucie; Novak, Leos

    2008-01-01

    The aim of the study is to determine distribution of air kerma-area product, fluoro time and number of frames values for the two most frequent procedures in the interventional cardiology, to reconstruct skin dose distributions for some patients undergoing coronarography and percutaneous transluminal coronary angioplasty procedures. Patient dose data were obtained from X-ray unit dose monitoring software report from one hospital and the reconstructions were performed in MATLAB. Dependence of maximum skin dose on air kerma-area product, fluoro time and number of frames was determined to assess trigger levels of these quantities, which can indicate possible exceeding of the 2 Gy skin dose threshold.

  6. VARSKIN MOD 2 and SADDE MOD2: Computer codes for assessing skin dose from skin contamination

    SciTech Connect

    Durham, J.S. )

    1992-12-01

    The computer code VARSKIN has been modified to calculate dose to skin from three-dimensional sources, sources separated from the skin by layers of protective clothing, and gamma dose from certain radionuclides correction for backscatter has also been incorporated for certain geometries. This document describes the new code, VARSKIN Mod 2, including installation and operation instructions, provides detailed descriptions of the models used, and suggests methods for avoiding misuse of the code. The input data file for VARSKIN Mod 2 has been modified to reflect current physical data, to include the contribution to dose from internal conversion and Auger electrons, and to reflect a correction for low-energy electrons. In addition, the computer code SADDE: Scaled Absorbed Dose Distribution Evaluator has been modified to allow the generation of scaled absorbed dose distributions for mixtures of radionuclides and intereat conversion and Auger electrons. This new code, SADDE Mod 2, is also described in this document. Instructions for installation and operation of the code and detailed descriptions of the models used in the code are provided.

  7. TLD skin dose measurements and acute and late effects after lumpectomy and high-dose-rate brachytherapy only for early breast cancer

    SciTech Connect

    Perera, Francisco . E-mail: francisco.perera@lrcc.on.ca; Chisela, Frank; Stitt, Larry; Engel, Jay; Venkatesan, Varagur

    2005-08-01

    Purpose: This report examines the relationships between measured skin doses and the acute and late skin and soft tissue changes in a pilot study of lumpectomy and high-dose-rate brachytherapy only for breast cancer. Methods and Materials: Thirty-seven of 39 women enrolled in this pilot study of high-dose-rate brachytherapy (37.2 Gy in 10 fractions b.i.d.) each had thermoluminescent dosimetry (TLD) at 5 points on the skin of the breast overlying the implant volume. Skin changes at TLD dose points and fibrosis at the lumpectomy site were documented every 6 to 12 months posttreatment using a standardized physician-rated cosmesis questionnaire. The relationships between TLD dose and acute skin reaction, pigmentation, or telangiectasia at 5 years were analyzed using the GEE algorithm and the GENMOD procedure in the SAS statistical package. Fisher's exact test was used to determine whether there were any significant associations between acute skin reaction and late pigmentation or telangiectasia or between the volumes encompassed by various isodoses and fibrosis or fat necrosis. Results: The median TLD dose per fraction (185 dose points) multiplied by 10 was 9.2 Gy. In all 37 patients, acute skin reaction Grade 1 or higher was observed at 5.9% (6 of 102) of dose points receiving 10 Gy or less vs. 44.6% (37 of 83) of dose points receiving more than 10 Gy (p < 0.0001). In 25 patients at 60 months, 1.5% telangiectasia was seen at dose points receiving 10 Gy or less (1 of 69) vs. 18% (10 of 56) telangiectasia at dose points receiving more than 10 Gy (p 0.004). Grade 1 or more pigmentation developed at 1.5% (1 of 69) of dose points receiving less than 10 Gy vs. 25% (14 of 56) of dose points receiving more than 10 Gy (p < 0.001). A Grade 1 or more acute skin reaction was also significantly associated with development of Grade 1 or more pigmentation or telangiectasia at 60 months. This association was most significant for acute reaction and telangiectasia directly over the

  8. Method for preparing dosimeter for measuring skin dose

    DOEpatents

    Jones, Donald E.; Parker, DeRay; Boren, Paul R.

    1982-01-01

    A personnel dosimeter includes a plurality of compartments containing thermoluminescent dosimeter phosphors for registering radiation dose absorbed in the wearer's sensitive skin layer and for registering more deeply penetrating radiation. Two of the phosphor compartments communicate with thin windows of different thicknesses to obtain a ratio of shallowly penetrating radiation, e.g. beta. A third phosphor is disposed within a compartment communicating with a window of substantially greater thickness than the windows of the first two compartments for estimating the more deeply penetrating radiation dose. By selecting certain phosphors that are insensitive to neutrons and by loading the holder material with neutron-absorbing elements, energetic neutron dose can be estimated separately from other radiation dose. This invention also involves a method of injection molding of dosimeter holders with thin windows of consistent thickness at the corresponding compartments of different holders. This is achieved through use of a die insert having the thin window of precision thickness in place prior to the injection molding step.

  9. Dosimeter for measuring skin dose and more deeply penetrating radiation

    DOEpatents

    Jones, Donald E.; Parker, DeRay; Boren, Paul R.

    1981-01-01

    A personnel dosimeter includes a plurality of compartments containing thermoluminescent dosimeter phosphors for registering radiation dose absorbed in the wearer's sensitive skin layer and for registering more deeply penetrating radiation. Two of the phosphor compartments communicate with thin windows of different thicknesses to obtain a ratio of shallowly penetrating radiation, e.g. beta. A third phosphor is disposed within a compartment communicating with a window of substantially greater thickness than the windows of the first two compartments for estimating the more deeply penetrating radiation dose. By selecting certain phosphors that are insensitive to neutrons and by loading the holder material with netruon-absorbing elements, energetic neutron dose can be estimated separately from other radiation dose. This invention also involves a method of injection molding of dosimeter holders with thin windows of consistent thickness at the corresponding compartments of different holders. This is achieved through use of a die insert having the thin window of precision thickness in place prior to the injection molding step.

  10. Improvement in severe onchocercal skin disease after a single dose of ivermectin.

    PubMed

    Pacqué, M; Elmets, C; Dukuly, Z D; Muñoz, B; White, A T; Taylor, H R; Greene, B M

    1991-05-01

    Skin disease is the most common clinically important manifestation of onchocerciasis. Ivermectin, a newly available drug, is well tolerated and effective in Onchocerca volvulus infection. However, little information is available regarding its effect on onchocercal skin disease. The purpose of this study was to examine, in patients with well-characterized onchodermatitis, the effect of a single dose of ivermectin. Twenty-one persons with severe onchodermatitis were followed over a 6-month period. In order to evaluate the effect of ivermectin on their skin lesions, photographic transparencies were made before treatment and at 3 and 6 months after treatment. These were then evaluated in a blinded fashion. Following a single dose of 150 micrograms/kg, there was a significant improvement in dermatitis in the first 3 months after treatment. All 14 persons with the worst skin disease showed improvement. The drug had no demonstrable effect on depigmented lesions over the period of observation. Treatment was well tolerated. Single-dose ivermectin shows promise as the first acceptable treatment for severe onchocercal dermatitis.

  11. Minimal skin dose increase in longitudinal rotating biplanar linac-MR systems: examination of radiation energy and flattening filter design

    NASA Astrophysics Data System (ADS)

    Keyvanloo, A.; Burke, B.; St. Aubin, J.; Baillie, D.; Wachowicz, K.; Warkentin, B.; Steciw, S.; Fallone, B. G.

    2016-05-01

    The magnetic fields of linac-MR systems modify the path of contaminant electrons in photon beams, which alters patient entrance skin dose. Also, the increased SSD of linac-MR systems reduces the maximum achievable dose rate. To accurately quantify the changes in entrance skin dose, the authors use EGSnrc Monte Carlo calculations that incorporate 3D magnetic field of the Alberta 0.5 T longitudinal linac-MR system. The Varian 600C linac head geometry assembled on the MRI components is used in the BEAMnrc simulations for 6 MV and 10 MV beam models and skin doses are calculated at an average depth of 70 μm using DOSXYZnrc. 3D modeling shows that magnetic fringe fields decay rapidly and are small at the linac head. SSDs between 100 and 120 cm result in skin-dose increases of between ~6%-19% and ~1%-9% for the 6 and 10 MV beams, respectively. For 6 MV, skin dose increases from ~10.5% to ~1.5% for field-size increases of 5  ×  5 cm2 to 20  ×  20 cm2. For 10 MV, skin dose increases by ~6% for a 5  ×  5 cm2 field, and decreases by ~1.5% for a 20  ×  20 cm2 field. Furthermore, the proposed reshaped flattening filter increases the dose rate from the current 355 MU min-1 to 529 MU min-1 (6 MV) or 604 MU min-1 (10 MV), while the skin-dose increases by only an additional ~2.6% (all percent increases in skin dose are relative to D max). This study suggests that there is minimal increase in the entrance skin dose and minimal/no decrease in the dose rate of the Alberta longitudinal linac-MR system. The even lower skin dose increase at 10 MV offers further advantages in future designs of linac-MR prototypes.

  12. Minimal skin dose increase in longitudinal rotating biplanar linac-MR systems: examination of radiation energy and flattening filter design.

    PubMed

    Keyvanloo, A; Burke, B; St Aubin, J; Baillie, D; Wachowicz, K; Warkentin, B; Steciw, S; Fallone, B G

    2016-05-07

    The magnetic fields of linac-MR systems modify the path of contaminant electrons in photon beams, which alters patient entrance skin dose. Also, the increased SSD of linac-MR systems reduces the maximum achievable dose rate. To accurately quantify the changes in entrance skin dose, the authors use EGSnrc Monte Carlo calculations that incorporate 3D magnetic field of the Alberta 0.5 T longitudinal linac-MR system. The Varian 600C linac head geometry assembled on the MRI components is used in the BEAMnrc simulations for 6 MV and 10 MV beam models and skin doses are calculated at an average depth of 70 μm using DOSXYZnrc. 3D modeling shows that magnetic fringe fields decay rapidly and are small at the linac head. SSDs between 100 and 120 cm result in skin-dose increases of between ~6%-19% and ~1%-9% for the 6 and 10 MV beams, respectively. For 6 MV, skin dose increases from ~10.5% to ~1.5% for field-size increases of 5  ×  5 cm(2) to 20  ×  20 cm(2). For 10 MV, skin dose increases by ~6% for a 5  ×  5 cm(2) field, and decreases by ~1.5% for a 20  ×  20 cm(2) field. Furthermore, the proposed reshaped flattening filter increases the dose rate from the current 355 MU min(-1) to 529 MU min(-1) (6 MV) or 604 MU min(-1) (10 MV), while the skin-dose increases by only an additional ~2.6% (all percent increases in skin dose are relative to D max). This study suggests that there is minimal increase in the entrance skin dose and minimal/no decrease in the dose rate of the Alberta longitudinal linac-MR system. The even lower skin dose increase at 10 MV offers further advantages in future designs of linac-MR prototypes.

  13. Total skin electron therapy technique for the canine patient.

    PubMed

    Rechner, Kerensa N; Weeks, Kenneth J; Pruitt, Amy F

    2011-01-01

    Cutaneous epitheliotropic T-cell lymphoma in canine patients is a radiation sensitive tumor but total skin electron therapy is used only rarely. Our purpose was to evaluate dose distribution from a total skin electron therapy technique using 6MeV electron beams. The treatment was comprised of 12 fields, with the dog in lateral recumbency in a stride position at an extended distance from the source. Uniformity, flatness and symmetry were determined for each beam. The composite percent depth dose profile for all beams was measured in solid water phantoms and skin dose was determined on a canine cadaver using thermoluminescent dosimeters. The resulting d(max) of the composite beams was 1mm and dose variation over the skin was 6.8%, with the extremities having the most uneven dose distribution. Dimensions of the fields were adequate to obtain an effective treatment profile for the entire thickness of canine epidermis and the technique was feasible for clinical application. Individual tailoring of the protocol to deal with hot and cold spots may be necessary and set up will likely involve a significant time commitment for the therapy team.

  14. Comparison of measured and estimated maximum skin doses during CT fluoroscopy lung biopsies

    SciTech Connect

    Zanca, F.; Jacobs, A.; Crijns, W.; De Wever, W.

    2014-07-15

    Purpose: To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. Methods: Data from 50 patients with lung lesions who underwent a CT fluoroscopy-guided biopsy were collected. The CT protocol consisted of a low-kilovoltage (80 kV) protocol used in combination with an algorithm for dose reduction to the radiology staff during the interventional procedure, HandCare (HC). MSD was assessed during each intervention using EBT2 gafchromic films positioned on patient skin. Lesion size, position, total fluoroscopy time, and patient-effective diameter were registered for each patient. Dose rates were also estimated at the surface of a normal-size anthropomorphic thorax phantom using a 10 cm pencil ionization chamber placed at every 30°, for a full rotation, with and without HC. Measured MSD was compared with MSD values estimated from the phantom measurements and with the cumulative CTDIvol of the procedure. Results: The median measured MSD was 141 mGy (range 38–410 mGy) while the median cumulative CTDIvol was 72 mGy (range 24–262 mGy). The ratio between the MSD estimated from phantom measurements and the measured MSD was 0.87 (range 0.12–4.1) on average. In 72% of cases the estimated MSD underestimated the measured MSD, while in 28% of the cases it overestimated it. The same trend was observed for the ratio of cumulative CTDIvol and measured MSD. No trend was observed as a function of patient size. Conclusions: On average, estimated MSD from dose rate measurements on phantom as well as from CTDIvol of patient examinations underestimates the measured value of MSD. This can be attributed to deviations of the patient's body habitus from the standard phantom size and to patient positioning in the gantry during the procedure.

  15. Immediate hypersensitivity to iodinated contrast media: diagnostic accuracy of skin tests and intravenous provocation test with low dose.

    PubMed

    Sesé, L; Gaouar, H; Autegarden, J-E; Alari, A; Amsler, E; Vial-Dupuy, A; Pecquet, C; Francès, C; Soria, A

    2016-03-01

    The diagnosis of HSR to iodinated contrast media (ICM) is challenging based on clinical history and skin tests. This study evaluates the negative predictive value (NPV) of skin tests and intravenous provocation test (IPT) with low-dose ICM in patients with suspected immediate hypersensitivity reaction (HSR) to ICM. Thirty-seven patients with suspected immediate hypersensitivity reaction to ICM were included retrospectively. Skin tests and a single-blind placebo-controlled intravenous provocation test (IPT) with low-dose iodinated contrast media (ICM) were performed. Skin tests with ICM were positive in five cases (one skin prick test and five intradermal test). Thirty-six patients were challenged successfully by IPT, and only one patient had a positive challenge result, with a grade I reaction by the Ring and Messmer classification. Ten of 23 patients followed up by telephone were re-exposed to a negative tested ICM during radiologic examination; two experienced a grade I immediate reaction. For immediate hypersensitivity reaction to ICM, the NPV for skin tests and IPT with low dose was 80% (95% CI 44-97%). © 2016 John Wiley & Sons Ltd.

  16. Improved-resolution real-time skin-dose mapping for interventional fluoroscopic procedures

    NASA Astrophysics Data System (ADS)

    Rana, Vijay K.; Rudin, Stephen; Bednarek, Daniel R.

    2014-03-01

    We have developed a dose-tracking system (DTS) that provides a real-time display of the skin-dose distribution on a 3D patient graphic during fluoroscopic procedures. Radiation dose to individual points on the skin is calculated using exposure and geometry parameters from the digital bus on a Toshiba C-arm unit. To accurately define the distribution of dose, it is necessary to use a high-resolution patient graphic consisting of a large number of elements. In the original DTS version, the patient graphics were obtained from a library of population body scans which consisted of larger-sized triangular elements resulting in poor congruence between the graphic points and the x-ray beam boundary. To improve the resolution without impacting real-time performance, the number of calculations must be reduced and so we created software-designed human models and modified the DTS to read the graphic as a list of vertices of the triangular elements such that common vertices of adjacent triangles are listed once. Dose is calculated for each vertex point once instead of the number of times that a given vertex appears in multiple triangles. By reformatting the graphic file, we were able to subdivide the triangular elements by a factor of 64 times with an increase in the file size of only 1.3 times. This allows a much greater number of smaller triangular elements and improves resolution of the patient graphic without compromising the real-time performance of the DTS and also gives a smoother graphic display for better visualization of the dose distribution.

  17. Improved-Resolution, Real-Time Skin-Dose Mapping for Interventional Fluoroscopic Procedures

    PubMed Central

    Rana, Vijay K.; Rudin, Stephen; Bednarek, Daniel R.

    2014-01-01

    We have developed a dose-tracking system (DTS) that provides a real-time display of the skin-dose distribution on a 3D patient graphic during fluoroscopic procedures. Radiation dose to individual points on the skin is calculated using exposure and geometry parameters from the digital bus on a Toshiba C-arm unit. To accurately define the distribution of dose, it is necessary to use a high-resolution patient graphic consisting of a large number of elements. In the original DTS version, the patient graphics were obtained from a library of population body scans which consisted of larger-sized triangular elements resulting in poor congruence between the graphic points and the x-ray beam boundary. To improve the resolution without impacting real-time performance, the number of calculations must be reduced and so we created software-designed human models and modified the DTS to read the graphic as a list of vertices of the triangular elements such that common vertices of adjacent triangles are listed once. Dose is calculated for each vertex point once instead of the number of times that a given vertex appears in multiple triangles. By reformatting the graphic file, we were able to subdivide the triangular elements by a factor of 64 times with an increase in the file size of only 1.3 times. This allows a much greater number of smaller triangular elements and improves resolution of the patient graphic without compromising the real-time performance of the DTS and also gives a smoother graphic display for better visualization of the dose distribution. PMID:25177446

  18. Antimicrobial Dose in Obese Patient

    PubMed Central

    Kassab, Sawsan; Syed Sulaiman, Syed Azhar; Abdul Aziz, Noorizan

    2007-01-01

    Introduction Obesity is a chronic disease that has become one of major public health issue in Malaysia because of its association with other disease states including cardiovascular disease and diabetes. Despite continuous efforts to educate the public about the health risks associated with obesity, prevalence of the disease continues to increase. Dosing of many medications are based on weight, limited data are available on how antimicrobial agents should be dosed in obesity. The aim of this case presentation is to discuss dose of antibiotic in obese patient. Case report: Patient: GMN, Malay, Female, 45 year old, 150kg, transferred from medical ward to ICU with problems of fever, orthopnea, sepsis secondary to nosocomial pneumonia. She was admitted to hospital a week ago for SOB on exertion, cyanosis, mildly dyspneic, somasthenia, bilateral ankle swelling. There was no fever, cough, chest pain, clubbing, flapping tremor. Her grand father has pre-morbid history of obesity, HPT, DM and asthma. She was non alcoholic, smoker, and not on diet control. The diagnosis Pickwickian syndrome was made. Patient was treated with IV Dopamine 11mcg/kg/min, IV Morphine 4mg/h. IV GTN 15mcg/min, IV Ca gluconate 10g/24h for 3/7, IV Zantac 50mg tds, IV Augmentin 1.2g tds, IV Lasix 40mg od, IV Plasil 10mg tds, S.c heparin 5000IU bd. patient become stable and moved to medical ward to continue her treatment. Discussion: The altered physiologic function seen in obese patients is a concern in patients receiving antimicrobial agents because therapeutic outcomes depend on achieving a minimum inhibitory concentration (MIC). The therapeutic effect of any drug can be altered when any of the 4 pharmacokinetic processes (absorption, distribution, metabolism, or elimination) are altered. Decreased blood flow rates and increased renal clearance in obese patients can affect drug distribution and elimination. Changes in serum protein levels can change the metabolism and distribution of drugs that are

  19. MO-D-213-04: The Proximity to the Skin of PTV Affects PTV Coverage and Skin Dose for TomoTherapy

    SciTech Connect

    Reynolds, T; Higgins, P; Watanabe, Y

    2015-06-15

    Purpose: The proximity to the skin surface of the PTV for the patients with skin disease could be a concern in terms of the PTV coverage and actual surface dose (SD). IMRT optimization algorithms increase the beam intensity close to the skin in order to compensate for lack of scattering material, leading to enhanced SD but potential hot spots. This study aims to investigate the effect of PTV proximity to the skin on planning and measured SD Methods: All measurements were done for 6 MV X-ray beam of Helical TomoTherapy. An anthropomorphic phantom was scanned in a CT simulator in a routine manner with thermoplastic mask immobilization. PTVs were created with varying distances to the skin of 0 mm -(PTV1), 1 mm- (PTV2), 2 mm-(PTV3) and 3 mm-(PTV4). Also, a 5 mm bolus was used with PTV1 (PTV5). All planning constraints were kept the same in all studies (hard constraint: 95% of the prescription dose covered 95% of the PTV). Gafchromic film (EBT3) was placed under the mask on the phantom surface, and the resulting dose was estimated using RIT software. Results: Optimizing the dose using different PTVs lead to average planned target doses of 10.8, 10.3, 10.2, 10.3 and 10.0 Gy, with maximum doses 12.2, 11.2, 11.1, 11.1 and 10.0 Gy for PTV1, PTV2, PTV3, PTV4 and PTV5, respectively. EBT3 measurements indicated a significant decrease of SD with skin distance by 12.7% (PTV1), 21.9% (PTV2), 24.8% (PTV3) and 28.4% (PTV4) comparing to prescription dose. Placement of a 5 mm bolus on the phantom surface resulted in a SD close to prescribed (+0.5%). Conclusion: This work provides a clear demonstration of the relationship between the skin dose and the PTV to the skin distance. The results indicate the necessity of a bolus even for TomoTherapy when high skin dose is required.

  20. Assessment of skin dose and its relation to cosmesis in the conservative treatment of early breast cancer

    SciTech Connect

    Habibollahi, F.; Mayles, H.M.; Mayles, W.P.; Winter, P.J.; Tong, D.; Fentiman, I.S.; Chaudary, M.A.; Hayward, J.L.

    1988-02-01

    A conservation technique has been developed for the treatment of early breast cancer which involved removal of the tumor, axillary clearance, tumor site implantation with Iridium-192 wires for a boost dose and subsequent treatment of the breast with radical megavoltage external beam therapy. Although the cosmetic results were satisfactory in the majority of the patients, for some it was rated as fair or poor. One variable factor which could have carried some morbidity was the dose of radiation received by the skin. In 51 patients, doses were measured at several points over the treated breast using Thermoluminescent Dosimetry (TLD) at the time of the iridium implant and during the subsequent external beam therapy. Development of skin pigmentation, edema, and fibrosis were unrelated to the dose received by the skin but the findings suggested that doses greater than 50 Gy to the skin increased the possibility of late (greater than 24 months) telangiectasia over the boosted area. Treatment of tumors in the lower half of the breast, or in large breasts, was associated with a higher incidence of poor cosmesis. This may have been the result of varying posture on the interstitial dose distribution from the Iridium-192 wires and comparison of dose distribution in both supine and erect positions was carried out.

  1. Verification of the performance accuracy of a real-time skin-dose tracking system for interventional fluoroscopic procedures

    NASA Astrophysics Data System (ADS)

    Bednarek, Daniel R.; Barbarits, Jeffery; Rana, Vijay K.; Nagaraja, Srikanta P.; Josan, Madhur S.; Rudin, Stephen

    2011-03-01

    A tracking system has been developed to provide real-time feedback of skin dose and dose rate during interventional fluoroscopic procedures. The dose tracking system (DTS) calculates the radiation dose rate to the patient's skin using the exposure technique parameters and exposure geometry obtained from the x-ray imaging system digital network (Toshiba Infinix) and presents the cumulative results in a color mapping on a 3D graphic of the patient. We performed a number of tests to verify the accuracy of the dose representation of this system. These tests included comparison of system-calculated dose-rate values with ionization-chamber (6 cc PTW) measured values with change in kVp, beam filter, field size, source-to-skin distance and beam angulation. To simulate a cardiac catheterization procedure, the ionization chamber was also placed at various positions on an Alderson Rando torso phantom and the dose agreement compared for a range of projection angles with the heart at isocenter. To assess the accuracy of the dose distribution representation, Gafchromic film (XR-RV3, ISP) was exposed with the beam at different locations. The DTS and film distributions were compared and excellent visual agreement was obtained within the cm-sized surface elements used for the patient graphic. The dose (rate) values agreed within about 10% for the range of variables tested. Correction factors could be applied to obtain even closer agreement since the variable values are known in real-time. The DTS provides skin-dose values and dose mapping with sufficient accuracy for use in monitoring diagnostic and interventional x-ray procedures.

  2. Incidence of malignant skin tumors in 14,140 patients after grenz-ray treatment for benign skin disorders

    SciTech Connect

    Lindeloef, B.E.; Eklund, G.

    1986-12-01

    During the years 1949 to 1975, 14,237 patients received therapeutic doses of grenz rays for the treatment of benign skin disorders such as chronic eczema, psoriasis, and warts. The records of 14,140 of these patients (99.3%) formed the basis for an epidemiologic study of the incidence of skin malignancies in this population. Information about the patients, diagnoses, doses, and sites of treatment was obtained from separate records. The follow-up time was 15 years on the average. We searched the Swedish Cancer Registry, Stockholm, for records reporting the incidence of malignant skin tumors in the study population (incidences of basal cell carcinoma are not registered). The expected number of malignancies was calculated on the basis of age- and sex-standardized incidence data from the Swedish Cancer Registry. In 58 patients, a malignant skin tumor was diagnosed more than five years after grenz-ray therapy had first been administered. Nineteen patients had malignant melanomas, and 39 patients had other malignant skin tumors. The expected number of melanomas was 17.8, and that of other malignant skin tumors was 26.9. None of the patients with melanomas, and only eight of the patients with other malignant skin tumors, had received grenz-ray therapy at the site of the tumor. Six of these eight patients had also been exposed to other known carcinogens. Four hundred eighty-one patients had received an accumulated high dose of grenz rays (greater than or equal to 10 000 rad (greater than or equal to 100 Gy)) on one and the same area. No malignancies were found on those areas. Although we cannot exclude grenz-ray therapy as a risk factor in the development of nonmelanoma skin malignancies, this risk, if any, is small, if recommendations for therapy are followed.

  3. Low-dose UVB irradiation prevents MMP2-induced skin hyperplasia by inhibiting inflammation and ROS.

    PubMed

    Dang, Lin; Wang, Yan; Xue, Yadong; He, Lei; Li, Yuzhen; Xiong, Jikui

    2015-09-01

    Skin cancer is one of the most common types of malignancy in the world. UV radiation is known as the primary environmental carcinogen responsible for skin cancer development. However, UV radiation is a ubiquitous substance existing in the environment and the physiological effect of UV radiation is consistently ignored. Therefore, in the present study, the physiological effect of UV radiation on inhibition of skin cancer was investigated. Normal mouse skin was processing by no pre-radiation or pre-radiation of low-dose UV before a medium or high dose of UV radiation. We found that the low-dose pre-radiated mouse skin tissue exhibited low skin inflammation, skin ROS production and consequently low skin epithelial hyperplasia after the medium-dose UV radiation compared with the no pre-radiated mouse. However, this inhibition was not indicated in the high-dose UV radiation group after low-dose pre-radiation. Furthermore, western blot analysis and gelatin zymography showed low expression and activation of MMP2 in the skin tissues processed following medium-dose radiation, but not in tissues treated with high-dose radiation after a low-dose pre-radiation. Further investigation of MMP2 inhibitors of TIMP2/TIMP4 showed an upregulated TIMP2 expression, but not TIMP4. Collectively, these data indicate that low-dose pre-radiation attenuates the skin inflammation and ROS production induced by medium-dose UV radiation and also elevates TIMP2 to withstand MMP2, therefore suppressing skin hyperplasia. The present study indicates a novel concept or prophylactic function of moderate UV radiation as a preventative strategy.

  4. High-dose Rate Electronic Brachytherapy: A Nonsurgical Treatment Alternative for Nonmelanoma Skin Cancer

    PubMed Central

    Patel, Rakesh; Werschler, William Philip; Ceilley, Roger I.; Strimling, Robert

    2016-01-01

    The authors summarized data from a group of physicians with experience using high-dose rate electronic brachytherapy for the treatment of nonmelanoma skin cancer. The data have been published or presented in abstract format at national dermatology and radiation oncology meetings. The data included 1,822 treated lesions from 2009 to 2014 in patients ranging in age from 52 to 104 years. Most lesions were basal cell carcinoma (57%) or squamous cell carcinoma (38%) less than 2cm in size (97%). Median follow-up at the various centers ranged from 4 to 16 months, and results yielded an extremely low recurrence rate of less than one percent. Results show that within the confines of this follow up period, electronic brachytherapy is an effective, convenient, nonsurgical treatment option for patients with nonmelanoma skin cancer with few recurrences and excellent cosmetic results. PMID:28210385

  5. Skin dose mapping for non-uniform x-ray fields using a backscatter point spread function

    PubMed Central

    Vijayan, Sarath; Xiong, Zhenyu; Shankar, Alok; Rudin, Stephen; Bednarek, Daniel R.

    2017-01-01

    Beam shaping devices like ROI attenuators and compensation filters modulate the intensity distribution of the x-ray beam incident on the patient. This results in a spatial variation of skin dose due to the variation of primary radiation and also a variation in backscattered radiation from the patient. To determine the backscatter component, backscatter point spread functions (PSF) are generated using EGS Monte-Carlo software. For this study, PSF’s were determined by simulating a 1 mm beam incident on the lateral surface of an anthropomorphic head phantom and a 20 cm thick PMMA block phantom. The backscatter PSF’s for the head phantom and PMMA phantom are curve fit with a Lorentzian function after being normalized to the primary dose intensity (PSFn). PSFn is convolved with the primary dose distribution to generate the scatter dose distribution, which is added to the primary to obtain the total dose distribution. The backscatter convolution technique is incorporated in the dose tracking system (DTS), which tracks skin dose during fluoroscopic procedures and provides a color map of the dose distribution on a 3D patient graphic model. A convolution technique is developed for the backscatter dose determination for the non-uniformly spaced graphic-model surface vertices. A Gafchromic film validation was performed for shaped x-ray beams generated with an ROI attenuator and with two compensation filters inserted into the field. The total dose distribution calculated by the backscatter convolution technique closely agreed with that measured with the film. PMID:28649154

  6. Skin dose mapping for non-uniform x-ray fields using a backscatter point spread function

    NASA Astrophysics Data System (ADS)

    Vijayan, Sarath; Xiong, Zhenyu; Shankar, Alok; Rudin, Stephen; Bednarek, Daniel R.

    2017-03-01

    Beam shaping devices like ROI attenuators and compensation filters modulate the intensity distribution of the xray beam incident on the patient. This results in a spatial variation of skin dose due to the variation of primary radiation and also a variation in backscattered radiation from the patient. To determine the backscatter component, backscatter point spread functions (PSF) are generated using EGS Monte-Carlo software. For this study, PSF's were determined by simulating a 1 mm beam incident on the lateral surface of an anthropomorphic head phantom and a 20 cm thick PMMA block phantom. The backscatter PSF's for the head phantom and PMMA phantom are curve fit with a Lorentzian function after being normalized to the primary dose intensity (PSFn). PSFn is convolved with the primary dose distribution to generate the scatter dose distribution, which is added to the primary to obtain the total dose distribution. The backscatter convolution technique is incorporated in the dose tracking system (DTS), which tracks skin dose during fluoroscopic procedures and provides a color map of the dose distribution on a 3D patient graphic model. A convolution technique is developed for the backscatter dose determination for the nonuniformly spaced graphic-model surface vertices. A Gafchromic film validation was performed for shaped x-ray beams generated with an ROI attenuator and with two compensation filters inserted into the field. The total dose distribution calculated by the backscatter convolution technique closely agreed with that measured with the film.

  7. High-dose immunosuppressant alters the immunological status of New Zealand white rabbits following skin transplantation

    PubMed Central

    CHENG, PEILUN; ZHONG, LIMING; JIANG, ZESHENG; WANG, YAN; PAN, MINGXIN; GAO, YI

    2015-01-01

    The aim of this study was to investigate the effect of an immunosuppressant on the immunological status of New Zealand white rabbits after skin grafting, and to evaluate a method for monitoring the immunological status of subjects with skin transplants. The rabbits were randomly divided into allograft rejection, autograft tolerance, nontransplant, allograft low-dose immunosuppressant and allograft high-dose immunosuppressant groups. The rabbits in the low- and high-dose immunosuppressant groups were treated with cyclosporine A intravenously 8 h prior to skin transplantation and once daily following transplantation at doses of 2 and 25 mg/kg, respectively. At 12 days after skin transplantation, the spleens of donor (female) rabbits and recipient (male) rabbits were harvested for the preparation of single-cell suspensions. The splenocytes from recipient and donor rabbits were labeled with 0.3 or 6 µM carboxy fluorescein diacetate succinimidyl ester, respectively, and a mixed cell suspension was prepared. The final preparation was intravenously injected into recipient New Zealand white rabbits. The ratio of the two fluorescently labeled cell populations in the peripheral blood was measured using flow cytometry at 1, 2, 4 and 8 h after the injection, and the cell death rate was calculated. Histological analysis was also performed on samples collected at the time of splenectomy. The cell death rates of the allograft rejection and low-dose immunosuppressant groups reached their highest levels 8 h after the injection of spleen cell suspension. Allogeneic spleen cells from donor male rabbits were almost completely removed within 8 h of injection. The cell death rate increased slowly in the nontransplant, autograft and high-dose immunosuppressant groups without specificity. This study provides a specific method for the in vivo monitoring of the immunological status of patients after skin grafting. This method can quickly and accurately detect the immunological status of

  8. Skin microvascular reactivity in patients with hypothyroidism.

    PubMed

    Mihor, Ana; Gergar, Maša; Gaberšček, Simona; Lenasi, Helena

    2016-11-04

    Hypothyroidism is associated with impaired vascular function; however, little is known about its impact on microcirculation. We aimed to determine skin microvascular reactivity in hypothyroidism focusing on endothelial function and the sympathetic response. We measured skin laser Doppler (LD) flux (LDF) on the volar forearm and the finger pulp using LD flowmetry in hypothyroid patients (N = 13) and healthy controls (N = 15). Skin microvascular reactivity was assessed by a three-minute occlusion of the brachial artery, inducing postocclusive reactive hyperaemia (PRH), and by a four-minute local cooling of the hand. An electrocardiogram (ECG), digital artery blood pressure and skin temperature at the measuring sites were recorded. Baseline LDF, the digital artery blood pressure and the heart rate were comparable between patients and controls. On the other hand, patients exhibited significantly longer PRH duration, significantly higher blood pressure during cooling (unpaired t-test, p <0.05) and lower, albeit not significant, LDF in the ipsilateral finger pulp during cooling compared to controls. Unexpectedly, the results of the present study point to an increased vasodilator capacity of skin microcirculation and an apparent increase in sympathetic reactivity after local cooling in hypothyroid patients. Hypothyroidism induces subtle changes of some haemodynamic parameters in skin microcirculation implying altered endothelial function and altered sympathetic reactivity.

  9. Non-melanoma skin cancer treated with high-dose-rate brachytherapy: a review of literature

    PubMed Central

    Rembielak, Agata; Manfredi, Bruno; Ursino, Stefano; Pasqualetti, Francesco; Laliscia, Concetta; Orlandi, Francesca; Morganti, Riccardo; Fabrini, Maria Grazia; Paiar, Fabiola

    2016-01-01

    Purpose The incidence of non-melanoma skin cancer (NMSC) has been increasing over the past 30 years. There are different treatment options and surgical excision is the most frequent treatment due to its low rates of recurrence. Radiotherapy is an effective alternative of surgery, and brachytherapy (BT) might be a better therapeutic option due to high radiation dose concentration to the tumor with rapid dose fall-off resulting in normal tissues sparing. The aim of this review was to evaluate the local control, toxicity, and cosmetic outcomes in NMSC treated with high-dose-rate BT (HDR-BT). Material and methods In May 2016, a systematic search of bibliographic database of PubMed, Web of Science, Scopus, and Cochrane Library with a combination of key words of “skin cancer”, “high dose rate brachytherapy”, “squamous cell carcinoma”, “basal cell carcinoma”, and “non melanoma skin cancer“ was performed. In this systematic review, we included randomized trials, non-randomized trials, prospective and retrospective studies in patients affected by NMSC treated with HDR-BT. Results Our searches generated a total of 85 results, and through a process of screening, 10 publications were selected for the review. Brachytherapy was well tolerated with acceptable toxicity and high local control rates (median: 97%). Cosmetic outcome was reported in seven study and consisted in an excellent and good cosmetic results in 94.8% of cases. Conclusions Based on the review data, we can conclude that the treatment of NMSC with HDR-BT is effective with excellent and good cosmetics results, even in elderly patients. The hypofractionated course appears effective with very good local disease control. More data with large-scale randomized controlled trials are needed to assess the efficacy and safety of brachytherapy. PMID:28115960

  10. Measuring radiation dose to patients undergoing fluoroscopically-guided interventions

    NASA Astrophysics Data System (ADS)

    Lubis, L. E.; Badawy, M. K.

    2016-03-01

    The increasing prevalence and complexity of fluoroscopically guided interventions (FGI) raises concern regarding radiation dose to patients subjected to the procedure. Despite current evidence showing the risk to patients from the deterministic effects of radiation (e.g. skin burns), radiation induced injuries remain commonplace. This review aims to increase the awareness surrounding radiation dose measurement for patients undergoing FGI. A review of the literature was conducted alongside previous researches from the authors’ department. Studies pertaining to patient dose measurement, its formalism along with current advances and present challenges were reviewed. Current patient monitoring techniques (using available radiation dosimeters), as well as the inadequacy of accepting displayed dose as patient radiation dose is discussed. Furthermore, advances in real-time patient radiation dose estimation during FGI are considered. Patient dosimetry in FGI, particularly in real time, remains an ongoing challenge. The increasing occurrence and sophistication of these procedures calls for further advances in the field of patient radiation dose monitoring. Improved measuring techniques will aid clinicians in better predicting and managing radiation induced injury following FGI, thus improving patient care.

  11. Skin Necrosis after a Low-Dose Vasopressin Infusion through a Central Venous Catheter for Treating Septic Shock

    PubMed Central

    Kim, Eun Hee; Lee, Sae Hwan; Byun, Seung Woon; Kang, Ho Suk; Koo, Dong Hoe; Park, Hyun-Gu

    2006-01-01

    This is a report on a case of severe skin necrosis in a vasodilatory septic shock patient after the infusion of low-dose vasopressin through a central venous catheter. An 84-year-old male was hospitalized for edema on both legs at Asan Medical Center, Seoul, Korea. On hospital day 8, the patient began to complain of dyspnea and he subsequently developed severe septic shock caused by E. coli. After being transferred to the medical intensive care unit, his hypotension, which was refractory to norepinephrine, was controlled by an infusion of low-dose vasopressin (0.02 unit/min) through a central venous catheter into the right subclavian vein. After the infusion of low-dose vasopressin, severe skin necrosis with bullous changes developed, necessitating discontinuation of the low-dose vasopressin infusion. The patient expired from refractory septic shock. Although low-dose vasopressin can control hypotension in septic shock patients, low-dose vasopressin must be used with caution because ischemic complications such as skin necrosis can develop even with administration through a central venous catheter. PMID:17249516

  12. Revisiting Low-Dose Total Skin Electron Beam Therapy in Mycosis Fungoides

    SciTech Connect

    Harrison, Cameron; Young, James; Navi, Daniel; Riaz, Nadeem; Lingala, Bharathi; Kim, Youn; Hoppe, Richard

    2011-11-15

    Purpose: Total skin electron beam therapy (TSEBT) is a highly effective treatment for mycosis fungoides (MF). The standard course consists of 30 to 36 Gy delivered over an 8- to 10-week period. This regimen is time intensive and associated with significant treatment-related toxicities including erythema, desquamation, anhydrosis, alopecia, and xerosis. The aim of this study was to identify a lower dose alternative while retaining a favorable efficacy profile. Methods and Materials: One hundred two MF patients were identified who had been treated with an initial course of low-dose TSEBT (5-<30 Gy) between 1958 and 1995. Patients had a T stage classification of T2 (generalized patch/plaque, n = 51), T3 (tumor, n = 29), and T4 (erythrodermic, n = 22). Those with extracutaneous disease were excluded. Results: Overall response (OR) rates (>50% improvement) were 90% among patients with T2 to T4 disease receiving 5 to <10 Gy (n = 19). In comparison, OR rates between the 10 to <20 Gy and 20 to <30 Gy subgroups were 98% and 97%, respectively. There was no significant difference in median progression free survival (PFS) in T2 and T3 patients when stratified by dose group, and PFS in each was comparable to that of the standard dose. Conclusions: OR rates associated with low-dose TSEBT in the ranges of 10 to <20 Gy and 20 to <30 Gy are comparable to that of the standard dose ({>=} 30 Gy). Efficacy measures including OS, PFS, and RFS are also favorable. Given that the efficacy profile is similar between 10 and <20 Gy and 20 and <30 Gy, the utility of TSEBT within the lower dose range of 10 to <20 Gy merits further investigation, especially in the context of combined modality treatment.

  13. Estimating pediatric entrance skin dose from digital radiography examination using DICOM metadata: A quality assurance tool

    SciTech Connect

    Brady, S. L. Kaufman, R. A.

    2015-05-15

    Purpose: To develop an automated methodology to estimate patient examination dose in digital radiography (DR) imaging using DICOM metadata as a quality assurance (QA) tool. Methods: Patient examination and demographical information were gathered from metadata analysis of DICOM header data. The x-ray system radiation output (i.e., air KERMA) was characterized for all filter combinations used for patient examinations. Average patient thicknesses were measured for head, chest, abdomen, knees, and hands using volumetric images from CT. Backscatter factors (BSFs) were calculated from examination kVp. Patient entrance skin air KERMA (ESAK) was calculated by (1) looking up examination technique factors taken from DICOM header metadata (i.e., kVp and mA s) to derive an air KERMA (k{sub air}) value based on an x-ray characteristic radiation output curve; (2) scaling k{sub air} with a BSF value; and (3) correcting k{sub air} for patient thickness. Finally, patient entrance skin dose (ESD) was calculated by multiplying a mass–energy attenuation coefficient ratio by ESAK. Patient ESD calculations were computed for common DR examinations at our institution: dual view chest, anteroposterior (AP) abdomen, lateral (LAT) skull, dual view knee, and bone age (left hand only) examinations. Results: ESD was calculated for a total of 3794 patients; mean age was 11 ± 8 yr (range: 2 months to 55 yr). The mean ESD range was 0.19–0.42 mGy for dual view chest, 0.28–1.2 mGy for AP abdomen, 0.18–0.65 mGy for LAT view skull, 0.15–0.63 mGy for dual view knee, and 0.10–0.12 mGy for bone age (left hand) examinations. Conclusions: A methodology combining DICOM header metadata and basic x-ray tube characterization curves was demonstrated. In a regulatory era where patient dose reporting has become increasingly in demand, this methodology will allow a knowledgeable user the means to establish an automatable dose reporting program for DR and perform patient dose related QA testing for

  14. Estimating pediatric entrance skin dose from digital radiography examination using DICOM metadata: A quality assurance tool.

    PubMed

    Brady, S L; Kaufman, R A

    2015-05-01

    To develop an automated methodology to estimate patient examination dose in digital radiography (DR) imaging using DICOM metadata as a quality assurance (QA) tool. Patient examination and demographical information were gathered from metadata analysis of DICOM header data. The x-ray system radiation output (i.e., air KERMA) was characterized for all filter combinations used for patient examinations. Average patient thicknesses were measured for head, chest, abdomen, knees, and hands using volumetric images from CT. Backscatter factors (BSFs) were calculated from examination kVp. Patient entrance skin air KERMA (ESAK) was calculated by (1) looking up examination technique factors taken from DICOM header metadata (i.e., kVp and mA s) to derive an air KERMA (k air) value based on an x-ray characteristic radiation output curve; (2) scaling k air with a BSF value; and (3) correcting k air for patient thickness. Finally, patient entrance skin dose (ESD) was calculated by multiplying a mass-energy attenuation coefficient ratio by ESAK. Patient ESD calculations were computed for common DR examinations at our institution: dual view chest, anteroposterior (AP) abdomen, lateral (LAT) skull, dual view knee, and bone age (left hand only) examinations. ESD was calculated for a total of 3794 patients; mean age was 11 ± 8 yr (range: 2 months to 55 yr). The mean ESD range was 0.19-0.42 mGy for dual view chest, 0.28-1.2 mGy for AP abdomen, 0.18-0.65 mGy for LAT view skull, 0.15-0.63 mGy for dual view knee, and 0.10-0.12 mGy for bone age (left hand) examinations. A methodology combining DICOM header metadata and basic x-ray tube characterization curves was demonstrated. In a regulatory era where patient dose reporting has become increasingly in demand, this methodology will allow a knowledgeable user the means to establish an automatable dose reporting program for DR and perform patient dose related QA testing for digital x-ray imaging.

  15. Skin dose estimation for various beam modifiers and source-to-surface distances for 6MV photons

    PubMed Central

    Yadav, Girigesh; Yadav, R. S.; Kumar, Alok

    2009-01-01

    The purpose of this study was to learn the skin dose estimation for various beam modifiers at various source-to-surface distances (SSDs) for a 6 MV photon. Surface and buildup region doses were measured with an acrylic slab phantom and Markus 0.055 cc parallel plate (PP) ionization chamber. Measurements were carried out for open fields, motorized wedge fields, acrylic block tray fields ranging from 3 × 3 cm2 to 30 × 30 cm2. Twenty-five percent of the field was blocked with a cerrobend block and a Multileaf collimator (MLC). The effect of the blocks on the skin dose was measured for a 20 × 20 cm2 field size, at 80 cm, 100 cm and 120 cm SSD. During the use of isocentric treatments, whereby the tumor is positioned at 100 cm from the source, depending on the depth of the tumor and size of the patient, the SSD can vary from 80 cm to 100 cm. To achieve a larger field size, the SSD can also be extended up to 120 cm at times. The skin dose increased as field size increased. The skin dose for the open 10 ×10 cm2 field was 15.5%, 14.8% and 15.5% at 80 cm, 100 cm and 120 cm SSDs, respectively. The skin dose due to a motorized 60° wedge for the 10 × 10 cm2 field was 9.9%, 9.5%, and 9.5% at 80 cm, 100 cm and 120 cm SSDs. The skin dose due to acrylic block tray, of thickness 1.0 cm for a 10 × 10 cm2 field was 27.0%, 17.2% and 16.1% at 80, 100 and 120 cm SSD respectively. Due to the use of an acrylic block tray, the surface dose was increased for all field sizes at the above three SSDs and the percentage skin dose was more dominant at the lower SSD and larger field size. The skin dose for a 30 × 30 cm2 field size at 80 cm SSD was 38.3% and it was 70.4% for the open and acrylic block tray fields, respectively. The skin doses for motorized wedge fields were lower than for open fields. The effect of SSDs on the surface dose for motorized 60° wedge fields was not significant for a small field size (difference was less than 1% up to a 15 × 15 cm2 field size), but for a

  16. Patient doses and dosimetric evaluations in interventional cardiology.

    PubMed

    Bor, Dogan; Olğar, Turan; Toklu, Türkay; Cağlan, Ayça; Onal, Elif; Padovani, Renato

    2009-03-01

    Interventional cardiological examinations may be associated with excessive radiation exposures which may cause skin injuries and higher probabilities of stochastic effects. Dose-area product (DAP) and skin doses of 325 patients were measured using alternative dosimetric techniques for different cardiological examinations. Data were collected from five different systems with the involvement of 11 cardiologists. All these dosimetric information has been collected separately for each of 10 projections together with the exposure parameters of X-ray systems. Mean DAP values measured with a transparent ion chamber were 49.1 Gy cm(2), 66.8 Gy cm(2), 106.9 Gy cm(2) and 124.7 Gy cm(2), respectively, for coronary angiography (CA), percutaneous transluminal coronary angioplasty (PTCA) or stent (PT-SI), coronary angiography and/or PTCA and/or stent (CA-PT-SI), and ablation examinations. Radiochromic films, thermoluminescent dosimeters (TLD) and point measurement of air kerma (AK) were carried out for skin dose assessments. Skin doses of 23 patients measured with radiochromic films were found to be between 2 Gy and 6 Gy. Although the complexity of the procedures was the major reason for these excessive doses, considerable contributions of high X-ray output of some fluoroscopy units were also noticed. In addition to the direct measurement of DAP, alternative DAP values were also determined from the skin dose measurement techniques; exposed areas were summed on digitized radiochromic films in one technique, The product of AK reading with X-ray field size measured at the patient entrance using slow X-ray films was taken as another DAP. Good correlations were found among the DAP results and also between the entrance skin doses calculated from AK measurements and direct DAP readings (R(2)=0.91). A trigger DAP value of 130 Gy cm(2) for the 2 Gy of skin doses was derived from this relationship. Collection of dosimetric data for each projection was also investigated regarding a

  17. Buildup region and skin-dose measurements for the Therac 6 Linear Accelerator for radiation therapy

    SciTech Connect

    Tannous, N.B.J.; Gagnon, W.F.; Almond, P.R.

    1981-05-01

    Buildup and surface-dose measurements were taken for the 6 MV photon beam from a Therac 6 linear accelerator manufactured by Atomic Energy of Canada Limited (AECL) with and without a lucite blocking tray in place. Further measurements were made with a copper filter designed to reduce secondary electrons emitted by photon interactions with the Lucite tray. The results are discussed in relation to skin-sparing for radiation therapy patients. The measurements were made with a fixed volume PTW parallel-plate ionization chamber and corrected to zero-chamber volume. The results were found to be consistent with similar measurements taken with a variable volume extrapolation chamber.

  18. Buildup region and skin-dose measurements for the Therac 6 linear accelerator for radiation therapy.

    PubMed

    Tannous, N B; Gagnon, W F; Almond, P R

    1981-01-01

    Buildup and surface-dose measurements were taken for the 6 MV photon beam from a Therac 6 linear accelerator manufactured by Atomic Energy of Canada Limited (AECL) with and without a lucite blocking tray in place. Further measurements were made with a copper filter designed to reduce secondary electrons emitted by photon interactions with the Lucite tray. The results are discussed in relation to skin-sparing for radiation therapy patients. The measurements were made with a fixed volume PTW parallel-plate ionization chamber and corrected to zero-chamber volume. The results were found to be consistent with similar measurements taken with a variable volume extrapolation chamber.

  19. Use of skin substitutes in pediatric patients.

    PubMed

    Ozerdem, Omer R; Wolfe, S Anthony; Marshall, Deirdre

    2003-07-01

    There are various artificial skin substitutes available commercially. The authors have used Integra, cultured epithelium, and Apligraf in their clinic. In the present report, they present their experiences based on two case reports. The first patient was a 12-year-old boy with widespread skin defects and left axillary contracture due to epidermolysis bullosa (EB). Apligraf was used to cover the skin defects on the trunk and face and to manage ectropion and axillary contracture. The second patient was a 6-year-old boy who suffered neurocutaneous melanosis. Partial excision of a pigmented lesion on the back created a large defect. Integra application followed by repair with cultured autologous skin was accomplished, and the results were satisfactory. Skin substitute products 1) are commercially immediately available; 2) are effective for management of contractures, chronic wounds, and chronic skin illnesses; 3) decrease or avoid the risk of donor area morbidity, which is more difficult to treat in children; 4) provide long-term coverage of the wound; and 5) can be used in conjunction with autologous tissue (e.g., Integra followed by cultured epithelium applications).

  20. Dosimetric evaluation of internal shielding in a high dose rate skin applicator

    PubMed Central

    Granero, Domingo; Perez-Calatayud, Jose; Carmona, Vicente; Pujades, M Carmen; Ballester, Facundo

    2011-01-01

    Purpose The Valencia HDR applicators are accessories of the microSelectron HDR afterloading system (Nucletron) shaped as truncated cones. The base of the cone is either 2 or 3 cm diameter. They are intended to treat skin lesions, being the typical prescription depth 3 mm. In patients with eyelid lesions, an internal shielding is very useful to reduce the dose to the ocular globe. The purpose of this work was to evaluate the dose enhancement from potential backscatter and electron contamination due to the shielding. Material and methods Two methods were used: a) Monte Carlo simulation, performed with the GEANT4 code, 2 cm Valencia applicator was placed on the surface of a water phantom in which 2 mm lead slab was located at 3 mm depth; b) radiochromic EBT films, used to verify the Monte Carlo results, positioning the films at 1.5, 3, 5 and 7 mm depth, inside the phantom. Two irradiations, with and without the lead shielding slab, were carried out. Results The Monte Carlo results showed that due to the backscatter component from the lead, the dose level raised to about 200% with a depth range of 0.5 mm. Under the lead the dose level was enhanced to about 130% with a depth range of 1 mm. Two millimeters of lead reduce the dose under the slab with about 60%. These results agree with film measurements within uncertainties. Conclusions In conclusion, the use of 2 mm internal lead shielding in eyelid skin treatments with the Valencia applicators were evaluated using MC methods and EBT film dosimetry. The minimum bolus thickness that was needed above and below the shielding was 0.5 mm and 1 mm respectively, and the shielding reduced the absorbed dose delivered to the ocular globe by about 60%. PMID:27877198

  1. Pharmacologic doses of nicotinamide in the treatment of inflammatory skin conditions: a review.

    PubMed

    Niren, Neil M

    2006-01-01

    Various skin disorders with an inflammatory component often have been treated with steroids and/or oral antibiotics. However, long-term use of these agents has drawbacks: steroids may induce numerous serious side effects such as hypertension, immunosuppression, and osteoporosis, and overuse of oral antibiotics may contribute to the development of bacterial resistance, as well as to a host of nuisance side effects such as diarrhea, yeast infections, and photosensitivity. As a result, alternative oral treatments, such as nicotinamide, have been investigated. During the past 50 years, many clinical reports have identified nicotinamide as a beneficial agent in the treatment of a variety of inflammatory skin disorders; what's more, its exceptional safety profile at pharmacologic doses makes it a potentially ideal long-term oral therapy for patients with inflammatory skin diseases. A recent large study evaluating nicotinamide for the treatment of acne or rosacea has confirmed the potential benefits of oral nicotinamide as an alternative approach to managing inflammatory lesions associated with acne vulgaris and acne rosacea. This article reviews the substantial number of reports published over the past 50 years that document the clinical utility and safety of oral and topical formulations of nicotinamide for the treatment of a variety of inflammatory skin conditions.

  2. Monte Carlo skin dose simulation in intraoperative radiotherapy of breast cancer using spherical applicators

    NASA Astrophysics Data System (ADS)

    Moradi, F.; Ung, N. M.; Khandaker, M. U.; Mahdiraji, G. A.; Saad, M.; Malik, R. Abdul; Bustam, A. Z.; Zaili, Z.; Bradley, D. A.

    2017-08-01

    The relatively new treatment modality electronic intraoperative radiotherapy (IORT) is gaining popularity, irradiation being obtained within a surgically produced cavity being delivered via a low-energy x-ray source and spherical applicators, primarily for early stage breast cancer. Due to the spatially dramatic dose-rate fall off with radial distance from the source and effects related to changes in the beam quality of the low keV photon spectra, dosimetric account of the Intrabeam system is rather complex. Skin dose monitoring in IORT is important due to the high dose prescription per treatment fraction. In this study, modeling of the x-ray source and related applicators were performed using the Monte Carlo N-Particle transport code. The dosimetric characteristics of the model were validated against measured data obtained using an ionization chamber and EBT3 film as dosimeters. By using a simulated breast phantom, absorbed doses to the skin for different combinations of applicator size (1.5-5 cm) and treatment depth (0.5-3 cm) were calculated. Simulation results showed overdosing of the skin (>30% of prescribed dose) at a treatment depth of 0.5 cm using applicator sizes larger than 1.5 cm. Skin doses were significantly increased with applicator size, insofar as delivering 12 Gy (60% of the prescribed dose) to skin for the largest sized applicator (5 cm diameter) and treatment depth of 0.5 cm. It is concluded that the recommended 0.5-1 cm distance between the skin and applicator surface does not guarantee skin safety and skin dose is generally more significant in cases with the larger applicators. Highlights: • Intrabeam x-ray source and spherical applicators were simulated and skin dose was calculated. • Skin dose for constant skin to applicator distance strongly depends on applicator size. • Use of larger applicators generally results in higher skin dose. • The recommended 0.5-1 cm skin to applicator distance does not guarantee skin

  3. Skin and gonadal dose reduction during hip radiography of the bull.

    PubMed

    Wood, A K; Blockey, B; Reynolds, K M; Leith, I S; Burns, P A

    1979-10-01

    Radiology is being used to an increasing extent in the clinical diagnosis of hip lameness in bulls. Consequent gonadal doses may have important implications in later breeding programmes. Skin and gonadal doses were recorded during hip radiography of 18 bulls. An additional 0.13 mm copper filtration reduced skin dose by more than one third, but had no effect on gonadal dose. The average radiation dose to the gonads was approximately halved by completely surrounding the scrotum with lead sheeting 0.95 mm in thickness.

  4. Assessment of patient and occupational dose in established and new applications of MDCT fluoroscopy.

    PubMed

    Joemai, Raoul M S; Zweers, Dirk; Obermann, Wim R; Geleijns, Jacob

    2009-04-01

    This study aimed to assess patient dose and occupational dose in established and new applications of MDCT fluoroscopy. Electronic personal dosimeters were used to measure occupational dose equivalent. Effective patient dose was derived from the recorded dose-length product. Acquisition parameters that were observed during CT fluoroscopy (CTF) provided the basis for the estimation of an entrance skin dose profile. Two hundred ten CT-guided interventional procedures were included in the study. The median effective patient dose was 10 mSv (range, 0.1-235 mSv; 107 procedures). The median peak entrance skin dose was 0.4 Sv (0.1-2.1 Sv; 27 procedures). From 547 measurements of occupational dose equivalent, a median occupational effective dose of 3 muSv per procedure was derived for the interventional radiologists and 0.4 muSv per procedure for the assisting radiologists and radiology technologists. The estimated maximum occupational effective dose reached 0.4 mSv. The study revealed high effective patient doses, up to 235 mSv, mainly for relatively new applications such as CTF-guided radiofrequency ablations using MDCT, vertebroplasty, and percutaneous ethanol injections of tumors. Entrance doses were occasionally in the range of the warning level for deterministic skin effects but were always below the threshold for serious deterministic effects. The complexity of the procedure, expected benefits of the treatment, and general health state of the patient contribute to the justification of observed high effective patient doses.

  5. Calculating the peak skin dose resulting from fluoroscopically guided interventions. Part I: Methods.

    PubMed

    Jones, A Kyle; Pasciak, Alexander S

    2011-11-15

    While direct measurement of the peak skin dose resulting from a fluoroscopically-guided procedure is possible, the decision must be made a priori at additional cost and time. It is most often the case that the need for accurate knowledge of the peak skin dose is realized only after a procedure has been completed, or after a suspected reaction has been discovered. Part I of this review article discusses methods for calculating the peak skin dose across a range of clinical scenarios. In some cases, a wealth of data are available, while in other cases few data are available and additional data must be measured in order to estimate the peak skin dose. Data may be gathered from a dose report, the DICOM headers of images, or from staff and physician interviews. After data are gathered, specific steps must be followed to convert dose metrics, such as the reference point air kerma (K(a,r)) or the kerma area product (KAP), into peak skin dose. These steps require knowledge of other related factors, such as the f-factor and the backscatter factor, tables of which are provided in this manuscript. Sources of error and the impact of these errors on the accuracy of the final estimate of the peak skin dose are discussed.

  6. Assessing patient dose in interventional fluoroscopy using patient-dependent hybrid phantoms

    NASA Astrophysics Data System (ADS)

    Johnson, Perry Barnett

    Interventional fluoroscopy uses ionizing radiation to guide small instruments through blood vessels or other body pathways to sites of clinical interest. The technique represents a tremendous advantage over invasive surgical procedures, as it requires only a small incision, thus reducing the risk of infection and providing for shorter recovery times. The growing use and increasing complexity of interventional procedures, however, has resulted in public health concerns regarding radiation exposures, particularly with respect to localized skin dose. Tracking and documenting patient-specific skin and internal organ dose has been specifically identified for interventional fluoroscopy where extended irradiation times, multiple projections, and repeat procedures can lead to some of the largest doses encountered in radiology. Furthermore, inprocedure knowledge of localized skin doses can be of significant clinical importance to managing patient risk and in training radiology residents. In this dissertation, a framework is presented for monitoring the radiation dose delivered to patients undergoing interventional procedures. The framework is built around two key points, developing better anthropomorphic models, and designing clinically relevant software systems for dose estimation. To begin, a library of 50 hybrid patient-dependent computational phantoms was developed based on the UF hybrid male and female reference phantoms. These phantoms represent a different type of anthropomorphic model whereby anthropometric parameters from an individual patient are used during phantom selection. The patient-dependent library was first validated and then used in two patient-phantom matching studies focused on cumulative organ and local skin dose. In terms of organ dose, patient-phantom matching was shown most beneficial for estimating the dose to large patients where error associated with soft tissue attenuation differences could be minimized. For small patients, inherent difference

  7. Estimation of the radiation dose from radiotherapy for skin haemangiomas in childhood: the ICTA software for epidemiology

    NASA Astrophysics Data System (ADS)

    Shamsaldin, A.; Lundell, M.; Diallo, I.; Ligot, L.; Chavaudra, J.; de Vathaire, F.

    2000-12-01

    Radium applicators and pure beta emitters have been widely used in the past to treat skin haemangioma in early childhood. A well defined relationship between the low doses received from these applicators and radiation-induced cancers requires accurate dosimetry. A human-based CT scan phantom has been used to simulate every patient and treatment condition and then to calculate the source-target distance when radium and pure beta applicators were used. The effective transmission factor ϕ(r) for the gamma spectrum emitted by the radium sources applied on the skin surface was modelled using Monte Carlo simulations. The well-known quantization approach was used to calculate gamma doses delivered from radium applicators to various anatomical points. For 32P, 90Sr/90Y applicators and 90Y needles we have used the apparent exponential attenuation equation. The dose calculation algorithm was integrated into the ICTA software (standing for a model that constructs an Individualized phantom based on CT slices and Auxological data), which has been developed for epidemiological studies of cohorts of patients who received radium and beta-treatments for skin haemangioma. The ϕ(r) values obtained for radium skin applicators are in good agreement with the available values in the first 10 cm but higher at greater distances. Gamma doses can be calculated with this algorithm at 165 anatomical points throughout the body of patients treated with radium applicators. Lung heterogeneity and air crossed by the gamma rays are considered. Comparison of absorbed doses in water from a 10 mg equivalent radium source simulated by ICTA with those measured at the Radiumhemmet, Karolinska Hospital (RAH) showed good agreement, but ICTA estimation of organ doses did not always correspond those estimated at the RAH. Beta doses from 32P, 90Sr/90Y applicators and 90Y needles are calculated up to the maximum beta range (11 mm).

  8. C-arm rotation as a method for reducing peak skin dose in interventional cardiology.

    PubMed

    Pasciak, Alexander S; Bourgeois, Austin C; Jones, A Kyle

    2014-01-01

    Prolonged interventional cardiology (IC) procedures may result in radiation-induced skin injury, a potentially preventable cause of patient morbidity. Rotating the C-arm during an IC procedure may reduce this risk, although the methods by which the technique can be practically applied remains unexplored. A previous study demonstrated that C-arm rotation often increases peak skin dose (PSD) in interventional radiology procedures. The purpose of this study was to determine whether C-arm rotation reduces the PSD in IC procedures and, if so, under what circumstances. Simulations were performed using a numerical ray-tracing algorithm to analyse the effect of C-arm rotation on PSD across a range of patient sizes, C-arm configurations and procedure types. Specific data from modern fluoroscopes and patient dimensions were used as inputs to the simulations. In many cases, modest C-arm rotation angles completely eliminated overlap between X-ray field sites on the skin. When overlap remained, PSD increases were generally small. One exception was craniocaudal rotation, which tended to increase PSD. C-arm rotation was most effective for large patients and small X-ray field sizes. Small patients may not benefit from C-arm rotation as a procedural modification. The use of a prophylactic method where the C-arm was rotated between small opposing oblique angles was effective in reducing PSD. With the exception of rotation to steep craniocaudal angles, rotating the C-arm reduces PSD in IC procedures when used as either a procedural modification or a prophylactic strategy. Tight collimation increases the benefit of C-arm rotation.

  9. C-arm rotation as a method for reducing peak skin dose in interventional cardiology

    PubMed Central

    Pasciak, Alexander S; Bourgeois, Austin C; Jones, A Kyle

    2014-01-01

    Purpose Prolonged interventional cardiology (IC) procedures may result in radiation-induced skin injury, a potentially preventable cause of patient morbidity. Rotating the C-arm during an IC procedure may reduce this risk, although the methods by which the technique can be practically applied remains unexplored. A previous study demonstrated that C-arm rotation often increases peak skin dose (PSD) in interventional radiology procedures. The purpose of this study was to determine whether C-arm rotation reduces the PSD in IC procedures and, if so, under what circumstances. Materials and methods Simulations were performed using a numerical ray-tracing algorithm to analyse the effect of C-arm rotation on PSD across a range of patient sizes, C-arm configurations and procedure types. Specific data from modern fluoroscopes and patient dimensions were used as inputs to the simulations. Results In many cases, modest C-arm rotation angles completely eliminated overlap between X-ray field sites on the skin. When overlap remained, PSD increases were generally small. One exception was craniocaudal rotation, which tended to increase PSD. C-arm rotation was most effective for large patients and small X-ray field sizes. Small patients may not benefit from C-arm rotation as a procedural modification. The use of a prophylactic method where the C-arm was rotated between small opposing oblique angles was effective in reducing PSD. Conclusions With the exception of rotation to steep craniocaudal angles, rotating the C-arm reduces PSD in IC procedures when used as either a procedural modification or a prophylactic strategy. Tight collimation increases the benefit of C-arm rotation. PMID:25568803

  10. [Skin diseases in geriatric patients. Epidemiologic data].

    PubMed

    Makrantonaki, E; Liakou, A I; Eckardt, R; Zens, M; Steinhagen-Thiessen, E; Zouboulis, C C

    2012-12-01

    The incidence of skin diseases more common in older patients, e.g. inflammatory and autoimmune diseases, benign and malignant tumors and paraneoplastic syndromes, is increasing worldwide rapidly mainly due to early or lifelong UV-overexposure and to an aging population. In order to transform this demographic change into a chance a better understanding of the pathomechanisms of these diseases, an early diagnosis and therapy are essential steps. In addition, a joint effort to raise public awareness, patient education, preventive measures and consistent monitoring of high-risk groups is of great importance. In this article, the relationship between aging and associated skin diseases will be presented with a particular focus on the epidemiology and risk factors.

  11. Time and dose-response effects of honokiol on UVB-induced skin cancer development.

    PubMed

    Guillermo, Ruth F; Chilampalli, Chandeshwari; Zhang, Xiaoying; Zeman, David; Fahmy, Hesham; Dwivedi, Chandradhar

    2012-06-01

    Honokiol has shown chemopreventive effects in chemically-induced and UVB-induced skin cancer in mice. In this investigation, we assessed the time-effects of a topical low dose of honokiol (30 μg), and then the effects of different honokiol doses (30, 45, and 60 μg) on a UVB-induced skin cancer model to find an optimal dose and time for desirable chemopreventive effects. UVB radiation (30 mJ/cm(2), 5 days/week for 25 or 27 weeks) was used to induce skin carcinogenesis in SKH-1 mice. For the time-response experiment 30 μg honokiol in acetone was applied topically to the animals before the UVB exposure (30 min, 1 h, and 2 h) and after the UVB exposure (immediately, 30 min, and 1 h). Control groups were treated with acetone. For the dose-response study, animals were treated topically with acetone or honokiol (30, 45, and 60 μg) one hour before the UVB exposure. In the time-response experiment, honokiol inhibited skin tumor multiplicity by 49-58% while reducing tumor volumes by 70-89%. In the dose-response study, honokiol (30, 45, and 60 μg) significantly decreased skin tumor multiplicity by 36-78% in a dose-dependent manner, while tumor area was reduced by 76-94%. Honokiol (60 μg) significantly reduced tumor incidence by 40% as compared to control group. Honokiol applied in very low doses (30 μg) either before or after UVB radiation shows chemopreventive effects. Honokiol (30, 45, and 60 μg) prevents UVB-induced skin cancer in a dose-dependent manner. Honokiol can be an effective chemopreventive agent against skin cancer.

  12. Patient Radiation Doses from Diagnostic Radiology.

    ERIC Educational Resources Information Center

    Hart, D.

    1996-01-01

    Explains how x-ray doses to patients are measured. Describes how different techniques expose patients to differing amounts of ionizing radiation. Compares these figures with other natural and man-made sources. (Author/MKR)

  13. Patient-specific dose calculation methods for high-dose-rate iridium-192 brachytherapy

    NASA Astrophysics Data System (ADS)

    Poon, Emily S.

    In high-dose-rate 192Ir brachytherapy, the radiation dose received by the patient is calculated according to the AAPM Task Group 43 (TG-43) formalism. This table-based dose superposition method uses dosimetry parameters derived with the radioactive 192Ir source centered in a water phantom. It neglects the dose perturbations caused by inhomogeneities, such as the patient anatomy, applicators, shielding, and radiographic contrast solution. In this work, we evaluated the dosimetric characteristics of a shielded rectal applicator with an endocavitary balloon injected with contrast solution. The dose distributions around this applicator were calculated by the GEANT4 Monte Carlo (MC) code and measured by ionization chamber and GAFCHROMIC EBT film. A patient-specific dose calculation study was then carried out for 40 rectal treatment plans. The PTRAN_CT MC code was used to calculate the dose based on computed tomography (CT) images. This study involved the development of BrachyGUI, an integrated treatment planning tool that can process DICOM-RT data and create PTRAN_CT input initialization files. BrachyGUI also comes with dose calculation and evaluation capabilities. We proposed a novel scatter correction method to account for the reduction in backscatter radiation near tissue-air interfaces. The first step requires calculating the doses contributed by primary and scattered photons separately, assuming a full scatter environment. The scatter dose in the patient is subsequently adjusted using a factor derived by MC calculations, which depends on the distances between the point of interest, the 192Ir source, and the body contour. The method was validated for multicatheter breast brachytherapy, in which the target and skin doses for 18 patient plans agreed with PTRAN_CT calculations better than 1%. Finally, we developed a CT-based analytical dose calculation method. It corrects for the photon attenuation and scatter based upon the radiological paths determined by ray tracing

  14. SU-E-T-632: Preliminary Study On Treating Nose Skin Using Energy and Intensity Modulated Electron Beams with Monte Carlo Based Dose Calculations

    SciTech Connect

    Jin, L; Eldib, A; Li, J; Price, R; Ma, C

    2015-06-15

    Purpose: Uneven nose surfaces and air cavities underneath and the use of bolus present complexity and dose uncertainty when using a single electron energy beam to plan treatments of nose skin with a pencil beam-based planning system. This work demonstrates more accurate dose calculation and more optimal planning using energy and intensity modulated electron radiotherapy (MERT) delivered with a pMLC. Methods: An in-house developed Monte Carlo (MC)-based dose calculation/optimization planning system was employed for treatment planning. Phase space data (6, 9, 12 and 15 MeV) were used as an input source for MC dose calculations for the linac. To reduce the scatter-caused penumbra, a short SSD (61 cm) was used. Our previous work demonstrates good agreement in percentage depth dose and off-axis dose between calculations and film measurement for various field sizes. A MERT plan was generated for treating the nose skin using a patient geometry and a dose volume histogram (DVH) was obtained. The work also shows the comparison of 2D dose distributions between a clinically used conventional single electron energy plan and the MERT plan. Results: The MERT plan resulted in improved target dose coverage as compared to the conventional plan, which demonstrated a target dose deficit at the field edge. The conventional plan showed higher dose normal tissue irradiation underneath the nose skin while the MERT plan resulted in improved conformity and thus reduces normal tissue dose. Conclusion: This preliminary work illustrates that MC-based MERT planning is a promising technique in treating nose skin, not only providing more accurate dose calculation, but also offering an improved target dose coverage and conformity. In addition, this technique may eliminate the necessity of bolus, which often produces dose delivery uncertainty due to the air gaps that may exist between the bolus and skin.

  15. Comparison of six phantoms for entrance skin dose evaluation in 11 standard X-ray examinations.

    PubMed

    Compagnone, Gaetano; Pagan, Laura; Bergamini, Carlo

    2005-01-01

    Entrance skin dose (ESD) is an important parameter for assessing the dose received by a patient in a single radiographic exposure. The most useful way to evaluate ESD is either by direct measurement on phantoms using an ionization chamber or using calculations based on a mathematical model. We compared six phantoms (three anthropomorphic, two physical, and one mathematical) in 11 standard clinical examinations (anterior-posterior (AP) abdomen, posterior-anterior (PA) chest, AP chest, lateral (LAT) chest, AP lumbar spine, LAT lumbar spine, LAT lumbo-sacral joint, AP pelvis, PA skull, LAT skull, and AP urinary tract) for two reasons: to determine the conversion factors to use for ESDs measured on different phantoms and to validate the mathematical model used. First, a comparison was done between the three anthropomorphic phantoms (Alderson Rando, chest RSD-77SPL, and 3M skull) and the two physical phantoms (Uniform and AAPM 31); for each examination we obtained "relative entrance skin dose factors." Second, we compared these five phantoms with the mathematical phantom: the overall accuracy of the model was better than 14%. Total mathematical model and total ionization chamber uncertainties, calculated by quadratic propagation of errors of the single components, were estimated to be on the order of +/-12% and +/-3%, respectively. To reduce the most significant source of uncertainty, the overall accuracy of the model was recalculated using new backscatter factors. The overall accuracy of the model improved: better than 12%. For each examination an anthropomorphic phantom was considered as the gold standard relative to the physical phantoms. In this way, it was possible to analyze the variations in phantom design and characteristics. Finally, the mathematical model was validated by more than 400 measurements taken on different phantoms and using a variety of radiological equipment. We conclude that the mathematical model can be used satisfactorily in ESD evaluations

  16. Measuring the skin dose protection afforded by protective apparel with a beta spectrometer

    SciTech Connect

    Martz, D.E.; Rich, B.L.; Johnson, L.O. )

    1986-10-01

    This paper reports that the protective apparel worn by radiation workers to avoid skin contamination also provides measurable protection against external beta sources. The beta contribution to the skin dose rate depends on the residual energy spectrum of the beta particles after they have penetrated the protective apparel. The shift in the beta energy spectra and consequent reduction in the shallow dose rates afforded by various items of protective apparel were investigated for a few laboratory beta sources using a beta spectrometer that is capable of dose calculations. The results presented here indicate that significant dose rates to the skin can occur despite the presence of protective apparel if high energy beta emitting isotopes are present.

  17. Skin diseases in geriatric patients: our experience from a public skin outpatient clinic in Siena.

    PubMed

    Rubegni, P; Poggiali, S; Nami, N; Rubegni, M; Fimiani, M

    2012-12-01

    With the progressive aging of the Italian population, geriatric health care has become a major issue for health authorities. However, little data is available regarding geriatric skin diseases. In order to provide rapid access to specialist help, in 2003 we created a dermatology clinic dedicated only to geriatric patients age 65 and older. To determine the characteristic pattern and the prevalence of various skin disorders among the geriatric patients seen at the clinic, we performed a retrospective and descriptive study of all skin diseases in patients seen in our office from January 2003 to December 2009. We evaluated: age, proportion and gender for all skin disease categories. A total of 2100 geriatric patients were examined. The male to female ratio was 1.4 to 1. The most common disorder was pruritus "sine materia" (18.9%) followed by benign tumors (13.5%); 9.1% of our patients presented with actinic keratoses and 13.2% with malignant tumors. As reported by others, the quality of life in patients with skin cancer was better than patients with rashes as skin cancer patients tended to wait longer before seeking specialist care. To improve the assessment of skin diseases, we often worked closely with The prevalence of skin diseases in our patients emphasized the importance of educating the elderly about sun protection, the early detection of skin cancer, the use of emollients and proper skin care in general.

  18. Rapidly progressive stage IVB mycosis fungoides treated with low-dose total skin electron beam therapy.

    PubMed

    Chowdhary, Mudit; Kabbani, Ahmad A; Rimtepathip, Parin; Cole, David A; Cohen, David J

    2015-01-01

    Mycosis fungoides (MF) is the most common subtype of primary cutaneous T-cell lymphoma. Normally, MF has an indolent course although patients can progress to an advanced disease state (stages IIB-IVB). Advanced-stage disease is typically aggressive, leaving patients with debilitating symptoms and a decreased quality of life. Moreover, advanced-stage MF often proves refractory to therapy and carries a very poor prognosis. Total skin electron beam (TSEB) therapy is a well-established and successful treatment for early stage MF; however, its efficacy dramatically decreases with advanced-stage disease. In fact, TSEB in advanced-stage MF is generally considered to be palliative. Current consensus guidelines recommend a dose of 30-36 Gy to be delivered in 8-10 weeks; however, limited studies exist to determine the ideal treatment in Stage IV MF. Herein, we describe a case of a 50-year-old male who developed rapidly progressive stage IVB (T3N3M1B0) MF and was treated with low-dose (24 Gy) TSEB over 8 weeks. The patient was not treated with any systemic therapy before starting TSEB due to the widespread nature and the speed of disease progression. Remarkably, our patient showed nearly complete (95%) response of his MF with no apparent side effects from radiation. Furthermore, he has remained in remission over 4 years, requiring only a small boost to a few "shadowed" areas. Our case illustrates the benefit of using TSEB in stage IV MF. Additionally, our experience shows that low-dose TSEB can occasionally be efficacious in stage IV disease.

  19. Hypofractionated high-dose-rate plesiotherapy in nonmelanoma skin cancer treatment.

    PubMed

    Arenas, Meritxell; Arguís, Monica; Díez-Presa, Lorena; Henríquez, Ivan; Murcia-Mejía, Mauricio; Gascón, Marina; Gómez, David; Lafuerza, Anna; Mur, Encarna; Azón, Antoni; Rovirosa, Àngels; Sabater, Sebastià

    2015-01-01

    Nonmelanoma skin cancer (NMSC) is the commonest cancer in humans. NMSC treatment currently includes surgery, radiation therapy, and topical approaches. The objective was to analyze and compare the outcomes, toxicity, and cosmesis of NMSC treated by two hypofractionated high-dose-rate (HDR) plesiotherapy techniques. A retrospective institutional clinical study of 134 basal cell or squamous cell skin carcinomas treated at Radiation Oncology Department. Lesions were treated from November 2006 to December 2011 with a moderate hypofractionated HDR plesiotherapy using a fixed applicator or a customized mold. After a median follow-up of 33 months, overall disease-free survival at 3 and 5 years was 95.12% and 93.36%, respectively. For Leipzig applicator, disease-free survival at 3 years was 94.9% and 94.9% at 5 years, for customized mold was 93.1% at 3 years and 88% at 5 years. Complete regression was achieved in 98% of lesions. Two lesions persisted after treatment; both had been treated by a Leipzig applicator. Six lesions suffered local recurrence (five Leipzig applicators and three molds, p = 0.404). Grade <2 acute toxicity noted in 57.3% of patients. Only 2.2% of lesions had Grade 4 acute toxicity. Borderline significant increase of toxicity was associated with customized molds (p = 0.067). Larger tumors were associated with higher acute skin toxicity. The cosmesis outcomes were excellent or good in 82% of patients, fair in 13%, and not available in 5%. Hypofractionated HDR plesiotherapy is an effective and well-tolerated treatment for NMSC with different toxicity levels depending on the plesiotherapy technique used. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  20. Measurement of maximum skin dose in interventional radiology and cardiology and challenges in the set-up of European alert thresholds.

    PubMed

    Farah, J; Trianni, A; Carinou, E; Ciraj-Bjelac, O; Clairand, I; Dabin, J; De Angelis, C; Domienik, J; Jarvinen, H; Kopec, R; Majer, M; Malchair, F; Negri, A; Novák, L; Siiskonen, T; Vanhavere, F; Knežević, Ž

    2015-04-01

    To help operators acknowledge patient dose during interventional procedures, EURADOS WG-12 focused on measuring patient skin dose using XR-RV3 gafchromic films, thermoluminescent detector (TLD) pellets or 2D TL foils and on investigating possible correlation to the on-line dose indicators such as fluoroscopy time, Kerma-area product (KAP) and cumulative air Kerma at reference point (CK). The study aims at defining non-centre-specific European alert thresholds for skin dose in three interventional procedures: chemoembolization of the liver (CE), neuroembolization (NE) and percutaneous coronary interventions (PCI). Skin dose values of >3 Gy (ICRP threshold for skin injuries) were indeed measured in these procedures confirming the need for dose indicators that correlate with maximum skin dose (MSD). However, although MSD showed fairly good correlation with KAP and CK, several limitations were identified challenging the set-up of non-centre-specific European alert thresholds. This paper presents preliminary results of this wide European measurement campaign and focuses on the main challenges in the definition of European alert thresholds.

  1. Single-Dose Oritavancin Treatment of Acute Bacterial Skin and Skin Structure Infections: SOLO Trial Efficacy by Eron Severity and Management Setting.

    PubMed

    Deck, Daniel H; Jordan, Jennifer M; Holland, Thomas L; Fan, Weihong; Wikler, Matthew A; Sulham, Katherine A; Ralph Corey, G

    2016-09-01

    Introduction of new antibiotics enabling single-dose administration, such as oritavancin may significantly impact site of care decisions for patients with acute bacterial skin and skin structure infections (ABSSSI). This analysis compared the efficacy of single-dose oritavancin with multiple-dose vancomycin in patients categorized according to disease severity via modified Eron classification and management setting. SOLO I and II were phase 3 studies evaluating single-dose oritavancin versus 7-10 days of vancomycin for treatment of ABSSSI. Patient characteristics were collected at baseline and retrospectively analyzed. Study protocols were amended, allowing outpatient management at the discretion of investigators. In this post hoc analysis, patients were categorized according to a modified Eron severity classification and management setting (outpatient vs. inpatient) and the efficacy compared. Overall, 1910 patients in the SOLO trials were categorized into Class I (520, 26.5%), II (790, 40.3%), and III (600, 30.6%). Of the 767 patients (40%) in the SOLO trials who were managed entirely in the outpatient setting 40.3% were categorized as Class II and 30.6% were Class III. Clinical efficacy was similar between oritavancin and vancomycin treatment groups, regardless of severity classification and across inpatient and outpatient settings. Class III patients had lower response rates (oritavancin 73.3%, vancomycin 76.6%) at early clinical evaluation when compared to patients in Class I (82.6%) or II (86.1%); however, clinical cure rates at the post-therapy evaluation were similar for Class III patients (oritavancin 79.8%, vancomycin 79.9%) when compared to Class I and II patients (79.1-85.7%). Single-dose oritavancin therapy results in efficacy comparable to multiple-dose vancomycin in patients categorized according to modified Eron disease severity classification regardless of whether management occurred in the inpatient or outpatient setting. The Medicines Company

  2. Introduction of novel 3D-printed superficial applicators for high-dose-rate skin brachytherapy.

    PubMed

    Jones, Emma-Louise; Tonino Baldion, Anna; Thomas, Christopher; Burrows, Tom; Byrne, Nick; Newton, Victoria; Aldridge, Sarah

    Custom-made surface mold applicators often allow more flexibility when carrying out skin brachytherapy, particularly for small treatment areas with high surface obliquity. They can, however, be difficult to manufacture, particularly if there is a lack of experience in superficial high-dose-rate brachytherapy techniques or with limited resources. We present a novel method of manufacturing superficial brachytherapy applicators utilizing three-dimensional (3D)-printing techniques. We describe the treatment planning process and the process of applicator manufacture. The treatment planning process, with the introduction of a pre-plan, allows for an "ideal" catheter arrangement within an applicator to be determined, exploiting varying catheter orientations, heights, and curvatures if required. The pre-plan arrangement is then 3D printed to the exact specifications of the pre-plan applicator design. This results in improved target volume coverage and improved sparing of organs at risk. Using a pre-plan technique for ideal catheter placement followed by automated 3D-printed applicator manufacture has greatly improved the entire process of superficial high-dose-rate brachytherapy treatment. We are able to design and manufacture flexible, well-fitting, superior quality applicators resulting in a more efficient and improved patient pathway and patient experience. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  3. Managing the hair and skin of African American pediatric patients.

    PubMed

    Smith, W; Burns, C

    1999-01-01

    In Africa, the ancestral home of most African Americans, hair is viewed as the epitome of beauty. However, when Africans were brought to America as slaves, they were unable to care for their hair and skin adequately and were exposed to the predominant white culture, which valued straight hair and light skin. As a result, many African Americans lost self-esteem because of the characteristics of their hair and skin. In this article we examine the anatomic and physiologic features of African American hair and skin and typical African American hair and skin care practices. Common African American hair and skin disorders and their management are discussed. The goal of this article is to help primary care providers understand the special hair and skin care required for African American children (as well as other dark-skinned patients). With good patient education, understanding one's own hair and skin characteristics can also support positive self-esteem.

  4. Incorporating Corrections for the Head-Holder and Compensation Filter when Calculating Skin Dose during Fluoroscopically-Guided Interventions

    PubMed Central

    Vijayan, Sarath; Rana, Vijay K.; Rudin, Stephen; Bednarek, Daniel R.

    2015-01-01

    The skin dose tracking system (DTS) that we developed provides a color-coded illustration of the cumulative skin dose distribution on a 3D graphic of the patient during fluoroscopic procedures for immediate feedback to the interventionist. To improve the accuracy of dose calculation, we now have incorporated two additional important corrections (1) for the holder used to immobilize the head in neuro-interventions and (2) for the built-in compensation filters used for beam equalization. Both devices have been modeled in the DTS software so that beam intensity corrections can be made. The head-holder is modeled as two concentric hemi-cylindrical surfaces such that the path length between those surfaces can be determined for rays to individual points on the skin surface. The head-holder on the imaging system we used was measured to attenuate the primary x-rays by 10 to 20% for normal incidence, and up to 40% at non-normal incidence. In addition, three compensation filters of different shape are built into the collimator apparatus and were measured to have attenuation factors ranging from 58% to 99%, depending on kVp and beam filtration. These filters can translate and rotate in the beam and their motion is tracked by the DTS using the digital signal from the imaging system. When it is determined that a ray to a given point on the skin passes through the compensation filter, the appropriate attenuation correction is applied. These corrections have been successfully incorporated in the DTS software to provide a more accurate determination of skin dose. PMID:26819488

  5. Incorporating corrections for the head-holder and compensation filter when calculating skin dose during fluoroscopically guided interventions

    NASA Astrophysics Data System (ADS)

    Vijayan, Sarath; Rana, Vijay K.; Rudin, Stephen; Bednarek, Daniel R.

    2015-03-01

    The skin dose tracking system (DTS) that we developed provides a color-coded illustration of the cumulative skin dose distribution on a 3D graphic of the patient during fluoroscopic procedures for immediate feedback to the interventionist. To improve the accuracy of dose calculation, we now have incorporated two additional important corrections (1) for the holder used to immobilize the head in neuro-interventions and (2) for the built-in compensation filters used for beam equalization. Both devices have been modeled in the DTS software so that beam intensity corrections can be made. The head-holder is modeled as two concentric hemi-cylindrical surfaces such that the path length between those surfaces can be determined for rays to individual points on the skin surface. The head-holder on the imaging system we used was measured to attenuate the primary x-rays by 10 to 20% for normal incidence, and up to 40% at non-normal incidence. In addition, three compensation filters of different shape are built into the collimator apparatus and were measured to have attenuation factors ranging from 58% to 99%, depending on kVp and beam filtration. These filters can translate and rotate in the beam and their motion is tracked by the DTS using the digital signal from the imaging system. When it is determined that a ray to a given point on the skin passes through the compensation filter, the appropriate attenuation correction is applied. These corrections have been successfully incorporated in the DTS software to provide a more accurate determination of skin dose.

  6. Dental orthopantomography: survey of patient dose

    SciTech Connect

    Bartolotta, A.; Calenda, E.; Calicchia, A.; Indovina, P.L.

    1983-03-01

    Absorbed dose to specific regions of the head and neck during dental orthopantomography with various commercial units was assessed using a Rando ''standard man'' phantom and TLD-100 LiF dosimeters. Relevance to patient protection is discussed.

  7. Measurement of skin dose variations produced by a silicon-based protective dressing in radiotherapy.

    PubMed

    Butson, Martin J; Cheung, Tsang; Yu, Peter K N; Metcalfe, Peter

    2002-06-07

    Variations in skin dose caused by a silicon-based burn dressing used in radiotherapy during treatment have been investigated. Measurement of these variations in skin dose has been achieved using thermoluminescent dosimeters (TLDs) and Gafchromic film. For a 6 MV x-ray beam results have shown that an approximately 0.4 mm thick silicon mesh dressing increases the average surface dose by approximately 12.5% to 14% of the maximum and average dose at 1 mm depth and by 4% to 6% of the maximum for field sizes ranging from 5 cm x 5 cm up to 40 cm x 40 cm at 100 cm source to surface distance (SSD). The radiation effective thickness of the silicon dressing was calculated to be 0.5 mm +/- 0.05 mm water equivalent. TLDs of various thicknesses provide point-dose assessment and Gafchromic film can provide a detailed two-dimensional dose map with a high spatial resolution. Results have shown that a large variation in skin dose is delivered under the dressing depending on the amount of material directly above it as defined by the silicon mesh outline.

  8. WE-E-18A-03: How Accurately Can the Peak Skin Dose in Fluoroscopy Be Determined Using Indirect Dose Metrics?

    SciTech Connect

    Jones, A; Pasciak, A

    2014-06-15

    Purpose: Skin dosimetry is important for fluoroscopically-guided interventions, as peak skin doses (PSD) that Result in skin reactions can be reached during these procedures. The purpose of this study was to assess the accuracy of different indirect dose estimates and to determine if PSD can be calculated within ±50% for embolization procedures. Methods: PSD were measured directly using radiochromic film for 41 consecutive embolization procedures. Indirect dose metrics from procedures were collected, including reference air kerma (RAK). Four different estimates of PSD were calculated and compared along with RAK to the measured PSD. The indirect estimates included a standard method, use of detailed information from the RDSR, and two simplified calculation methods. Indirect dosimetry was compared with direct measurements, including an analysis of uncertainty associated with film dosimetry. Factors affecting the accuracy of the indirect estimates were examined. Results: PSD calculated with the standard calculation method were within ±50% for all 41 procedures. This was also true for a simplified method using a single source-to-patient distance (SPD) for all calculations. RAK was within ±50% for all but one procedure. Cases for which RAK or calculated PSD exhibited large differences from the measured PSD were analyzed, and two causative factors were identified: ‘extreme’ SPD and large contributions to RAK from rotational angiography or runs acquired at large gantry angles. When calculated uncertainty limits [−12.8%, 10%] were applied to directly measured PSD, most indirect PSD estimates remained within ±50% of the measured PSD. Conclusions: Using indirect dose metrics, PSD can be determined within ±50% for embolization procedures, and usually to within ±35%. RAK can be used without modification to set notification limits and substantial radiation dose levels. These results can be extended to similar procedures, including vascular and interventional oncology

  9. Beta skin dose determination using TLDs, Monte-Carlo calculations, and extrapolation chamber.

    PubMed

    Ben-Shachar, B; Levine, S H; Hoffman, J M

    1989-12-01

    The beta doses produced by 90Sr-Y and 204 Tl beta sources were determined using three methods: Monte-Carlo calculations, measurements with TLDs, and measurements with an extrapolation chamber. Excellent agreement was obtained by all three methods, except a TLD nonlinear response to beta s was observed, which gives doses approximately 20% high for the 90Sr-Y source and 5% low for the 204Tl source. Also, analyses performed with low-energy beta s using these methods can determine errors in shield thickness covering TLD elements. Direct measurement of skin dose is not possible by the TLDs because the minimum shield thickness for the elements is 13 mg cm-2. A thinner shield for the elements must be used or the data must be extrapolated. Presently, thinner shields for TLD elements are not available, and the thick shields can lead to significant errors in skin dose when exposed to low-energy beta s.

  10. Lack of correlation between minimal erythema dose and skin phototype in a Colombian scholar population.

    PubMed

    Sanclemente, Gloria; Zapata, José-F; García, José-J; Gaviria, Angela; Gómez, Luis-F; Barrera, Marcela

    2008-11-01

    Sun exposure and skin phototype are the most relevant risk factors for skin cancer. Colombia has high levels of ultraviolet radiation during the whole year, therefore, both, high UVI's and outdoor worker's daily activities, in our country are very important risk factors for the development of cutaneous cancer. To date no study has evaluated the usefulness of Fitzpatrick's skin phototype classification in Colombians and its correlation with the minimal erythema dose (MED) and constitutional skin color. Such information is gaining importance in other nations due to the fact that several country's population is becoming more ethnically diverse. To determine the skin phototype, accumulated sun exposure, sun protection behavior, MED and phenotype in a Colombian school population. Last year high school students from the western Antioquia were invited to participate by phone and letter through their respective school directors. A self-questionnaire was handled to each student. A representative sample of the universe was selected for a medical examination by a dermatologist in order to validate the results of the self-questionnaire. The constitutional skin color was determined with the chromameter CR 300 Minolta. The MED was defined as the minimal dose of UVB being able to induce erythema 24 h later. Eight schools of the area agreed to participate in the study, and a total of 911 students (58% girls and 42% boys) filled-out the self-questionnaire. Sun exposure in the majority of individuals was in a level between moderate and very high. Ninety percent of students do not use any sun protection device or cream. Only a 50% of concordance between self-assessed skin phototype vs. medical skin phototype was found, and the highest concordance corresponded to skin phototype II (82%). There was a marked difference in skin photosensitivity of Colombians compared with reports in Caucasians. We observed a marked overlapping in MED's and L* values in phototypes II and III. The

  11. Wound care for patients with darkly pigmented skin.

    PubMed

    Bethell, Elaine

    This article examines the main skin or wound assessment parameters used for patients with darkly pigmented skin. Differences in skin pigmentation are discussed along with the challenges health professionals encounter in clinical practice and why linking theory to practice is vital.

  12. Suitability of resin-coated photographic paper for skin dose measurement during fluoroscopically-guided X-ray procedures.

    PubMed

    Guibelalde, E; González, L; Vañó, E

    2004-10-01

    The need for mapping skin doses during fluoroscopically-guided X-ray procedures has been described by a number of institutions and experts. Different large photographic or X-ray films placed on the patient's skin have been found to be useful for recording doses up to 1.0-2.0 Gy - depending on the film - and up to 15 Gy using radiochromic films. Though the upper limit of the film sensitivity is seldom exceeded during interventional procedures, the main disadvantage of the X-ray films is still the excessive sensitivity for long, high dose procedures. Radiochromic films show poor definition for doses below 0.5 Gy and are expensive. The goal of the present paper is to analyse the possibilities of using common resin-coated photographic paper for this purpose. Sensitometric curves obtained with different paper types processed in conventional X-ray film automatic processors demonstrate that some of them can be used with better results than X-ray films at a very low cost. Doses from about 10 mGy to near 3.0 Gy can be measured with good accuracy using a variety of glossy photographic papers.

  13. Measurement of skin dose from cone-beam computed tomography imaging

    PubMed Central

    2013-01-01

    Objective To measure surface skin dose from various cone-beam computed tomography (CBCT) scanners using point-dosimeters. Materials & methods A head anthropomorphic phantom was used with nanoDOT optically stimulated luminescence (OSL) dosimeters (Landauer Corp., Glenwood, IL) attached to various anatomic landmarks. The phantom was scanned using multiple exposure protocols for craniofacial evaluations in three different CBCT units and a conventional x-ray imaging system. The dosimeters were calibrated for each of the scan protocols on the different imaging systems. Peak skin dose and surface doses at the eye lens, thyroid, submandibular and parotid gland levels were measured. Results The measured skin doses ranged from 0.09 to 4.62 mGy depending on dosimeter positions and imaging systems. The average surface doses to the lens locations were ~4.0 mGy, well below the threshold for cataractogenesis (500 mGy). The results changed accordingly with x-ray tube output (mAs and kV) and also were sensitive to scan field of view (SFOV). As compared to the conventional panoramic and cephalometric imaging system, doses from all three CBCT systems were at least an order of magnitude higher. Conclusions Peak skin dose and surface doses at the eye lens, thyroid, and salivary gland levels measured from the CBCT imaging systems were lower than the thresholds to induce deterministic effects. However, our findings do not justify the routine use of CBCT imaging in orthodontics considering the lifetime-attributable risk to the individual. PMID:24192155

  14. Patient Dose Management: Focus on Practical Actions

    PubMed Central

    2016-01-01

    Medical radiation is a very important part of modern medicine, and should be only used when needed and optimized. Justification and optimization of radiation examinations must be performed. The first step of reduction of medical exposure is to know the radiation dose in currently performed examinations. This review covers radiation units, how various imaging modalities report dose, and the current status of radiation dose reports and legislation. Also, practical tips that can be applied to clinical practice are introduced. Afterwards, the importance of radiology exposure related education is emphasized and the current status of education for medical personal and the public is explained, and appropriate education strategies are suggested. Commonly asked radiation dose related example questions and answers are provided in detail to allow medical personnel to answer patients. Lastly, we talk about computerized programs that can be used in medical facilities for managing patient dose. While patient dose monitoring and management should be used to decrease and optimize overall radiation dose, it should not be used to assess individual cancer risk. One must always remember that medically justified examinations should always be performed, and unneeded examinations should be avoided in the first place. PMID:26908988

  15. Patients' experience of surplus skin after laparoscopic gastric bypass.

    PubMed

    Biörserud, Christina; Olbers, Torsten; Fagevik Olsén, Monika

    2011-03-01

    Previous studies have described that many obese patients who undergo bariatric surgery develop surplus skin. However, there is a lack of knowledge about where on the body the problems are located and to what extent surplus skin affects the person. The aim of this study was to examine whether and where patients develop surplus skin after laparoscopic gastric bypass and if there is any relation between surplus skin and the patient's sex, age, weight loss, or activity level. A questionnaire was constructed which included questions about surplus skin. The questionnaire was sent to 148 patients who had been operated with laparoscopic gastric bypass. One hundred and twelve (76%) responded of whom 77 were women and 35 men. At follow-up, 94 persons (84%) reported problems with surplus skin. The surplus skin was situated most commonly on the abdomen, the upper arms, and the inside of the thighs, but also on the back, the cheek and over the knees. Significantly, more women than men reported complications with surplus skin (p = 0.018), distributed over more body parts, specifically on the upper arms, medial thigh, and lateral back (p < 0.05). The surplus skin caused problems with fungal infections and itching, physical unpleasantness and complicated physical activity. There was no correlation between degree of problems with surplus skin and age, weight loss, or activity rate. Weight loss after gastric bypass reduces the medical risks of obesity but the psychosocial problems remain in many patients due to problems with surplus skin.

  16. The radiation dose from a proposed measurement of arsenic and selenium in human skin

    NASA Astrophysics Data System (ADS)

    Gherase, Mihai R.; Mader, Joanna E.; Fleming, David E. B.

    2010-09-01

    Dose measurements following 10 min irradiations with a portable x-ray fluorescence spectrometer composed of a miniature x-ray tube and a silicon PiN diode detector were performed using thermoluminescent dosimeters consisting of LiF:Mg,Ti chips of 3 mm diameter and 0.4 mm thickness. The table-top setup of the spectrometer was used for all measurements. The setup included a stainless steel lid which served as a radiation shield. Two rectangular polyethylene skin/soft tissue phantoms with two cylindrical plaster of Paris bone phantoms were used to study the effect of x-ray beam attenuation and backscatter on the measured dose. Eight different irradiation experiments were performed. The average dose rate values measured with TLD chips within a 1 × 1 cm2 area were between 4.8 and 12.8 mGy min-1. The equivalent dose for a 1 × 1 cm2 skin area was estimated to be 13.2 mSv. The maximum measured dose rate values with a single TLD chip were between 7.5 and 25.1 mGy min-1. The effective dose corresponding to a proposed arsenic/selenium skin measurement was estimated to be 0.13 µSv for a 2 min irradiation.

  17. An ultrasonographic evaluation of skin thickness in breast cancer patients after postmastectomy radiation therapy.

    PubMed

    Wong, Sharon; Kaur, Amarjit; Back, Michael; Lee, Khai Mun; Baggarley, Shaun; Lu, Jiade Jay

    2011-01-24

    To determine the usefulness of ultrasonography in the assessment of post radiotherapy skin changes in postmastectomy breast cancer patients. Patients treated for postmastectomy radiotherapy in National University Hospital (NUH) and Tan Tock Seng Hospital (TTSH), Singapore between January 2004- December 2005 was recruited retrospectively. Ultrasound scan was performed on these Asian patients who had been treated to a total dose of 46-50 Gy with 1 cm bolus placed on the skin. The ultrasound scans were performed blinded to the RTOG scores, and the skin thickness of the individually marked points on the irradiated chest wall was compared to the corresponding points on the non-irradiated breast. The mean total skin thickness inclusive of the epidermis and the dermis of the right irradiated chest wall was 0.1712 mm (± 0.03392 mm) compared with the contra-lateral non-irradiated breast which was 0.1845 mm (± 0.04089 mm; p = 0.007). The left irradiated chest wall had a mean skin thickness of 0.1764 mm (± 0.03184 mm) compared with the right non-irradiated breast which was 0.1835 mm (± 0.02584 mm; p = 0.025). These independent t-tests produced a significant difference of reduced skin thickness on the right irradiated chest wall, p = 0.007 (p < 0.05) and left irradiated chest wall p = 0.025 (p < 0.025) in comparison to the non-irradiated skin thickness investigating chronic skin reactions. Patients with grade 2 acute skin toxicity presented with thinner skin as compared to patients with grade 1 (p = 0.006). This study has shown that there is a statistically significant difference between the skin thicknesses of the irradiated chest wall and the contra-lateral non-irradiated breast and a predisposition to chronic reactions was found in patients with acute RTOG scoring of grade1 and grade 2.

  18. Sunscreens, Skin Cancer, and Your Patient.

    ERIC Educational Resources Information Center

    Davidson, Terence M.; Wolfe, Dana P.

    1986-01-01

    The effects of sunlight on skin are described. The principal types of sunscreens and their properties are discussed. The three types of skin tumors, their cure rates, and treatment methods are examined. (Author/MT)

  19. Sunscreens, Skin Cancer, and Your Patient.

    ERIC Educational Resources Information Center

    Davidson, Terence M.; Wolfe, Dana P.

    1986-01-01

    The effects of sunlight on skin are described. The principal types of sunscreens and their properties are discussed. The three types of skin tumors, their cure rates, and treatment methods are examined. (Author/MT)

  20. Arsenic in drinking water and skin lesions: dose-response data from West Bengal, India.

    PubMed

    Haque, Reina; Mazumder, D N Guha; Samanta, Sambit; Ghosh, Nilima; Kalman, David; Smith, Meera M; Mitra, Soma; Santra, Amal; Lahiri, Sarbari; Das, Subhankar; De, Binay K; Smith, Allan H

    2003-03-01

    Over 6 million people live in areas of West Bengal, India, where groundwater sources are contaminated with naturally occurring arsenic. The key objective of this nested case-control study was to characterize the dose-response relation between low arsenic concentrations in drinking water and arsenic-induced skin keratoses and hyperpigmentation. We selected cases (persons with arsenic-induced skin lesions) and age- and sex-matched controls from participants in a 1995-1996 cross-sectional survey in West Bengal. We used a detailed assessment of arsenic exposure that covered at least 20 years. Participants were reexamined between 1998 and 2000. Consensus agreement by four physicians reviewing the skin lesion photographs confirmed the diagnosis in 87% of cases clinically diagnosed in the field. The average peak arsenic concentration in drinking water was 325 microg/liter for cases and 180 microg/liter for controls. The average latency for skin lesions was 23 years from first exposure. We found strong dose-response gradients with both peak and average arsenic water concentrations. The lowest peak arsenic ingested by a confirmed case was 115 microg/liter. Confirmation of case diagnosis and intensive longitudinal exposure assessment provide the basis for a detailed dose-response evaluation of arsenic-caused skin lesions.

  1. Indicators of the maximum radiation dose to the skin during percutaneous coronary intervention in different target vessels.

    PubMed

    Chida, Koichi; Saito, Haruo; Kagaya, Yutaka; Kohzuki, Masahiro; Takai, Yoshihiro; Takahashi, Shoki; Yamada, Shogo; Zuguchi, Masayuki

    2006-08-01

    To evaluate whether the maximum radiation dose to the patient's skin (MSD) can be estimated during percutaneous coronary intervention (PCI) procedures, we investigated the relationship between the MSD and fluoroscopic time, dose-area product (DAP), and body weight, separately analyzing the relationships for different target vessels. Many cases of skin injury caused by excessive radiation exposure during cardiac intervention procedures have been reported. However, real-time maximum-dose monitoring of the skin is unavailable for many cardiac intervention procedures. We studied 197 consecutive PCI procedures that involved a single target vessel and were conducted. The DAP was measured, and the MSD was calculated by a skin-dose mapping software program (Caregraph). The target vessels of the PCI procedures were divided into four groups based on the AHA classification system: AHA 5-10, left anterior descending artery domain (LAD), AHA 11-15, left circumflex artery domain (LCx), AHA 1-3 = R 1-3, and AHA 4 = R 4. The correlation coefficient (r) between the MSD and fluoroscopic time was higher for the right coronary artery (RCA) vessels (R 1-3, 0.852; R 4, 0.715) than for the left coronary artery (LCA) vessels (LAD, 0.527; LCx, 0.646), and the r value between the MSD and DAP was higher for the RCA vessels (R 1-3, 0.871; R 4, 0.898) than for the LCA vessels (LAD, 0.628; LCx, 0.694). Similarly, the correlation coefficient between the MSD and weight x fluoroscopic time (WFP) was higher for the RCA vessels (R 1-3, 0.874; R 4, 0.807) than for the LCA vessels (LAD, 0.551; LCx, 0.735). The DAP and WFP can be used to estimate the MSD during PCI in the RCA but not in the LCA, especially the LAD.

  2. Dose response of retinol and isotretinoin in the prevention of nonmelanoma skin cancer recurrence.

    PubMed

    Clouser, Mary C; Roe, Denise J; Foote, Janet A; Harris, Robin B; Alberts, David S

    2010-01-01

    Using data from a randomized, double blind, study of the efficacy of retinol or isotretinoin vs. placebo on recurrence of nonmelanoma skin cancer in high-risk subjects, a reanalysis of the original intent to treat analysis was performed in a dose-response format. Cox proportional hazards models describe the relationship between dose quartiles of isotretinoin and retinol use and time to first occurrence of squamous cell carcinoma (SCC) or basal cell carcinoma (BCC) in crude and adjusted models. Neither the isotretinoin nor retinol models showed any significance at any quartile for reduction in first BCC or SCC occurrence. Crude and adjusted retinol models show a statistically significant increase in risk of developing an SCC in the first quartile, whereas only the crude model shows a statistically significant increase in risk in the first quartile of the isotretinoin model. For retinol and SCC, hazard ratios (HRs) for the first quartile were as follows: HR = 2.92, 95% confidence interval (CI) = 1.67-5.10 crude; HR = 1.95, 95% CI = 1.00-3.80 adjusted. For isotretinoin and SCC, HRs for the first quartile were as follows: HR = 2.38, 95% CI = 1.35-4.19 crude; HR = 1.69, 95% CI = 0.87-3.31 adjusted. Test for trend was not significant in any of the models. These analyses confirm the results of the original intent to treat analyses and raise an interesting question related to the potential for increased risk for patients in the first quartile of retinol dose.

  3. Clinical characteristics and awareness of skin cancer in Hispanic patients.

    PubMed

    Javed, Saba; Javed, Syed A; Mays, Rana M; Tyring, Stephen K

    2013-09-14

    Skin cancer in darker skin is associated with considerable morbidity and mortality. We sought to assess the clinical characteristics of cutaneous malignancy amongst Hispanic skin cancer patients and compare them to age-matched non-Hispanic Caucasians. In this retrospective study, 150 Hispanic skin cancer patients were identified from electronic medical records and age-matched to 150 non-Hispanic Caucasian controls with skin cancer. The incidence of actinic keratoses (AKs) in Hispanic skin cancer patients (34.0%) was statistically lower than age-matched non-Hispanic Caucasian skin cancer controls (61.3%, P <0.001; odds ratio, 3.08; 95% confidence interval, 1.92 - 4.93). Moreover, non-Hispanic Caucasian SCC (squamous cell cancer) controls were much more likely to report AKs (36.1%, P = 0.003) than Hispanic SCC patients (25.0%, P = 0.19). This study illustrates a lower incidence of AKs in Hispanic skin cancer patients as compared to their age-matched non-Hispanic Caucasians. The Hispanic skin malignancies present at a more advanced state and there is usually a lack of awareness in such cases. Therefore, patient knowledge and education is crucial for early detection and prevention of skin cancer in the Hispanic population.

  4. Increased Skin Dose With the Use of a Custom Mattress for Prone Breast Radiotherapy

    SciTech Connect

    Becker, Stewart J. Patel, Rakesh R.; Mackie, Thomas R.

    2007-10-01

    The purpose of this study was to measure and compare the loss of buildup to the skin of the breast in the prone position due to 2 different positioning systems during tangential external beam irradiation. Two experiments were performed; one with a standard nylon-covered foam support and another with a novel helium-filled Mylar bag support. The choice of helium-filled Mylar was to reduce the contamination to as low as possible. The experiments were designed to allow a surface dose measurement and a depth dose profile with the pads placed in the path of the beam in front of the detector. All measurements were taken using a Capintec PS-033 thin-window parallel plate ionization chamber. The standard nylon-covered foam pad caused the surface dose to rise as it got closer to the skin. When the pad was directly touching the surface, the surface dose increased by 300% compared to the result when no pad was present. This loss of buildup to the surface was similar to that of a custom bolus material. The opposite effect occurred with the use of the helium-filled Mylar bag, namely the surface dose gradually decreased as the pad got closer to the phantom. When the Mylar pad was directly touching the phantom, the surface dose was decreased by 7% compared to when no pad was present. The use of a foam pad could potentially result in a significant higher dose to the skin, resulting in an enhanced acute skin reaction. Therefore, special care should be taken in this clinical scenario and further investigation of an air- or helium-based mylar support pad should be investigated in the context of definitive breast radiation treatment.

  5. Structural changes of skin and amnion grafts for transplantation purposes following different doses of irradiation.

    PubMed

    Mrázová, H; Koller, J; Fujeríková, G; Babál, P

    2014-09-01

    An important part of the preparation of biological material for transplantation is sterilization. The aim of our study was to assess the impact of ionizing radiation on three types of biological tissues and the impact of different doses on cells and extracellular matrix. Three types of frozen tissues (porcine skin xenografts, human skin allografts and human amnion) were divided into five groups, control and groups according to the dose of radiation to which these samples were exposed (12.5, 25, 35 and 50 kGy). The tissue samples were fixed by formalin, processed by routine paraffin technique and stained with hematoxylin and eosin, alcian blue at pH 2.5, orcein, periodic acid schiff reaction and silver impregnation. The staining with hematoxylin and eosin showed hydropic degeneration of the cells of epidermis in xenografts by the dose of 12.5 kGy, in human skin it was observed by the dose of 35 kGy. The staining for elastic fibers revealed damage of fine elastic fibers in the xenografts dermis by the dose of 12.5 kGy, in the allografts by 35 kGy. Another change was the disintegration of basement membrane of epithelium, especially in the human amnion at the dose of 50 kGy. The silver impregnation visualized nuclear chromatin condensation mainly in human amnion at the dose of 12.5 kGy. Our results have shown that the porcine xenografts and human amnion were more sensitive to irradiation than the human skin. In the next phase of the project we will focus at more detailed changes in the tissues using immunohistochemical techniques.

  6. SU-E-CAMPUS-I-04: Automatic Skin-Dose Mapping for An Angiographic System with a Region-Of-Interest, High-Resolution Detector

    SciTech Connect

    Vijayan, S; Rana, V; Setlur Nagesh, S; Ionita, C; Rudin, S; Bednarek, D

    2014-06-15

    Purpose: Our real-time skin dose tracking system (DTS) has been upgraded to monitor dose for the micro-angiographic fluoroscope (MAF), a high-resolution, small field-of-view x-ray detector. Methods: The MAF has been mounted on a changer on a clinical C-Arm gantry so it can be used interchangeably with the standard flat-panel detector (FPD) during neuro-interventional procedures when high resolution is needed in a region-of-interest. To monitor patient skin dose when using the MAF, our DTS has been modified to automatically account for the change in scatter for the very small MAF FOV and to provide separated dose distributions for each detector. The DTS is able to provide a color-coded mapping of the cumulative skin dose on a 3D graphic model of the patient. To determine the correct entrance skin exposure to be applied by the DTS, a correction factor was determined by measuring the exposure at the entrance surface of a skull phantom with an ionization chamber as a function of entrance beam size for various beam filters and kVps. Entrance exposure measurements included primary radiation, patient backscatter and table forward scatter. To allow separation of the dose from each detector, a parameter log is kept that allows a replay of the procedure exposure events and recalculation of the dose components.The graphic display can then be constructed showing the dose distribution from the MAF and FPD separately or together. Results: The DTS is able to provide separate displays of dose for the MAF and FPD with field-size specific scatter corrections. These measured corrections change from about 49% down to 10% when changing from the FPD to the MAF. Conclusion: The upgraded DTS allows identification of the patient skin dose delivered when using each detector in order to achieve improved dose management as well as to facilitate peak skin-dose reduction through dose spreading. Research supported in part by Toshiba Medical Systems Corporation and NIH Grants R43FD0158401, R44FD

  7. The minimal melanogenesis dose/minimal erythema dose ratio declines with increasing skin pigmentation using solar simulator and narrowband ultraviolet B exposure.

    PubMed

    Ravnbak, Mette H; Philipsen, Peter A; Wulf, Hans Christian

    2010-06-01

    To investigate the relation between pre-exposure skin pigmentation and the minimal melanogenesis dose (MMD)/minimal erythema dose (MED) ratio after a single narrowband ultraviolet B (nUVB) and solar simulator (Solar) exposure. In fair-skinned individuals, it is well known that the UV dose to give pigmentation (MMD) after a single exposure to UVB is larger than the UV dose to elicit erythema (MED) (MEDskinned individuals. Eighty-four volunteers with a wide variation in skin pigmentation (Fitzpatrick skin types I-V) were included. After a single Solar or nUVB exposure we found that the ratio MMD/MED depends on skin pigmentation. In light-pigmented individuals, up to 1.9 MED is required to induce pigmentation (MMD). The MMD/MED ratio is about 1.5 in medium-pigmented and dark-pigmented individuals. In very brown-pigmented individuals the MMD/MED ratio is 1 (MED=MMD). This connection was most pronounced for facultative skin at wintertime. The ratio was almost stable for constitutive pigmentation with MMD/MED=1.3. The ratios were almost independent of skin type. The ratio MMD/MED is highly dependent on skin pigmentation after a single exposure to Solar or nUVB and is independent of skin type.

  8. High and Low Doses of Ionizing Radiation Induce Different Secretome Profiles in a Human Skin Model

    SciTech Connect

    Zhang, Qibin; Matzke, Melissa M.; Schepmoes, Athena A.; Moore, Ronald J.; Webb-Robertson, Bobbie-Jo M.; Hu, Zeping; Monroe, Matthew E.; Qian, Weijun; Smith, Richard D.; Morgan, William F.

    2014-03-18

    It is postulated that secreted soluble factors are important contributors of bystander effect and adaptive responses observed in low dose ionizing radiation. Using multidimensional liquid chromatography-mass spectrometry based proteomics, we quantified the changes of skin tissue secretome – the proteins secreted from a full thickness, reconstituted 3-dimensional skin tissue model 48 hr after exposure to 3, 10 and 200 cGy of X-rays. Overall, 135 proteins showed statistical significant difference between the sham (0 cGy) and any of the irradiated groups (3, 10 or 200 cGy) on the basis of Dunnett adjusted t-test; among these, 97 proteins showed a trend of downregulation and 9 proteins showed a trend of upregulation with increasing radiation dose. In addition, there were 21 and 8 proteins observed to have irregular trends with the 10 cGy irradiated group either having the highest or the lowest level among all three radiated doses. Moreover, two proteins, carboxypeptidase E and ubiquitin carboxyl-terminal hydrolase isozyme L1 were sensitive to ionizing radiation, but relatively independent of radiation dose. Conversely, proteasome activator complex subunit 2 protein appeared to be sensitive to the dose of radiation, as rapid upregulation of this protein was observed when radiation doses were increased from 3, to 10 or 200 cGy. These results suggest that different mechanisms of action exist at the secretome level for low and high doses of ionizing radiation.

  9. Psoriasis and staphylococcus aureus skin colonization in Moroccan patients

    PubMed Central

    Elfatoiki, Fatima Zahra; El Azhari, Mohamed; El Kettani, Assiya; Serhier, Zineb; Othmani, Mohamed Bennani; Timinouni, Mohamed; Benchikhi, Hakima; Chiheb, Soumiya; Fellah, Hassan

    2016-01-01

    Psoriatic lesions are rarely complicated by recurrent infections. The aim of our study is to determine skin colonisation and nasal carriage of Staphylococcus aureus in patients with psoriasis and in healthy persons. Patients and methods: a comparative study that include 33 patients with psoriasis and 33 healthy persons. Samples were taken from lesional and non lesional psoriatic skin and from healthy skin of control group. For S. aureus nasal carriage, we used sterile cotton tipped swabs. Out of165 samples (66 skin samples and 33 nasal swabs), 26 S. Aureus strains were isolated in 26 persons, 57.69% in the control group and 42.3% in the psoriasisgroup. S. aureus skin colonization was found in one case (3%) inlesional psoriatic skin vs 9 cases (27.3%) in control skin OR=0.08 IC 95% (0.01-0.70) p=0.02 and in 12,1% in non lesional soriatic skin vs 27, 3% in control skin (p =0,13). This colonization was less important in lesional psoriatic skin (3%) than in non lesional psoriatic skin (12.1%) p= 0.20. Nasal screening identified (7/33) 21, 21% S. aureus carriers in psoriasis group and in control group. Our results are in consensus withliterature findings. They have confirmed the importance of antimicrobial peptides in Innateimmunity of human skin. These peptides are normally produced bykeratinocytes in response to inflammatory stimuli such as psoriasis. Their high expression in psoriasis skin reduces the risk of skin infection and skin colonization with S. Aureus. PMID:27200138

  10. Estimates of absorbed dose in different organs in children treated with radium for skin hemangiomas

    SciTech Connect

    Lundell, M.

    1994-12-01

    Between 1930 and 1959, more than 10,000 infants were treated at Radiumhemmet, Stockholm, with radium ({sup 226}Ra) needles and/or tubes for hemangioma of the skin. Absorbed dose to the brain, eye lenses, parotid glands, thyroid gland, breast enlarge, lungs, stomach, intestine, ovaries, testicles and bone marrow were calculated for each individual. The mean absorbed dose to the different organs ranged from 0.06 to 0.48 Gy. The highest absorbed dose was given to the breast (maximum 47.7 Gy). There was a wide dose range for each organ which was due mainly to differences in the distance between the applicator and the organ. The absorbed dose to all organs decreased on average by 32% during the study period. This was due to a 25% decrease in the treatment time and a change in the distribution of the treatment sites. 17 refs., 4 figs., 4 tabs.

  11. Efficacy of a single high dose versus multiple low doses of LLLT on wounded skin fibroblasts

    NASA Astrophysics Data System (ADS)

    Hawkins, Denise H.; Abrahamse, Heidi

    2007-07-01

    Background/purpose: In vivo studies have demonstrated that phototherapy accelerates wound healing in the clinical environment; however the exact mechanism is still not completely understood. The main focus of this study was to use in vitro laboratory results to establish an effective treatment regimen that may be practical and applicable to the clinical environment. This in vitro study aimed to compare the cellular responses of wounded fibroblasts following a single exposure of 5 J/cm2 or multiple exposures of low doses (2.5 J/cm2 or 5 J/cm2) on one day of the week to a single application of a higher dose (16 J/cm2) on day 1 and day 4. Methodology: Cellular responses to Helium-Neon (632.8 nm) laser irradiation were evaluated by measuring changes in cell morphology, cell viability, cell proliferation, membrane integrity and DNA damage. Results: Wounded cells exposed to 5 J/cm2 on day 1 and day 4 showed an increase in cell viability, increase in the release of bFGF, increase in cell density, decrease in ALP enzyme activity and decrease in caspase 3/7 activity indicating a stimulatory effect. Wounded cells exposed to three doses of 5 J/cm2 on day 1 showed a decrease in cell viability and cell proliferation and an increase in LDH cytotoxicity and DNA damage indicating an inhibitory effect. Conclusion: Results indicate that cellular responses are influenced by the combination of dose administered, number of exposures and time between exposures. Single doses administered with sufficient time between exposures is more beneficial to restoring cell function than multiple doses within a short period. Although this work confirms previous reports on the cumulative effect of laser irradiation it provides essential information for the initiation of in vivo clinical studies.

  12. Estimating peak skin and eye lens dose from neuroperfusion examinations: use of Monte Carlo based simulations and comparisons to CTDIvol, AAPM Report No. 111, and ImPACT dosimetry tool values.

    PubMed

    Zhang, Di; Cagnon, Chris H; Villablanca, J Pablo; McCollough, Cynthia H; Cody, Dianna D; Zankl, Maria; Demarco, John J; McNitt-Gray, Michael F

    2013-09-01

    CT neuroperfusion examinations are capable of delivering high radiation dose to the skin or lens of the eyes of a patient and can possibly cause deterministic radiation injury. The purpose of this study is to: (a) estimate peak skin dose and eye lens dose from CT neuroperfusion examinations based on several voxelized adult patient models of different head size and (b) investigate how well those doses can be approximated by some commonly used CT dose metrics or tools, such as CTDIvol, American Association of Physicists in Medicine (AAPM) Report No. 111 style peak dose measurements, and the ImPACT organ dose calculator spreadsheet. Monte Carlo simulation methods were used to estimate peak skin and eye lens dose on voxelized patient models, including GSF's Irene, Frank, Donna, and Golem, on four scanners from the major manufacturers at the widest collimation under all available tube potentials. Doses were reported on a per 100 mAs basis. CTDIvol measurements for a 16 cm CTDI phantom, AAPM Report No. 111 style peak dose measurements, and ImPACT calculations were performed for available scanners at all tube potentials. These were then compared with results from Monte Carlo simulations. The dose variations across the different voxelized patient models were small. Dependent on the tube potential and scanner and patient model, CTDIvol values overestimated peak skin dose by 26%-65%, and overestimated eye lens dose by 33%-106%, when compared to Monte Carlo simulations. AAPM Report No. 111 style measurements were much closer to peak skin estimates ranging from a 14% underestimate to a 33% overestimate, and with eye lens dose estimates ranging from a 9% underestimate to a 66% overestimate. The ImPACT spreadsheet overestimated eye lens dose by 2%-82% relative to voxelized model simulations. CTDIvol consistently overestimates dose to eye lens and skin. The ImPACT tool also overestimated dose to eye lenses. As such they are still useful as a conservative predictor of dose for CT

  13. Estimating peak skin and eye lens dose from neuroperfusion examinations: Use of Monte Carlo based simulations and comparisons to CTDIvol, AAPM Report No. 111, and ImPACT dosimetry tool values

    PubMed Central

    Zhang, Di; Cagnon, Chris H.; Villablanca, J. Pablo; McCollough, Cynthia H.; Cody, Dianna D.; Zankl, Maria; Demarco, John J.; McNitt-Gray, Michael F.

    2013-01-01

    Purpose: CT neuroperfusion examinations are capable of delivering high radiation dose to the skin or lens of the eyes of a patient and can possibly cause deterministic radiation injury. The purpose of this study is to: (a) estimate peak skin dose and eye lens dose from CT neuroperfusion examinations based on several voxelized adult patient models of different head size and (b) investigate how well those doses can be approximated by some commonly used CT dose metrics or tools, such as CTDIvol, American Association of Physicists in Medicine (AAPM) Report No. 111 style peak dose measurements, and the ImPACT organ dose calculator spreadsheet. Methods: Monte Carlo simulation methods were used to estimate peak skin and eye lens dose on voxelized patient models, including GSF's Irene, Frank, Donna, and Golem, on four scanners from the major manufacturers at the widest collimation under all available tube potentials. Doses were reported on a per 100 mAs basis. CTDIvol measurements for a 16 cm CTDI phantom, AAPM Report No. 111 style peak dose measurements, and ImPACT calculations were performed for available scanners at all tube potentials. These were then compared with results from Monte Carlo simulations. Results: The dose variations across the different voxelized patient models were small. Dependent on the tube potential and scanner and patient model, CTDIvol values overestimated peak skin dose by 26%–65%, and overestimated eye lens dose by 33%–106%, when compared to Monte Carlo simulations. AAPM Report No. 111 style measurements were much closer to peak skin estimates ranging from a 14% underestimate to a 33% overestimate, and with eye lens dose estimates ranging from a 9% underestimate to a 66% overestimate. The ImPACT spreadsheet overestimated eye lens dose by 2%–82% relative to voxelized model simulations. Conclusions: CTDIvol consistently overestimates dose to eye lens and skin. The ImPACT tool also overestimated dose to eye lenses. As such they are still

  14. Skin disorders in peritoneal dialysis patients: An underdiagnosed subject

    PubMed Central

    Gursu, Meltem; Uzun, Sami; Topcuoğlu, Derya; Koc, Leyli Kadriye; Yucel, Lamiye; Sumnu, Abdullah; Cebeci, Egemen; Ozkan, Oktay; Behlul, Ahmet; Koc, Leyla; Ozturk, Savas; Kazancioglu, Rumeyza

    2016-01-01

    AIM: To examine all skin changes in peritoneal dialysis (PD) patients followed up in our unit. METHODS: Patients on PD program for at least three months without any known chronic skin disease were included in the study. Patients with already diagnosed skin disease, those who have systemic diseases that may cause skin lesions, patients with malignancies and those who did not give informed consent were excluded from the study. All patients were examined by the same predetermined dermatologist with all findings recorded. The demographic, clinical and laboratory data including measures of dialysis adequacy of patients were recorded also. Statistical Package for Social Sciences (SPSS) for Windows 16.0 standard version was used for statistical analysis. RESULTS: Among the patients followed up in our PD unit, those without exclusion criteria who gave informed consent, 38 patients were included in the study with male/female ratio and mean age of 26/12 and 50.3 ± 13.7 years, respectively. The duration of CKD was 7.86 ± 4.16 years and the mean PD duration was 47.1 ± 29.6 mo. Primary kidney disease was diabetic nephropathy in 11, nephrosclerosis in six, uropathologies in four, chronic glomerulonephritis in three, chronic pyelonephritis in three, autosomal dominant polycystic kidney disease in three patients while cause was unknown in eight patients. All patients except for one patient had at least one skin lesion. Loss of lunula, onychomycosis and tinea pedis are the most frequent skin disorders recorded in the study group. Diabetic patients had tinea pedis more frequently (P = 0.045). No relationship of skin findings was detected with primary renal diseases, comorbidities and medications that the patients were using. CONCLUSION: Skin abnormalities are common in in PD patients. The most frequent skin pathologies are onychomycosis and tinea pedis which must not be overlooked. PMID:27458566

  15. Doses metrics and patient age in CT.

    PubMed

    Huda, Walter; Tipnis, Sameer V

    2016-03-01

    The aim of this study was to investigate how effective dose and size-specific dose estimate (SSDE) change with patient age (size) for routine head and abdominal/pelvic CT examinations. Heads and abdomens of patients were modelled as a mass-equivalent cylinder of water corresponding to the patient 'effective diameter'. Head CT scans were performed at CTDIvol(S) of 40 mGy, and abdominal CT scans were performed at CTDIvol(L) of 10 mGy. Values of SSDE were obtained using conversion factors in AAPM Task Group Report 204. Age-specific scan lengths for head and abdominal CT scans obtained from the authors' clinical practice were used to estimate the dose-length product for each CT examination. Effective doses were calculated from previously published age- and sex-specific E/DLP conversion factors, based on ICRP 103 organ-weighting factors. For head CT examinations, the scan length increased from 15 cm in a newborn to 20 cm in adults, and for an abdominal/pelvic CT, the scan length increased from 20 cm in a newborn to 45 cm in adults. For head CT scans, SSDE ranged from 37.2 mGy in adults to 48.8 mGy in a newborn, an increase of 31 %. The corresponding head CT effective doses range from 1.4 mSv in adults to 5.2 mSv in a newborn, an increase of 270 %. For abdomen CT scans, SSDE ranged from 13.7 mGy in adults to 23.0 mGy in a newborn, an increase of 68 %. The corresponding abdominal CT effective doses ranged from 6.3 mSv in adults to 15.4 mSv in a newborn, an increase of 140 %. SSDE increases much less than effective dose in paediatric patients compared with adults because it does not account for scan length or scattered radiation. Size- and age-specific effective doses better quantify the total radiation received by patients in CT by explicitly accounting for all organ doses, as well as their relative radio sensitivity.

  16. Patient experiences living with split thickness skin grafts.

    PubMed

    Burnett, L N; Carr, E; Tapp, D; Raffin Bouchal, S; Horch, J D; Biernaskie, J; Gabriel, V

    2014-09-01

    The standard of care for deep burns is autologous split thickness skin grafting. Although adequate to resurface a deep wound, the resulting skin is chronically abnormal. The purpose of this study was to describe the experience of patients with split thickness skin grafts to help guide future investigations related to skin regeneration. In this study, an interpretive description qualitative methodology was employed. Subjects participated in a two-part single patient interview that was recorded and transcribed. A nurse with experience in clinical burn care coded and interpreted the data. Participants were recruited through presentation to a university based outpatient burn clinic for follow up from autologous split thickness skin grafting. Eight male patients and four female patients 20-62 years old ranging 2-29 months post-skin grafting were enrolled in the study. The most significant concerns voiced by patients were identified and organized into five themes: (1) a new normal, (2) split thickness skin graft symptoms, (3) appearance of new skin, (4) coping, and (5) participation in future clinical trials. Participants reported that the abnormalities related to their split thickness skin grafts were significant enough that they would be willing to participate in a future clinical trial investigating new cell-based therapies.

  17. The antimicrobial skin barrier in patients with atopic dermatitis.

    PubMed

    Schittek, Birgit

    2011-01-01

    Keratinocytes represent the major cell population in the epithelial skin barrier and actively participate in innate immune responses by recognizing pathogenic microorganisms, followed by a fine-tuned production of cytokines, chemokines and antimicrobial peptides or proteins (AMPs). Patients with atopic dermatitis (AD) suffer from a defective permeability barrier which favors pathogen infection indicating that the permeability and antimicrobial barrier functions are interdependent. Several early studies showed that the inducible AMPs LL-37, HBD-2 and HBD-3 are expressed at lower levels in atopic skin compared to psoriatic skin. However, recent data indicate that AMP induction is not compromised in AD patients and that several AMPs are expressed at significantly higher amounts in AD compared to healthy skin. AD patients have an increased susceptibility to Staphylococcus aureus skin infection suggesting that AMP levels expressed by keratinocytes of AD patients might not be sufficient to combat pathogenic skin infection or that AMP function is disturbed. Increasing AMP expression in AD skin and repairing the skin barrier defect might have a therapeutic effect in AD patients enabling the skin to mount an enhanced response to pathogens.

  18. Measurement of Entrance Skin Dose and Calculation of Effective Dose for Common Diagnostic X-Ray Examinations in Kashan, Iran.

    PubMed

    Aliasgharzadeh, Akbar; Mihandoost, Ehsan; Masoumbeigi, Mahboubeh; Salimian, Morteza; Mohseni, Mehran

    2015-02-24

    The knowledge of the radiation dose received by the patient during the radiological examination is essential to prevent risks of exposures. The aim of this work is to study patient doses for common diagnostic radiographic examinations in hospitals affiliated to Kashan University of Medical sciences, Iran. The results of this survey are compared with those published by some national and international values. Entrance surface dose (ESD) was measured based on the exposure parameters used for the actual examination and effective dose (ED) was calculated by use of conversion coefficients calculated by Monte Carlo methods. The mean entrance surface dose and effective dose for examinations of the chest (PA, Lat), abdomen (AP), pelvis (AP), lumbar spine (AP, Lat) and skull (AP, Lat) are 0.37, 0.99, 2.01, 1.76, 2.18, 5.36, 1.39 and 1.01 mGy, and 0.04, 0.1, 0.28, 0,28, 0.23, 0.13, 0.01 and 0.01 mSv, respectively. The ESDs and EDs reported in this study, except for examinations of the chest, are generally lower than comparable reference dose values published in the literature. On the basis of the results obtained in this study can conclude that use of newer equipment and use of the proper radiological parameter can significantly reduce the absorbed dose. It is recommended that radiological parameter in chest examinations be revised.

  19. Measurement of Entrance Skin Dose and Calculation of Effective Dose for Common Diagnostic X-Ray Examinations in Kashan, Iran

    PubMed Central

    Aliasgharzadeh, Akbar; Mihandoost, Ehsan; Masoumbeigi, Mahboubeh; Salimian, Morteza; Mohseni, Mehran

    2015-01-01

    The knowledge of the radiation dose received by the patient during the radiological examination is essential to prevent risks of exposures. The aim of this work is to study patient doses for common diagnostic radiographic examinations in hospitals affiliated to Kashan University of Medical sciences, Iran. The results of this survey are compared with those published by some national and international values. Entrance surface dose (ESD) was measured based on the exposure parameters used for the actual examination and effective dose (ED) was calculated by use of conversion coefficients calculated by Monte Carlo methods. The mean entrance surface dose and effective dose for examinations of the chest (PA, Lat), abdomen (AP), pelvis (AP), lumbar spine (AP, Lat) and skull (AP, Lat) are 0.37, 0.99, 2.01, 1.76, 2.18, 5.36, 1.39 and 1.01 mGy, and 0.04, 0.1, 0.28, 0,28, 0.23, 0.13, 0.01 and 0.01 mSv, respectively. The ESDs and EDs reported in this study, except for examinations of the chest, are generally lower than comparable reference dose values published in the literature. On the basis of the results obtained in this study can conclude that use of newer equipment and use of the proper radiological parameter can significantly reduce the absorbed dose. It is recommended that radiological parameter in chest examinations be revised. PMID:26156930

  20. SU-F-P-44: A Direct Estimate of Peak Skin Dose for Interventional Fluoroscopy Procedures

    SciTech Connect

    Weir, V; Zhang, J

    2016-06-15

    Purpose: There is an increasing demand for medical physicist to calculate peak skin dose (PSD) for interventional fluoroscopy procedures. The dose information (Dose-Area-Product and Air Kerma) displayed in the console cannot directly be used for this purpose. Our clinical experience shows that the use of the existing methods may overestimate or underestimate PSD. This study attempts to develop a direct estimate of PSD from the displayed dose metrics. Methods: An anthropomorphic torso phantom was used for dose measurements for a common fluoroscopic procedure. Entrance skin doses were measured with a Piranha solid state point detector placed on the table surface below the torso phantom. An initial “reference dose rate” (RE) measurement was conducted by comparing the displayed dose rate (mGy/min) to the dose rate measured. The distance from table top to focal spot was taken as the reference distance (RD at the RE. Table height was then adjusted. The displayed air kerma and DAP were recorded and sent to three physicists to estimate PSD. An inverse square correction was applied to correct displayed air kerma at various table heights. The PSD estimated by physicists and the PSD by the proposed method were then compared with the measurements. The estimated DAPs were compared to displayed DAP readings (mGycm2). Results: The difference between estimated PSD by the proposed method and direct measurements was less than 5%. For the same set of data, the estimated PSD by each of three physicists is different from measurements by ±52%. The DAP calculated by the proposed method and displayed DAP readings in the console is less than 20% at various table heights. Conclusion: PSD may be simply estimated from displayed air kerma or DAP if the distance between table top and tube focal spot or if x-ray beam area on table top is available.

  1. Skin dose saving of the staff in 90Y/177Lu peptide receptor radionuclide therapy with the automatic dose dispenser.

    PubMed

    Fioroni, Federica; Grassi, Elisa; Giorgia, Cavatorta; Sara, Rubagotti; Piccagli, Vando; Filice, Angelina; Mostacci, Domiziano; Versari, Annibale; Iori, Mauro

    2016-10-01

    When handling Y-labelled and Lu-labelled radiopharmaceuticals, skin exposure is mainly due to β-particles. This study aimed to investigate the equivalent dose saving of the staff when changing from an essentially manual radiolabelling procedure to an automatic dose dispenser (ADD). The chemist and physician were asked to wear thermoluminescence dosimeters on their fingertips to evaluate the quantity of Hp(0.07) on the skin. Data collected were divided into two groups: before introducing ADD (no ADD) and after introducing ADD. For the chemist, the mean values (95th percentile) of Hp(0.07) for no ADD and ADD are 0.030 (0.099) and 0.019 (0.076) mSv/GBq, respectively, for Y, and 0.022 (0.037) and 0.007 (0.023) mSv/GBq, respectively, for Lu. The reduction for ADD was significant (t-test with P<0.05) for both isotopes. The relative differences before and after ADD collected for every finger were treated using the Wilcoxon test, proving a significantly higher reduction in extremity dose to each fingertip for Lu than for Y (P<0.05). For the medical staff, the mean values of Hp(0.07) (95th percentile) for no ADD and ADD are 0.021 (0.0762) and 0.0143 (0.0565) mSv/GBq, respectively, for Y, and 0.0011 (0.00196) and 0.0009 (0.00263) mSv/GBq, respectively, for Lu. The t-test provided a P-value less than 0.05 for both isotopes, making the difference between ADD and no ADD significant. ADD positively affects the dose saving of the chemist in handling both isotopes. For the medical staff not directly involved with the introduction of the ADD system, the analysis shows a learning curve of the workers over a 5-year period. Specific devices and procedures allow staff skin dose to be limited.

  2. Skin effector memory T cells do not recirculate and provide immune protection in alemtuzumab-treated CTCL patients

    PubMed Central

    Clark, Rachael A.; Watanabe, Rei; Teague, Jessica E.; Schlapbach, Christoph; Tawa, Marianne C.; Adams, Natalie; Dorosario, Andrew A.; Chaney, Keri S.; Cutler, Corey S.; LeBoeuf, Nicole R.; Carter, Joi B.; Fisher, David C.; Kupper, Thomas S.

    2012-01-01

    CTCL is a cancer of skin homing T cells with variants that include leukemic CTCL (L-CTCL), a malignancy of central memory T cells (TCM), and mycosis fungoides (MF), a malignancy of skin resident effector memory T cells (TEM). We report that low-dose alemtuzumab (αCD52) effectively treated patients with refractory L-CTCL but not MF. Alemtuzumab depleted all T cells in blood and depleted both benign and malignant TCM from skin, but a diverse population of skin resident TEM remained in skin after therapy. T-cell depletion with alemtuzumab required the presence of neutrophils, a cell type frequent in blood but rare in normal skin. These data suggest that TCM were depleted because they recirculate between the blood and skin whereas skin resident TEM were spared because they are sessile and non-recirculating. After alemtuzumab treatment, skin T cells produced lower amounts of IL-4 and higher amounts of IFNγ. Moreover, there was a marked lack of infections in alemtuzumab-treated L-CTCL patients despite the complete absence of T cells in blood, suggesting that skin resident TEM can protect the skin from pathogens even in the absence of T cell recruitment from the circulation. Together, these data suggest that alemtuzumab may treat refractory L-CTCL without severely compromising the immune response to infection by depleting circulating TCM but sparing the skin resident TEM that provide local immune protection of the skin. PMID:22261031

  3. Potent response of QS-21 as a vaccine adjuvant in the skin when delivered with the Nanopatch, resulted in adjuvant dose sparing

    PubMed Central

    Ng, Hwee-Ing; Fernando, Germain J. P.; Depelsenaire, Alexandra C. I.; Kendall, Mark A. F.

    2016-01-01

    Adjuvants play a key role in boosting immunogenicity of vaccines, particularly for subunit protein vaccines. In this study we investigated the induction of antibody response against trivalent influenza subunit protein antigen and a saponin adjuvant, QS-21. Clinical trials of QS-21 have demonstrated the safety but, also a need of high dose for optimal immunity, which could possibly reduce patient acceptability. Here, we proposed the use of a skin delivery technology – the Nanopatch – to reduce both adjuvant and antigen dose but also retain its immune stimulating effects when compared to the conventional needle and syringe intramuscular (IM) delivery. We have demonstrated that Nanopatch delivery to skin requires only 1/100th of the IM antigen dose to induce equivalent humoral response. QS-21 enhanced humoral response in both skin and muscle route. Additionally, Nanopatch has demonstrated 30-fold adjuvant QS-21 dose sparing while retaining immune stimulating effects compared to IM. QS-21 induced localised, controlled cell death in the skin, suggesting that the danger signals released from dead cells contributed to the enhanced immunogenicity. Taken together, these findings demonstrated the suitability of reduced dose of QS-21 and the antigen using the Nanopatch to enhance humoral responses, and the potential to increase patient acceptability of QS-21 adjuvant. PMID:27404789

  4. Potent response of QS-21 as a vaccine adjuvant in the skin when delivered with the Nanopatch, resulted in adjuvant dose sparing.

    PubMed

    Ng, Hwee-Ing; Fernando, Germain J P; Depelsenaire, Alexandra C I; Kendall, Mark A F

    2016-07-11

    Adjuvants play a key role in boosting immunogenicity of vaccines, particularly for subunit protein vaccines. In this study we investigated the induction of antibody response against trivalent influenza subunit protein antigen and a saponin adjuvant, QS-21. Clinical trials of QS-21 have demonstrated the safety but, also a need of high dose for optimal immunity, which could possibly reduce patient acceptability. Here, we proposed the use of a skin delivery technology - the Nanopatch - to reduce both adjuvant and antigen dose but also retain its immune stimulating effects when compared to the conventional needle and syringe intramuscular (IM) delivery. We have demonstrated that Nanopatch delivery to skin requires only 1/100(th) of the IM antigen dose to induce equivalent humoral response. QS-21 enhanced humoral response in both skin and muscle route. Additionally, Nanopatch has demonstrated 30-fold adjuvant QS-21 dose sparing while retaining immune stimulating effects compared to IM. QS-21 induced localised, controlled cell death in the skin, suggesting that the danger signals released from dead cells contributed to the enhanced immunogenicity. Taken together, these findings demonstrated the suitability of reduced dose of QS-21 and the antigen using the Nanopatch to enhance humoral responses, and the potential to increase patient acceptability of QS-21 adjuvant.

  5. SU-E-T-185: Clinically-Relevant Investigation of Flattening Filter Free Skin Dose

    SciTech Connect

    Guy, C; Karki, K; Sharma, M; Kim, S

    2015-06-15

    Purpose: Flattening-filter-free (FFF) beams are increasingly used for small-field treatments due to inherent advantages like higher MU efficiency and reduced treatment time and scatter dose. Removal of the flattening-filter increases the electron contamination and low-energy x-rays. As such, surface-dose characteristics are different from traditional flattened (FF) beams. The goal of this work is to investigate surface dose of 6/10 MV FFF and FF beams under conditions representative of emerging complex techniques like small-field stereotactic treatments which use small fields formed with multi-leaf-collimators (MLCs) at closer SSDs. Methods: A parallel-plate PTW Markus-chamber (N23343) placed in custom air- and water-equivalent phantoms was used to measure surface-dose at 2/3/4/6/8/10/20/30 cm{sup 2} field sizes, at 80/90/100 cm source-to-surface distances, and at fields defined by jaws and MLCs. The effect of dose rate (600 and 1400/2400 MU/min) was also investigated at 100 cm SSD. Measurements were performed on TrueBeam linac (Varian Medical Systems, Palo Alto, CA) for 6X/6XFFF/10X/10XFFF beam energies. Results: No dose-rate dependence was seen for FFF skin-dose. Air-phantom measurements were, on average, 5±3% larger than for water-phantom measurements. With SSD increase from 80 to 100 cm, skin-dose decreased by an average of 3.9±2.5%. FFF beams were found to be more sensitive to SSD changes in comparison to FF beams. The difference in skin dose between MLC- and jaw-fields was less variable with field size for FFF compared to FF beams. 10 MV beams showed greater difference in FFF-to-FF ratio, 50% (jaws) and 22% (MLC), between the largest and smallest field sizes compared to 6 MV beams, 30% (jaws) and 9% (MLC). Conclusion: Under clinically-relevant conditions, surface dose for FFF beams was higher at small field size (<10 cm), lower at largest field size (30 cm), more sensitive to SSD changes, and had less variation with field size compared to dose for FF beams.

  6. Phenytoin dose adjustment in epileptic patients

    PubMed Central

    Mawer, G. E.; Mullen, P. W.; Rodgers, Margaret; Robins, A. J.; Lucas, S. B.

    1974-01-01

    1 A preliminary survey showed that many outpatients with partially controlled epilepsy had serum concentrations of phenytoin below the recommended therapeutic range (10-20 μg/ml). A phenytoin tolerance test was devised with the intention of predicting a more adequate daily dose for such a patient. 2 Fifteen patients were each given an oral test dose of 600 mg phenytoin sodium and the serum concentration of phenytoin was measured at intervals over 48 h; the concentration rose during the first 4 h and decayed between 12-48 h as an almost linear function of time. 3 The serum concentration/time curves were fitted by an interative computer program based on the Michaelis-Menten equation. The mean saturated rate of elimination of phenytoin was 435 mg/day and the serum concentration (Km) corresponding with 50% saturation was 3.8 μg/ml. The mean calculated dose of phenytoin sodium required for a steady state serum concentration of 10-20 μg/ml was 345-400 mg/day. 4 The Michaelis-Menten principle was used to predict steady state serum phenytoin concentrations in individual patients receiving daily doses of phenytoin sodium adjusted by steps of 100 mg. The serum concentrations tended to be either too low or too high. The steep relationship between phenytoin concentration and dose indicates that when the concentration reaches 5-10 μg/ml it is then appropriate to adjust dose by small steps of about 25 mg. PMID:22454904

  7. Phenytoin dose adjustment in epileptic patients.

    PubMed

    Mawer, G E; Mullen, P W; Rodgers, M; Robins, A J; Lucas, S B

    1974-04-01

    1 A preliminary survey showed that many outpatients with partially controlled epilepsy had serum concentrations of phenytoin below the recommended therapeutic range (10-20 μg/ml). A phenytoin tolerance test was devised with the intention of predicting a more adequate daily dose for such a patient. 2 Fifteen patients were each given an oral test dose of 600 mg phenytoin sodium and the serum concentration of phenytoin was measured at intervals over 48 h; the concentration rose during the first 4 h and decayed between 12-48 h as an almost linear function of time. 3 The serum concentration/time curves were fitted by an interative computer program based on the Michaelis-Menten equation. The mean saturated rate of elimination of phenytoin was 435 mg/day and the serum concentration (K(m)) corresponding with 50% saturation was 3.8 μg/ml. The mean calculated dose of phenytoin sodium required for a steady state serum concentration of 10-20 μg/ml was 345-400 mg/day. 4 The Michaelis-Menten principle was used to predict steady state serum phenytoin concentrations in individual patients receiving daily doses of phenytoin sodium adjusted by steps of 100 mg. The serum concentrations tended to be either too low or too high. The steep relationship between phenytoin concentration and dose indicates that when the concentration reaches 5-10 μg/ml it is then appropriate to adjust dose by small steps of about 25 mg.

  8. Determination of minimal erythema dose and anomalous reactions to UVA radiation by skin phototype.

    PubMed

    Pérez Ferriols, A; Aguilera, J; Aguilera, P; de Argila, D; Barnadas, M A; de Cabo, X; Carrrascosa, J M; de Gálvez Aranda, M V; Gardeazábal, J; Giménez-Arnau, A; Lecha, M; Lorente, J; Martínez-Lozano, J A; Rodríguez Granados, M T; Sola, Y; Utrillas, M P

    2014-10-01

    Phototesting is a technique that assesses the skin's sensitivity to UV radiation by determining the smallest dose of radiation capable of inducing erythema (minimal erythema dose [MED]) and anomalous responses to UV-A radiation. No phototesting protocol guidelines have been published to date. This was a multicenter prospective cohort study in which 232 healthy volunteers were recruited at 9 hospitals. Phototests were carried out with solar simulators or fluorescent broadband UV-B lamps. Each individual received a total of 5 or 6 incremental doses of erythemal radiation and 4 doses of UV-A radiation. The results were read at 24hours. At hospitals where solar simulators were used, the mean (SD) MED values were 23 (8), 28 (4), 35 (4), and 51 (6) mJ/cm(2) for skin phototypes i to iv, respectively. At hospitals where broadband UV-B lamps were used, these values were 28 (5), 32 (3), and 34 (5) mJ/cm(2) for phototypes ii to iv, respectively. MED values lower than 7, 19, 27, and 38 mJ/cm(2) obtained with solar simulators were considered to indicate a pathologic response for phototypes I to IV, respectively. MED values lower than 18, 24, and 24mJ/cm(2) obtained with broadband UV-B lamps were considered to indicate a pathologic response for phototypes ii to iv, respectively. No anomalous responses were observed at UV-A radiation doses of up to 20J/cm(2). Results were homogeneous across centers, making it possible to standardize diagnostic phototesting for the various skin phototypes and establish threshold doses that define anomalous responses to UV radiation. Copyright © 2014 Elsevier España, S.L.U. y AEDV. All rights reserved.

  9. Increased dose near the skin due to electromagnetic surface beacon transponder.

    PubMed

    Ahn, Kang-Hyun; Manger, Ryan; Halpern, Howard J; Aydogan, Bulent

    2015-05-08

    The purpose of this study was to evaluate the increased dose near the skin from an electromagnetic surface beacon transponder, which is used for localization and tracking organ motion. The bolus effect due to the copper coil surface beacon was evaluated with radiographic film measurements and Monte Carlo simulations. Various beam incidence angles were evaluated for both 6 MV and 18 MV experimentally. We performed simulations using a general-purpose Monte Carlo code MCNPX (Monte Carlo N-Particle) to supplement the experimental data. We modeled the surface beacon geometry using the actual mass of the glass vial and copper coil placed in its L-shaped polyethylene terephthalate tubing casing. Film dosimetry measured factors of 2.2 and 3.0 enhancement in the surface dose for normally incident 6 MV and 18 MV beams, respectively. Although surface dose further increased with incidence angle, the relative contribution from the bolus effect was reduced at the oblique incidence. The enhancement factors were 1.5 and 1.8 for 6 MV and 18 MV, respectively, at an incidence angle of 60°. Monte Carlo simulation confirmed the experimental results and indicated that the epidermal skin dose can reach approximately 50% of the dose at dmax at normal incidence. The overall effect could be acceptable considering the skin dose enhancement is confined to a small area (~ 1 cm2), and can be further reduced by using an opposite beam technique. Further clinical studies are justified in order to study the dosimetric benefit versus possible cosmetic effects of the surface beacon. One such clinical situation would be intact breast radiation therapy, especially large-breasted women.

  10. Patient doses from CT examinations in Turkey

    PubMed Central

    Ataç, Gökçe Kaan; Parmaksız, Aydın; İnal, Tolga; Bulur, Emine; Bulgurlu, Figen; Öncü, Tolga; Gündoğdu, Sadi

    2015-01-01

    PURPOSE We aimed to establish the first diagnostic reference levels (DRLs) for computed tomography (CT) examinations in adult and pediatric patients in Turkey and compare these with international DRLs. METHODS CT performance information and examination parameters (for head, chest, high-resolution CT of the chest [HRCT-chest], abdominal, and pelvic protocols) from 1607 hospitals were collected via a survey. Dose length products and effective doses for standard patient sizes were calculated from the reported volume CT dose index (CTDIvol). RESULTS The median number of protocols reported from the 167 responding hospitals (10% response rate) was 102 across five different age groups. Third quartile CTDIvol values for adult pelvic and all pediatric body protocols were higher than the European Commission standards but were comparable to studies conducted in other countries. CONCLUSION The radiation dose indicators for adult patients were similar to those reported in the literature, except for those associated with head protocols. CT protocol optimization is necessary for adult head and pediatric chest, HRCT-chest, abdominal, and pelvic protocols. The findings from this study are recommended for use as national DRLs in Turkey. PMID:26133189

  11. Measurement of radiotherapy x-ray skin dose on a chest wall phantom.

    PubMed

    Quach, K Y; Morales, J; Butson, M J; Rosenfeld, A B; Metcalfe, P E

    2000-07-01

    Sufficient skin dose needs to be delivered by a radiotherapy chest wall treatment regimen to ensure the probability of a near surface tumor recurrence is minimized. To simulate a chest wall treatment a hemicylindrical solid water phantom of 7.5 cm radius was irradiated with 6 MV x-rays using 20x20 cm2 and 10x20 cm2 fields at 100 cm source surface distance (SSD) to the base of the phantom. A surface dose profile was obtained from 0 to 180 degrees, in 10 degrees increments around the circumference of the phantom. Dosimetry results obtained from radiochromic film (effective depth of 0.17 mm) were used in the investigation, the superficial doses were found to be 28% (of Dmax) at the 0 degrees beam entry position and 58% at the 90 degrees oblique beam position. Superficial dose results were also obtained using extra thin thermoluminescent dosimeters (TLD) (effective depth 0.14 mm) of 30% at 0 degrees, 57% at 90 degrees, and a metal oxide semiconductor field effect transistor (MOSFET) detector (effective depth 0.5 mm) of 43% at 0 degrees, 62% at 90 degrees. Because the differences in measured superficial doses were significant and beyond those related to experimental error, these differences are assumed to be mostly attributable to the effective depth of measurement of each detector. We numerically simulated a bolus on/bolus off technique and found we could increase the coverage to the skin. Using an alternate "bolus on," "bolus off" regimen, the skin would receive 36.8 Gy at 0 degrees incidence and 46.4 Gy at 90 degrees incidence for a prescribed midpoint dose of 50 Gy. From this work it is evident that, as the circumference of the phantom is traversed the SSD increases and hence there is an inverse square fluence fall-off, this is more than offset by the increase in skin dose due to surface curvature to a plateau at about 90 degrees. Beyond this angle it is assumed that beam attenuation through the phantom and inverse square fall-off is causing the surface dose to

  12. Patient radiation dose audits for fluoroscopically guided interventional procedures

    SciTech Connect

    Balter, Stephen; Rosenstein, Marvin; Miller, Donald L.; Schueler, Beth; Spelic, David

    2011-03-15

    Purpose: Quality management for any use of medical x-ray imaging should include monitoring of radiation dose. Fluoroscopically guided interventional (FGI) procedures are inherently clinically variable and have the potential for inducing deterministic injuries in patients. The use of a conventional diagnostic reference level is not appropriate for FGI procedures. A similar but more detailed quality process for management of radiation dose in FGI procedures is described. Methods: A method that takes into account both the inherent variability of FGI procedures and the risk of deterministic injuries from these procedures is suggested. The substantial radiation dose level (SRDL) is an absolute action level (with regard to patient follow-up) below which skin injury is highly unlikely and above which skin injury is possible. The quality process for FGI procedures collects data from all instances of a given procedure from a number of facilities into an advisory data set (ADS). An individual facility collects a facility data set (FDS) comprised of all instances of the same procedure at that facility. The individual FDS is then compared to the multifacility ADS with regard to the overall shape of the dose distributions and the percent of instances in both the ADS and the FDS that exceed the SRDL. Results: Samples of an ADS and FDS for percutaneous coronary intervention, using the dose metric of reference air kerma (K{sub a,r}) (i.e., the cumulative air kerma at the reference point), are used to illustrate the proposed quality process for FGI procedures. Investigation is warranted whenever the FDS is noticeably different from the ADS for the specific FGI procedure and particularly in two circumstances: (1) When the facility's local median K{sub a,r} exceeds the 75th percentile of the ADS and (2) when the percent of instances where K{sub a,r} exceeds the facility-selected SRDL is greater for the FDS than for the ADS. Conclusions: Analysis of the two data sets (ADS and FDS) and

  13. Characterization of MOSkin detector for in vivo skin dose measurement during megavoltage radiotherapy.

    PubMed

    Jong, Wei Loong; Wong, Jeannie Hsiu Ding; Ung, Ngie Min; Ng, Kwan Hoong; Ho, Gwo Fuang; Cutajar, Dean L; Rosenfeld, Anatoly B

    2014-09-08

    In vivo dosimetry is important during radiotherapy to ensure the accuracy of the dose delivered to the treatment volume. A dosimeter should be characterized based on its application before it is used for in vivo dosimetry. In this study, we characterize a new MOSFET-based detector, the MOSkin detector, on surface for in vivo skin dosimetry. The advantages of the MOSkin detector are its water equivalent depth of measurement of 0.07 mm, small physical size with submicron dosimetric volume, and the ability to provide real-time readout. A MOSkin detector was calibrated and the reproducibility, linearity, and response over a large dose range to different threshold voltages were determined. Surface dose on solid water phantom was measured using MOSkin detector and compared with Markus ionization chamber and GAFCHROMIC EBT2 film measurements. Dependence in the response of the MOSkin detector on the surface of solid water phantom was also tested for different (i) source to surface distances (SSDs); (ii) field sizes; (iii) surface dose; (iv) radiation incident angles; and (v) wedges. The MOSkin detector showed excellent reproducibility and linearity for dose range of 50 cGy to 300 cGy. The MOSkin detector showed reliable response to different SSDs, field sizes, surface, radiation incident angles, and wedges. The MOSkin detector is suitable for in vivo skin dosimetry.

  14. Radiation Dose Estimation for Pediatric Patients Undergoing Cardiac Catheterization

    NASA Astrophysics Data System (ADS)

    Wang, Chu

    correction factors for the MOSFET organ dose measurements in the following studies. Minor angular dependence (< +/-20% at all angles tested, < +/-10% at clinically relevant angles in cardiac catheterization) was observed. Second, the cardiac dose for common fluoroscopic imaging techniques for pediatric patients in the two age groups was measured. Imaging technique settings with variations of individual key imaging parameters were tested to observe the quantitative effect of imaging optimization or lack thereof. Along with each measurement, the two standard system output indices, the Air Kerma (AK) and Dose-Area Product (DAP), were also recorded and compared to the measured cardiac and skin doses -- the lack of correlation between the indices and the organ doses shed light to the substantial limitation of the indices in representing patient radiation dose, at least within the scope of this dissertation. Third, the effective dose (ED) for Posterior-Anterior and Lateral fluoroscopic imaging techniques for pediatric patients in the two age groups was determined. In addition, the dosimetric effect of removing the anti-scatter grid was studied, for which a factor-of-two ED rate reduction was observed for the imaging techniques. The Clinical Component involved analytical research to develop a validated retrospective cardiac dose reconstruction formulation and to propose the new Optimization Index which evaluates the level of optimization of the clinician's imaging usage during a procedure; and small sample group of actual procedures were used to demonstrate applicability of these formulations. In its entirety, the research represents a first-of-its-kind comprehensive approach in radiation dosimetry for pediatric cardiac catheterization; and separately, it is also modular enough that each individual section can serve as study templates for small-scale dosimetric studies of similar purposes. The data collected and algorithmic formulations developed can be of use in areas of

  15. A spatially encoded dose difference maximal intensity projection map for patient dose evaluation: A new first line patient quality assurance tool

    SciTech Connect

    Hu Weigang; Graff, Pierre; Boettger, Thomas; Pouliot, Jean; and others

    2011-04-15

    Purpose: To develop a spatially encoded dose difference maximal intensity projection (DD-MIP) as an online patient dose evaluation tool for visualizing the dose differences between the planning dose and dose on the treatment day. Methods: Megavoltage cone-beam CT (MVCBCT) images acquired on the treatment day are used for generating the dose difference index. Each index is represented by different colors for underdose, acceptable, and overdose regions. A maximal intensity projection (MIP) algorithm is developed to compress all the information of an arbitrary 3D dose difference index into a 2D DD-MIP image. In such an algorithm, a distance transformation is generated based on the planning CT. Then, two new volumes representing the overdose and underdose regions of the dose difference index are encoded with the distance transformation map. The distance-encoded indices of each volume are normalized using the skin distance obtained on the planning CT. After that, two MIPs are generated based on the underdose and overdose volumes with green-to-blue and green-to-red lookup tables, respectively. Finally, the two MIPs are merged with an appropriate transparency level and rendered in planning CT images. Results: The spatially encoded DD-MIP was implemented in a dose-guided radiotherapy prototype and tested on 33 MVCBCT images from six patients. The user can easily establish the threshold for the overdose and underdose. A 3% difference between the treatment and planning dose was used as the threshold in the study; hence, the DD-MIP shows red or blue color for the dose difference >3% or {<=}3%, respectively. With such a method, the overdose and underdose regions can be visualized and distinguished without being overshadowed by superficial dose differences. Conclusions: A DD-MIP algorithm was developed that compresses information from 3D into a single or two orthogonal projections while hinting the user whether the dose difference is on the skin surface or deeper.

  16. Dose delivered from Varian's CBCT to patients receiving IMRT for prostate cancer

    NASA Astrophysics Data System (ADS)

    Wen, Ning; Guan, Huaiqun; Hammoud, Rabih; Pradhan, Deepak; Nurushev, T.; Li, Shidong; Movsas, Benjamin

    2007-04-01

    With the increased use of cone beam CT (CBCT) for daily patient setup, the accumulated dose from CBCT may be significantly higher than that from simulation CT or portal imaging. The objective of this work is to measure the dose from daily pelvic scans with fixed technical settings and collimations. CBCT scans were acquired in half-fan mode using a half bowtie and x-rays were delivered in pulsed-fluoro mode. The skin doses for seven prostate patients were measured on an IRB-approved protocol. TLD capsules were placed on the patient's skin at the central axis of three beams: AP, left lateral (Lt Lat) and right lateral (Rt Lat). To avoid the ring artefacts centred in the prostate, the treatment couch was dropped 3 cm from the patient's tattoo (central axis). The measured AP skin doses ranged 3-6 cGy for 20-33 cm separation. The larger the patient size the less the AP skin dose. Lateral doses did not change much with patient size. The Lt Lat dose was ~4.0 cGy, which was ~40% higher than the Rt Lat dose of ~2.6 cGy. To verify this dose asymmetry, surface doses on an IMRT QA phantom (oval shaped, 30 cm × 20 cm) were measured at the same three sites using TLD capsules with 3 cm table-drop. The dose asymmetry was due to: (1) kV source rotation which always starts from the patient's Lt Lat and ends at Lt Lat. Gantry rotation gets much slower near the end of rotation but dose rate stays constant and (2) 370° scan rotation (10° scan overlap on the Lt Lat side). In vivo doses were measured inside a Rando pelvic heterogeneous phantom using TLDs. The left hip (femoral head and neck) received the highest doses of ~10-11 cGy while the right hip received ~6-7 cGy. The surface and in vivo doses were also measured for phantoms at the central-axis setup. The difference was less than ~12% to the table-drop setup.

  17. Complete response of endemic Kaposi sarcoma lesions with high-dose-rate brachytherapy: treatment method, results, and toxicity using skin surface applicators.

    PubMed

    Kasper, Michael E; Richter, Sam; Warren, Nicholas; Benda, Rashmi; Shang, Charles; Ouhib, Zoubir

    2013-01-01

    To analyze the clinical outcome of Kaposi sarcoma skin lesions treated with high-dose-rate (HDR) brachytherapy in patients with a minimum of 2 years of followup. Between February 2006 and July 2008, all patients with Kaposi sarcoma who received (192)Ir HDR brachytherapy using a skin surface applicator were evaluated for clinical response. Responses to treatment and toxicity were scored using standard criteria. Sixteen cases were collected. Treatment was delivered in four to six fractions, over a period of approximately 12 days. The specified dose ranged from 24 to 35Gy. Median followup the lesion was 41.4 months. No lesion was greater than 2cm. All patients had a complete response to treatment, with no evidence of local recurrence or tumor progression. Thirteen lesions developed Grade 1 and two lesions had Grade 2 acute skin reactions. One patient developed late skin changes with telangiectasias and hypopigmentation. HDR brachytherapy treatment seems to be an effective noninvasive option for patients with small cutaneous Kaposi sarcoma lesions, delivering excellent cosmesis and local control in our small series. Fewer fractions over a shorter period used in our group offer patients more convenience compared with other common regimens. Although HDR is being used more frequently for many surface applications, additional clinical studies with larger numbers of patients and longer followup are needed to confirm the general impression that it is an excellent option for many patients. Copyright © 2013 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  18. Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

    SciTech Connect

    Lucero, J. F.; Rojas, J. I.

    2016-07-07

    Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient’s entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

  19. Skin Biophysical Characteristics in Patients with Keratoconus: A Controlled Study.

    PubMed

    Robati, Reza M; Einollahi, Bahram; Einollahi, Hoda; Younespour, Shima; Fadaifard, Shahed

    2016-01-01

    Background. Keratoconus is a relatively common corneal disease causing significant visual disability. Individuals with connective tissue disorders that affect the skin such as Marfan's syndrome and Ehlers-Danlos syndrome or patients with atopic dermatitis show an increased prevalence of keratoconus. It seems that there are some concurrent alterations of skin and cornea in patients with keratoconus. Objective. We plan to compare skin biophysical characteristics in patients with keratoconus and healthy controls. Methods. Forty patients with keratoconus (18 females and 22 males) with mean (SD) age of 33.32 (9.55) years (range 19-56) and 40 healthy controls were recruited to this study. Skin biophysical characteristics including cutaneous resonance running time (CRRT), stratum corneum hydration, and melanin values were measured in patients and controls. Results. The median CRRT, stratum corneum hydration, and melanin measurements were significantly lower in patients with keratoconus in comparison with healthy controls. Conclusion. There are some alterations of skin biophysical properties in patients with keratoconus. Therefore, the assessment of these skin parameters could provide us some clues to the possible common biophysical variations of cornea and skin tissue in diseases such as keratoconus.

  20. Low-dose radiation modifies skin response to acute gamma-rays and protons.

    PubMed

    Mao, Xiao Wen; Pecaut, Michael J; Cao, Jeffrey D; Moldovan, Maria; Gridley, Daila S

    2013-01-01

    The goal of the present study was to obtain pilot data on the effects of protracted low-dose/low-dose-rate (LDR) γ-rays on the skin, both with and without acute gamma or proton irradiation (IR). Six groups of C57BL/6 mice were examined: a) 0 Gy control, b) LDR, c) Gamma, d) LDR+Gamma, e) Proton, and f) LDR+Proton. LDR radiation was delivered to a total dose of 0.01 Gy (0.03 cGy/h), whereas the Gamma and Proton groups received 2 Gy (0.9 Gy/min and 1.0 Gy/min, respectively). Assays were performed 56 days after exposure. Skin samples from all irradiated groups had activated caspase-3, indicative of apoptosis. The significant (p<0.05) increases in immunoreactivity in the Gamma and Proton groups were not present when LDR pre-exposure was included. However, the terminal deoxynucleotidyl transferase dUTP nick-end labeling assay for DNA fragmentation and histological examination of hematoxylin and eosin-stained sections revealed no significant differences among groups, regardless of radiation regimen. The data demonstrate that caspase-3 activation initially triggered by both forms of acute radiation was greatly elevated in the skin nearly two months after whole-body exposure. In addition, LDR γ-ray priming ameliorated this response.

  1. Feasibility of a semiconductor dosimeter to monitor skin dose in interventional radiology.

    PubMed

    Meyer, P; Regal, R; Jung, M; Siffert, P; Mertz, L; Constantinesco, A

    2001-10-01

    The design and preliminary test results of a semiconductor silicon dosimeter are presented in this article. Use of this dosimeter is foreseen for real-time skin dose control in interventional radiology. The strong energy dependence of this kind of radiation detector is well overcome by filtering the silicon diode. Here, the optimal filter features have been calculated by numerical Monte Carlo simulations. A prototype has been built and tested in a radiological facility. The first experimental results show a good match between the filtered semiconductor diode response and an ionization chamber response, within 2% fluctuation in a 2.2 to 4.1 mm Al half-value layer (HVL) energy range. Moreover, the semiconductor sensor response is linear from 0.02 Gy/min to at least 6.5 Gy/min, covering the whole dose rate range found in interventional radiology. The results show that a semiconductor dosimeter could be used to monitor skin dose during the majority of procedures using x-rays below 150 keV. The use of this device may assist in avoiding radiation-induced skin injuries and lower radiation levels during interventional procedures.

  2. Quantitative Proteomic Profiling of Low Dose Ionizing Radiation Effects in a Human Skin Model

    SciTech Connect

    Hengel, Shawna; Aldrich, Joshua T.; Waters, Katrina M.; Pasa-Tolic, Ljiljana; Stenoien, David L.

    2014-07-29

    To assess molecular responses to low doses of radiation that may be encountered during medical diagnostic procedures, nuclear accidents, or terrorist acts, a quantitative global proteomic approach was used to identify protein alterations in a reconstituted human skin tissue treated with 10 cGy of ionizing radiation. Subcellular fractionation was employed to remove highly abundant structural proteins and provide insight on radiation induced alterations in protein abundance and localization. In addition, peptides were post-fractionated using high resolution 2-dimensional liquid chromatography to increase the dynamic range of detection of protein abundance and translocation changes. Quantitative data was obtained by labeling peptides with 8-plex isobaric iTRAQ tags. A total of 207 proteins were detected with statistically significant alterations in abundance and/or subcellular localization compared to sham irradiated tissues. Bioinformatics analysis of the data indicated that the top canonical pathways affected by low dose radiation are related to cellular metabolism. Among the proteins showing alterations in abundance, localization and proteolytic processing was the skin barrier protein filaggrin which is consistent with our previous observation that ionizing radiation alters profilaggrin processing with potential effects on skin barrier functions. In addition, a large number of proteases and protease regulators were affected by low dose radiation exposure indicating that altered proteolytic activity may be a hallmark of low dose radiation exposure. While several studies have demonstrated altered transcriptional regulation occurs following low dose radiation exposures, the data presented here indicates post-transcriptional regulation of protein abundance, localization, and proteolytic processing play an important role in regulating radiation responses in complex human tissues.

  3. Multiple Methods for Assessing the Dose to Skin Exposed to Radioactive Contamination.

    PubMed

    Dubeau, J; Heinmiller, B E; Corrigan, M

    2017-04-28

    There is the possibility for a worker at a nuclear installation, such as a nuclear power reactor, a fuel production facility or a medical facility, to come in contact with radioactive contaminants. When such an event occurs, the first order of business is to care for the worker by promptly initiating a decontamination process. Usually, the radiation protection personnel performs a G-M pancake probe measurement of the contamination in situ and collects part or all of the radioactive contamination for further laboratory analysis. The health physicist on duty must then perform, using the available information, a skin dose assessment that will go into the worker's permanent dose record. The contamination situations are often complex and the dose assessment can be laborious. This article compares five dose assessment methods that involve analysis, new technologies and new software. The five methods are applied to 13 actual contamination incidents consisting of direct skin contact, contamination on clothing and contamination on clothing in the presence of an air gap between the clothing and the skin. This work shows that, for the cases studied, the methods provided dose estimates that were usually within 12% (1σ) of each other, for those cases where absolute activity information for every radionuclide was available. One method, which relies simply on a G-M pancake probe measurement, appeared to be particularly useful in situations where a contamination sample could not be recovered for laboratory analysis. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Low-Dose (10-Gy) Total Skin Electron Beam Therapy for Cutaneous T-Cell Lymphoma: An Open Clinical Study and Pooled Data Analysis

    SciTech Connect

    Kamstrup, Maria R.; Gniadecki, Robert; Iversen, Lars; Skov, Lone; Petersen, Peter Meidahl; Loft, Annika; Specht, Lena

    2015-05-01

    Purpose: Cutaneous T-cell lymphomas (CTCLs) are dominated by mycosis fungoides (MF) and Sézary syndrome (SS), and durable disease control is a therapeutic challenge. Standard total skin electron beam therapy (TSEBT) is an effective skin-directed therapy, but the possibility of retreatments is limited to 2 to 3 courses in a lifetime due to skin toxicity. This study aimed to determine the clinical effect of low-dose TSEBT in patients with MF and SS. Methods and Materials: In an open clinical study, 21 patients with MF/SS stages IB to IV were treated with low-dose TSEBT over <2.5 weeks, receiving a total dose of 10 Gy in 10 fractions. Data from 10 of these patients were published previously but were included in the current pooled data analysis. Outcome measures were response rate, duration of response, and toxicity. Results: The overall response rate was 95% with a complete cutaneous response or a very good partial response rate (<1% skin involvement with patches or plaques) documented in 57% of the patients. Median duration of overall cutaneous response was 174 days (5.8 months; range: 60-675 days). TSEBT-related acute adverse events (grade 1 or 2) were observed in 60% of patients. Conclusions: Low-dose (10-Gy) TSEBT offers a high overall response rate and is relatively safe. With this approach, reirradiation at times of relapse or progression is likely to be less toxic than standard dose TSEBT. It remains to be established whether adjuvant and combination treatments can prolong the beneficial effects of low-dose TSEBT.

  5. Comparison of skin stripping, in vitro release, and skin blanching response methods to measure dose response and similarity of triamcinolone acetonide cream strengths from two manufactured sources.

    PubMed

    Pershing, Lynn K; Bakhtian, Shahrzad; Poncelet, Craig E; Corlett, Judy L; Shah, Vinod P

    2002-05-01

    The collective studies compare in vitro drug release, in vivo skin stripping, and skin blanching response methods for dose responsiveness and bioequivalence assessment of triamcinolone acetonide cream products, as a function of application duration, drug concentration, and manufacturer source. Commercially available triamcinolone acetonide creams (0.025%, 0.1%, and 0.5%) from two manufacturers were evaluated in vitro for rate and extent of drug release across synthetic membranes and in vivo for rate, extent, and variability of drug uptake into human stratum corneum and skin blanching response in human forearm skin. Data demonstrate that increasing triamcinolone acetonide cream concentration applied increased the rate and extent of drug released in vitro as well as the extent of drug uptake and skin blanching response in human skin in vivo. No difference (p < 0.05) between the two sources of 0.1% or 0.5% creams was measured by the skin stripping or skin blanching response methods. Dermatopharmacokinetic analysis of triamcinonide acetonide in vivo is therefore dose responsive to drug concentration applied and application duration and agrees with in vivo skin blanching results. Data support the use of dermatopharmacokinetic methods for bioequivalence and bioavailability assessment of topical drug products.

  6. Persistent DNA Damage after High Dose In Vivo Gamma Exposure of Minipig Skin

    PubMed Central

    Ahmed, Emad A.; Agay, Diane; Schrock, Gerrit; Drouet, Michel; Meineke, Viktor; Scherthan, Harry

    2012-01-01

    Background Exposure to high doses of ionizing radiation (IR) can lead to localized radiation injury of the skin and exposed cells suffer dsDNA breaks that may elicit cell death or stochastic changes. Little is known about the DNA damage response after high-dose exposure of the skin. Here, we investigate the cellular and DNA damage response in acutely irradiated minipig skin. Methods and Findings IR-induced DNA damage, repair and cellular survival were studied in 15 cm2 of minipig skin exposed in vivo to ∼50 Co-60 γ rays. Skin biopsies of control and 4 h up to 96 days post exposure were investigated for radiation-induced foci (RIF) formation using γ-H2AX, 53BP1, and active ATM-p immunofluorescence. High-dose IR induced massive γ-H2AX phosphorylation and high 53BP1 RIF numbers 4 h, 20 h after IR. As time progressed RIF numbers dropped to a low of <1% of keratinocytes at 28–70 days. The latter contained large RIFs that included ATM-p, indicating the accumulation of complex DNA damage. At 96 days most of the cells with RIFs had disappeared. The frequency of active-caspase-3-positive apoptotic cells was 17-fold increased 3 days after IR and remained >3-fold elevated at all subsequent time points. Replicating basal cells (Ki67+) were reduced 3 days post IR followed by increased proliferation and recovery of epidermal cellularity after 28 days. Conclusions Acute high dose irradiation of minipig epidermis impaired stem cell replication and induced elevated apoptosis from 3 days onward. DNA repair cleared the high numbers of DBSs in skin cells, while RIFs that persisted in <1% cells marked complex and potentially lethal DNA damage up to several weeks after exposure. An elevated frequency of keratinocytes with persistent RIFs may thus serve as indicator of previous acute radiation exposure, which may be useful in the follow up of nuclear or radiological accident scenarios. PMID:22761813

  7. Confirmation of skin doses resulting from bolus effect of intervening alpha-cradle and carbon fiber couch in radiotherapy.

    PubMed

    Chan, Maria F; Chiu-Tsao, Sou-Tung; Li, Jingdong; Schupak, Karen; Parhar, Preeti; Burman, Chandra

    2012-12-01

    In this study, we verified the treatment planning calculations of skin doses with the incorporation of the bolus effect due to the intervening alpha-cradle (AC) and carbon fiber couch (CFC) using radiochromic EBT2 films. A polystyrene phantom (25 × 25 × 15 cm(3)) with six EBT2 films separated by polystyrene slabs, at depths of 0, 0.1, 0.2, 0.5, 1, 1.4 cm, was positioned above an AC, which was ~1 cm thick. The phantom and AC assembly were CT scanned and the CT-images were transferred to the treatment planning system (TPS) for calculations in three scenarios: (A) ignoring AC and CFC, (B) accounting for AC only, (C) accounting for both AC and CFC. A single posterior 10 × 10 cm(2) field, a pair of posterior-oblique 10 × 10 cm(2) fields, and a posterior IMRT field (6 MV photons from a Varian Trilogy linac) were planned. For each radiation field configuration, the same MU were used in all three scenarios in the TPS. Each plan for scenario C was delivered to expose a stack of EBT2 films in the phantom through AC and CFC. In addition, in vivo EBT2 film measurement on a lung cancer patient immobilized with AC undergoing IMRT was also included in this study. Point doses and planar distributions generated from the TPS for the three scenarios were compared with the data from the EBT2 film measurements. For all the field arrangements, the EBT2 film data including the in vivo measurement agreed with the doses calculated for scenario (C), within the uncertainty of the EBT2 measurements (~4%). For the single posterior field (a pair of posterior-oblique fields), the TPS generated doses were lower than the EBT2 doses by 34%, 33%, 31%, 13% (34%, 31%, 31%, 11%) for scenario A and by 27%, 25%, 22%, 8% (25%, 21%, 21%, 6%) for scenario B at the depths of 0, 0.1, 0.2, 0.5 cm, respectively. For the IMRT field, the 2D dose distributions at each depth calculated in scenario C agree with those measured data. When comparing the central axis doses for the IMRT field, we found the TPS

  8. SU-E-T-233: Modeling Linac Couch Effects On Attenuation and Skin Dose

    SciTech Connect

    Xiong, L; Halvorsen, P

    2014-06-01

    Purpose: Treatment couch tops in medical LINAC rooms lead to attenuation to beams penetrating them, plus higher skin dose which can become a significant concern with the high fraction doses associated with Stereotactic Body Radiation Therapy. This work measures the attenuation and shallow depth dose due to a BrainLab couch, and studies the modeling of the couch top in our treatment planning system (TPS) as a uniform solid material with homogeneous density. Methods: LINAC photon beams of size 10×10 cm and nominal energy 6 MV were irradiated from different gantry angles on a stack of solid water. Depth dose were measured with two types of parallel plate chambers, MPPK and Markus. In the Philips Pinnacle TPS, the couch was modeled as a slab with varying thickness and density. A digital phantom of size 30×30×10 cm with density 1 g/cc was created to simulate the measurement setup. Both the attenuation and skin dose effects due to the couch were studied. Results: An orthogonal attenuation rate of 3.2% was observed with both chamber measurements. The attenuation can be modeled by couch models of varying thicknesses. Once the orthogonal attenuation was modeled well, the oblique beam attenuation in TPS agreed with measurement within 1.5%. The depth dose at shallow depth (0.5 cm) was also shown to be modeled correctly within 1.5% of the measurement using a 12 mm thick couch model with density of 0.9 g/cc. Agreement between calculation and measurement diverges at very shallow depths (≤1 mm) but remains acceptable (<5%) with the aforementioned couch model parameters. Conclusion: Modeling the couch top as a uniform solid in a treatment planning system can predict both the attenuation and surface dose simultaneously well within clinical tolerance in the same model.

  9. Patient doses from fluoroscopically guided cardiac procedures in pediatrics

    NASA Astrophysics Data System (ADS)

    Martinez, L. C.; Vano, E.; Gutierrez, F.; Rodriguez, C.; Gilarranz, R.; Manzanas, M. J.

    2007-08-01

    Infants and children are a higher risk population for radiation cancer induction compared to adults. Although some values on pediatric patient doses for cardiac procedures have been reported, data to determine reference levels are scarce, especially when compared to those available for adults in diagnostic and therapeutic procedures. The aim of this study is to make a new contribution to the scarce published data in pediatric cardiac procedures and help in the determination of future dose reference levels. This paper presents a set of patient dose values, in terms of air kerma area product (KAP) and entrance surface air kerma (ESAK), measured in a pediatric cardiac catheterization laboratory equipped with a biplane x-ray system with dynamic flat panel detectors. Cardiologists were properly trained in radiation protection. The study includes 137 patients aged between 10 days and 16 years who underwent diagnostic catheterizations or therapeutic procedures. Demographic data and technical details of the procedures were also gathered. The x-ray system was submitted to a quality control programme, including the calibration of the transmission ionization chamber. The age distribution of the patients was 47 for <1 year; 52 for 1-<5 years; 25 for 5-<10 years and 13 for 10-<16 years. Median values of KAP were 1.9, 2.9, 4.5 and 15.4 Gy cm2 respectively for the four age bands. These KAP values increase by a factor of 8 when moving through the four age bands. The probability of a fatal cancer per fluoroscopically guided cardiac procedure is about 0.07%. Median values of ESAK for the four age bands were 46, 50, 56 and 163 mGy, which lie far below the threshold for deterministic effects on the skin. These dose values are lower than those published in previous papers.

  10. Patient doses from fluoroscopically guided cardiac procedures in pediatrics.

    PubMed

    Martinez, L C; Vano, E; Gutierrez, F; Rodriguez, C; Gilarranz, R; Manzanas, M J

    2007-08-21

    Infants and children are a higher risk population for radiation cancer induction compared to adults. Although some values on pediatric patient doses for cardiac procedures have been reported, data to determine reference levels are scarce, especially when compared to those available for adults in diagnostic and therapeutic procedures. The aim of this study is to make a new contribution to the scarce published data in pediatric cardiac procedures and help in the determination of future dose reference levels. This paper presents a set of patient dose values, in terms of air kerma area product (KAP) and entrance surface air kerma (ESAK), measured in a pediatric cardiac catheterization laboratory equipped with a biplane x-ray system with dynamic flat panel detectors. Cardiologists were properly trained in radiation protection. The study includes 137 patients aged between 10 days and 16 years who underwent diagnostic catheterizations or therapeutic procedures. Demographic data and technical details of the procedures were also gathered. The x-ray system was submitted to a quality control programme, including the calibration of the transmission ionization chamber. The age distribution of the patients was 47 for <1 year; 52 for 1-<5 years; 25 for 5-<10 years and 13 for 10-<16 years. Median values of KAP were 1.9, 2.9, 4.5 and 15.4 Gy cm(2) respectively for the four age bands. These KAP values increase by a factor of 8 when moving through the four age bands. The probability of a fatal cancer per fluoroscopically guided cardiac procedure is about 0.07%. Median values of ESAK for the four age bands were 46, 50, 56 and 163 mGy, which lie far below the threshold for deterministic effects on the skin. These dose values are lower than those published in previous papers.

  11. Severe Imatinib-Associated Skin Rash in Gastrointestinal Stromal Tumor Patients: Management and Clinical Implications

    PubMed Central

    Park, Sook Ryun; Ryu, Min-Hee; Ryoo, Baek-Yeol; Beck, Mo Youl; Lee, In Soon; Choi, Mi Jung; Lee, Mi Woo; Kang, Yoon-Koo

    2016-01-01

    Purpose This study evaluated the incidence of imatinib-associated skin rash, the interventional outcomes of severe rash, and impact of severe rash on the outcomes of imatinib treatment in gastrointestinal stromal tumor (GIST) patients. Materials and Methods A total of 620 patients were administered adjuvant or palliative imatinib for GIST at Asan Medical Center between January 2000 and July 2012. This analysis focused on a group of 42 patients who developed a severe rash requiring major interventions, defined as dose interruption or reduction of imatinib or systemic steroid use. Results Of the 620 patients treated with imatinib, 148 patients (23.9%) developed an imatinib-associated skin rash; 42 patients (6.8%) developed a severe rash requiring major intervention. Of these, 28 patients (66.8%) successfully continued imatinib with interventions. Serial blood eosinophil levels during imatinib treatment were associated with skin rash and severity. A significant association was observed between successful intervention and blood eosinophil level at the time of intervention initiation. In metastatic settings, patients with severe rash requiring major interventions tended to show poorer progression-free survival than patients who did not require major intervention and patients with no rash, although this finding was not statistically significant (p=0.326). Conclusion By aggressive treatment of severe rash through modification of imatinib dose or use of systemic steroid, the majority of patients can continue on imatinib. In particular, imatinib dose intensity can be maintained with use of systemic steroid. Measuring the blood eosinophil levels may be helpful in guiding the management plan for skin rash regarding the intensity and duration of interventions. PMID:26323636

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

    SciTech Connect

    Romero-Expósito, M. Domingo, C.; Ortega-Gelabert, O.; Gallego, S.; Sánchez-Doblado, F.

    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

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

    PubMed

    Romero-Expósito, M; Domingo, C; Sánchez-Doblado, F; Ortega-Gelabert, O; Gallego, S

    2016-01-01

    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 wR, 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 wR. 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. 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%. Quality factor can be replaced by the radiation weighting factor in the evaluation of dose equivalent in radiotherapy environments simplifying the

  14. Antibiotic dose optimization in critically ill patients.

    PubMed

    Cotta, M O; Roberts, J A; Lipman, J

    2015-12-01

    The judicious use of existing antibiotics is essential for preserving their activity against infections. In the era of multi-drug resistance, this is of particular importance in clinical areas characterized by high antibiotic use, such as the ICU. Antibiotic dose optimization in critically ill patients requires sound knowledge not only of the altered physiology in serious infections - including severe sepsis, septic shock and ventilator-associated pneumonia - but also of the pathogen-drug exposure relationship (i.e. pharmacokinetic/pharmacodynamic index). An important consideration is the fact that extreme shifts in organ function, such as those seen in hyperdynamic patients or those with multiple organ dysfunction syndrome, can have an impact upon drug exposure, and constant vigilance is required when reviewing antibiotic dosing regimens in the critically ill. The use of continuous renal replacement therapy and extracorporeal membrane oxygenation remain important interventions in these patients; however, both of these treatments can have a profound effect on antibiotic exposure. We suggest placing emphasis on the use of therapeutic drug monitoring and dose individualization when optimizing therapy in these settings. Copyright © 2015 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  15. Comparison of cutaneous bioavailability of cosmetic preparations containing caffeine or alpha-tocopherol applied on human skin models or human skin ex vivo at finite doses.

    PubMed

    Dreher, Frank; Fouchard, Frédéric; Patouillet, Claire; Andrian, Michèle; Simonnet, Jean-Thierry; Benech-Kieffer, Florence

    2002-01-01

    The use of human skin models for performing cutaneous bioavailability studies has been little investigated. For instance, only few studies have been reported on human skin models dealing with vehicle effects on percutaneous penetration. The present study aimed at evaluating the influence on caffeine's and alpha-tocopherol's cutaneous bioavailability of cosmetic vehicles such as a water-in-oil emulsion, an oil-in-water emulsion, a liposome dispersion and a hydrogel applied at finite dose using the reconstructed human skin models EpiDerm and Episkin. The results were compared with those obtained in human skin ex vivo using similar experimental conditions. It was demonstrated that the rank order of solute permeability could be correctly predicted when the preparation was applied at a finite dose in human skin models, at least when solutes with far different physicochemical properties such as caffeine and alpha-tocopherol were used. If only slight effects of cosmetic vehicle on skin bioavailability were observed in human skin ex vivo, they were less predictable using skin models. Especially, alcohol-containing vehicles seemed to behave differently in EpiDerm as well as in Episkin than on human skin ex vivo. Stratum corneum intercellular lipid composition and organization of human skin models differ to some extent from that of human stratum corneum ex vivo, which contributes to less pronounced barrier properties, together with the increased hydration of the outermost stratum corneum layers of the models. These features, as well as still unknown factors, may explain the differences observed in vehicle effects in human skin ex vivo versus human skin models. Copyright 2002 S. Karger AG, Basel

  16. The Effects of Low Dose Irradiation on Inflammatory Response Proteins in a 3D Reconstituted Human Skin Tissue Model

    SciTech Connect

    Varnum, Susan M.; Springer, David L.; Chaffee, Mary E.; Lien, Katie A.; Webb-Robertson, Bobbie-Jo M.; Waters, Katrina M.; Sacksteder, Colette A.

    2012-12-01

    Skin responses to moderate and high doses of ionizing radiation include the induction of DNA repair, apoptosis, and stress response pathways. Additionally, numerous studies indicate that radiation exposure leads to inflammatory responses in skin cells and tissue. However, the inflammatory response of skin tissue to low dose radiation (<10 cGy) is poorly understood. In order to address this, we have utilized a reconstituted human skin tissue model (MatTek EpiDerm FT) and assessed changes in 23 cytokines twenty-four and forty eight hours following treatment of skin with either 3 or 10 cGy low-dose of radiation. Three cytokines, IFN-γ, IL-2, MIP-1α, were significantly altered in response to low dose radiation. In contrast, seven cytokines were significantly altered in response to a high radiation dose of 200 cGy (IL-2, IL-10, IL-13, IFN-γ, MIP-1α, TNF α, and VEGF) or the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (G-CSF, GM-CSF, IL-1α, IL-8, MIP-1α, MIP-1β, RANTES). Additionally, radiation induced inflammation appears to have a distinct cytokine response relative to the non-radiation induced stressor, TPA. Overall, these results indicate that there are subtle changes in the inflammatory protein levels following exposure to low dose radiation and this response is a sub-set of what is seen following a high dose in a human skin tissue model.

  17. [Dialysis dose quantification in critically ill patients].

    PubMed

    Casino, Francesco Gaetano

    2010-01-01

    Acute kidney injury affects about 35% of intensive care unit patients. Renal replacement therapy is required in about 5% of such patients and is associated with a mortality rate as high as 50% to 80%. The latter is likely more related to the failure of extrarenal organs than to an insufficient dialysis dose. This could explain, at least in part, the findings of 2 recent trials (VA/ NIH and RENAL) where the expected dose-outcome relationship was not confirmed. These results cannot be taken to infer that assessing the dialysis dose is no longer required. The contrary is true, in that the common finding of large differences between prescribed and delivered doses calls for accurate dose assessment, at least to avoid underdialysis. The minimum adequate levels are now a Kt/V urea of 1.2 to 1.4 three times a week (3x/wk) on intermittent hemodialysis (IHD), and an effluent of 20 mL/kg/h for 85% of the time on continuous renal replacement therapy (CRTT). Both these parameters can be easily measured but are far from ideal indices because they account neither for residual renal function nor for irregular dose delivery. The equivalent renal urea clearance (EKRjc), by expressing the averaged renal+dialytic urea clearance over the whole treatment period, is able to account for the above factors. Although assessing EKRjc is quite complex, for regular 3x/wk IHD one could use the formula EKRjc=10 Kt/V+1 to compute that a Kt/V of 1.2 and 1.4 corresponds to an EKRjc of 13 and 15 mL/min, respectively. On the other hand, the hourly effluent per kg is numerically similar to EKRjc. On this basis it can be calculated that in non-prediluted really continuous treatment, the recommended CRRT dose (EKRjc=20 mL/min) is 33% higher than the EKRjc of 15 mL/min, corresponding to the recommended Kt/V of 1.4 on 3x/wk IHD.

  18. High Levels of Gadolinium Deposition in the Skin of a Patient With Normal Renal Function.

    PubMed

    Roberts, Donna R; Lindhorst, Scott M; Welsh, Cynthia T; Maravilla, Kenneth R; Herring, Mary N; Braun, K Adam; Thiers, Bruce H; Davis, W Clay

    2016-05-01

    The aim of this study was to assess gadolinium deposition in the skin of a patient with normal renal function, based on estimated glomerular filtration rate values greater than 59 mL/min/1.73 m(2) after exposure to large cumulative doses of gadolinium-based contrast agents (GBCAs). The patient underwent 61 contrasted brain MRI scans over the course of 11 years. Skin biopsies from the forearm and lower extremity were analyzed with inductively coupled plasma mass spectrometry (ICP-MS), laser ablation ICP-MS, and hydrophilic interaction liquid chromatography ICP-MS. The ICP-MS demonstrated high levels of gadolinium deposition (14.5 ± 0.4 μg/g), similar to previously reported gadolinium levels within the skin of patients with nephrogenic systemic fibrosis. The laser ablation ICP-MS demonstrated deposition of gadolinium within the deep layers of skin. Speciation analysis using hydrophilic interaction liquid chromatography ICP-MS demonstrated the presence of intact gadolinium-chelate species, although most of the gadolinium present could not be further characterized. Light microscopy demonstrated increased CD34 immunoreactivity in the connective tissue septations of the subcutaneous adipose tissue. The patient had no history of skin disorders and did not have a history of nephrogenic systemic fibrosis but did have severe joint contractures of unknown etiology. Our results, in contradiction to published literature, suggest that in patients with normal renal function, exposure to GBCAs in extremely high cumulative doses can lead to significant gadolinium deposition in the skin. This finding is in line with more recent reports of gadolinium deposition in the brain of patients with normal renal function. Future studies are required to address possible clinical consequences of gadolinium deposition in the skin, brain, and potentially other organs in patients with normal renal function. We recommend, in addition to following current US Food and Drug Administration and

  19. Exploring the prevalence of skin tears and skin properties related to skin tears in elderly patients at a long-term medical facility in Japan.

    PubMed

    Koyano, Yuiko; Nakagami, Gojiro; Iizaka, Shinji; Minematsu, Takeo; Noguchi, Hiroshi; Tamai, Nao; Mugita, Yuko; Kitamura, Aya; Tabata, Keiko; Abe, Masatoshi; Murayama, Ryoko; Sugama, Junko; Sanada, Hiromi

    2016-04-01

    The identification of appropriate skin tear prevention guidelines for the elderly requires clinicians to focus on local risk factors such as structural alterations of the epidermis and dermis related to skin tears. The aim of this cross-sectional study is to explore the prevalence of skin tears and to explore skin properties related to skin tears in elderly Japanese patients at a long-term medical facility. After doing the prevalence study, 18 participants with skin tears and 18 without were recruited and an evaluation of their skin properties using 20-MHz ultrasonography, skin blotting and also Corneometer CM-825, Skin-pH-meterPH905, VapoMeter, Moisture Meter-D and CutometerMPA580 was undertaken. A total of 410 patients were examined, the median age was 87 years and 73·2% were women. The prevalence of skin tears was 3·9%, and 50% of skin tears occurred on the dorsal forearm. The changes in skin properties associated with skin tears included increased low-echogenic pixels (LEP) by 20-MHz ultrasonography, decreased type IV collagen and matrix metalloproteinase-2, and increased tumour necrosis factor-α by skin blotting. In conclusion, this study suggests that increased dermal LEP, including solar elastosis, may represent a risk factor for skin tears; this indicates that skin tear risk factors might not only represent chronological ageing but also photoageing. © 2014 The Authors. International Wound Journal © 2014 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

  20. SU-E-T-232: Custom High-Dose-Rate Brachytherapy Surface Mold Applicators: The Importance Source to Skin Distance

    SciTech Connect

    Park, S; Demanes, J; Kamrava, M

    2015-06-15

    Purpose: Surface mold applicators can be customized to fit irregular skin surfaces that are difficult to treat with other radiation therapy techniques. Optimal design of customized HDR skin brachytherapy is not well-established. We evaluated the impact of applicator thickness (source to skin distance) on target dosimetry. Methods: 27 patients had 34 treated sites: scalp 4, face 13, extremity 13, and torso 4. Custom applicators were constructed from 5–15 mm thick thermoplastic bolus molded over the skin lesion. A planar array of plastic brachytherapy catheters spaced 5–10 mm apart was affixed to the bolus. CT simulation was used to contour the target volume and to determine the prescription depth. Inverse planning simulated annealing followed by graphical optimization was used to plan and deliver 40–56 Gy in 8–16 fractions. Target coverage parameters (D90, Dmean, and V100) and dose uniformity (V110–200, D0.1cc, D1cc, and D2cc) were studied according to target depth (<5mm vs. ≥5mm) and applicator thickness (5–10mm vs. ≥10mm). Results: The average prescription depth was 4.2±1.5mm. The average bolus thickness was 9.2±2.4mm. The median CTV volume was 10.0 cc (0.2–212.4 cc). Similar target coverage was achieved with prescription depths of <5mm and ≥5mm (Dmean = 113.8% vs. 112.4% and D90 = 100.2% vs. 98.3%). The <5mm prescription depth plans were more uniform (D0.1cc = 131.8% vs. 151.8%). Bolus thickness <10mm vs. ≥10mm plans also had similar target coverage (Dmean = 118.2% vs. 110.7% and D90 = 100.1% vs. 99.0%). Applicators ≥10mm thick, however, provide more uniform target dosimetry (D0.1cc = 146.9% vs. 139.5%). Conclusion: Prescription depth is based upon the thickness of the lesion and upon the clinical needs of the patient. Applicators ≥10mm thick provide more dose uniformity than 5–10mm thick applicators. Applicator thickness is an important variable that should be considered during treatment planning to achieve optimal dose uniformity.

  1. [Risk factors for skin cancer development in patients after organ transplantation].

    PubMed

    Imko-Walczuk, Beata; Piesiaków, Maria Luiza; Okuniewska, Aleksandra; Jaśkiewicz, Janusz; Lizakowski, Sławomir; Dębska-Ślizień, Alicja; Rutkowski, Bolesław

    2012-11-13

    Cancer has become the second most common cause of death in patients after organ transplantation. Among all cancers arising de novo after transplantation skin cancers are the most common, accounting for 95% of all skin neoplasms. Due to the significantly higher morbidity, aggressive, rapid progression of cancer and unfavorable prognosis, the population requires a specific oncological approach. Therefore, special attention should be paid to factors predisposing to the development of cancer, including skin cancer, in patients after organ transplantation. Some of these factors are well understood, while the role of others is still ambiguous. Among the etiological factors mentioned are those that are associated with the recipient. These include genetic factors such as male sex, fair skin and inability to be tanned, and compatibility of the HLA system, and non genetic factors such as patient age, chronic skin ulcers and scars, the type of transplanted organ, immunosuppression, and particularly the type and cumulative doses of drugs. In addition, the pathogenesis of cancer is influenced by environmental factors such as exposure to sunlight and therefore latitude, ionizing radiation, chemical carcinogens and viral infections. Knowledge of etiological factors and mechanisms of etiopathogenesis allow for indication and observation of patients with increased risk of cancer as well as faster healing in these patients.  

  2. The maximal cumulative solar UVB dose allowed to maintain healthy and young skin and prevent premature photoaging.

    PubMed

    Ichihashi, Masamitsu; Ando, Hideya

    2014-10-01

    The young facial skin of children with a smooth healthy appearance changes over time to photoaged skin having mottled pigmentation, solar lentigines, wrinkles, dry and rough skin, leathery texture, and benign and malignant tumors after exposure to chronic, repeated solar radiation. The first sign of photoaging in Japanese subjects is usually solar lentigines appearing around 20 years of age on the face. Fine wrinkles can then appear after 30 years of age, and benign skin tumors, seborrhoeic keratoses, can occur after 35 years of age in sun-exposed skin. We theoretically calculated the maximal daily exposure time to solar radiation, which could prevent the development of photoaged skin until 60 and 80 years of age, based on published data of personal solar UVB doses in sun-exposed skin. One MED (minimal erythema dose) was determined to be 20 mJ/cm(2) , and 200 MED was used as the average yearly dose of Japanese children. Further, we hypothesized that the annual dose of Japanese adults is the same as that of the children. The cumulative UVB dose at 20 years of age was thus calculated to be 4000 MED, and 22 MED was used as the maximal daily UVB dose based on data measured in Kobe, located in the central area of Japan. We used the solar UVB dose from 10:00 a.m. to 14:00 p.m. which occupies 60% of the total daily UV dose, to obtain the maximal UVB per hour in a day, and calculated the maximal daily UV exposure time that would delay the onset of solar lentigines until 60 or 80 years of age. The mean daily sun exposure time to maintain healthy skin until 80 years of age in the summer was calculated to be 2.54 min (0.14 MED) for unprotected skin and 127 min with the use of a sunscreen of SPF (sun protection factor) of 50. In this study, we did not evaluate the photoaging effect of UVA radiation, but findings of the adverse effects of UVA radiation on the skin have accumulated in the last decade. Therefore, it will be important to estimate the maximal dose of solar

  3. Dose-survival relationship for epithelial cells of human skin after multifraction irradiation: evaluation by a quantitative method in vivo

    SciTech Connect

    Arcangeli, G.; Mauro, F.; Nervi, C.; Withers, H.R.

    1980-07-01

    The dose-survival relationship for normal epithelial cells after single and fractionated radiation exposures has been established by Withers for the mouse, but it is not available for humans according to a strict criterion for survival of single cell reproductive integrity. In an attempt to obtain such a quantitative estimation, 2 patients requiring radical radiation therapy to the chest wall were treated according to particular Multiple Daily Fractionation (MDF) protocols: i) 250 + 150 + 150 rad/day, 4 hr interval, 5 days/week; and ii) 150 + 150 + 150 + 150 rad/day, 3.5 hr interval, 5 days/week. In both cases, different strips of skin received different total doses: 6300, 6850, and 7150 rad, and 6300, 6750, and 7200 rad, respectively. In case (i), moist desquamation appeared and thereafter repopulating colonies of epithelium could be recognized and counted. Using these counts a survival curve having a D/sub o/ value of 490 +- 150 rad was estimated according to the formula proposed by Withers. In case (ii), no moist desquamation was reached at the doses delivered. The difference observed may imply that the initial region of the survival curve deviates appreciably from exponential between doses of 150 and 250 rad. If such is the case, a /sub 1/D/sub o/ value of 490 rad may represent an underestimate. These results are discussed from the point of view of both the shape of the survival curve and the effectiveness of nonconventional fractionation courses.

  4. Evaluation of exposure dose to patients undergoing catheter ablation procedures--a phantom study.

    PubMed

    Seguchi, S; Aoyama, T; Koyama, S; Kawaura, C; Fujii, K

    2008-11-01

    The aim of this study was to evaluate entrance skin dose (ESD), organ dose and effective dose to patients undergoing catheter ablation for cardiac arrhythmias, based on the dosimetry in an anthropomorphic phantom. ESD values associated with mean fluoroscopy time and digital cine frames were in a range of 0.12-0.30 Gy in right anterior oblique (RAO) and 0.05-0.40 Gy in left anterior oblique (LAO) projection, the values which were less than a threshold dose of 2 Gy for the onset of skin injury. Organs that received high doses in ablation procedures were lung, followed by bone surface, esophagus, liver and red bone marrow. Doses for lung were 24.8-122.7 mGy, and effective doses were 7.9-34.8 mSv for mean fluoroscopy time of 23.4-92.3 min and digital cine frames of 263-511. Conversion coefficients of dose-area product (DAP) to ESD were 8.7 mGy/(Gy cm(2)) in RAO and 7.4 mGy/(Gy cm(2)) in LAO projection. The coefficients of DAP to the effective dose were 0.37 mSv/(Gy cm(2)) in RAO, and 0.41 mSv/(Gy cm(2)) in LAO projection. These coefficients enabled us to estimate patient exposure in real time by using monitored values of DAP.

  5. Skin surveillance intentions among family members of patients with melanoma

    PubMed Central

    2011-01-01

    Background First-degree relatives of individuals diagnosed with melanoma are at increased disease risk. However, many first-degree relatives do not receive a periodic total cutaneous examination from a health care provider or engage in regular skin self-examination. The goal of this study was to identify correlates of total cutaneous examination and skin self-examination intentions among first-degree relatives of melanoma patients, thus providing insight on factors that should be targeted in future intervention research. Methods The participants were 545 first-degree relatives of melanoma patients at increased disease risk due to their risk factor profile and lack of skin surveillance behaviors. Participants completed a telephone survey regarding their total cutaneous examination and skin self-examination intentions and potential correlates, including demographics, medical factors, psychological factors, knowledge, and social influence factors. Results Intentions to receive a total cutaneous examination were higher among first-degree relatives with more education, those perceiving higher benefits and lower barriers to an examination, and those reporting greater physician and family support. Intentions to receive a skin self-examination were higher among those with higher benefits and lower barriers to self-examination, and higher family support. Conclusions Interventions to promote skin surveillance behaviors among first-degree relatives of melanoma patients should highlight the benefits of early detection of melanoma, address barriers to receipt of total cutaneous examination and engagement in skin self-examination, and promote support from physicians and family members. PMID:22082038

  6. Skin autofluorescence predicts cardiovascular mortality in patients on chronic hemodialysis.

    PubMed

    Kimura, Hiroshi; Tanaka, Kenichi; Kanno, Makoto; Watanabe, Kimio; Hayashi, Yoshimitsu; Asahi, Koichi; Suzuki, Hodaka; Sato, Keiji; Sakaue, Michiaki; Terawaki, Hiroyuki; Nakayama, Masaaki; Miyata, Toshio; Watanabe, Tsuyoshi

    2014-10-01

    Tissue accumulation of advanced glycation end products (AGE) is thought to contribute to the progression of cardiovascular disease (CVD). Skin autofluorescence, a non-invasive measure of AGE accumulation using autofluorescence of the skin under ultraviolet light, has been reported to be an independent predictor of mortality associated with CVD in Caucasian patients on chronic hemodialysis. The aim of this study was to assess the predictive value of skin autofluorescence on all-cause and cardiovascular mortality in non-Caucasian (Japanese) patients on chronic hemodialysis. Baseline skin autofluorescence was measured with an autofluorescence reader in 128 non-Caucasian (Japanese) patients on chronic hemodialysis. All-cause and cardiovascular mortality was monitored prospectively during a period of 6 years. During the follow-up period, 42 of the 128 patients died; 19 of those patients died of CVD. Skin autofluorescence did not have a significant effect on all-cause mortality. However, age, carotid artery intima-media thickness (IMT), serum albumin, high-sensitivity C-reactive protein (hsCRP), skin autofluorescence and pre-existing CVD were significantly correlated with cardiovascular mortality. Multivariate Cox regression analysis showed skin autofluorescence (adjusted hazard ratio [HR] 3.97; 95% confidence interval [CI]1.67-9.43), serum albumin (adjusted HR 0.05; 95% CI 0.01-0.32), and hsCRP (adjusted HR 1.55; 95% CI 1.18-2.05) to be independent predictors of cardiovascular mortality. The present study suggests that skin autofluorescence is an independent predictor of cardiovascular mortality in non-Caucasian (Japanese) patients on chronic hemodialysis.

  7. Estimated UV doses to psoriasis patients during climate therapy at Gran Canaria in March 2006

    NASA Astrophysics Data System (ADS)

    Nilsen, L. T. N.; Søyland, E.; Krogstad, A. L.

    2008-01-01

    Psoriasis is a chronic inflammatory disease involving about 2-3% of the Norwegian population. Sun exposure has a positive effect on most psoriasis lesions, but ultraviolet (UV) radiation also causes a direct DNA damage in the skin cells and comprises a carcinogenic potential. UV exposure on the skin causes a local as well as a systemic immune suppressive effect, but the relation between sun exposure and these biological effects is not well known. In March 2006 a study was carried out to investigate possible therapeutic outcome mechanisms in 20 psoriasis patients receiving climate therapy at Gran Canaria. This paper presents estimates of their individual skin UV-doses based on UV measurements and the patients' diaries with information on time spent in the sun. On the first day of exposure the patients received on average 5.1 Standard Erythema Doses (SED: median=4.0 SED, range 2.6-10.3 SED) estimated to the skin. During the 15 days study they received 165.8 SED (range 104.3-210.1 SED). The reduction in PASI score was 72.8% on average, but there was no obvious relation between the improvement and the UV dose. The UV doses were higher than those found from climate therapy studies at other locations. It seems beneficial to use more strict exposure schedules that consider the available UV irradiance, depending on time of the day, time of the year and weather conditions.

  8. Metabolomic Response of Human Skin Tissue to Low Dose Ionizing Radiation

    SciTech Connect

    Hu, Zeping; Kim, Young-Mo; Sowa, Marianne B.; Robinson, Robert J.; Gao, Xiaoli; Metz, Thomas O.; Morgan, William F.; Zhang, Qibin

    2012-05-18

    Understanding how human organs respond to ionizing radiation (IR) at a systems biology level and identifying biomarkers for IR exposure at low doses can help provide a scientific basis for establishing radiation protection standards. Little is known regarding the physiological responses to low dose IR at the metabolite level, which represents the end-point of biochemical processes inside cells. Using a full thickness human skin tissue model and GC-MS-based metabolomics analysis, we examined the metabolic perturbations at three time points (3, 24 and 48 hr) after exposure to 3, 10 and 200 cGy of X-rays. PLS-DA score plots revealed dose- and time-dependent clustering between sham and irradiated groups. Importantly, a comparable number of metabolites were detected to have significant change 48 hr after exposure to 3 and 10 cGy of irradiation, when compared with the high dose of 200 cGy. Biochemical pathway analysis showed perturbations to DNA/RNA damage and repair, lipid and energy metabolisms, even at low doses of IR.

  9. Population pharmacokinetics of ceftaroline in patients with acute bacterial skin and skin structure infections or community-acquired bacterial pneumonia.

    PubMed

    Van Wart, Scott A; Forrest, Alan; Khariton, Tatiana; Rubino, Christopher M; Bhavnani, Sujata M; Reynolds, Daniel K; Riccobene, Todd; Ambrose, Paul G

    2013-11-01

    Ceftaroline, the active form of ceftaroline fosamil, is a broad-spectrum cephalosporin antibiotic. A population pharmacokinetic (PPK) model for ceftaroline was developed in NONMEM® using data from 185 healthy subjects and 92 patients with acute bacterial skin and skin structure infection (ABSSSI). Data from 128 patients with community-acquired bacterial pneumonia (CABP) were used for external model validation. Healthy subjects received 50-2,000 mg ceftaroline fosamil via intravenous (IV) infusion over 1 hour or intramuscular (IM) injection q12h or q24h. ABSSSI and CABP patients received 600 mg of ceftaroline fosamil IV over 1 hour q12h. A three-compartment model with zero-order IV or parallel first-order IM input and first-order elimination described ceftaroline fosamil PK. A two-compartment model with first-order conversion of prodrug to ceftaroline and parallel linear and saturable elimination described ceftaroline PK. Creatinine clearance was the primary determinant of ceftaroline exposure. Good agreement between the observed data and both population (r(2)  = 0.93) and individual post-hoc (r(2)  = 0.98) predictions suggests the PPK model can adequately approximate ceftaroline PK using covariate information. Such a PPK model can evaluate dose adjustments for patients with renal impairment and generate ceftaroline exposures for use in pharmacokinetic-pharmacodynamic assessments of efficacy in patients with ABSSSI or CABP.

  10. Dose-Dependent Onset of Regenerative Program in Neutron Irradiated Mouse Skin

    PubMed Central

    Artibani, Mara; Kobos, Katarzyna; Colautti, Paolo; Negri, Rodolfo; Amendola, Roberto

    2011-01-01

    Background Tissue response to irradiation is not easily recapitulated by cell culture studies. The objective of this investigation was to characterize, the transcriptional response and the onset of regenerative processes in mouse skin irradiated with different doses of fast neutrons. Methodology/Principal Findings To monitor general response to irradiation and individual animal to animal variation, we performed gene and protein expression analysis with both pooled and individual mouse samples. A high-throughput gene expression analysis, by DNA oligonucleotide microarray was done with three months old C57Bl/6 mice irradiated with 0.2 and 1 Gy of mono-energetic 14 MeV neutron compared to sham irradiated controls. The results on 440 irradiation modulated genes, partially validated by quantitative real time RT-PCR, showed a dose-dependent up-regulation of a sub-class of keratin and keratin associated proteins, and members of the S100 family of Ca2+-binding proteins. Immunohistochemistry confirmed mRNA expression data enabled mapping of protein expression. Interestingly, proteins up-regulated in thickening epidermis: keratin 6 and S100A8 showed the most significant up-regulation and the least mouse-to-mouse variation following 0.2 Gy irradiation, in a concerted effort toward skin tissue regeneration. Conversely, mice irradiated at 1 Gy showed most evidence of apoptosis (Caspase-3 and TUNEL staining) and most 8-oxo-G accumulation at 24 h post-irradiation. Moreover, no cell proliferation accompanied 1 Gy exposure as shown by Ki67 immunohistochemistry. Conclusions/Significance The dose-dependent differential gene expression at the tissue level following in vivo exposure to neutron radiation is reminiscent of the onset of re-epithelialization and wound healing and depends on the proportion of cells carrying multiple chromosomal lesions in the entire tissue. Thus, this study presents in vivo evidence of a skin regenerative program exerted independently from DNA repair

  11. Skin cancer prevention in annual performance of total skin examination, photoprotection counseling, and patient instruction of self-skin examination.

    PubMed

    Yiannias, James A; Laman, Susan D; Stevens, Ryan; Rkein, Ali M; Nelson, Evan; Noble, Brie N

    2014-08-01

    Prevention of skin cancer includes early diagnosis and photoprotection, such as by physician-performed total skin examination (TSE) and patient-performed self-skin examination (SSE). Hypothesizing that 90% of our patients receive an annual TSE, photoprotection counseling, and SSE instruction, we assessed the extent to which this was documented in patients' records. We also sought to identify differences in documentation of TSE, photoprotection counseling, and instruction on SSE with or without use of a dictation template prompting documentation. Retrospective review of a random sample of 400 patients in an outpatient dermatology practice of a tertiary care academic medical center for any dermatology appointment between May 1 and July 31, 2007. Exclusion criteria included refusal to undergo TSE, lack of access to skin (e.g., wheelchair-bound or in cast), or inappropriate visit type (e.g., for acne, psoriasis, or lupus). Of 400 randomly selected patients, 313 met inclusion criteria. The dictation template was used in 133; of these, 89% (119/133) had documentation in their clinical note of a TSE (exclusive of the buttocks or groin area), and 98% (130/133) had documentation of instruction on sun protection and SSE. Without use of the dictation template, these percentages dropped to 78% (140/180) and 20% (36/180), respectively. Physicians using a dictation template were more likely to document having conducted a TSE and instructed patients on photoprotection and SSE. A dictation template aids documentation of annual TSE and patient education efforts on photoprotection and SSE. © 2013 The International Society of Dermatology.

  12. An ultrasonographic evaluation of skin thickness in breast cancer patients after postmastectomy radiation therapy

    PubMed Central

    2011-01-01

    Background To determine the usefulness of ultrasonography in the assessment of post radiotherapy skin changes in postmastectomy breast cancer patients. Methods Patients treated for postmastectomy radiotherapy in National University Hospital (NUH) and Tan Tock Seng Hospital (TTSH), Singapore between January 2004- December 2005 was recruited retrospectively. Ultrasound scan was performed on these Asian patients who had been treated to a total dose of 46-50 Gy with 1 cm bolus placed on the skin. The ultrasound scans were performed blinded to the RTOG scores, and the skin thickness of the individually marked points on the irradiated chest wall was compared to the corresponding points on the non-irradiated breast. Results The mean total skin thickness inclusive of the epidermis and the dermis of the right irradiated chest wall was 0.1712 mm (± 0.03392 mm) compared with the contra-lateral non-irradiated breast which was 0.1845 mm (± 0.04089 mm; p = 0.007). The left irradiated chest wall had a mean skin thickness of 0.1764 mm (± 0.03184 mm) compared with the right non-irradiated breast which was 0.1835 mm (± 0.02584 mm; p = 0.025). These independent t-tests produced a significant difference of reduced skin thickness on the right irradiated chest wall, p = 0.007 (p < 0.05) and left irradiated chest wall p = 0.025 (p < 0.025) in comparison to the non-irradiated skin thickness investigating chronic skin reactions. Patients with grade 2 acute skin toxicity presented with thinner skin as compared to patients with grade 1 (p = 0.006). Conclusions This study has shown that there is a statistically significant difference between the skin thicknesses of the irradiated chest wall and the contra-lateral non-irradiated breast and a predisposition to chronic reactions was found in patients with acute RTOG scoring of grade1 and grade 2. PMID:21261940

  13. SU-E-T-373: Evaluation and Reduction of Contralateral Skin /subcutaneous Dose for Tangential Breast Irradiation

    SciTech Connect

    Butson, M; Carroll, S; Whitaker, M; Odgers, D; Martin, D; Hinds, S; Kader, J; Ho, K; Amos, S; Toohey, J

    2015-06-15

    Purpose: Tangential breast irradiation is a standard treatment technique for breast cancer therapy. One aspect of dose delivery includes dose delivered to the skin caused by electron contamination. This effect is especially important for highly oblique beams used on the medical tangent where the electron contamination deposits dose on the contralateral breast side. This work aims to investigate and predict as well as define a method to reduce this dose during tangential breast radiotherapy. Methods: Analysis and calculation of breast skin and subcutaneous dose is performed using a Varian Eclipse planning system, AAA algorithm for 6MV x-ray treatments. Measurements were made using EBT3 Gafchromic film to verify the accuracy of planning data. Various materials were tested to assess their ability to remove electron contamination on the contralateral breast. Results: Results showed that the Varian Eclipse AAA algorithm could accurately estimate contralateral breast dose in the build-up region at depths of 2mm or deeper. Surface dose was underestimated by the AAA algorithm. Doses up to 12% of applied dose were seen on the contralateral breast surface and up to 9 % at 2mm depth. Due to the nature of this radiation, being mainly low energy electron contamination, a bolus material could be used to reduce this dose to less than 3%. This is accomplished by 10 mm of superflab bolus or by 1 mm of lead. Conclusion: Contralateral breast skin and subcutaneous dose is present for tangential breast treatment and has been measured to be up to 12% of applied dose from the medial tangent beam. This dose is deposited at shallow depths and is accurately calculated by the Eclipse AAA algorithm at depths of 2mm or greater. Bolus material placed over the contralateral can be used to effectively reduce this skin dose.

  14. Role of mild cleansing in the management of patient skin.

    PubMed

    Subramanyan, Kumar

    2004-01-01

    Routine everyday care of skin is an essential part of optimal patient management. Common problems such as xerosis, dermatitis, eczema, psoriasis, acne, rosacea, and photodamage leave the skin vulnerable to external insults, partly as a result of varying levels of barrier dysfunction. Cosmetic surgery procedures also typically damage the stratum corneum (SC) and leave skin with a very weak barrier during recovery phase. Cleansing is an important aspect of any skin care, since it not only removes unwanted dirt, soil, and bacteria from skin, but also removes dead surface cells, preparing skin to better absorb topically applied drugs/medication. Care must be taken to minimize any further weakening of the SC barrier during cleansing. Cleansers based on mild synthetic surfactants and/or emollients that cause minimal barrier perturbation are ideal for these patients. The present paper is a brief review of four clinical trials that evaluated the efficacy and compatibility of either mild syndet bars or cleansers in patients with atopic dermatitis, acne, rosacea, or patients who had received chemical peels or Retin-A(R) (tretinoin) treatment for sustained photodamage.

  15. Skin care in the frail, elderly, dependent, incontinent patient.

    PubMed

    Jeter, K F; Lutz, J B

    1996-01-01

    Despite a plethora of recommendations, protocols and dictums in the nursing literature, no research studies have defined the basic elements of preventive skin care for incontinent patients, and the prevalence of skin problems associated with incontinence is unknown. Yet the importance of skin care for incontinent elderly or immobilized patients has long been acknowledged. This literature review sought to determine current practices and principles for skin care of frail, elderly, dependent, incontinent patients. Protocols vary widely. And although there is mounting evidence that incontinence, particularly fecal incontinence, is a primary risk factor for pressure ulcer development, most preventive efforts focus on pressure relief, repositioning, and nutrition, rather than incontinence care. More clinical trials are needed in this area. The design and analysis of these trials should take into account the frequency and manner in which skin is cleansed, products used for skin care, risks and benefits of absorbent products and devices, the presence of infection, and patients' concomitant medical conditions and degree of immobility.

  16. Significance of including field non-uniformities such as the heel effect and beam scatter in the determination of the skin dose distribution during interventional fluoroscopic procedures

    NASA Astrophysics Data System (ADS)

    Rana, Vijay; Gill, Kamaljit; Rudin, Stephen; Bednarek, Daniel R.

    2012-03-01

    The current version of the real-time skin-dose-tracking system (DTS) we have developed assumes the exposure is contained within the collimated beam and is uniform except for inverse-square variation. This study investigates the significance of factors that contribute to beam non-uniformity such as the heel effect and backscatter from the patient to areas of the skin inside and outside the collimated beam. Dose-calibrated Gafchromic film (XR-RV3, ISP) was placed in the beam in the plane of the patient table at a position 15 cm tube-side of isocenter on a Toshiba Infinix C-Arm system. Separate exposures were made with the film in contact with a block of 20-cm solid water providing backscatter and with the film suspended in air without backscatter, both with and without the table in the beam. The film was scanned to obtain dose profiles and comparison of the profiles for the various conditions allowed a determination of field non-uniformity and backscatter contribution. With the solid-water phantom and with the collimator opened completely for the 20-cm mode, the dose profile decreased by about 40% on the anode side of the field. Backscatter falloff at the beam edge was about 10% from the center and extra-beam backscatter decreased slowly with distance from the field, being about 3% of the beam maximum at 6 cm from the edge. Determination of the magnitude of these factors will allow them to be included in the skin-dose-distribution calculation and should provide a more accurate determination of peak-skin dose for the DTS.

  17. Finite dose skin mass balance including the lateral part: comparison between experiment, pharmacokinetic modeling and diffusion models.

    PubMed

    Selzer, D; Hahn, T; Naegel, A; Heisig, M; Kostka, K H; Lehr, C M; Neumann, D; Schaefer, U F; Wittum, G

    2013-01-28

    This work investigates in vitro finite dose skin absorption of the model compounds flufenamic acid and caffeine experimentally and mathematically. The mass balance in different skin compartments (donor, stratum corneum (SC), deeper skin layers (DSL), lateral skin parts and acceptor) is analyzed as a function of time. For both substances high amounts were found in the lateral skin compartment after 6h of incubation, which emphasizes not to elide these parts in the modeling. Here, three different mathematical models were investigated and tested with the experimental data: a pharmacokinetic model (PK), a detailed microscopic two-dimensional diffusion model (MICRO) and a macroscopic homogenized diffusion model (MACRO). While the PK model was fitted to the experimental data, the MICRO and the MACRO models employed input parameters derived from infinite dose studies to predict the underlying diffusion process. All models could satisfyingly predict or describe the experimental data. The PK model and MACRO model also feature the lateral parts.

  18. Estimation of beta-ray skin dose from exposure to fission fallout from the Hiroshima atomic bomb.

    PubMed

    Endo, Satoru; Tanaka, Kenichi; Shizuma, Kiyoshi; Hoshi, Masaharu; Imanaka, Tetsuji

    2012-03-01

    Beta-ray skin dose due to the fission fallout from the Hiroshima atomic bomb is potentially related to the epilation in the black rain area. The absorbed dose to the skin from beta-rays emitted by fission fallout has been estimated for an initial ¹³⁷Cs deposition of 1 kBq m⁻² on the ground at 0.5 h after the explosion. The estimated skin dose takes into account both external exposure from fission fallout radionuclides uniformly distributed in 1 mm of soil on the surface of the ground and from a 26 μm thickness of contaminated soil on the skin, using the Monte Carlo radiation transport code MCNP-4C. The cumulative skin dose for 1 month after the explosion is taken as the representative value. The estimated skin dose for an initial ¹³⁷Cs deposition of 1 kBq m⁻² was determined to be about 500 mSv.

  19. Patient dose considerations in computed tomography examinations

    PubMed Central

    Tsalafoutas, Ioannis A; Koukourakis, Georgios V

    2010-01-01

    Ionizing radiation is extensively used in medicine and its contribution to both diagnosis and therapy is undisputable. However, the use of ionizing radiation also involves a certain risk since it may cause damage to tissues and organs and trigger carcinogenesis. Computed tomography (CT) is currently one of the major contributors to the collective population radiation dose both because it is a relatively high dose examination and an increasing number of people are subjected to CT examinations many times during their lifetime. The evolution of CT scanner technology has greatly increased the clinical applications of CT and its availability throughout the world and made it a routine rather than a specialized examination. With the modern multislice CT scanners, fast volume scanning of the whole human body within less than 1 min is now feasible. Two dimensional images of superb quality can be reconstructed in every possible plane with respect to the patient axis (e.g. axial, sagital and coronal). Furthermore, three-dimensional images of all anatomic structures and organs can be produced with only minimal additional effort (e.g. skeleton, tracheobronchial tree, gastrointestinal system and cardiovascular system). All these applications, which are diagnostically valuable, also involve a significant radiation risk. Therefore, all medical professionals involved with CT, either as referring or examining medical doctors must be aware of the risks involved before they decide to prescribe or perform CT examinations. Ultimately, the final decision concerning justification for a prescribed CT examination lies upon the radiologist. In this paper, we summarize the basic information concerning the detrimental effects of ionizing radiation, as well as the CT dosimetry background. Furthermore, after a brief summary of the evolution of CT scanning, the current CT scanner technology and its special features with respect to patient doses are given in detail. Some numerical data is also

  20. SU-E-I-22: Dependence On Calibration Phantom and Field Area of the Conversion Factor Used to Calculate Skin Dose During Neuro-Interventional Fluoroscopic Procedures

    SciTech Connect

    Rana, V K; Vijayan, S; Rudin, S R; Bednarek, D R

    2014-06-01

    Purpose: To determine the appropriate calibration factor to use when calculating skin dose with our real-time dose-tracking system (DTS) during neuro-interventional fluoroscopic procedures by evaluating the difference in backscatter from different phantoms and as a function of entrance-skin field area. Methods: We developed a dose-tracking system to calculate and graphically display the cumulative skin-dose distribution in real time. To calibrate the DTS for neuro-interventional procedures, a phantom is needed that closely approximates the scattering properties of the head. We compared the x-ray backscatter from eight phantoms: 20-cm-thick solid water, 16-cm diameter water-filled container, 16-cm CTDI phantom, modified-ANSI head phantom, 20-cm-thick PMMA, Kyoto-Kagaku PBU- 50 head, Phantom-Labs SK-150 head, and RSD RS-240T head. The phantoms were placed on the patient table with the entrance surface at 15 cm tube-side from the isocenter of a Toshiba Infinix C-arm, and the entrance-skin exposure was measured with a calibrated 6-cc PTW ionization chamber. The measurement included primary radiation, backscatter from the phantom and forward scatter from the table and pad. The variation in entrance-skin exposure was also measured as a function of the skin-entrance area for a 30x30 cm by 20-cm-thick PMMA phantom and the SK-150 head phantom using four different added beam filters. Results: The entranceskin exposure values measured for eight different phantoms differed by up to 12%, while the ratio of entrance exposure of all phantoms relative to solid water showed less than 3% variation with kVp. The change in entrance-skin exposure with entrance-skin area was found to differ for the SK-150 head compared to the 20-cm PMMA phantom and the variation with field area was dependent on the added beam filtration. Conclusion: To accurately calculate skin dose for neuro-interventional procedures with the DTS, the phantom for calibration should be carefully chosen since different

  1. Sentinel Lymph Node Biopsy in Nonmelanoma Skin Cancer Patients

    PubMed Central

    Matthey-Giè, Marie-Laure; Boubaker, Ariane; Letovanec, Igor; Demartines, Nicolas; Matter, Maurice

    2013-01-01

    The management of lymph nodes in nonmelanoma skin cancer patients is currently still debated. Merkel cell carcinoma (MCC), squamous cell carcinoma (SCC), pigmented epithelioid melanocytoma (PEM), and other rare skin neoplasms have a well-known risk to spread to regional lymph nodes. The use of sentinel lymph node biopsy (SLNB) could be a promising procedure to assess this risk in clinically N0 patients. Metastatic SNs have been observed in 4.5–28% SCC (according to risk factors), in 9–42% MCC, and in 14–57% PEM. We observed overall 30.8% positive SNs in 13 consecutive patients operated for high-risk nonmelanoma skin cancer between 2002 and 2011 in our institution. These high rates support recommendation to implement SLNB for nonmelanoma skin cancer especially for SCC patients. Completion lymph node dissection following positive SNs is also a matter of discussion especially in PEM. It must be remembered that a definitive survival benefit of SLNB in melanoma patients has not been proven yet. However, because of its low morbidity when compared to empiric elective lymph node dissection or radiation therapy of lymphatic basins, SLNB has allowed sparing a lot of morbidity and could therefore be used in nonmelanoma skin cancer patients, even though a significant impact on survival has not been demonstrated. PMID:23476781

  2. Evaluation of two-dimensional bolus effect of immobilization/support devices on skin doses: A radiochromic EBT film dosimetry study in phantom

    SciTech Connect

    Chiu-Tsao, Sou-Tung; Chan, Maria F.

    2010-07-15

    Purpose: In this study, the authors have quantified the two-dimensional (2D) perspective of skin dose increase using EBT film dosimetry in phantom in the presence of patient immobilization devices during conventional and IMRT treatments. Methods: For 6 MV conventional photon field, the authors evaluated and quantified the 2D bolus effect on skin doses for six different common patient immobilization/support devices, including carbon fiber grid with Mylar sheet, Orfit carbon fiber base plate, balsa wood board, Styrofoam, perforated AquaPlast sheet, and alpha-cradle. For 6 and 15 MV IMRT fields, a stack of two film layers positioned above a solid phantom was exposed at the air interface or in the presence of a patient alpha-cradle. All the films were scanned and the pixel values were converted to doses based on an established calibration curve. The authors determined the 2D skin dose distributions, isodose curves, and cross-sectional profiles at the surface layers with or without the immobilization/support device. The authors also generated and compared the dose area histograms (DAHs) and dose area products from the 2D skin dose distributions. Results: In contrast with 20% relative dose [(RD) dose relative to d{sub max} on central axis] at 0.0153 cm in the film layer for 6 MV 10x10 cm{sup 2} open field, the average RDs at the same depth in the film layer were 71%, 69%, 55%, and 57% for Orfit, balsa wood, Styrofoam, and alpha-cradle, respectively. At the same depth, the RDs were 54% under a strut and 26% between neighboring struts of a carbon fiber grid with Mylar sheet, and between 34% and 56% for stretched perforated AquaPlast sheet. In the presence of the alpha-cradle for the 6 MV (15 MV) IMRT fields, the hot spot doses at the effective measurement depths of 0.0153 and 0.0459 cm were 140% and 150% (83% and 89%), respectively, of the isocenter dose. The enhancement factor was defined as the ratio of a given DAH parameter (minimum dose received in a given area) with

  3. Characterization of differences in calculated and actual measured skin doses to canine limbs during stereotactic radiosurgery using Gafchromic film

    SciTech Connect

    Walters, Jerri; Ryan, Stewart; Harmon, Joseph F.

    2012-07-01

    Accurate calculation of absorbed dose to the skin, especially the superficial and radiosensitive basal cell layer, is difficult for many reasons including, but not limited to, the build-up effect of megavoltage photons, tangential beam effects, mixed energy scatter from support devices, and dose interpolation caused by a finite resolution calculation matrix. Stereotactic body radiotherapy (SBRT) has been developed as an alternative limb salvage treatment option at Colorado State University Veterinary Teaching Hospital for dogs with extremity bone tumors. Optimal dose delivery to the tumor during SBRT treatment can be limited by uncertainty in skin dose calculation. The aim of this study was to characterize the difference between measured and calculated radiation dose by the Varian Eclipse (Varian Medical Systems, Palo Alto, CA) AAA treatment planning algorithm (for 1-mm, 2-mm, and 5-mm calculation voxel dimensions) as a function of distance from the skin surface. The study used Gafchromic EBT film (International Specialty Products, Wayne, NJ), FilmQA analysis software, a limb phantom constructed from plastic water Trade-Mark-Sign (fluke Biomedical, Everett, WA) and a canine cadaver forelimb. The limb phantom was exposed to 6-MV treatments consisting of a single-beam, a pair of parallel opposed beams, and a 7-beam coplanar treatment plan. The canine forelimb was exposed to the 7-beam coplanar plan. Radiation dose to the forelimb skin at the surface and at depths of 1.65 mm and 1.35 mm below the skin surface were also measured with the Gafchromic film. The calculation algorithm estimated the dose well at depths beyond buildup for all calculation voxel sizes. The calculation algorithm underestimated the dose in portions of the buildup region of tissue for all comparisons, with the most significant differences observed in the 5-mm calculation voxel and the least difference in the 1-mm voxel. Results indicate a significant difference between measured and calculated data

  4. Patient doses in {gamma}-intracoronary radiotherapy: The Radiation Burden Assessment Study

    SciTech Connect

    Thierens, Hubert . E-mail: hubert.thierens@Ughent.be; Reynaert, Nick; Bacher, Klaus; Eijkeren, Marc van; Taeymans, Yves

    2004-10-01

    Purpose: To determine accurately the radiation burden of both patients and staff from intracoronary radiotherapy (IRT) with {sup 192}Ir and to investigate the importance of IRT in the patient dose compared with interventional X-rays. Methods and materials: The Radiation Burden Assessment Study (RABAS) population consisted of 9 patients undergoing {gamma}-IRT after percutaneous transluminal coronary angioplasty and 14 patients undergoing percutaneous transluminal coronary angioplasty only as the control group. For each patient, the dose to the organs and tissues from the internal and external exposure was determined in detail by Monte Carlo N-particle simulations. Patient skin dose measurements with thermoluminescence dosimeters served as verification. Staff dosimetry was performed with electronic dosimeters, thermoluminescence dosimeters, and double film badge dosimetry. Results: With respect to the patient dose from IRT, the critical organs are the thymus (58 mGy), lungs (31 mGy), and esophagus (27 mGy). The mean effective dose from IRT was 8 mSv. The effective dose values from interventional X-rays showed a broad range (2-28 mSv), with mean values of 8 mSv for the IRT patients and 13 mSv for the control group. The mean dose received by the radiotherapist from IRT was 4 {mu}Sv/treatment. The doses to the other staff members were completely negligible. Conclusion: Our results have shown that the patient and personnel doses in {gamma}-IRT remain at an acceptable level. The patient dose from IRT was within the variations in dose from the accompanying interventional X-rays.

  5. Patient dose, gray level and exposure index with a computed radiography system

    NASA Astrophysics Data System (ADS)

    Silva, T. R.; Yoshimura, E. M.

    2014-02-01

    Computed radiography (CR) is gradually replacing conventional screen-film system in Brazil. To assess image quality, manufactures provide the calculation of an exposure index through the acquisition software of the CR system. The objective of this study is to verify if the CR image can be used as an evaluator of patient absorbed dose too, through a relationship between the entrance skin dose and the exposure index or the gray level values obtained in the image. The CR system used for this study (Agfa model 30-X with NX acquisition software) calculates an exposure index called Log of the Median (lgM), related to the absorbed dose to the IP. The lgM value depends on the average gray level (called Scan Average Level (SAL)) of the segmented pixel value histogram of the whole image. A Rando male phantom was used to simulate a human body (chest and head), and was irradiated with an X-ray equipment, using usual radiologic techniques for chest exams. Thermoluminescent dosimeters (LiF, TLD100) were used to evaluate entrance skin dose and exit dose. The results showed a logarithm relation between entrance dose and SAL in the image center, regardless of the beam filtration. The exposure index varies linearly with the entrance dose, but the angular coefficient is beam quality dependent. We conclude that, with an adequate calibration, the CR system can be used to evaluate the patient absorbed dose.

  6. Iron deposition in skin of patients with haemochromatosis

    NASA Astrophysics Data System (ADS)

    Pinheiro, T.; Silva, J. N.; Alves, L. C.; Filipe, P.

    2003-09-01

    Haemochromatosis is the most common inherited liver disease in Caucasians and the most common autosomal recessive genetic disorder. It is characterized by inappropriately high iron absorption resulting in progressive iron overload in parenchymal organs such as liver, heart, pancreas, pituitary, joints, and skin. Upon early detection, haemochromatosis can be a manageable chronic disease but, if undetected, is potentially fatal. Skin biopsies were obtained from patients and from healthy donors. Images of the elemental distributions in skin were obtained using nuclear microscopy techniques (nuclear microprobe, NMP). Elemental profiles along skin, and intra-, and extra-cellular iron concentrations, were determined. Results for patients with haemochromatosis were cross-examined with morphologic features and with data obtained for healthy skin. Skin iron content is much increased in patients with haemochromatosis when compared with healthy subjects. Extensive iron deposits are observed at dermis, at the dermo-epidermal interface, at upper epidermis layers and at stratum corneum. Iron deposition was observed preferentially at cell boundaries or at the interstitial matrix.

  7. Development and Comparison of Warfarin Dosing Algorithms in Stroke Patients.

    PubMed

    Cho, Sun-Mi; Lee, Kyung-Yul; Choi, Jong Rak; Lee, Kyung-A

    2016-05-01

    The genes for cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) have been identified as important genetic determinants of warfarin dosing and have been studied. We developed warfarin algorithm for Korean patients with stroke and compared the accuracy of warfarin dose prediction algorithms based on the pharmacogenetics. A total of 101 patients on stable maintenance dose of warfarin were enrolled. Warfarin dosing algorithm was developed using multiple linear regression analysis. The performance of all the algorithms was characterized with coefficient of determination, determined by linear regression, and the mean of percent deviation was used to predict doses from the actual dose. In addition, we compared the performance of the algorithms using percentage of predicted dose falling within ±20% of clinically observed doses and dividing the patients into a low-dose group (≤3 mg/day), an intermediate-dose group (3-7 mg/day), and high-dose group (≥7 mg/day). A new developed algorithms including the variables of age, body weight, and CYP2C9 and VKORC1 genotype. Our algorithm accounted for 51% of variation in the warfarin stable dose, and performed best in predicting dose within 20% of actual dose and intermediate-dose group. Our warfarin dosing algorithm may be useful for Korean patients with stroke. Further studies to elucidate clinical utility of genotype-guided dosing and find the additional genetic association are necessary.

  8. Patient-specific organ dose estimation during transcatheter arterial embolization using Monte Carlo method and adaptive organ segmentation

    NASA Astrophysics Data System (ADS)

    Tsai, Hui-Yu; Lin, Yung-Chieh; Tyan, Yeu-Sheng

    2014-11-01

    The purpose of this study was to evaluate organ doses for individual patients undergoing interventional transcatheter arterial embolization (TAE) for hepatocellular carcinoma (HCC) using measurement-based Monte Carlo simulation and adaptive organ segmentation. Five patients were enrolled in this study after institutional ethical approval and informed consent. Gafchromic XR-RV3 films were used to measure entrance surface dose to reconstruct the nonuniform fluence distribution field as the input data in the Monte Carlo simulation. XR-RV3 films were used to measure entrance surface doses due to their lower energy dependence compared with that of XR-RV2 films. To calculate organ doses, each patient's three-dimensional dose distribution was incorporated into CT DICOM images with image segmentation using thresholding and k-means clustering. Organ doses for all patients were estimated. Our dose evaluation system not only evaluated entrance surface doses based on measurements, but also evaluated the 3D dose distribution within patients using simulations. When film measurements were unavailable, the peak skin dose (between 0.68 and 0.82 of a fraction of the cumulative dose) can be calculated from the cumulative dose obtained from TAE dose reports. Successful implementation of this dose evaluation system will aid radiologists and technologists in determining the actual dose distributions within patients undergoing TAE.

  9. Skin wound trauma, following high-dose radiation exposure, amplifies and prolongs skeletal tissue loss.

    PubMed

    Swift, Joshua M; Swift, Sibyl N; Smith, Joan T; Kiang, Juliann G; Allen, Matthew R

    2015-12-01

    The present study investigated the detrimental effects of non-lethal, high-dose (whole body) γ-irradiation on bone, and the impact that radiation combined with skin trauma (i.e. combined injury) has on long-term skeletal tissue health. Recovery of bone after an acute dose of radiation (RI; 8 Gy), skin wounding (15-20% of total body skin surface), or combined injury (RI+Wound; CI) was determined 3, 7, 30, and 120 days post-irradiation in female B6D2F1 mice and compared to non-irradiated mice (SHAM) at each time-point. CI mice demonstrated long-term (day 120) elevations in serum TRAP 5b (osteoclast number) and sclerostin (bone formation inhibitor), and suppression of osteocalcin levels through 30 days as compared to SHAM (p<0.05). Radiation-induced reductions in distal femur trabecular bone volume fraction and trabecular number through 120 days post-exposure were significantly greater than non-irradiated mice (p<0.05) and were exacerbated in CI mice by day 30 (p<0.05). Negative alterations in trabecular bone microarchitecture were coupled with extended reductions in cancellous bone formation rate in both RI and CI mice as compared to Sham (p<0.05). Increased osteoclast surface in CI animals was observed for 3 days after irradiation and remained elevated through 120 days (p<0.01). These results demonstrate a long-term, exacerbated response of bone to radiation when coupled with non-lethal wound trauma. Changes in cancellous bone after combined trauma were derived from extended reductions in osteoblast-driven bone formation and increases in osteoclast activity.

  10. Effects and dose-response relationships of skin cancer and blackfoot disease with arsenic

    PubMed Central

    Tseng, Wen-Ping

    1977-01-01

    In a limited area on the southwest coast of Taiwan, where artesian well water with a high concentration of arsenic has been used for more than 60 years, a high prevalence of chronic arsenicism has been observed in recent years. The total population of this “endemic” area is approximately 100,000. A general survey of 40,421 inhabitants and follow-up of 1,108 patients with blackfoot disease were made. Blackfoot disease, so-termed locally, is a peripheral vascular disorder resulting in gangrene of the extremities, especially the feet. The overall prevalence rates for skin cancer was 10.6 per 1000, and for blackfoot disease 8.9 per 1000. Generally speaking, the prevalence increased steadily with age in both diseases. The prevalence rates for skin cancer and blackfoot disease increased with the arsenic content of well water, i.e., the higher the arsenic content, the more patients with skin cancer and blackfoot disease. A dose–response relationship between blackfoot disease and the duration of water intake was also noted. Furthermore, the degree of permanent impairment of function in the patient was directly related to duration of intake of arsenical water and to duration of such intake at the time of onset. The most common cause of death in the patients with skin cancer and blackfoot disease was carcinoma of various sites. The 5-year survival rate after the onset of blackfoot disease was 76.3%; the 10-year survival rate was 63.3% and 15-year survival rate, 52.2%. The 50% survival point was 16 years after onset of the disease. ImagesFIGURE 1.FIGURE 2. PMID:908285

  11. Treatment with low-dose cytokines reduces oxidative-mediated injury in perilesional keratinocytes from vitiligo skin.

    PubMed

    Barygina, Victoria; Becatti, Matteo; Lotti, Torello; Moretti, Silvia; Taddei, Niccolò; Fiorillo, Claudia

    2015-08-01

    Vitiligo is a systemic dermatological disorder characterized by the loss of skin pigmentation due to melanocyte injury or aberrant functioning. Recent data underline its multifactorial etiology with significant involvement of autoimmune and redox alterations. The major role in vitiligo cellular immunity is displayed by augmented Th1 and Th17 and suppressed TREGs and Th2 lymphocyte populations. Our previous studies indicate a marked redox imbalance in perilesional ("PL", i.e. obtained from visibly unaffected skin surrounding the depigmented area in vitiligo patients) keratinocytes where the massive infiltration of inflammatory cells takes place. No defined therapy exists for vitiligo. Although a number of approaches have been used for the induction of TREGs and Th2 cells, they may be associated with significant off-target effects. In order to identify a targeted approach for vitiligo treatment we, first, aimed to investigate the possible source of ROS overproduction in PL keratinocytes. Second, we tested the effect of low-dose selected cytokines, on intra- and extracellular ROS production, cell viability and cell cycle of PL keratinocytes. The in vitro study was conducted on primary PL keratinocytes obtained from the skin of vitiligo patients in our previous studies. The activity of NADPH oxidase was measured on intact PL and control keratinocytes, treated or not with cytokines, by luminometric assay. The following cytokines were selected for PL keratinocytes treatment: IL-10 and IL-4 (produced by TREGs and Th2, respectively), basic fibroblasts growth factor (bFGF) and neuropeptide β-endorphin (modulating the cellular resistance to oxidative stress and the immune response, respectively). All cytokines were used at concentration of 10fg/ml and were prepared by sequential-kinetic-activation (SKA). Intracellular ROS production and cell cycle were analyzed by flow cytometry using H2DCFDA and propidium iodide dyes, respectively. Cell viability was measured by

  12. Patient-specific Monte Carlo dose calculations for 103Pd breast brachytherapy

    NASA Astrophysics Data System (ADS)

    Miksys, N.; Cygler, J. E.; Caudrelier, J. M.; Thomson, R. M.

    2016-04-01

    This work retrospectively investigates patient-specific Monte Carlo (MC) dose calculations for 103Pd permanent implant breast brachytherapy, exploring various necessary assumptions for deriving virtual patient models: post-implant CT image metallic artifact reduction (MAR), tissue assignment schemes (TAS), and elemental tissue compositions. Three MAR methods (thresholding, 3D median filter, virtual sinogram) are applied to CT images; resulting images are compared to each other and to uncorrected images. Virtual patient models are then derived by application of different TAS ranging from TG-186 basic recommendations (mixed adipose and gland tissue at uniform literature-derived density) to detailed schemes (segmented adipose and gland with CT-derived densities). For detailed schemes, alternate mass density segmentation thresholds between adipose and gland are considered. Several literature-derived elemental compositions for adipose, gland and skin are compared. MC models derived from uncorrected CT images can yield large errors in dose calculations especially when used with detailed TAS. Differences in MAR method result in large differences in local doses when variations in CT number cause differences in tissue assignment. Between different MAR models (same TAS), PTV {{D}90} and skin {{D}1~\\text{c{{\\text{m}}3}}} each vary by up to 6%. Basic TAS (mixed adipose/gland tissue) generally yield higher dose metrics than detailed segmented schemes: PTV {{D}90} and skin {{D}1~\\text{c{{\\text{m}}3}}} are higher by up to 13% and 9% respectively. Employing alternate adipose, gland and skin elemental compositions can cause variations in PTV {{D}90} of up to 11% and skin {{D}1~\\text{c{{\\text{m}}3}}} of up to 30%. Overall, AAPM TG-43 overestimates dose to the PTV ({{D}90} on average 10% and up to 27%) and underestimates dose to the skin ({{D}1~\\text{c{{\\text{m}}3}}} on average 29% and up to 48%) compared to the various MC models derived using the post-MAR CT images studied

  13. Patient-specific Monte Carlo dose calculations for (103)Pd breast brachytherapy.

    PubMed

    Miksys, N; Cygler, J E; Caudrelier, J M; Thomson, R M

    2016-04-07

    This work retrospectively investigates patient-specific Monte Carlo (MC) dose calculations for (103)Pd permanent implant breast brachytherapy, exploring various necessary assumptions for deriving virtual patient models: post-implant CT image metallic artifact reduction (MAR), tissue assignment schemes (TAS), and elemental tissue compositions. Three MAR methods (thresholding, 3D median filter, virtual sinogram) are applied to CT images; resulting images are compared to each other and to uncorrected images. Virtual patient models are then derived by application of different TAS ranging from TG-186 basic recommendations (mixed adipose and gland tissue at uniform literature-derived density) to detailed schemes (segmented adipose and gland with CT-derived densities). For detailed schemes, alternate mass density segmentation thresholds between adipose and gland are considered. Several literature-derived elemental compositions for adipose, gland and skin are compared. MC models derived from uncorrected CT images can yield large errors in dose calculations especially when used with detailed TAS. Differences in MAR method result in large differences in local doses when variations in CT number cause differences in tissue assignment. Between different MAR models (same TAS), PTV [Formula: see text] and skin [Formula: see text] each vary by up to 6%. Basic TAS (mixed adipose/gland tissue) generally yield higher dose metrics than detailed segmented schemes: PTV [Formula: see text] and skin [Formula: see text] are higher by up to 13% and 9% respectively. Employing alternate adipose, gland and skin elemental compositions can cause variations in PTV [Formula: see text] of up to 11% and skin [Formula: see text] of up to 30%. Overall, AAPM TG-43 overestimates dose to the PTV ([Formula: see text] on average 10% and up to 27%) and underestimates dose to the skin ([Formula: see text] on average 29% and up to 48%) compared to the various MC models derived using the post-MAR CT images

  14. Spontaneous skin regression and predictors of skin regression in Thai scleroderma patients.

    PubMed

    Foocharoen, Chingching; Mahakkanukrauh, Ajanee; Suwannaroj, Siraphop; Nanagara, Ratanavadee

    2011-09-01

    Skin tightness is a major clinical manifestation of systemic sclerosis (SSc). Importantly for both clinicians and patients, spontaneous regression of the fibrosis process has been documented. The purpose of this study is to identify the incidence and related clinical characteristics of spontaneous regression among Thai SSc patients. A historical cohort with 4 years of follow-up was performed among SSc patients over 15 years of age diagnosed with SSc between January 1, 2005 and December 31, 2006 in Khon Kaen, Thailand. The start date was the date of the first symptom and the end date was the date of the skin score ≤2. To estimate the respective probability of regression and to assess the associated factors, the Kaplan-Meier method and Cox regression analysis was used. One hundred seventeen cases of SSc were included with a female to male ratio of 1.5:1. Thirteen patients (11.1%) experienced regression. The incidence rate of spontaneous skin regression was 0.31 per 100 person-months and the average duration of SSc at the time of regression was 35.9±15.6 months (range, 15.7-60 months). The factors that negatively correlated with regression were (a) diffuse cutaneous type, (b) Raynaud's phenomenon, (c) esophageal dysmotility, and (d) colchicine treatment at onset with a respective hazard ratio (HR) of 0.19, 0.19, 0.26, and 0.20. By contrast, the factor that positively correlated with regression was active alveolitis with cyclophosphamide therapy at onset with an HR of 4.23 (95% CI, 1.23-14.10). After regression analysis, only Raynaud's phenomenon at onset and diffuse cutaneous type had a significantly negative correlation to regression. A spontaneous regression of the skin fibrosis process was not uncommon among Thai SSc patients. The factors suggesting a poor predictor for cutaneous manifestation were Raynaud's phenomenon, diffuse cutaneous type while early cyclophosphamide therapy might be related to a better skin outcome.

  15. Self-assessment of skin tightness severity by scleroderma patients.

    PubMed

    Daungkum, Kittikorn; Foocharoen, Chingching; Mahakkanukrauh, Ajanee; Suwannaroj, Siraphop; Thinkhamrop, Bandit; Nanagara, Ratanavadee

    2016-10-01

    Skin tightness progression determines the severity and mortality of systemic sclerosis (SSc). The modified Rodnan skin score (mRSS) is a skin tightness assessment tool, albeit inter-physician variability is a limitation. Our objectives were to evaluate the correlation and agreement of skin tightness assessment between patient self-assessment and physician-assessment. A descriptive study was conducted on the masked, self-assessments of mRSS (at week 0, 4 and 12) by 23 Thai adult SSc patients seen at Srinagarind Hospital, KhonKaen University, between March 2014 and February 2015. Correlation between the physician and patient assessments was estimated using Pearson's. The intra-class correlation coefficient (ICC) and limit of agreement by Bland-Altman were determined. We included 23 SSc patients (female to male ratio being 1.1:1). All had the diffuse cutaneous SSc subset. The skin thickness assessment correlation was moderate at baseline (Pearson's r = 0.68) and improved to a good correlation at week 4 and 12 (r = 0.78 and 0.86, respectively). The ICC showed good agreement (0.761) at week 0 and increased to excellent at week 4 (0.846) and 12 (0.910). The patient self-assessment score was higher than the physician assessment, which slightly decreased over time: mean difference = 4.30 (95% LOA;-9.54 to 18.14) at week 0, then 3.78 (95% LOA,-10.20 to 17.77) at week 4, and 3.16 (95% LOA,-7.78 to 14.10) at week 12. The respective modified Rodnan skin score assessment by patient versus the physician was highly correlated with a high level of agreement. Validation of generalized patient self-assessment needs to be confirmed. © 2016 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.

  16. Ultraviolet-B radiation increases serum 25-hydroxyvitamin D levels: the effect of UVB dose and skin color.

    PubMed

    Armas, Laura A G; Dowell, Susan; Akhter, Mohammed; Duthuluru, Sowjanya; Huerter, Christopher; Hollis, Bruce W; Lund, Richard; Heaney, Robert P

    2007-10-01

    Ultraviolet (UV)-B light increases vitamin D levels, but the dose response and the effect of skin pigmentation have not been well characterized. We sought to define the relationship between UVB exposure and 25-hydroxyvitamin D (25-OH-D) concentrations as a function of skin pigmentation. Seventy two participants with various skin tones had 90% of their skin exposed to UVB light (20-80 mJ/cm2) 3 times a week for 4 weeks. Serum 25-OH-D was measured weekly. Eighty percent of the variation in treatment response was explained by UVB dose and skin tone. Therapeutically important changes in 25-OH-D were achieved with minimal tanning. Four weeks was not long enough to reach a steady state at the higher dose rates. The response of 25-OH-D levels to UVB light is dependent on skin pigmentation and the amount of UVB given, and useful increases in vitamin D status can be achieved by defined UVB doses small enough to produce only minimal tanning.

  17. Combination of MALDI-MSI and cassette dosing for evaluation of drug distribution in human skin explant.

    PubMed

    Sørensen, Isabella S; Janfelt, Christian; Nielsen, Mette Marie B; Mortensen, Rasmus W; Knudsen, Nina Ø; Eriksson, André H; Pedersen, Anders J; Nielsen, Kim T

    2017-08-01

    Study of skin penetration and distribution of the drug compounds in the skin is a major challenge in the development of topical drug products for treatment of skin diseases. It is crucial to have fast and efficacious screening methods which can provide information concerning the skin penetration and the distribution of the drug molecules in the region of the target. Mass spectrometry imaging (MSI) such as matrix-assisted laser desorption/ionization (MALDI)-MSI offers the opportunity to analyze the drug distribution at micrometer scale, but is a low throughput technique. Cassette dosing of drug molecules has been widely used for two decades as a high throughput screening tool for plasma pharmacokinetic analysis. The purpose of this study is to evaluate the utility of combining MALDI-MSI with cassette dosing to obtain a medium throughput screening technique for drug distribution in the skin directly from thin tissue sections. Excised fresh human skin was treated with two different formulation types containing both single drugs and a cassette with four drugs. Biopsies were taken and analyzed with traditional UHPLC-MS/MS and MALDI-MSI. The results reveal that skin penetration data of the four drugs administered together were in agreement with skin penetration data obtained when the molecules were administered individually. Furthermore, the MALDI-MSI data reveal different distribution profiles of the four drugs which were not possible to deduce from the UHPLC-MS/MS bioanalysis. These findings suggest that combination of MALDI-MSI and cassette dosing can be used as a medium throughput screening tool at an early stage in the drug discovery/development process. Graphical abstract Investigation of drug distribution in human skin explant by MALDI-MSI after cassette dosing.

  18. Recommendations for adjunctive basic skin care in patients with psoriasis.

    PubMed

    Luger, Thomas; Seite, Sophie; Humbert, Philippe; Krutmann, Jean; Triller, Raoul; Dréno, Brigitte

    2014-01-01

    Psoriasis is a multifactorial disease involving both genetic predisposition and external triggers, resulting in epidermal and immune dysfunctions. Regardless of the severity of the disease, patients require additional basic topical treatment with emollients. Basic skin care products are well known for their role in moisture retention and symptom control in psoriasis, yet patients underuse them. Dry skin and cutaneous inflammation are associated with an impaired epidermal barrier function. This breakdown of the skin barrier causes the release of pro-inflammatory mediators that exaggerate inflammation. to provide recommendations for the use of emollients (including ceramides, urea, keratolytic agents, zinc salts, niacinamide), thermal water and skin care products in psoriasis. A review of the current literature from 2000 to 2012 using Medline and Ovid was performed by a working group of five European Dermatologists with clinical and research experience in psoriasis. Either alone or used adjunctively, basic topical therapy can restore and protect skin barrier function, increase remission times between flare-ups and enhance the effects of pharmaceutical therapy. We provide physicians with a tool to assist them in implementing basic skin care in an integrated disease management approach.

  19. Low-dose versus standard-dose CT protocol in patients with clinically suspected renal colic.

    PubMed

    Poletti, Pierre-Alexandre; Platon, Alexandra; Rutschmann, Olivier T; Schmidlin, Franz R; Iselin, Christophe E; Becker, Christoph D

    2007-04-01

    The purpose of our study was to compare a low-dose abdominal CT protocol, delivering a dose of radiation close to the dose delivered by abdominal radiography, with standard-dose unenhanced CT in patients with suspected renal colic. One hundred twenty-five patients (87 men, 38 women; mean age, 45 years) who were admitted with suspected renal colic underwent both abdominal low-dose CT (30 mAs) and standard-dose CT (180 mAs). Low-dose CT and standard-dose CT were independently reviewed, in a delayed fashion, by two radiologists for the characterization of renal and ureteral calculi (location, size) and for indirect signs of renal colic (renal enlargement, pyeloureteral dilatation, periureteral or renal stranding). Results reported for low-dose CT, with regard to the patients' body mass indexes (BMIs), were compared with those obtained with standard-dose CT (reference standard). The presence of non-urinary tract-related disorders was also assessed. Informed consent was obtained from all patients. In patients with a BMI < 30, low-dose CT achieved 96% sensitivity and 100% specificity for the detection of indirect signs of renal colic and a sensitivity of 95% and a specificity of 97% for detecting ureteral calculi. In patients with a BMI < 30, low-dose CT was 86% sensitive for detecting ureteral calculi < 3 mm and 100% sensitive for detecting calculi > 3 mm. Low-dose CT was 100% sensitive and specific for depicting non-urinary tract-related disorders (n = 6). Low-dose CT achieves sensitivities and specificities close to those of standard-dose CT in assessing the diagnosis of renal colic, depicting ureteral calculi > 3 mm in patients with a BMI < 30, and correctly identifying alternative diagnoses.

  20. Patient doses using multidetector computed tomography scanners in Kenya.

    PubMed

    Korir, G K; Wambani, J S; Korir, I K

    2012-08-01

    Assessment of patient dose attributed to multislice computed tomography (CT) examination. A questionnaire method was developed and used in recording the patient dose and scanning parameters for the head, chest, abdomen and lumbar spine examinations. The patient doses due to brain, chest and abdomen examination were above the international diagnostic reference levels (DRLs) by factors of between one and four. The study demonstrated that the use of multislice CT elevates patient radiation dose, justifying the need for local optimised scanning protocols and the use of institutional DRL for dose management without affecting diagnostic image quality.

  1. A trace metal (zinc and iron) study on low dose x-radiation response in rat skin.

    PubMed

    Chatterjee, J; Chaudhuri, K; Das, A K; Basu, S K; De, K; Majumdar, S

    1997-08-01

    There is no reliable bio-dosimeter regarding low dose radiation effects in mammalian systems. In this study, chronic low dose (< 1 cGy) whole body x-irradiated rat skin have shown altered trace metal (zinc and iron) content which clearly indicated the redistribution of these metals in the integumentary system. The decreased zinc to iron ratios suggested enhanced oxidative stress of the tissue. Changes in trace metal content in irradiated rat skin, as a biological response to low dose radiation, were non-linear. Moreover, the lowered zinc content of E2, E3, E4 and E5 dose groups suggested a different steady state, compared to the control. The Zn: Fe ratio decreased with increasing radiation dose.

  2. The effect of low dose ionizing radiation on homeostasis and functional integrity in an organotypic human skin model.

    PubMed

    von Neubeck, Claere; Geniza, Matthew J; Kauer, Paula M; Robinson, R Joe; Chrisler, William B; Sowa, Marianne B

    2015-05-01

    Outside the protection of Earth's atmosphere, astronauts are exposed to low doses of high linear energy transfer (LET) radiation. Future NASA plans for deep space missions or a permanent settlement on the moon are limited by the health risks associated with space radiation exposures. There is a paucity of direct epidemiological data for low dose exposures to space radiation-relevant high LET ions. Health risk models are used to estimate the risk for such exposures, though these models are based on high dose experiments. There is increasing evidence, however, that low and high dose exposures result in different signaling events at the molecular level, and may involve different response mechanisms. Further, despite their low abundance, high LET particles have been identified as the major contributor to health risk during manned space flight. The human skin is exposed in every external radiation scenario, making it an ideal epithelial tissue model in which to study radiation induced effects. Here, we exposed an in vitro three dimensional (3-D) human organotypic skin tissue model to low doses of high LET oxygen (O), silicon (Si) and iron (Fe) ions. We measured proliferation and differentiation profiles in the skin tissue and examined the integrity of the skin's barrier function. We discuss the role of secondary particles in changing the proportion of cells receiving a radiation dose, emphasizing the possible impact on radiation-induced health issues in astronauts.

  3. An effective dose assessment technique with NORM added consumer products using skin-point source on computational human phantom.

    PubMed

    Yoo, Do Hyeon; Shin, Wook-Geun; Lee, Hyun Cheol; Choi, Hyun Joon; Testa, Mauro; Lee, Jae Kook; Yeom, Yeon Soo; Kim, Chan Hyeong; Min, Chul Hee

    2016-12-01

    The aim of this study is to develop the assessment technique of the effective dose by calculating the organ equivalent dose with a Monte Carlo (MC) simulation and a computational human phantom for the naturally occurring radioactive material (NORM) added consumer products. In this study, we suggests the method determining the MC source term based on the skin-point source enabling the convenient and conservative modeling of the various type of the products. To validate the skin-point source method, the organ equivalent doses were compared with that by the product modeling source of the realistic shape for the pillow, waist supporter, sleeping mattress etc. Our results show that according to the source location, the organ equivalent doses were observed as the similar tendency for both source determining methods, however, it was observed that the annual effective dose with the skin-point source was conservative than that with the modeling source with the maximum 3.3 times higher dose. With the assumption of the gamma energy of 1MeV and product activity of 1Bqg(-1), the annual effective doses of the pillow, waist supporter and sleeping mattress with skin-point source was 3.09E-16SvBq(-1)year(-1), 1.45E-15SvBq(-1)year(-1), and 2,82E-16SvBq(-1)year(-1), respectively, while the product modeling source showed 9.22E-17SvBq(-1)year(-1), 9.29E-16SvBq(-1)year(-1), and 8.83E-17SvBq(-1)year(-1), respectively. In conclusion, it was demonstrated in this study that the skin-point source method could be employed to efficiently evaluate the annual effective dose due to the usage of the NORM added consumer products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Effects of filters and wedges on skin sparing and gamma/neutron dose ratios in neutron teletherapy.

    PubMed

    Smathers, J; Graves, R; Almond, P; Otte, V; Grant, W

    1980-01-01

    The effects of skin sparing and the gamma/neutron dose ratios in the clinical situations presently in use at the TAMVEC neutron teletherapy facility are not appreciably affected by the presence of filters and/or wedges. It is also shown that if skin sparing is lost due to close proximity of a hydrogenous scattering source, it can be restored by the use of thin lead filters.

  5. Evaluation of skin thickness lesions in patients with Lyme disease measured by modified Rodnan total skin score.

    PubMed

    Moniuszko, A; Gińdzieńska-Sieśkiewicz, E; Pancewicz, S A; Czupryna, P; Zajkowska, J; Sierakowski, S

    2012-10-01

    Recently, a possible etiological connection between infection with Borrelia burgdorferi and various skin lesions, including morphea and systemic sclerosis (SSc), has been discussed. The aim of our study was the evaluation of frequency of skin thickening typical of SSc or morphea in the group of patients with Lyme disease (LD) with frequent exposition to tick bites. The group consisted of 110 patients with LD frequently exposed to tick bites form the northeastern Poland, which is an endemic area for this disease. To measure the skin lesions, the modified Rodnan total skin score (RTSS) was used. In the analyzed group, no skin changes typical of morphea or skin thickening were found. According to RTSS, all patients scored 0 points. Raynaud's phenomenon in all patients was not found. The relationship between scleroderma or morphea and LD is still a matter of controversy. Described by some authors, cases with LD and scleroderma may be associated with co-existence of B. burgdorferi infection with autoimmune process.

  6. Carcinogenically relevant split dose repair increased with age in rat skin model.

    NASA Astrophysics Data System (ADS)

    Burns, Fredric; Tang, Moon-Shong Eric; Wu, Feng; Uddin, Ahmed

    2012-07-01

    These experiments utilize cancer induction to evaluate cancer-relevant repair during the interval between dose fractions. Low LET electron radiation(LET ~ 0.34 keV/u) were utilized in experiments that involved exposing rat dorsal skin to 2 equal 8 Gy dose fractions separated at various intervals from 0.25 h to 24 h. Cancer onset was established for 80 weeks after the exposures and only histologically verified cancers were included in the analysis. This experiment involved a total of 540 rats and 880 induced cancers. In the youngest rats (irradiated at 28 days of age) the cancer yield declined with a halftime of approximately 3.5 hrs. In 113 day old rats the cancer yield halftime was shortened to 1.3 hrs. In the oldest rats (182 days of age), the halftime could not be established quantitatively, because it was less than the shortest interval (15 min) utilized in the protocol (best estimate ~5 min). In the oldest rats the cancer yields for all fractionated exposures dropped essentially to the expected level of 2 single fractions, below which theoretically no further reduction is possible. The follow-up times for obtaining cancer yields were the same for all exposure groups in spite of the differing ages at exposure. These results indicate that repair of carcinogenically-relevant damage accelerates with age of the rat. No information is available on the possible mechanistic basis for this finding, although the model might be useful for delineating which of the many postulated split dose repair pathways is the correct one. The finding indicates that older rats should be less susceptible to the carcinogenic action of single doses of low LET radiation in comparison to younger rats, which has been verified in separate studies.

  7. Optimisation of a dosing regime for a topical skin protectant (barrier cream).

    PubMed

    Chilcott, Robert P; Larner, Joanne; Matar, Hazem; Kansagra, Sneha; Theivendran, Baveetharan; Viegas, Vanessa Anne; Goldman, Virginia Streusand

    2015-01-01

    Topical skin protectants (barrier creams) have the potential to reduce or enhance the severity of dermal lesions following exposure to allergens or irritants. Therefore, it is essential that such products are subject to appropriate clinical evaluation prior to marketing. Consequently, it is important to accurately define a dosing regime in order to assess test products under appropriate conditions. In this study, we extended the use of a standard rubefacient (methyl nicotinate; MN) assay to establish the optimum thickness and duration of action of a novel barrier cream (RD1433). White petroleum jelly (Vaseline(®)) was used as a comparator product. The dermal response to MN was measured on the volar forearm skin of volunteers (n = 12; average age 47.5 years) using an array of biophysical instruments and visual scoring. When applied at a nominal thickness of 0.1 mm, RD1433 retained effectiveness against MN for up to six hours. In contrast, Vaseline(®) was relatively ineffective. Moreover, RD1433 provoked no measurable signs of irritation and so can be considered acceptable for further clinical evaluation. Future clinical studies using RD1433 should be based on topical application of a 0.1 mm thickness layer every six hours.

  8. Quantitative Proteomic Profiling of Low-Dose Ionizing Radiation Effects in a Human Skin Model

    PubMed Central

    Hengel, Shawna M.; Aldrich, Joshua T.; Waters, Katrina M.; Pasa-Tolic, Ljiljana; Stenoien, David L.

    2014-01-01

    To assess responses to low-dose ionizing radiation (LD-IR) exposures potentially encountered during medical diagnostic procedures, nuclear accidents or terrorist acts, a quantitative proteomic approach was used to identify changes in protein abundance in a reconstituted human skin tissue model treated with 0.1 Gy of ionizing radiation. To improve the dynamic range of the assay, subcellular fractionation was employed to remove highly abundant structural proteins and to provide insight into radiation-induced alterations in protein localization. Relative peptide quantification across cellular fractions, control and irradiated samples was performing using 8-plex iTRAQ labeling followed by online two-dimensional nano-scale liquid chromatography and high resolution MS/MS analysis. A total of 107 proteins were detected with statistically significant radiation-induced change in abundance (>1.5 fold) and/or subcellular localization compared to controls. The top biological pathways identified using bioinformatics include organ development, anatomical structure formation and the regulation of actin cytoskeleton. From the proteomic data, a change in proteolytic processing and subcellular localization of the skin barrier protein, filaggrin, was identified, and the results were confirmed by western blotting. This data indicate post-transcriptional regulation of protein abundance, localization and proteolytic processing playing an important role in regulating radiation response in human tissues. PMID:28250387

  9. The relationship between skin symptoms and the scleroderma modification of the health assessment questionnaire, the modified Rodnan skin score, and skin pathology in patients with systemic sclerosis.

    PubMed

    Ziemek, Jessica; Man, Ada; Hinchcliff, Monique; Varga, John; Simms, Robert W; Lafyatis, Robert

    2016-05-01

    To determine how well skin symptoms considered specific to SSc are captured by patient reported outcomes currently used for assessing patients with SSc, the SHAQ, or skin disease, the Skindex-29; and how well these symptoms correlate with the extent of skin disease on physical exam and skin pathology. SSc patients completed the scleroderma modification of the Health Assessment Questionnaire (SHAQ), Skindex-29 and a Skin Symptom Assessment questionnaire developed for this study. Correlations were assessed between the Skin Symptom Assessment and SHAQ, Skindex-29, modified Rodnan skin score, and skin pathological features including myofibroblast staining completed on the same date. Tight, hard and rigid/stiff skin symptoms correlated moderately highly with the modified Rodnan skin score (r = 0.445, P = 0.0008; r = 0.486, P = 0.0002; and r = 0.488, P = 0.0002, respectively). Tight skin symptoms correlated moderately with myofibroblast infiltration (r = 0.544, P = 0.0023) and hyalinized collagen (r = 0.442, P = 0.0164), while both hard and rigid/stiff skin correlated moderately with inflammation (r = 0.401, P = 0.0310 and r = 0.513, P = 0.0045), myofibroblast infiltration(r = 0.480, P = 0.0084 and r = 0.527, P = 0.0033) and hyalinized collagen (r = 0.453, P = 0.0137 and r = 0.478, P = 0.0087), while the SHAQ was not found to correlate with any of these pathological changes. In contrast, painful skin symptoms correlated moderately with the SHAQ (r = 0.413, P = 0.0073), and with the three domains of Skindex-29: Symptoms, Emotions and Functioning. Skindex-29 indicates that dcSSc patient skin symptoms are nearly as severe as those of patients with psoriasis or atopic dermatitis. Patient reported skin symptoms correlate with clinical and pathological measures in the skin. A validated patient reported skin symptom instrument might considerably improve evaluation of SSc skin disease. © The Author 2016. Published by Oxford University Press on behalf of the British Society for

  10. Warfarin maintenance dose in older patients: higher average dose and wider dose frequency distribution in patients of African ancestry than those of European ancestry.

    PubMed

    Garwood, Candice L; Clemente, Jennifer L; Ibe, George N; Kandula, Vijay A; Curtis, Kristy D; Whittaker, Peter

    2010-06-15

    Studies report that warfarin doses required to maintain therapeutic anticoagulation decrease with age; however, these studies almost exclusively enrolled patients of European ancestry. Consequently, universal application of dosing paradigms based on such evidence may be confounded because ethnicity also influences dose. Therefore, we determined if warfarin dose decreased with age in Americans of African ancestry, if older African and European ancestry patients required different doses, and if their daily dose frequency distributions differed. Our chart review examined 170 patients of African ancestry and 49 patients of European ancestry cared for in our anticoagulation clinic. We calculated the average weekly dose required for each stable, anticoagulated patient to maintain an international normalized ratio of 2.0 to 3.0, determined dose averages for groups <70, 70-79, and >80 years of age and plotted dose as a function of age. The maintenance dose in patients of African ancestry decreased with age (P<0.001). In addition, older patients of African ancestry required higher average weekly doses than patients of European ancestry: 33% higher in the 70- to 79-year-old group (38.2+/-1.9 vs. 28.8+/-1.7 mg; P=0.006) and 52% in the >80-year-old group (33.2+/-1.7 vs. 21.8+/-3.8 mg; P=0.011). Therefore, 43% of older patients of African ancestry required daily doses >5mg and hence would have been under-dosed using current starting-dose guidelines. The dose frequency distribution was wider for older patients of African ancestry compared to those of European ancestry (P<0.01). The higher doses required by older patients of African ancestry indicate that strategies for initiating warfarin therapy based on studies of patients of European ancestry could result in insufficient anticoagulation and thereby potentially increase their thromboembolism risk. Copyright 2010 Elsevier Inc. All rights reserved.

  11. Patient radiation doses for electron beam CT

    SciTech Connect

    Castellano, Isabel A.; Dance, David R.; Skinner, Claire L.; Evans, Phil M.

    2005-08-15

    A Monte Carlo based computer model has been developed for electron beam computed tomography (EBCT) to calculate organ and effective doses in a humanoid hermaphrodite phantom. The program has been validated by comparison with experimental measurements of the CT dose index in standard head and body CT dose phantoms; agreement to better than 8% has been found. The robustness of the model has been established by varying the input parameters. The amount of energy deposited at the 12:00 position of the standard body CT dose phantom is most susceptible to rotation angle, whereas that in the central region is strongly influenced by the beam quality. The program has been used to investigate the changes in organ absorbed doses arising from partial and full rotation about supine and prone subjects. Superficial organs experience the largest changes in absorbed dose with a change in subject orientation and for partial rotation. Effective doses for typical clinical scan protocols have been calculated and compared with values obtained using existing dosimetry techniques based on full rotation. Calculations which make use of Monte Carlo conversion factors for the scanner that best matches the EBCT dosimetric characteristics consistently overestimate the effective dose in supine subjects by typically 20%, and underestimate the effective dose in prone subjects by typically 13%. These factors can therefore be used to correct values obtained in this way. Empirical dosimetric techniques based on the dose-length product yield errors as great as 77%. This is due to the sensitivity of the dose length product to individual scan lengths. The magnitude of these errors is reduced if empirical dosimetric techniques based on the average absorbed dose in the irradiated volume (CTDI{sub vol}) are used. Therefore conversion factors specific to EBCT have been calculated to convert the CTDI{sub vol} to an effective dose.

  12. Invasive Aspergillosis with Disseminated Skin Involvement in a Patient with Acute Myeloid Leukemia: A Rare Case

    PubMed Central

    Mert, Duygu; Iskender, Gülşen; Duygu, Fazilet; Merdin, Alparslan; Dal Mehmet, Sinan; Dogan, Mehmet; Tekgündüz, Emre; Ertek, Mustafa; Altuntaş, Fevzi

    2017-01-01

    Invasive pulmonary aspergillosis is most commonly seen in immunocompromised patients. Besides, skin lesions may also develop due to invasive aspergillosis in those patients. A 49-year-old male patient was diagnosed with acute myeloid leukemia. The patient developed bullous and zosteriform lesions on the skin after the 21st day of hospitalization. The skin biopsy showed hyphae. Disseminated skin aspergillosis was diagnosed to the patient. Voricanazole treatment was initiated. The patient was discharged once the lesions started to disappear. PMID:28626542

  13. Detection of human papillomavirus in nonmelanoma skin cancer lesions and healthy perilesional skin in kidney transplant recipients and immunocompetent patients.

    PubMed

    Bernat-García, J; Morales Suárez-Varela, M; Vilata-Corell, J J; Marquina-Vila, A

    2014-04-01

    The influence of human papillomavirus (HPV) on the development of nonmelanoma skin cancer (NMSC) is a topic of debate. HPV types from the beta genus (HPV-β) have been most frequently associated with the development of skin cancer. To analyze the prevalence and range of HPV types in NMSC lesions and healthy perilesional skin in immunodepressed and immunocompetent patients and to evaluate the influence of various clinical factors on the prevalence of HPV in skin cancer. Nested polymerase chain reaction and sequencing were used to detect HPV in 120 NMSC samples obtained by biopsy from 30 kidney transplant recipients and 30 immunocompetent patients. In all cases, a sample was taken from the tumor site and the surrounding healthy skin. Potential confounders were assessed and the data analyzed by multivariate logistic regression. HPV DNA was detected in 44 (73.3%) of the 60 samples from immunodepressed patients and in 32 (53.3%) of the 60 samples from immunocompetent patients (adjusted odds ratio, 3.4; 95% CI, 1.2-9.6). In both groups of patients, HPV was more common in healthy perilesional skin than in lesional skin. HPV-β was the most common type isolated. We found a wide range of HPV types (mostly HPV-β) in the skin of kidney transplant recipients and immunocompetent patients with skin cancer. Copyright © 2013 Elsevier España, S.L. and AEDV. All rights reserved.

  14. Effects of chronic low-dose ultraviolet B radiation on DNA damage and repair in mouse skin.

    PubMed

    Mitchell, D L; Greinert, R; de Gruijl, F R; Guikers, K L; Breitbart, E W; Byrom, M; Gallmeier, M M; Lowery, M G; Volkmer, B

    1999-06-15

    Chronic exposure to sunlight causes skin cancer in humans, yet little is known about how habitual exposure to low doses of ultraviolet B radiation (UVB) affects DNA damage in the skin. We treated Skh-1 hairless mice with daily doses of suberythemal UVB for 40 days and analyzed the amount and distribution of DNA photodamage using RIAs and immunofluorescence micrography. We found that DNA damage accumulated in mouse skin as a result of chronic irradiation and that this damage persisted in the dermis and epidermis for several weeks after the chronic treatment was terminated. Although the persistent damage was evenly distributed throughout the dermis, it remained in the epidermis as a small number of heavily damaged cells at the dermal-epidermal boundary. Rates of DNA damage induction and repair were determined at different times over the course of chronic treatment in response to a higher challenge dose of UVB light. The amount of damage induced by the challenge dose increased in response to chronic exposure, and excision repair of cyclobutane pyrimidine dimers and pyrimidine(6-4)pyrimidone dimers was significantly reduced. The sensitization of mouse epidermal DNA to photoproduct induction, the reduction in excision repair, and the accumulation of nonrepairable DNA damage in the dermis and epidermis suggest that chronic low-dose exposure to sunlight may significantly enhance the predisposition of mammalian skin to sunlight-induced carcinogenesis.

  15. Trends in Opioid Dosing Among Washington State Medicaid Patients Before and After Opioid Dosing Guideline Implementation.

    PubMed

    Sullivan, Mark D; Bauer, Amy M; Fulton-Kehoe, Deborah; Garg, Renu K; Turner, Judith A; Wickizer, Thomas; Franklin, Gary M

    2016-05-01

    By 2007, opioid-related mortality in Washington state (WA) was 50% higher than the national average, with Medicaid patients showing nearly 6 times the mortality of commercially-insured patients. In 2007, the WA Interagency Guideline on Opioid Dosing for Chronic Non-cancer Pain was released, which recommended caution in prescribing >120 mg morphine-equivalent dose per day for patients not showing clinically meaningful improvement in pain and function. We report on opioid dosing in the WA Medicaid fee-for-service population for 273,200 adults with a paid claim for an opioid prescription between April 1, 2006 and December 31, 2010. Linear regression was used to test for trends in dosing over that time period, with quarter-year as the independent variable and median daily dose as the dependent variable. Prescription opioid use among WA Medicaid adults peaked in 2009, as evidenced by the unique number of opioid users (105,232), the total number of prescriptions (556,712), and the total person-years of prescription opioid use (29,442). Median opioid dose was unchanged from 2006 to 2010 at 37.5 mg morphine-equivalent dose, but doses at the 75th, 90th, 95th, and 99th percentiles declined significantly (P < .001). These results suggest that opioid treatment guidelines with dosing guidance may be able to reduce high-dose opioid use without affecting the median dose used. Some fear that opioid dosing guidelines might restrict access to opioid therapy for patients who could benefit. However, there is evidence that high-dose opioid therapy entails significant risks without demonstrated benefit. These findings indicate that high-dose opioid therapy can be reduced without altering median opioid dose in a Medicaid population. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

  16. Radiation dose enhancement in skin therapy with nanoparticle addition: A Monte Carlo study on kilovoltage photon and megavoltage electron beams.

    PubMed

    Zheng, Xiao J; Chow, James C L

    2017-02-28

    To investigated the dose enhancement due to the incorporation of nanoparticles in skin therapy using the kilovoltage (kV) photon and megavoltage (MV) electron beams. Monte Carlo simulations were used to predict the dose enhancement when different types and concentrations of nanoparticles were added to skin target layers of varying thickness. Clinical kV photon beams (105 and 220 kVp) and MV electron beams (4 and 6 MeV), produced by a Gulmay D3225 orthovoltage unit and a Varian 21 EX linear accelerator, were simulated using the EGSnrc Monte Carlo code. Doses at skin target layers with thicknesses ranging from 0.5 to 5 mm for the photon beams and 0.5 to 10 mm for the electron beams were determined. The skin target layer was added with the Au, Pt, I, Ag and Fe2O3 nanoparticles with concentrations ranging from 3 to 40 mg/mL. The dose enhancement ratio (DER), defined as the dose at the target layer with nanoparticle addition divided by the dose at the layer without nanoparticle addition, was calculated for each nanoparticle type, nanoparticle concentration and target layer thickness. It was found that among all nanoparticles, Au had the highest DER (5.2-6.3) when irradiated with kV photon beams. Dependence of the DER on the target layer thickness was not significant for the 220 kVp photon beam but it was for 105 kVp beam for Au nanoparticle concentrations higher than 18 mg/mL. For other nanoparticles, the DER was dependent on the atomic number of the nanoparticle and energy spectrum of the photon beams. All nanoparticles showed an increase of DER with nanoparticle concentration during the photon beam irradiations regardless of thickness. For electron beams, the Au nanoparticles were found to have the highest DER (1.01-1.08) when the beam energy was equal to 4 MeV, but this was drastically lower than the DER values found using photon beams. The DER was also found affected by the depth of maximum dose of the electron beam and target thickness. For other nanoparticles with

  17. Investigation of dose-related effects of carnosine on anxiety with sympathetic skin response and T-maze.

    PubMed

    Dolu, Nazan; Acer, Hale; Kara, Ali Yucel

    2014-01-01

    Carnosine is a dipeptide formed of the amino acids β-alanine and histidine. Only a limited number of studies have examined the effects of carnosine on sympathetic nerve activation and anxiety. The present study was undertaken to determine the dose-related effects of carnosine on anxiety in the elevated T-maze test (ETM) with electrodermal activity (EDA). Carnosine was injected in three groups of rats with doses of 10 (low dose), 100 (medium dose) and 1000 (high dose) mg/kg i.p. Physiological saline was injected in the sham group. The anxiety scores of the rats were measured with ETM 20 minutes after injection. Then, SCL was measured. The decreased number of entries into the open arm (NEOA), the percentage of time spent in the open arm (% TSOA) and higher EDA [shown by skin conductance level (SCL)] indicate higher anxiety. The NEOA and % TSOA were lower in the high-dose group than in the other groups. SCL was lower in the medium-dose carnosine group than in the high-dose carnosine and sham groups. SCL was higher in the high-dose group than in the medium-dose and sham groups. Our results suggest that high-dose carnosine produced anxiety-like effects as assessed in the SCL and ETM. Medium-dose carnosine acted as an anxiolytic. The anxiety-related responses of carnosine depend on its dose-related effect.

  18. Management of "refractory" skin disease in patients with lupus erythematosus.

    PubMed

    Callen, Jeffrey P

    2005-10-01

    Skin disease in patients with lupus erythematosus can be subdivided into two broad categories-those lesions that, when biopsied, demonstrate an interface dermatitis and those that do not demonstrate an interface dermatitis. The skin lesions that are represented by the interface dermatitis include discoid lupus erythematosus (DLE), subacute cutaneous lupus erythematosus (SCLE), and acute cutaneous lupus erythematosus. Many patients with these cutaneous lesions can be managed with "standard" therapies, including sunscreens, protective clothing and behavioral alteration, and topical corticosteroids with or without an oral antimalarial agent. These standard therapies are often not used appropriately, resulting in a situation in which the patient is felt to have refractory disease. This chapter discusses these therapies and defines what is meant by refractory disease and how the author approaches these patients.

  19. 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.

    PubMed

    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.

  20. Skin testing and drug challenge outcomes in antibiotic-allergic patients with immediate-type hypersensitivity.

    PubMed

    Mawhirt, Stephanie L; Fonacier, Luz S; Calixte, Rose; Davis-Lorton, Mark; Aquino, Marcella R

    2017-01-01

    The evaluation of antibiotic immediate-type hypersensitivity is intricate because of nonstandardized skin testing and challenge method variability. To determine the safety outcomes and risk factors for antibiotic challenge reactions in patients reporting a history of antibiotic immediate-type hypersensitivity. A 5-year retrospective review of patients evaluated for immediate-type antibiotic allergy was conducted. Data analyzed included patient demographics, index reaction details, and outcomes of skin testing and challenges, classified as single-step or multistep. Antibiotic hypersensitivity history was identified in 211 patients: 78% to penicillins, 10% to fluoroquinolones, 7.6% to cephalosporins, and 3.8% to carbapenems. In total, 179 patients completed the challenges (median age 67 years, range 50-76 years, 56% women), and compared with nonchallenged patients, they reported nonanaphylactic (P < .001) and remote index (P = .003) reactions. Sixteen patients (8.9%) experienced challenge reactions (5 of 28 for single-step challenge, 11 of 151 for multistep challenge), and 11 of these patients had negative skin testing results before the challenge. Challenge-reactive patients were significantly younger (P = .007), more often women (P = .036), and had additional reported antibiotic allergies (P = .005). No correlation was detected between the reported index and observed challenge reaction severities (κ = -0.05, 95% confidence interval -0.34 to 0.24). Anaphylactic rates were similar during single-step and multistep challenges (3.6% vs 3.3%). In the present population, younger women with multiple reported antibiotic allergies were at greatest risk for challenge reactions. Negative skin testing results did not exclude reactions, and index severity was not predictive of challenge outcome. The multistep and full-dose methods demonstrated a comparable reaction risk for anaphylaxis. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by

  1. Care and management of patients with skin-tunnelled catheters.

    PubMed

    Green, Julie

    Central venous access devices (CVADs) are used in secondary and, increasingly, primary care settings to provide access to the central circulation. Skin-tunnelled catheters (STCs) are frequently used as the vascular access device of choice, particularly for patients receiving chemotherapy and for those who require long-term access for repeated transfusions. Despite the increased use of STCs, practice varies between trusts and community teams. This article provides an overview of the care and management of patients with STCs.

  2. Electron contamination modeling and skin dose in 6 MV longitudinal field MRIgRT: Impact of the MRI and MRI fringe field

    SciTech Connect

    Oborn, B. M.; Metcalfe, P. E.; Butson, M. J.; Rosenfeld, A. B.; Keall, P. J.

    2012-02-15

    Purpose: In recent times, longitudinal field MRI-linac systems have been proposed for 6 MV MRI-guided radiotherapy (MRIgRT). The magnetic field is parallel with the beam axis and so will alter the transport properties of any electron contamination particles. The purpose of this work is to provide a first investigation into the potential effects of the MR and fringe magnetic fields on the electron contamination as it is transported toward a phantom, in turn, providing an estimate of the expected patient skin dose changes in such a modality. Methods: Geant4 Monte Carlo simulations of a water phantom exposed to a 6 MV x-ray beam were performed. Longitudinal magnetic fields of strengths between 0 and 3 T were applied to a 30 x 30 x 20 cm{sup 3} phantom. Surrounding the phantom there is a region where the magnetic field is at full MRI strength, consistent with clinical MRI systems. Beyond this the fringe magnetic field entering the collimation system is also modeled. The MRI-coil thickness, fringe field properties, and isocentric distance are varied and investigated. Beam field sizes of 5 x 5, 10 x 10, 15 x 15 and 20 x 20 cm{sup 2} were simulated. Central axis dose, 2D virtual entry skin dose films, and 70 {mu}m skin depth doses were calculated using high resolution scoring voxels. Results: In the presence of a longitudinal magnetic field, electron contamination from the linear accelerator is encouraged to travel almost directly toward the patient surface with minimal lateral spread. This results in a concentration of electron contamination within the x-ray beam outline. This concentration is particularly encouraged if the fringe field encompasses the collimation system. Skin dose increases of up to 1000% were observed for certain configurations and increases above Dmax were common. In nonmagnetically shielded cases, electron contamination generated from the jaw faces and air column is trapped and propagated almost directly to the phantom entry region, giving rise to

  3. Development and Comparison of Warfarin Dosing Algorithms in Stroke Patients

    PubMed Central

    Cho, Sun-Mi; Lee, Kyung-Yul; Choi, Jong Rak

    2016-01-01

    Purpose The genes for cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) have been identified as important genetic determinants of warfarin dosing and have been studied. We developed warfarin algorithm for Korean patients with stroke and compared the accuracy of warfarin dose prediction algorithms based on the pharmacogenetics. Materials and Methods A total of 101 patients on stable maintenance dose of warfarin were enrolled. Warfarin dosing algorithm was developed using multiple linear regression analysis. The performance of all the algorithms was characterized with coefficient of determination, determined by linear regression, and the mean of percent deviation was used to predict doses from the actual dose. In addition, we compared the performance of the algorithms using percentage of predicted dose falling within ±20% of clinically observed doses and dividing the patients into a low-dose group (≤3 mg/day), an intermediate-dose group (3–7 mg/day), and high-dose group (≥7 mg/day). Results A new developed algorithms including the variables of age, body weight, and CYP2C9 and VKORC1 genotype. Our algorithm accounted for 51% of variation in the warfarin stable dose, and performed best in predicting dose within 20% of actual dose and intermediate-dose group. Conclusion Our warfarin dosing algorithm may be useful for Korean patients with stroke. Further studies to elucidate clinical utility of genotype-guided dosing and find the additional genetic association are necessary. PMID:26996562

  4. The cutting edge of skin cancer in transplant recipients: scientific retreat of international transplant Skin Cancer Collaborative and Skin Cancer in Organ Transplant Patients Europe.

    PubMed

    Hanlon, A; Colegio, O R

    2014-05-01

    The International Transplant Skin Cancer Collaborative (ITSCC) is an organization of more than 300 physicians and scientists focused on the study of dermatologic changes following solid organ transplantation. Transplant patients have a 100-fold increased risk of developing skin cancer. In October 2012, ITSCC and its European counterpart Skin Cancer in Organ Transplant Patients Europe held a joint biennial retreat in Essex, MA to discuss novel findings in the pathogenesis and management of skin cancer in solid organ transplant recipients. This meeting report is a summary of the novel findings discussed.

  5. The effect of low dose ionizing radiation on homeostasis and functional integrity in an organotypic human skin model

    SciTech Connect

    von Neubeck, Claere; Geniza, Matthew; Kauer, Paula M.; Robinson, Joseph E.; Chrisler, William B.; Sowa, Marianne B.

    2015-05-01

    Outside the protection of earth’s atmosphere, astronauts are exposed to low doses of high linear energy transfer (LET) radiation. Future NASA plans for deep space missions or a permanent settlement on the moon are limited by the health risks associated with space radiation exposures. There is a paucity of direct epidemiological data for low dose exposures to space radiation-relevant high LET ions. Health risk models are used to estimate the risk for such exposures, though these models are based on high dose experiments. There is increasing evidence, however, that low and high dose exposures result in different signaling events at the molecular level, and may involve different response mechanisms. Further, despite their low abundance, high LET particles have been identified as the major contributor to health risk during manned space flight. The human skin is exposed in every external radiation scenario, making it an ideal epithelial tissue model in which to study radiation induced effects. Here, we exposed an in vitro three dimensional (3-D) human organotypic skin tissue model to low doses of high LET oxygen (O), silicon (Si) and iron (Fe) ions. We measured proliferation and differentiation profiles in the skin tissue and examined the integrity of the skin’s barrier function. We discuss the role of secondary particles in changing the proportion of cells receiving a radiation dose, emphasizing the possible impact on radiation-induced health issues in astronauts.

  6. [Application of amniotic membrane dressings in patients with skin damage].

    PubMed

    Carrera González, Elier; Noa Hernández, Jose Eduardo; Marín Rojo, Carlos A

    2011-01-01

    The application of amniotic membranes in patients diagnosed with skin damage is a valid treatment option. A care plan following the Virginia Henderson model and NANDA, NOC and NIC taxonomy was applied to 36 patients admitted to the Dr. Miguel Enríquez hospital with different cutaneous lesions. This membrane has already been used for years due to its healing properties. These are attributed to antimicrobial properties reducing infection risk and promoting epithelial activity. They can decrease the need for the use of antibiotics, expendable materials, and can be applied during long periods of healing. This decreases the cost of wide spectrum antibiotic treatments, as well as the time patients spend in hospital. We present the results of this application in cases with several types of skin lesions.

  7. Poster — Thur Eve — 10: Partial kV CBCT, complete kV CBCT and EPID in breast treatment: a dose comparison study for skin, breasts, heart and lungs

    SciTech Connect

    Roussin, E; Archambault, L K; Wierzbicki, W

    2014-08-15

    The advantages of kilovoltage cone beam CT (kV CBCT) imaging over electronic portal imaging device (EPID) such as accurate 3D anatomy, soft tissue visualization, fast rigid registration and enhanced precision on patient positioning has lead to its increasing use in clinics. The benefits of this imaging technique are at the cost of increasing the dose to healthy surrounding organs. Our center has moved toward the use of daily partial rotation kV CBCT to restrict the dose to healthy tissues. This study aims to better quantify radiation doses from different image-guidance techniques such as tangential EPID, complete and partial kV CBCT for breast treatments. Cross-calibrated ionization chambers and kV calibrated Gafchromic films were used to measure the dose to the heart, lungs, breasts and skin. It was found that performing partial kV CBCT decreases the heart dose by about 36%, the lungs dose by 31%, the contralateral breast dose by 41% and the ipsilateral breast dose by 43% when compared to a full rotation CBCT. The skin dose measured for a full rotation CBCT was about 0.8 cGy for the contralateral breast and about 0.3 cGy for the ipsilateral breast. The study is still ongoing and results on skin doses for partial rotation kV CBCT as well as for tangential EPID images are upcoming.

  8. Importance of physical appearance in patients with skin cancer.

    PubMed

    Sobanko, Joseph F; Sarwer, David B; Zvargulis, Zinta; Miller, Christopher J

    2015-02-01

    Physical appearance influences nearly every aspect of human life-impacting how people are judged and subsequently treated by others. To summarize the literature that addresses the psychosocial impact of facial scarring, with a particular emphasis on scarring after skin cancer treatment. A comprehensive PubMed search was conducted to find articles related to scarring and appearance in the contexts of cutaneous oncology and surgical reconstruction. References from retrieved articles were also considered for review. Scars, especially on the head and neck, change physical appearance and can negatively impact psychosocial functioning. Medical professionals may underestimate the importance of physical appearance for patients with skin cancer. Validated patient-reported outcome (PRO) tools may prove better than objective scar ratings to identify patients who may experience psychosocial impairment from scarring. Scarring after skin cancer surgery can profoundly affect psychosocial functioning. Perioperative use of validated PRO tools can help to identify patients with scar concerns. Heightened awareness of patients' psychosocial status will allow practitioners to offer appropriate counseling or support.

  9. Measurement of protein fractional synthesis and breakdown rates in the skin of rabbits using a subflooding dose method.

    PubMed

    Zhang, Xiao-Jun; Chinkes, David L; Herndon, David N; Wolfe, Robert R

    2009-09-01

    The flooding dose method continues to be useful in measuring protein fractional synthetic rate (FSR) in a tissue. However, flooding of free amino acid pools eliminates enrichment difference between plasma and tissue free amino acid pools, which makes it impossible to concomitantly measure protein fractional breakdown rate (FBR). We hypothesized that a subflooding dose of an amino acid reduces the enrichment difference between plasma and tissue free amino acid pool to a minimal measurable level, thus allowing concomitant measurement of protein FSR and FBR. Phenylalanine (40% enriched) at 50 mg/kg was intravenously injected as a bolus in 6 anesthetized rabbits. Arterial blood and chest skin samples were taken before the injection and for 120 minutes after the injection. Fractional breakdown rate of skin protein calculated from 15-60-120-minute sampling times was 11.3%/d +/- 2.0%/d, which was close (P = .66) to the corresponding FSR of 10.0%/d +/- 2.3%/d. The subflooding dose injection did not disturb the FBR approach because modifications on the FBR equation to account for the changes of plasma phenylalanine concentration resulted in the same value (11.5%/d +/- 1.4%/d). The FBR was positively correlated with the FSR (r = 0.80, P < .05). These findings indicate maintenance of protein mass in the skin, which is a metabolic characteristic of the skin. This subflooding dose method provides a methodological choice to concomitantly measure both FSR and FBR in a tissue.

  10. Warfarin-Induced Skin Necrosis in Patients With Low Protein C Levels.

    PubMed

    Marčić, Marino; Marčić, Ljiljana; Titlić, Marina

    2016-08-01

    Warfarin-induced skin necrosis (WISN) is a rare complication of anticoagulant therapy associated with a high incidence of  morbidity and mortality requiring immediate drug cessation. At particular risk are those with various thrombophilic abnormalities, especially when warfarinisation is undertaken rapidly with large loading doses of warfarin. Cutaneous findings include petechiae that progress to ecchymosis and hemorrhagic bullae. With the increasing number of patients anticoagulated as out-patients for thromboprophylaxis, we are concerned that the incidence of skin necrosis may increase. We present a case of WISN with low protein C level. He was a 50-year-old male who came to our department because of acute infarction in irrigation area of the superior cerebellar artery. He had intermittent atrial fibrillation and was started on anticoagulant therapy.  After few day of therapy, he developed skin necrosis, and his level of protein C was low. Warfarin-induced skin necrosis is a rare but serious complication that can be prevented by routine screening for protein C, protein S or antithrombin deficiencies or for the presence of antiphospholipid antibodies before beginning warfarin therapy.

  11. Estimation of doses to personnel and patients during endovascular brachytherapy applications.

    PubMed

    Kirisits, Christian; Hefner, Alfred; Wexberg, Paul; Pokrajac, Boris; Glogar, Dietmar; Pötter, Richard; Georg, Dietmar

    2004-01-01

    In the last few years coronary endovascular brachytherapy using gamma- and beta-emitting radionuclides has been established as a standard treatment procedure to prevent restenosis after percutaneous coronary interventions. Direct measurements and calculations were made to determine personnel doses and organ doses of patients due to gamma rays of 192Ir and beta rays of 90Sr/90Y and 32P sources. In general, our results show that the dose levels are low compared with the X-ray exposure from angiography. The dose rate from bremsstrahlung at 1 m distance from a device containing a 90Sr/90Y source of 2.3 GBq is 4 micro Sv h(-1). The skin dose from beta rays during source transfer into and from the patient was estimated with the directional dose equivalent H'(0.07) of 10 micro Sv at 1 m distance from the catheter. By maintaining safe distances, the dose levels can be kept well within annual dose limits.

  12. 77 FR 71804 - Antiseptic Patient Preoperative Skin Preparation Products; Public Hearing; Request for Comments...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Antiseptic Patient Preoperative Skin Preparation Products...). The document announced a public hearing entitled ``Antiseptic Patient Preoperative Skin Preparation...

  13. Management of Skin Cancer in the High-Risk Patient.

    PubMed

    Behan, James W; Sutton, Adam; Wysong, Ashley

    2016-12-01

    Skin cancer is the most common of human cancers and outnumbers all other types of cancer combined in the USA by over threefold. The majority of non-melanoma skin cancers are easily treated with surgery or locally destructive techniques performed under local anesthesia in the cost-effective outpatient setting. However, there is a subset of "high-risk" cases that prove challenging in terms of morbidity, mortality, adjuvant treatment required, as well as overall cost to the health care system. In our opinion, the term "high risk" when applied to skin cancer can mean one of three things: a high-risk tumor with aggressive histologic and/or clinical features with an elevated risk for local recurrence or regional/distant metastasis, a high-risk patient with the ongoing development of multiple skin cancers, and a high-risk patient based on immunosuppression. We have recently proposed classifying NMSC as a chronic disease in a certain subset of patients. Although no consensus definition exists for a chronic disease in medicine, there are three components that are present in most definitions: duration of at least 1 year, need for ongoing medical care, and functional impairment and/or alteration of activities of daily living (ADLs) and quality of life (QOL). Immunosuppression can refer to exogenous (organ or stem cell transplant patients,) or endogenous (HIV, leukemia, lymphoma, genodermatoses with DNA mismatch repair problems or other immunosuppression) causes. These patients are at risk for high-risk tumors and/or the development of multiple tumors.

  14. Skin aging in patients with acquired immunodeficiency syndrome.

    PubMed

    de Aquino Favarato, Grace Kelly Naves; da Silva, Aline Cristina Souza; Oliveira, Lívia Ferreira; da Fonseca Ferraz, Mara Lúcia; de Paula Antunes Teixeira, Vicente; Cavellani, Camila Lourencini

    2016-10-01

    To evaluate the histomorphometric skin changes over aging patients with autopsied acquired immunodeficiency syndrome (AIDS). In 29 skin fragments of autopsied elderly (older than 50 years) and nonelderly patients with AIDS, epidermal thickness, the number of layers, the diameter of cells, the percentage of collagen and elastic fibers in the dermis, and the number and morphology of Langerhans cells were assessed. Statistical analysis was performed by SigmaStat 2.03 program. The thickness of the epidermis (92.55 × 158.94 μm), the number of layers (7 × 9 layers), and the diameter of the cells (13.27 × 17.6 μm) were statistically lower among the elderly. The quantity of collagen fibers (9.68 × 14.11%) and elastic fibers (11.89 × 15.31%) was also significantly lower in the elderly. There was a decrease in total (10.61 × 12.38 cel/mm(2)) and an increase in immature Langerhans cells (6.31 × 4.98 cel/mm(2)) in elderly patients with AIDS. The aging of the skin of patients with AIDS is amended in different histomorphometric aspects, the epidermis constituents suffer less pronounced changes in normal aging, and the dermis has more intense changes in elastic fibers and collagen.

  15. Hair loss in patients with skin of color.

    PubMed

    Semble, Ashley L; McMichael, Amy J

    2015-06-01

    Hair loss in skin of color patients can vary from the very simplest of diagnoses to a unique diagnostic challenge requiring extensive knowledge of historical symptoms, haircare practices, and previous treatments. There are several disorders in the literature that are noted to be more common in patients of African descent as compared to Caucasian populations. These disorders include central centrifugal cicatricial alopecia, dissecting cellulitis, discoid lesions of lupus erythematosus, traction alopecia, seborrheic dermatitis, and hair breakage. While there is no definitive prevalence data for the various forms of hair loss in the skin of color population, it is clear that these disorders are a concern for many patients in this population along with common hair loss concerns, such as telogen effluvium and pattern hair loss. A careful detailed clinical examination, history, and potential histopathology will guide the clinician to appropriate management. Hair disorders in skin of color patients may present unique challenges to the clinician, and knowledge of accurate clinical presentation and treatment approaches is essential to providing quality care. ©2015 Frontline Medical Communications.

  16. Minimal and maximal incidence rates of skin cancer in Caucasians estimated by use of sigmoidal UV dose-incidence curves.

    PubMed

    Juzeniene, Asta; Grigalavicius, Mantas; Baturaite, Zivile; Moan, Johan

    2014-11-01

    Sigmoidal (S-shaped) dose-cancer incidence relationships are often observed in animal bioassays for carcinogenicity. Ultraviolet (UV) radiation is an established skin carcinogen. The aim of this study is to examine if S-shaped curves describe the relationship between solar UV doses and skin cancer incidences, and if such relationships can be used to estimate threshold levels of non-carcinogenic UV exposure, as well as maximal incidence rates. We studied the incidence rate-annual erythema-effective UV dose relationship for squamous cell carcinoma (SCC), basal cell carcinoma (BCC) and cutaneous melanoma (CM) among different Caucasian populations in Europe, Australia and New Zealand. Our analysis indicates that S-shaped associations describe the data well (P < 0.0001). The age-adjusted incidence rates for cases expected to be due to other causes than solar UV exposure (at zero UV dose) were found to be around 0.6, 9.7 and 4.0 per 100,000 for women in 1997-2007 for SCC, BCC and CM, respectively, and around 1.2, 14.3 and 2.6 per 100,000 for men. The analysis indicates that SCC, BCC and CM have maximal incidence of 361 ± 24, 1544 ± 49 and 36 ± 4 per 100,000 for women, and 592 ± 35, 2204 ± 109 and 50 ± 4 per 100,000 for men. Between 89 and 95% of the annual CM cases, around 99.8% SCC and 99.4% BCC cases are caused by solar UV exposure. The analysis did not identify any "safe" UV dose below which the risk for skin cancer was absent. Avoidance of UV radiation has a potential to reduce the incidence of skin cancer in fair-skinned population. Copyright © 2014 Elsevier GmbH. All rights reserved.

  17. Development and validation of a bedside risk score for MRSA among patients hospitalized with complicated skin and skin structure infections.

    PubMed

    Zilberberg, Marya D; Chaudhari, Paresh; Nathanson, Brian H; Campbell, Rebecca S; Emons, Matthew F; Fiske, Suzanne; Hays, Harlen D; Shorr, Andrew F

    2012-07-11

    Methicillin-resistant Staphylococcus aureus (MRSA) is a frequent cause of complicated skin and skin structure infections (cSSSI). Patients with MRSA require different empiric treatment than those with non-MRSA infections, yet no accurate tools exist to aid in stratifying the risk for a MRSA cSSSI. We sought to develop a simple bedside decision rule to tailor empiric coverage more accurately. We conducted a large multicenter (N=62 hospitals) retrospective cohort study in a US-based database between April 2005 and March 2009. All adult initial admissions with ICD-9-CM codes specific to cSSSI were included. Patients admitted with MRSA vs. non-MRSA were compared with regard to baseline demographic, clinical and hospital characteristics. We developed and validated a model to predict the risk of MRSA, and compared its performance via sensitivity, specificity and other classification statistics to the healthcare-associated (HCA) infection risk factors. Of the 7,183 patients with cSSSI, 2,387 (33.2%) had MRSA. Factors discriminating MRSA from non-MRSA were age, African-American race, no evidence of diabetes mellitus, cancer or renal dysfunction, and prior history of cardiac dysrhythmia. The score ranging from 0 to 8 points exhibited a consistent dose-response relationship. A MRSA score of 5 or higher was superior to the HCA classification in all characteristics, while that of 4 or higher was superior on all metrics except specificity. MRSA is present in 1/3 of all hospitalized cSSSI. A simple bedside risk score can help discriminate the risk for MRSA vs. other pathogens with improved accuracy compared to the HCA definition.

  18. Evaluation of selenium in biological sample of arsenic exposed female skin lesions and skin cancer patients with related to non-exposed skin cancer patients.

    PubMed

    Kolachi, Nida F; Kazi, Tasneem G; Wadhwa, Sham K; Afridi, Hassan I; Baig, Jameel A; Khan, Sumaira; Shah, Faheem

    2011-08-01

    The antagonistic effects between selenium (Se) and arsenic (As) suggest that low Se status plays an important role in arsenism development. The objective of present study was to assess Se contents in biological samples of As exposed females have skin lesions and cancer with related to non-exposed skin cancer patients. The biological samples (blood and scalp hair) of As exposed group comprises, female skin cancer (ESC) patients admitted in cancer hospitals have skin lesions (ESL) and exposed referents have not both diseases (ER), belongs to As exposed area of Pakistan. For comparative purposes, age matched female skin cancerous patient (RP) and non-cancerous females (NER) belong to non-exposed areas were also selected. The As and Se in acid digests of biological samples were pre-concentrated by complexing with chelating agent (ammonium pyrrolidinedithiocarbamate), and resulted complexes were extracted into non-ionic extractant (Triton X-114), prior to analysis by electrothermal atomic absorption spectrometry. The enhancement factor of about 25 was obtained by pre-concentrating 10 mL of sample solutions. The accuracy of the optimized procedure was evaluated by using certified reference material (BCR 397) with certified values for Se and As and standard addition method at three concentration levels in real samples. No significant differences was observed (p>0.05) when comparing the values obtained by the proposed method, added and certified values of both elements. The biological samples of ESC patients had 2-3 folds higher As and lower Se levels as compared to RP (p<0.001). Understudied exposed referents have high level of As and lower Se contents as compared to referents subjects of non-exposed area (p<0.01). The higher concentration of As and lower levels of Se in biological samples of cancerous patients are consisted with reported studies. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Plasma, urine and skin pharmacokinetics of cefepime in burns patients.

    PubMed

    Sampol, E; Jacquet, A; Viggiano, M; Bernini, V; Manelli, J C; Lacarelle, B; Durand, A

    2000-08-01

    We studied the pharmacokinetics of cefepime (2 g bd) in six burns patients. Blood, urine and skin samples were collected to measure cefepime concentrations. A two-compartment model was fitted to the data. At day 1, t(1/2beta) was 2.45 +/- 0.56 h, V(ss) 0.36 +/- 0.1 L/kg, total clearance 152 +/- 25.2 mL/min, and AUC 217 +/- 34 mg*h/L. There was no statistical difference between day 1 and day 3 for any of the pharmacokinetic parameters. We demonstrated good penetration of cefepime in skin. These results show that it is not necessary to change the standard dosage of cefepime in burns patients.

  20. [Aeroallergens, skin tests and allergic diseases in 1091 patients].

    PubMed

    Enríquez Palomec, O; Hernández Chávez, L; Sarrazola Sanjuan, D M; Segura Méndez, N H; Hernández Colín, D D; Martínez-Cairo, S

    1997-01-01

    To know the frequency of positively of several skin tests, data cards from patients, of the Allergy and Clinic Immunology Service of the Hospital de Especialidades del Centro Medico Nacional Siglo XXI (Mexico City), between January, 1989 and March, 1995, were reviewed. Aqueous extracts manufactures by our laboratory were applied, in a dilution of 1:1000 weight-volume. 1091 from 5,651 skin tests patients were positive. Asthma and rhinitis were diagnosed in 492, allergic rhinitis in 289, allergic asthma in 111, and other diagnosis in 199 cases. The most frequent inhalable aeroallergens were house dust and perennial Dermatophagoides p and f1 with predominance in the rainy season, followed by pollens from Fraxinus a. Quercus a and Capriola, with predominance in the rainy season. The most frequent fungi were Candida and Fusarium, with predominance in the dry season.

  1. Transcriptional response of ex vivo human skin to ionizing radiation: comparison between low- and high-dose effects.

    PubMed

    Albrecht, Huguette; Durbin-Johnson, Blythe; Yunis, Reem; Kalanetra, Karen M; Wu, Shiquan; Chen, Rachel; Stevenson, Thomas R; Rocke, David M

    2012-01-01

    Although human exposure to low-dose ionizing radiation can occur through a variety of sources, including natural, medical, occupational and accidental, the true risks of low-dose ionizing radiation are still poorly understood in humans. Here, the global transcriptional responses of human skin after ex vivo exposure to low (0.05 Gy) and high (5 Gy) doses of X rays and of time in culture (0 Gy) at 0, 2, 8 and 30 h postirradiation were analyzed and compared. Responses to low and high doses differed quantitatively and qualitatively. Differentially expressed genes fell into three groups: (1) unique genes defined as responsive to either 0.05 or 5 Gy but not both and also responsive to time in culture, (2) specific genes defined as responsive to either 0.05 or 5 Gy but not both and not responsive to time in culture, and (3) dose-independent responsive genes. Major differences observed in ex vivo irradiated skin between transcriptional responses to low or high doses were twofold. First, gene expression modulated by 0.05 Gy was transient, while in response to 5 Gy persistence of modified gene expression was observed for a limited number of genes. Second, neither TP53 nor TGFβ target genes were modulated after exposure to an acute low dose, suggesting that the TP53-dependent DNA damage response either was not triggered or was triggered only briefly.

  2. Transcriptional Response of Ex Vivo Human Skin to Ionizing Radiation: Comparison Between Low- and High-Dose Effects

    PubMed Central

    Albrecht, Huguette; Durbin-Johnson, Blythe; Yunis, Reem; Kalanetra, Karen M.; Wu, Shiquan; Chen, Rachel; Stevenson, Thomas R.; Rocke, David M.

    2013-01-01

    Although human exposure to low-dose ionizing radiation can occur through a variety of sources, including natural, medical, occupational and accidental, the true risks of low-dose ionizing radiation are still poorly understood in humans. Here, the global transcriptional responses of human skin after ex vivo exposure to low (0.05 Gy) and high (5 Gy) doses of X rays and of time in culture (0 Gy) at 0, 2, 8 and 30 h postirradiation were analyzed and compared. Responses to low and high doses differed quantitatively and qualitatively. Differentially expressed genes fell into three groups: (1) unique genes defined as responsive to either 0.05 or 5 Gy but not both and also responsive to time in culture, (2) specific genes defined as responsive to either 0.05 or 5 Gy but not both and not responsive to time in culture, and (3) dose-independent responsive genes. Major differences observed in ex vivo irradiated skin between transcriptional responses to low or high doses were twofold. First, gene expression modulated by 0.05 Gy was transient, while in response to 5 Gy persistence of modified gene expression was observed for a limited number of genes. Second, neither TP53 nor TGFβ target genes were modulated after exposure to an acute low dose, suggesting that the TP53-dependent DNA damage response either was not triggered or was triggered only briefly. PMID:22029842

  3. A Phase I Study of Muscadine Grape Skin Extract in Men with Biochemically Recurrent Prostate Cancer: Safety, Tolerability, and Dose Determination

    PubMed Central

    Paller, CJ; Rudek, MA; Zhou, XC; Wagner, WD; Hudson, TS; Anders, N; Hammers, HJ; Dowling, D; King, S; Antonarakis, ES; Drake, CG; Eisenberger, MA; Denmeade, SR; Rosner, GL; Carducci, MA

    2015-01-01

    Background New therapies are being explored as therapeutic options for men with biochemically recurrent prostate cancer (BRPC) who wish to defer androgen deprivation therapy. MPX is pulverized muscadine grape (Vitis rotifundolia) skin that contains ellagic acid, quercetin, and resveratrol and demonstrates preclinical activity against prostate cancer cells in vitro. Methods In the phase I portion of this phase I/II study non-metastatic BRPC patients were assigned to increasing doses of MPX (Muscadine Naturals Inc., Clemmons, NC) in cohorts of 2 patients, with 6 patients at the highest dose, using a modified continual reassessment method. Initial dose selection was based on preclinical data showing the equivalent of 500 to 4,000 mg of MPX to be safe in mouse models. The primary end point was the recommended phase II dosing regimen. Results The cohort (n=14, 71% Caucasian, 29% black) had a median follow-up of 19.2 (6.2 – 29.7) months, median age 61 years, and median Gleason of 7. Four patients had possibly related gastrointestinal symptoms, including grade 1 flatulence, grade 1 soft stools, and grade 1 eructation. No other related adverse events were reported and one patient reported improvement of chronic constipation. Six of 14 patients came off study for disease progression (5 metastatic, 1 rising PSA) after exposure for a median of 15 months. One patient came off for myasthenia gravis that was unrelated to treatment. Seven patients remain on study. The lack of dose limiting toxicities led to the selection of 4000 mg/d as the highest dose for further study. Median within-patient PSADT increased by 5.3 months (non-significant, p = 0.17). No patients experienced a maintained decline in serum PSA from baseline. Conclusions These data suggest that 4000 mg of MPX is safe, and exploratory review of a lengthening in PSADT of a median of 5.3 months supports further exploration of MPX. Both low dose (500 mg) and high dose (4,000 mg) MPX are being further investigated in a

  4. A phase I study of muscadine grape skin extract in men with biochemically recurrent prostate cancer: Safety, tolerability, and dose determination.

    PubMed

    Paller, Channing J; Rudek, Michelle A; Zhou, Xian C; Wagner, William D; Hudson, Tamaro S; Anders, Nicole; Hammers, Hans J; Dowling, Donna; King, Serina; Antonarakis, Emmanuel S; Drake, Charles G; Eisenberger, Mario A; Denmeade, Samuel R; Rosner, Gary L; Carducci, Michael A

    2015-10-01

    New therapies are being explored as therapeutic options for men with biochemically recurrent prostate cancer (BRPC) who wish to defer androgen deprivation therapy. MPX is pulverized muscadine grape (Vitis rotundifolia) skin that contains ellagic acid, quercetin, and resveratrol and demonstrates preclinical activity against prostate cancer cells in vitro. In the phase I portion of this phase I/II study, non-metastatic BRPC patients were assigned to increasing doses of MPX (Muscadine Naturals. Inc., Clemmons, NC) in cohorts of two patients, with six patients at the highest dose, using a modified continual reassessment method. Initial dose selection was based on preclinical data showing the equivalent of 500 to 4,000 mg of MPX to be safe in mouse models. The primary endpoint was the recommended phase II dosing regimen. The cohort (n = 14, 71% Caucasian, 29% black) had a median follow-up of 19.2 (6.2-29.7) months, median age of 61 years, and median Gleason score of 7. Four patients had possibly related gastrointestinal symptoms, including grade 1 flatulence, grade 1 soft stools, and grade 1 eructation. No other related adverse events were reported and one patient reported improvement of chronic constipation. Six of 14 patients came off study for disease progression (five metastatic, one rising PSA) after exposure for a median of 15 months. One patient came off for myasthenia gravis that was unrelated to treatment. Seven patients remain on study. The lack of dose-limiting toxicities led to the selection of 4,000 mg/d as the highest dose for further study. Median within-patient PSADT increased by 5.3 months (non-significant, P = 0.17). No patients experienced a maintained decline in serum PSA from baseline. These data suggest that 4,000 mg of MPX is safe, and exploratory review of a lengthening in PSADT of a median of 5.3 months supports further exploration of MPX. Both low-dose (500 mg) and high-dose (4,000 mg) MPX are being further investigated in a randomized

  5. Radiation dose to patients and radiologists during transcatheter arterial embolization: comparison of a digital flat-panel system and conventional unit.

    PubMed

    Suzuki, Shigeru; Furui, Shigeru; Kobayashi, Ikuo; Yamauchi, Teiyu; Kohtake, Hiroshi; Takeshita, Koji; Takada, Koichi; Yamagishi, Masafumi

    2005-10-01

    The objective of our study was to evaluate the exposure doses to patients and radiologists during transcatheter arterial embolization (TAE) for hepatocellular carcinoma (HCC) using a new angiographic unit with a digital flat-panel system. Doses were assessed for 24 procedures: 12 using a new unit with a digital flat-panel system and 12 using a conventional unit. Doses to patients' skin were evaluated with thermoluminescent dosimeters behind the left, middle, and right portions of the liver. The doses to the radiologists were measured by an electronic personal dosimeter placed on the chest outside a lead protector. The maximal skin doses to the patients and the dose equivalents, Hp(0.07), to the radiologists were compared between the two procedure groups with each angiographic unit. For procedures with the new unit, the mean maximal skin dose to the patients was 284 +/- 127 (SD) mGy (range, 130-467 mGy), and Hp(0.07) to the radiologists was 62.8 +/- 17.4 muSv. For procedures with the conventional unit, the maximal skin dose to the patients was 1,068 +/- 439 mGy (range, 510-1,882 mGy), and Hp(0.07) to the radiologists was 68.4 +/- 25.7 muSv. The maximal skin dose to the patients was significantly lower with the new unit than with the conventional unit (p < 0.0005). There was no significant difference in the Hp(0.07) to the radiologists between the two procedure groups. The new digital flat-panel system for angiographic imaging can reduce the radiation dose to patients' skin during TAE for HCC as compared with the conventional system.

  6. Histopathological study of perilesional skin in patients diagnosed with nonmelanoma skin cancer.

    PubMed

    Apalla, Z; Calzavara-Pinton, P; Lallas, A; Argenziano, G; Kyrgidis, A; Crotti, S; Facchetti, F; Monari, P; Gualdi, G

    2016-01-01

    Epidemiological and clinical data suggest that actinic damage to the skin is an important predictor of skin carcinogenesis. To investigate the association of squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) with sun-damage alterations seen by histopathology. In the current prospective study, perilesional skin of SCC or BCC lesions was evaluated for presence of alterations associated with chronic photodamage. Presence of scarring, perineural/perivascular invasion, haemorrhage/haemorrhagic crust, ulceration/erosion and margin involvement were also assessed. Of 6038 included lesions, 4523 (74.9%) were BCCs and 1515 (25.1%) were SCCs. Presence of actinic damage was five times more frequent in SCC than in BCC (OR = 5.29, 95% CI 4.44-6.00, P < 0.001), and diagnosis of SCC was twice as common in photo-exposed than nonphoto-exposed body sites (OR = 2.34, 95% CI 2.03-2.70, P < 0.001). There were twofold higher odds for actinic damage in SCC compared with Bowen disease (OR = 2.015, 95% CI 1.55-2.61, P < 0.001). Assessing the different BCC histological subtypes, we found that nodular BCC had at least twofold higher odds (OR = 2.63, 95% CI 2.09-3.32), infiltrative BCC had 48% higher odds (OR = 1.487, 95% CI 1.18-1.87) and basosquamous BCC had fourfold higher odds (OR = 4.10, 95% CI 3.01-5.57) of having actinic damage compared with superficial BCC. Histological verification of ultraviolet-associated alterations in the perilesional skin in patients with NMSC in our study confirms the aetiopathogenic link between sun exposure and epithelial carcinogenesis on a histopathological basis. This correlation was stronger for SCCs than for BCCs. © 2015 British Association of Dermatologists.

  7. Patient-specific dose estimation for pediatric chest CT

    SciTech Connect

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

    2008-12-15

    Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9-18.2 kg) were created based on the patients' actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120 kVp, 70 or 75 mA, 0.4 s gantry rotation period, pitch of 1.375, 20 mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7-5.3 mSv/100 mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4-12.6 mGy/100 mAs and 11.2-13.3 mGy/100 mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%-18%) and for partially or indirectly exposed organs (11%-77%). Normalized effective dose correlated weakly with body weight (correlation coefficient: r=-0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=-0.99, heart: r=-0.93); these strong correlation relationships can be used to estimate patient-specific organ dose for

  8. VirtualDose: a software for reporting organ doses from CT for adult and pediatric patients.

    PubMed

    Ding, Aiping; Gao, Yiming; Liu, Haikuan; Caracappa, Peter F; Long, Daniel J; Bolch, Wesley E; Liu, Bob; Xu, X George

    2015-07-21

    This paper describes the development and testing of VirtualDose--a software for reporting organ doses for adult and pediatric patients who undergo x-ray computed tomography (CT) examinations. The software is based on a comprehensive database of organ doses derived from Monte Carlo (MC) simulations involving a library of 25 anatomically realistic phantoms that represent patients of different ages, body sizes, body masses, and pregnant stages. Models of GE Lightspeed Pro 16 and Siemens SOMATOM Sensation 16 scanners were carefully validated for use in MC dose calculations. The software framework is designed with the 'software as a service (SaaS)' delivery concept under which multiple clients can access the web-based interface simultaneously from any computer without having to install software locally. The RESTful web service API also allows a third-party picture archiving and communication system software package to seamlessly integrate with VirtualDose's functions. Software testing showed that VirtualDose was compatible with numerous operating systems including Windows, Linux, Apple OS X, and mobile and portable devices. The organ doses from VirtualDose were compared against those reported by CT-Expo and ImPACT-two dosimetry tools that were based on the stylized pediatric and adult patient models that were known to be anatomically simple. The organ doses reported by VirtualDose differed from those reported by CT-Expo and ImPACT by as much as 300% in some of the patient models. These results confirm the conclusion from past studies that differences in anatomical realism offered by stylized and voxel phantoms have caused significant discrepancies in CT dose estimations.

  9. Vemurafenib skin phototoxicity is indirectly linked to ultraviolet A minimal erythema dose decrease.

    PubMed

    Brugière, C; Stefan, A; Morice, C; Cornet, E; Moreau, A; Allouche, S; Verneuil, L

    2014-12-01

    Vemurafenib, an anti-rapidly accelerated fibrosarcoma kinase B (BRAF) molecule, improves survival among patients with metastatic BRAF-mutated melanoma. Photosensitivity, a frequent cutaneous adverse effect induced by vemurafenib, can lead to cessation of treatment. To investigate photosensitivity mechanisms in patients treated with vemurafenib for metastatic melanoma. In a prospective study of 12 patients, photobiological explorations with measurements of ultraviolet A (UVA) minimal erythema dose (MED) and polychromatic MED were performed over 3 days in all 12 patients. UVA MED and polychromatic MED were also assessed for four patients before treatment. We then performed spectrophotometric analyses of (i) serum and faeces in these four patients, before and after introduction of vemurafenib; (ii) the lyophilized form of vemurafenib without excipient added; and (iii) the lyophilized form of vemurafenib added to serum and faeces before treatment. Photosensitivity was present in 92% of the patients. UVA MED was normal before treatment and decreased after treatment, while polychromatic MED remained normal. The same three peaks (210, 260 and 310 nm) were identified in the spectrum for UVB and UVC but not for UVA on spectrophotometric analyses for each condition (lyophilized vemurafenib; serum and faeces after introduction of vemurafenib; and lyophilized vemurafenib added to serum and faeces before treatment). The peaks were different before treatment. Our study confirms that photosensitivity under vemurafenib treatment was a UVA phototoxicity reaction, and our results suggest that a metabolite of vemurafenib rather than the parent molecule is involved in this phototoxicity. © 2014 British Association of Dermatologists.

  10. The effects of grape seeds polyphenols on SKH-1 mice skin irradiated with multiple doses of UV-B.

    PubMed

    Filip, Adriana; Daicoviciu, Doina; Clichici, Simona; Bolfa, Pompei; Catoi, Cornel; Baldea, Ioana; Bolojan, Laura; Olteanu, Diana; Muresan, Adriana; Postescu, I D

    2011-11-03

    The study investigated the protective activity of red grape seeds (Vitis vinifera L, Burgund Mare variety) (BM) extracts in vivo on multiple doses of ultraviolet radiation (UV)-B-induced deleterious effects in SKH-1 mice skin. Eighty 8-weeks-old female SKH-1 mice were divided into 8 groups: control, vehicle, UV-B irradiated, vehicle+UV-B irradiated, BM 2.5mg polyphenols (PF)/cm(2)+UV-B irradiated, BM 4 mg PF/cm(2)+UV-B irradiated, UV-B+BM 2.5mg PF/cm(2), UV-B+BM 4 mg PF/cm(2). The extract was applied topically before or after each UV-B exposure (240 mJ/cm(2)), for 10 days consecutively. The antioxidant activity of BM extract is higher than gallic acid (k(BM)=0.017, k(gallic acid)=0.013). Multiple doses of UV-B generated the formation of cyclobutane pyrimidine dimers (CPDs) and sunburn cells, increased glutathione peroxidase (GPx) and catalase (CAT) activities respectively glutathione (GSH) and IL-1β levels in skin. In group treated with 2.5mg PF/cm(2) before UV-B irradiation BM extract inhibited UV-B-induced sunburn cells, restored the superoxide dismutase (MnSOD) activity, increased insignificantly CAT and GPx activities and reduced IL-1β level. The BM 4.0 mg PF/cm(2) treatment decreased GSH level and reduced the percentage of CPDs positive cells in skin. Both doses of BM extract administered after UV-B irradiation increased the MnSOD and GPx activities and reduced the formation of sunburn cells in skin. Our results suggest that BM extract might be a potential chemo-preventive candidate in reducing the oxidative stress and apoptosis induced by multiple doses of UV-B in skin. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Sensitivity and specificity of dosing alerts for dosing errors among hospitalized pediatric patients.

    PubMed

    Stultz, Jeremy S; Porter, Kyle; Nahata, Milap C

    2014-10-01

    To determine the sensitivity and specificity of a dosing alert system for dosing errors and to compare the sensitivity of a proprietary system with and without institutional customization at a pediatric hospital. A retrospective analysis of medication orders, orders causing dosing alerts, reported adverse drug events, and dosing errors during July, 2011 was conducted. Dosing errors with and without alerts were identified and the sensitivity of the system with and without customization was compared. There were 47,181 inpatient pediatric orders during the studied period; 257 dosing errors were identified (0.54%). The sensitivity of the system for identifying dosing errors was 54.1% (95% CI 47.8% to 60.3%) if customization had not occurred and increased to 60.3% (CI 54.0% to 66.3%) with customization (p=0.02). The sensitivity of the system for underdoses was 49.6% without customization and 60.3% with customization (p=0.01). Specificity of the customized system for dosing errors was 96.2% (CI 96.0% to 96.3%) with a positive predictive value of 8.0% (CI 6.8% to 9.3). All dosing errors had an alert over-ridden by the prescriber and 40.6% of dosing errors with alerts were administered to the patient. The lack of indication-specific dose ranges was the most common reason why an alert did not occur for a dosing error. Advances in dosing alert systems should aim to improve the sensitivity and positive predictive value of the system for dosing errors. The dosing alert system had a low sensitivity and positive predictive value for dosing errors, but might have prevented dosing errors from reaching patients. Customization increased the sensitivity of the system for dosing errors. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  12. Correlation between DNA damage responses of skin to a test dose of radiation and late adverse effects of earlier breast radiotherapy.

    PubMed

    Somaiah, Navita; Chua, Melvin L K; Bourne, Sara; Daley, Frances; A' Hern, Roger; Nuta, Otilia; Gothard, Lone; Boyle, Sue; Herskind, Carsten; Pearson, Ann; Warrington, Jim; Helyer, Sarah; Owen, Roger; Rothkamm, Kai; Yarnold, John

    2016-05-01

    To correlate residual double strand breaks (DSB) 24h after 4Gy test doses to skin in vivo and to lymphocytes in vitro with adverse effects of earlier breast radiotherapy (RT). Patients given whole breast RT ⩾5years earlier were identified on the basis of moderate/marked or minimal/no adverse effects despite the absence ('RT-Sensitive', RT-S) or presence ('RT-Resistant', RT-R) of variables predisposing to late adverse effects. Residual DSB were quantified in skin 24h after a 4Gy test dose in 20 RT-S and 15 RT-R patients. Residual DSB were quantified in lymphocytes irradiated with 4Gy in vitro in 30/35 patients. Mean foci per dermal fibroblast were 3.29 (RT-S) vs 2.80 (RT-R) (p=0.137); 3.28 (RT-S) vs 2.60 (RT-R) in endothelium (p=0.158); 2.50 (RT-S) vs 2.41 (RT-R) in suprabasal keratinocytes (p=0.633); 2.70 (RT-S) vs 2.35 (RT-R) in basal epidermis (p=0.419); 12.1 (RT-S) vs 10.3 (RT-R) in lymphocytes (p=0.0052). Residual DSB in skin following a 4Gy dose were not significantly associated with risk of late adverse effects of breast radiotherapy, although exploratory analyses suggested an association in severely affected individuals. By contrast, a significant association was detected based on the in vitro response of lymphocytes. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  13. Risk of skin cancer in patients with diabetes mellitus

    PubMed Central

    Tseng, Hui-Wen; Shiue, Yow-Ling; Tsai, Kuo-Wang; Huang, Wei-Chun; Tang, Pei-Ling; Lam, Hing-Chung

    2016-01-01

    Abstract Increasing evidence suggests that certain types of cancers are more common in people with diabetes mellitus (DM). This study aimed to investigate the risk of skin cancer in patients with DM in Taiwan. In this retrospective cohort study using data from the Taiwan Longitudinal Health Insurance Research Database, the risk of developing overall skin cancer, including nonmelanoma skin cancer (NMSC) and melanoma, was compared by Poisson regression analysis and Cox regression analysis between the DM and non-DM cohorts. The DM cohort with newly diagnosed DM (n = 41,898) and a non-DM cohort were one-to-one matched by age, sex, index date, and comorbidities (coronary artery disease, hyperlipidemia, hypertension, chronic kidney disease, chronic obstructive pulmonary disease, and obesity). Compared with non-DM cohort statistically, for the people with DM aged ≥60 years, the incidence rates of overall skin cancer and NMSC were significantly higher (overall: DM/non-DM: number [n] = 99/76, incidence rate ratio [IRR] = 1.44, P = 0.02; NMSC: DM/non-DM: n = 94/66, IRR = 1.57, P = 0.005). By Cox regression analysis, the risk of developing overall skin cancer or NMSC was significantly higher after adjusting for sex, comorbidities, and overall diseases with immunosuppression status (overall: adjusted hazard ratio [AHR] = 1.46, P = 0.01; NMSC: AHR = 1.6, P = 0.003). Other significant risk factors were older males for skin cancer (overall: AHR = 1.68, P = 0.001; NMSC: AHR = 1.59, P = 0.004; melanoma: AHR = 3.25, P = 0.04), chronic obstructive pulmonary disease for NMSC (AHR = 1.44, P = 0.04), and coronary artery disease for melanoma (AHR = 4.22, P = 0.01). The risk of developing melanoma was lower in the DM cohort than in the non-DM cohort, but without significance (AHR = 0.56, P = 0.28; DM/non-DM: n = 5/10). The incidence rate and risk of developing overall skin cancer, including NMSC, was significantly higher in older adults with DM. Other significant risk factors for older

  14. A new reference point for patient dose estimation in neurovascular interventional radiology.

    PubMed

    Kawasaki, Kohei; Imazeki, Masaharu; Hasegawa, Ryota; Shiba, Shinichi; Takahashi, Hiroyuki; Sato, Kazuhiko; Ota, Jyoji; Suzuki, Hiroaki; Awai, Kazuo; Sakamoto, Hajime; Tajima, Osamu; Tsukamoto, Atsuko; Kikuchi, Tatsuya; Kageyama, Takahiro; Kato, Kyoichi

    2013-07-01

    In interventional radiology, dose estimation using the interventional reference point (IRP) is a practical method for obtaining the real-time skin dose of a patient. However, the IRP is defined in terms of adult cardiovascular radiology and is not suitable for dosimetry of the head. In the present study, we defined a new reference point (neuro-IRP) for neuro-interventional procedures. The neuro-IRP was located on the central ray of the X-ray beam, 9 cm from the isocenter, toward the focal spot. To verify whether the neuro-IRP was accurate in dose estimation, we compared calculated doses at the neuro-IRP and actual measured doses at the surface of the head phantom for various directions of the X-ray projection. The resulting calculated doses were fairly consistent with actual measured doses, with the error in this estimation within approximately 15%. These data suggest that dose estimation using the neuro-IRP for the head is valid.

  15. Utilisation of PACS to monitor patient CT doses.

    PubMed

    AlSuwaidi, J S; Bayoumi, M; Al Shibli, N; Sulaiman, H; Urrahman, T; AlYarah, M

    2011-09-01

    In the past 5 y, the number of computed tomography (CT) studies has doubled at Dubai Health Authority hospitals. This situation, along with patient's overdoses reported internationally, has prompted action to establish a system to manage patient doses incurred due to medical imaging practices. In this work, the authors aim to homogenise dose reporting to monitor radiation dose levels and facilitate the establishment of local and national dose reference levels. The two hospitals enrolled in this study are equipped with three CT systems (two 4 slices and one 64 slices). Through the Picture Archive and Communication Systems (PACS) tracking system, it is mandatory to fill CT patient doses in radiology information system (RIS). Dose length product (mGy cm) was recorded for 2502 adult and 178 paediatric patients. All patients' dosimetry data were collected from the RIS by Cogonos statistical software. The PACS data were reviewed to exclude incomplete data. Average and range of effective doses for adult and paediatric patients were calculated using an appropriate weighting factor. Individual accumulated effective doses for adult and paediatric patients were calculated for 4s-scanner-1 only. Adult average effective doses for the head (1482 exams) were 1.23 ± 0.58, 2.84 ± 0.83 and 2.98 ± 1.103 mSv, the chest (545 exams) were 5.39 ± 1.63, 21.85 ± 5.63 and 18.19 ± 3.22 mSv and for the abdomen and pelvis (1183 exams) were 10.85 ± 4.26, 25.66 ± 8.83 and 26.46 ± 13.75 mSv for 4s-scanner-1, 4s-scanner-2 and 64 s, respectively. The paediatric average effective dose for the head (127 exams) was 1.77 ± 0.82 mSv, for the chest (22 exams) was 3.3 ± 1.29 mSv and for the abdomen and pelvis (27 exams) was 6.16 ± 2.64 mSv. Results of individual accumulated effective doses for adult and paediatric patients were presented. PACS dose reporting facilitated dosimetry clinical auditing. Effective doses obtained in this work demonstrated that the results of one scanner were within

  16. High-dose gallium-67 therapy in patients with relapsed acute leukaemia: a feasibility study.

    PubMed Central

    Jonkhoff, A. R.; Plaizier, M. A.; Ossenkoppele, G. J.; Teule, G. J.; Huijgens, P. C.

    1995-01-01

    Gallium-67 (67Ga) accumulates in malignant tissues via the transferrin receptor without need for a monoclonal antibody and emits cytotoxic low-energy electrons. In this study we investigated the feasibility, pharmacokinetics, toxicity and preliminary efficiency of high-dose 67Ga injected intravenously (i.v.) in patients with acute leukaemia not responding to conventional therapy. Twelve doses of 36-105 mCi of Gallium67 citrate were administered as a push injection to eight patients with resistant leukaemia in a pilot study. All five patients with acute myeloid leukaemia (AML) and three patients with acute lymphoblastic leukaemia (ALL) had resistant disease or resistant relapse. No (sub)acute toxicity was observed. Independent of the administered dose, whole-blood radioactivity levels 10 min after administration measured only 1.25 +/- 1.39 microCi ml-1, indicating a large volume of distribution. Urine excretion in the first 24 h ranged from 18% to 51.5% (median 29.5%) of the administered dose. Cellular uptake of 67Ga was less than in previous in vitro studies. Whole-body radiation dose was estimated to be 0.25 +/- 0.03 cGy mCi-1. Red marrow dose was estimated to be between 0.18 +/- 0.02 and 0.97 +/- 0.12 cGy mCi-1. One definite response was observed in an ALL patient with disappearance of skin lesions, normalisation of the enlarged spleen and profound leucopenia. Three other patients showed transient reductions in white blood cell counts without disappearance of blasts from the peripheral blood. We conclude that high-dose i.v. 67Ga can be safely administered but that the uptake of 67Ga in blast cells must increase to make 67Ga therapeutically useful in patients with relapsed leukaemia. Images Figure 2 PMID:8519674

  17. Skin dose measurements using radiochromic films, TLDS and ionisation chamber and comparison with Monte Carlo simulation.

    PubMed

    Alashrah, Saleh; Kandaiya, Sivamany; Maalej, Nabil; El-Taher, A

    2014-12-01

    Estimation of the surface dose is very important for patients undergoing radiation therapy. The purpose of this study is to investigate the dose at the surface of a water phantom at a depth of 0.007 cm as recommended by the International Commission on Radiological Protection and International Commission on Radiation Units and Measurement with radiochromic films (RFs), thermoluminescent dosemeters and an ionisation chamber in a 6-MV photon beam. The results were compared with the theoretical calculation using Monte Carlo (MC) simulation software (MCNP5, BEAMnrc and DOSXYZnrc). The RF was calibrated by placing the films at a depth of maximum dose (d(max)) in a solid water phantom and exposing it to doses from 0 to 500 cGy. The films were scanned using a transmission high-resolution HP scanner. The optical density of the film was obtained from the red component of the RGB images using ImageJ software. The per cent surface dose (PSD) and percentage depth dose (PDD) curve were obtained by placing film pieces at the surface and at different depths in the solid water phantom. TLDs were placed at a depth of 10 cm in a solid water phantom for calibration. Then the TLDs were placed at different depths in the water phantom and were exposed to obtain the PDD. The obtained PSD and PDD values were compared with those obtained using a cylindrical ionisation chamber. The PSD was also determined using Monte Carlo simulation of a LINAC 6-MV photon beam. The extrapolation method was used to determine the PSD for all measurements. The PSD was 15.0±3.6% for RF. The TLD measurement of the PSD was 16.0±5.0%. The (0.6 cm(3)) cylindrical ionisation chamber measurement of the PSD was 50.0±3.0%. The theoretical calculation using MCNP5 and DOSXYZnrc yielded a PSD of 15.0±2.0% and 15.7±2.2%. In this study, good agreement between PSD measurements was observed using RF and TLDs with the Monte Carlo calculation. However, the cylindrical chamber measurement yielded an overestimate of the PSD

  18. Skin function parameters in intensive-care patients.

    PubMed

    Fischer, Matthias; Donath, Christian; Radke, Joachim; Marsch, Wolfgang Ch; Soukup, Jens

    2005-11-01

    The study was performed to investigate the transepidermal water loss (TEWL) and pH-value in patients in intensive care. Forty intensive-care patients (22 men, 18 women) were included in the study. TEWL and pH-values were measured at admission, and after 24, 96 and 168 h. The areas of measurement were the forehead, the volar forearm, paraumbilical and the ventral thigh. The measurements were made under standardized environmental conditions according to the recommendations of the EMCO Group. Elevated values were found on the forehead compared with the other skin areas examined. There was no significant change in mean TEWL-values in any patient in the course of the study. There was also no significant influence of TEWL at the time of admission on the prognosis. The course analysis of the mean pH-values, however, showed that patients who developed a systemic inflammatory response syndrome (SIRS) or sepsis during the further course had a higher pH-value over the entire study period. TEWL and the pH of the skin surface could be measured at bedside in the intensive-care unit and delivered reproducible results. These parameters appear, however, to be relevant only for subgroups of patients under intensive care.

  19. Galvanic skin response of oral cancer patients during speech.

    PubMed

    Nishigawa, G; Natsuaki, N; Maruo, Y; Okamoto, M; Minagi, S

    2003-05-01

    Severe speech difficulty is often caused after surgery of an oral cancer. Prosthetic treatment with a removable obturator prosthesis is generally provided for such patients. Although some speech ability is recovered with prosthetic treatment, patients sometimes complain of continued dissatisfaction with their speech. However, it is difficult to evaluate the dissatisfaction. Therefore, a new method for evaluation is desirable. In this study, such a new method using the galvanic skin response as the index for the dissatisfaction of the patient was developed, and its objectivity was investigated. Eleven patients with maxillary bone defects were selected. Prior to the evaluation, improvement of speech with the removable prosthesis was confirmed using the speech intelligibility test and the visual analogue scale. The electrical resistant value at pronunciation was measured with the measuring system composed with the apparatus (galvanic skin response (GSR) measuring apparatus), the personal computer program. The changes for the electrical resistant value after pronunciation were evaluated by calculating the decrease ratio at pronunciation [(the mean electrical resistance before pronunciation - the mean electrical resistance after pronunciation)/the mean electrical resistance before pronunciation]. This decrease ratio at pronunciation was defined as the index of the speech dissatisfaction of the subject. The mean values for the decrease ratio with prosthesis were significantly smaller than the values without prosthesis (P < 0.05). From the results of this study, it is suggested that the measurement of the electrical resistance change of the skin during speech could be a new method for evaluating the speech dissatisfaction of the post-oral-cancer patient.

  20. Patient doses from hybrid SPECT-CT procedures.

    PubMed

    Avramova-Cholakova, S; Dimcheva, M; Petrova, E; Garcheva, M; Dimitrova, M; Palashev, Y; Vassileva, J

    2015-07-01

    The aim of this work is to estimate patient doses from hybrid single-photon emission computed tomography (SPECT) and computed tomography (CT) procedures. The study involved all four SPECT-CT systems in Bulgaria. Effective dose was estimated for about 100 patients per system. Ten types of examinations were considered, representing all diagnostic procedures performed in the SPECT-CT systems. Effective doses from the SPECT component were calculated applying the ICRP 53 and ICRP 80 conversion coefficients. Computed tomography dose index and dose length product were retrospectively obtained from the archives of the systems, and effective doses from the CT component were calculated with CT-Expo software. Parallel estimation of CT component contribution with the National Radiological Protection Board (NRPB) conversion coefficients was performed where applicable. Large variations were found in the current practice of SPECT-CT imaging. Optimisation actions and diagnostic reference levels were proposed.

  1. Docetaxel-induced skin toxicities in breast cancer patients subsequent to paclitaxel shortage: a case series and literature review

    PubMed Central

    Poi, Ming J.; Berger, Michael; Lustberg, Maryam; Layman, Rachel; Shapiro, Charles L.; Ramaswamy, Bhuvaneswari; Mrozek, Ewa; Olson, Erin

    2013-01-01

    Purpose As the result of a recent national shortage in paclitaxel, some patients who were receiving or scheduled to receive weekly paclitaxel were converted to every 3-week (q3w) docetaxel with granulocyte colony-stimulating factor support. Our institution noted higher than expected incidence of severe skin toxicity events attributable to docetaxel during the shortage period among our breast cancer patients. In this report, we summarize the clinical course of the first five cases, review the literature surrounding docetaxel-induced skin toxicity, and offer possible prevention and treatment strategies to improve docetaxel tolerability. Methods The observation period for this case series was August 1 through October 21, 2011. All patients treated with docetaxel were identified from our electronic medical record. Operable stage I–III breast cancer patients who received ≥1 dose of docetaxel monotherapy at 75–100 mg/m2 q3w were included in this study. The cases of grade 3–4 docetaxel-induced skin toxicities identified by the treating oncologists were then contacted and signed an informed consent through an Institutional Review Board-approved protocol. Results Thirty-four patients met the inclusion criteria. Five patients (14.7 %) experienced grade 3 skin toxicity events attributable to docetaxel, a significantly higher rate than previously reported for docetaxel dosed at 75–100 mg/m2. Conclusions Docetaxel-induced dermatologic toxicity is well characterized; nonetheless, its etiology is largely unknown and evidence-based prevention and management strategies are lacking. This report shows that the use of docetaxel 75–100 mg/m2 q3w subsequent to dose-dense doxorubicin and cyclophosphamide regimen can lead to unacceptable rate of severe skin toxicity. PMID:23686402

  2. [Long-term effect of a single dose of ivermectin on skin microfilarial density in an endemic onchocerciasis area of North Cameroon].

    PubMed

    Boussinesq, M; Prod'hon, J; Chippaux, J P; Quillévéré, D

    1993-09-01

    The long-term efficacy of a single dose of ivermectin (150 micrograms/kg) on skin microfilarial densities was evaluated by comparing parasite levels, before and after treatment, in 192 patients living in an area endemic for onchocerciasis in North Cameroon. A mass treatment with ivermectin has been undertaken in 1989 in two villages, where pretreatment community microfilarial loads (CMFL) were 5.5 and 25.1 microfilariae per snip. The parasitological examination carried out 32 months later showed that the microfilarial densities in the adults where only 24 and 51% of the initial values, respectively. In a third village, treated once in 1989 but located in an area where annual mass distributions of ivermectin have been undertaken since 1987, the mean microfilarial density 28 months after treatment was only 12% of the initial value. In 1992, the mean microfilarial load in children had decreased significantly in comparison with those of 1989 only in the village where the level of endemicity was initially the lowest. The rate of increase in the number of skin microfilariae after one dose of ivermectin is related with the pretreatment endemicity level. The impact of large-scale ivermectin treatments on the transmission of onchocerciasis enhances the long-term efficacy of this drug on the skin microfilarial densities.

  3. Skin graft

    MedlinePlus

    ... that need skin grafts to heal Venous ulcers, pressure ulcers , or diabetic ulcers that do not heal Very ... graft; Full thickness skin graft Patient Instructions Preventing pressure ulcers Surgical wound care - open Images Skin graft Skin ...

  4. Association of Dermatology Consultations With Patient Care Outcomes in Hospitalized Patients With Inflammatory Skin Diseases.

    PubMed

    Milani-Nejad, Nima; Zhang, Myron; Kaffenberger, Benjamin H

    2017-06-01

    The value of inpatient dermatology consultations has traditionally been demonstrated with frequency in changes of diagnosis and management; however, the impact of dermatology consultations on metrics such as hospital length of stay and readmission rates remains unknown. To determine the association of dermatology consultations with patient care in hospitalized patients using objective values. We retrospectively queried the deidentified database of patients hospitalized between January 1, 2012, and December 31, 2014, at a single university medical center. A total of 413 patients with a primary inflammatory skin condition discharge diagnosis and 647 patients with primary inflammatory skin condition admission diagnosis were selected. Hospital length of stay and 1-year readmission with inflammatory skin conditions. The 413 patients with a primary inflammatory skin condition discharge diagnosis were 61.0% female and had a mean (SD) age of 55.1 (16.4) years. The 647 patients with primary inflammatory skin condition admission diagnosis were 50.8% female and had a mean (SD) age of 57.8 (15.9) years. Multivariable modeling showed that dermatology consultations were associated with a reduction of 1-year inflammatory skin condition readmissions among patients who were discharged primarily with an inflammatory skin condition (readmission probability, 0.0025; 95% CI, 0.00020-0.030 with dermatology consult vs 0.026; 95% CI, 0.0065-0.10 without; odds ratio, 0.093; 95% CI, 0.010-0.840; P = .03). No other confounding variable was associated with reduction in readmissions. Multivariable modeling also showed that dermatology consultations were associated with a reduction in the adjusted hospital length of stay by 2.64 days (95% CI, 1.75-3.53 days; P < .001). Dermatology consultations were associated with improvements of outcomes among hospitalized patients. The expansion of the role of dermatology consultation services may improve patient care in a cost-effective manner.

  5. Automatic computed tomography patient dose calculation using DICOM header metadata.

    PubMed

    Jahnen, A; Kohler, S; Hermen, J; Tack, D; Back, C

    2011-09-01

    The present work describes a method that calculates the patient dose values in computed tomography (CT) based on metadata contained in DICOM images in support of patient dose studies. The DICOM metadata is preprocessed to extract necessary calculation parameters. Vendor-specific DICOM header information is harmonized using vendor translation tables and unavailable DICOM tags can be completed with a graphical user interface. CT-Expo, an MS Excel application for calculating the radiation dose, is used to calculate the patient doses. All relevant data and calculation results are stored for further analysis in a relational database. Final results are compiled by utilizing data mining tools. This solution was successfully used for the 2009 CT dose study in Luxembourg. National diagnostic reference levels for standard examinations were calculated based on each of the countries' hospitals. The benefits using this new automatic system saved time as well as resources during the data acquisition and the evaluation when compared with earlier questionnaire-based surveys.

  6. Feasibility Study of Intra-patient Sorafenib Dose-Escalation or Re-Escalation in Patients with Previously Treated Advanced Solid Tumors

    PubMed Central

    Semrad, Thomas J.; Eddings, Courtney; Pan, Chong-Xian; Lau, Derick H.; Gandara, David; Beckett, Laurel; Lara, Primo N.

    2014-01-01

    Purpose To determine if intra-patient dose escalation of the multi-targeted kinase inhibitor sorafenib is feasible in patients with advanced pretreated solid malignancies. Methods An intra-patient dose escalation scheme starting at 400 mg BID was employed in this prospective trial. Doses were escalated to 600 mg BID for the second cycle and to 800 mg BID for the third cycle in the absence of grade 3+ adverse events. In the event of grade 3+ adverse events during cycle 1, doses were reduced to 400 mg daily through cycle 2. Dose re-escalation for cycle 3 was allowed in the absence of grade 3+ adverse events during cycle 2. Further dose escalation was prohibited. The primary endpoint was the overall percentage of patients tolerating dose escalation to 600 mg BID through cycle 2 or tolerating re-escalation to 400 mg BID through cycle 3. Results Fifty eligible patients with various solid tumors and a median of 3 prior therapies were enrolled. Eleven patients (22%) tolerated primary dose escalation or re-escalation. Only 14 patients (28%) completed cycle 1 without dose modification or discontinuing treatment. Seven of 13 patients tolerated primary dose escalation through cycle 2. Four of 5 patients tolerated dose re-escalation through cycle 3. Reasons for escalation failure included tumor progression (42%) and adverse events (26%). Common grade 3+ adverse events included hand-foot skin reaction, hypertension, and hypophosphatemia. Conclusions Intra-patient dose escalation and/or re-escalation of sorafenib were not feasible in pretreated solid tumor patients. Sorafenib dose escalation remains an investigational approach. PMID:22015991

  7. EYE LENS EXPOSURE TO MEDICAL STAFF PERFORMING ELECTROPHYSIOLOGY PROCEDURES: DOSE ASSESSMENT AND CORRELATION TO PATIENT DOSE.

    PubMed

    Ciraj-Bjelac, Olivera; Antic, Vojislav; Selakovic, Jovana; Bozovic, Predrag; Arandjic, Danijela; Pavlovic, Sinisa

    2016-12-01

    The purpose of this study was to assess the patient exposure and staff eye dose levels during implantation procedures for all types of pacemaker therapy devices performed under fluoroscopic guidance and to investigate potential correlation between patients and staff dose levels. The mean eye dose during pacemaker/defibrillator implementation was 12 µSv for the first operator, 8.7 µSv for the second operator/nurse and 0.50 µSv for radiographer. Corresponding values for cardiac resynchronisation therapy procedures were 30, 26 and 2.0 µSv, respectively. Significant (p < 0.01) correlation between the eye dose and the kerma-area product was found for the first operator and radiographers, but not for other staff categories. The study revealed eye dose per procedure and eye dose normalised to patient dose indices for different staff categories and provided an input for radiation protection in electrophysiology procedures. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. [Skin diseases in hemodialysis and kidney transplant patients].

    PubMed

    Gerhardt, Clarissa Morais Busatto; Gussão, Bruna Calvi; de Matos, Jorge Paulo Strogoff; Lugon, Jocemir Ronaldo; Pinto, Jane Marcy Neffá

    2011-01-01

    Recently, the world is facing an escalate in the incidence of chronic kidney disease (CKD). Databases containing information about patients in end stage renal disease (ESRD), especially in the United States, were the sources of initial information about it. Brazil has the third largest population on dialysis in the world, and there are about 680 dialysis centers, spread across all units of the federation in the present, providing treatment to an estimated population of almost 90,000 patients. Cutaneous involvement in the chronic renal failure is characterized by a number of manifestations, which may be related to three processes: the primary renal disease, the uremic state, or the therapeutic measures used in their handling. The skin changes in these two classes of patients, dialysis and transplant recipients, have been the subject of several studies. n recent years, however, great progress has been achieved in these two therapeutic modalities, which may have changed not only the type of the dermatologic disorders associated with these two conditions, but also their intensity or frequency. This article aims to yield an update as to the topic skin diseases in hemodialysis and kidney transplant patients.

  9. Patient release criteria for low dose rate brachytherapy implants.

    PubMed

    Boyce, Dale E; Sheetz, Michael A

    2013-04-01

    A lack of consensus regarding a model governing the release of patients following sealed source brachytherapy has led to a set of patient release policies that vary from institution to institution. The U.S. Nuclear Regulatory Commission has issued regulatory guidance on patient release in NUREG 1556, Volume 9, Rev. 2, Appendix U, which allows calculation of release limits following implant brachytherapy. While the formalism presented in NUREG is meaningful for the calculation of release limits in the context of relatively high energy gamma emitters, it does not estimate accurately the effective dose equivalent for the common low dose rate brachytherapy sources Cs, I, and Pd. NUREG 1556 states that patient release may be based on patient-specific calculations as long as the calculation is documented. This work is intended to provide a format for patient-specific calculations to be used for the consideration of patients' release following the implantation of certain low dose rate brachytherapy isotopes.

  10. VirtualDose: a software for reporting organ doses from CT for adult and pediatric patients

    NASA Astrophysics Data System (ADS)

    Ding, Aiping; Gao, Yiming; Liu, Haikuan; Caracappa, Peter F.; Long, Daniel J.; Bolch, Wesley E.; Liu, Bob; Xu, X. George

    2015-07-01

    This paper describes the development and testing of VirtualDose—a software for reporting organ doses for adult and pediatric patients who undergo x-ray computed tomography (CT) examinations. The software is based on a comprehensive database of organ doses derived from Monte Carlo (MC) simulations involving a library of 25 anatomically realistic phantoms that represent patients of different ages, body sizes, body masses, and pregnant stages. Models of GE Lightspeed Pro 16 and Siemens SOMATOM Sensation 16 scanners were carefully validated for use in MC dose calculations. The software framework is designed with the ‘software as a service (SaaS)’ delivery concept under which multiple clients can access the web-based interface simultaneously from any computer without having to install software locally. The RESTful web service API also allows a third-party picture archiving and communication system software package to seamlessly integrate with VirtualDose’s functions. Software testing showed that VirtualDose was compatible with numerous operating systems including Windows, Linux, Apple OS X, and mobile and portable devices. The organ doses from VirtualDose were compared against those reported by CT-Expo and ImPACT—two dosimetry tools that were based on the stylized pediatric and adult patient models that were known to be anatomically simple. The organ doses reported by VirtualDose differed from those reported by CT-Expo and ImPACT by as much as 300% in some of the patient models. These results confirm the conclusion from past studies that differences in anatomical realism offered by stylized and voxel phantoms have caused significant discrepancies in CT dose estimations.

  11. Advantages and implications of high dose rate (HDR) total skin electron irradiation (TSEI) for the management of Mycosis Fungoides. Indian experience.

    PubMed

    Parida, Dillip Kumar; Rath, Goura Kishore

    2014-03-01

    Mycosis Fungoides (MF) is an indolent lymphoproliferative disorder affecting dermis caused by abnormal proliferation of CD4+ T-cells. Radiation therapy is the most effective modality of treatment for MF which offers cure in limited stage disease and desirable palliation in advance stage disease. Treating entire skin having many curved surfaces and folds with radiation is the real challenge for the radiation oncologist. Many techniques, dose schedules and modifications in total skin electron irradiation (TSEI) have been tried since 1950s. TSEI treatment is a very time consuming, inconvenient and physically challenging to both patient as well as oncologist. At our center TSEI was performed since 1983 with conventional linear accelerator where the treatment time was prolonged beyond two hours, which was very difficult or the patient, oncologist, technical officer and eating away the machine time hampering the treatment of other patients. From 1998 we shifted to high dose rate (HDR) mode, in order to bring down the treatment time of a single patient every day from two and half hour to 15 min. The reduction of treatment time increases patient compliance and at the same time saved machine time. Between 1998 and 2003, eleven pathological diagnosed MF patients were treated using HDR TSEI. All the patients were male between 40 and 70 years of age, who had the history of having the disease for 7-22 months. Four patients had T2 and seven patients had T3 stage disease with more than 90% skin surface involvement. TSEI was performed with 4 MeV electrons with a daily fraction size of 120 cGy to a total dose of 36 Gy. At the end of 36 Gy, boost dose of 10 Gy was delivered to self shielding regions like sole, scalp and perineum. Considering the treatment related toxicities and consequent treatment interruptions, in the first seven patients, the last four patients were treated using similar HDR TSEI technique with modified treatment schedule, where the treatment was given on

  12. WE-AB-303-06: Combining DAO with MV + KV Optimization to Improve Skin Dose Sparing with Real-Time Fluoroscopy

    SciTech Connect

    Grelewicz, Z; Wiersma, R

    2015-06-15

    Purpose: Real-time fluoroscopy may allow for improved patient positioning and tumor tracking, particularly in the treatment of lung tumors. In order to mitigate the effects of the imaging dose, previous studies have demonstrated the effect of including both imaging dose and imaging constraints into the inverse treatment planning object function. That method of combined MV+kV optimization may Result in plans with treatment beams chosen to allow for more gentle imaging beam-on times. Direct-aperture optimization (DAO) is also known to produce treatment plans with fluence maps more conducive to lower beam-on times. Therefore, in this work we demonstrate the feasibility of a combination of DAO and MV+kV optimization for further optimized real-time kV imaging. Methods: Therapeutic and imaging beams were modeled in the EGSnrc Monte Carlo environment, and applied to a patient model for a previously treated lung patient to provide dose influence matrices from DOSXYZnrc. An MV + kV IMRT DAO treatment planning system was developed to compare DAO treatment plans with and without MV+kV optimization. The objective function was optimized using simulated annealing. In order to allow for comparisons between different cases of the stochastically optimized plans, the optimization was repeated twenty times. Results: Across twenty optimizations, combined MV+kV IMRT resulted in an average of 12.8% reduction in peak skin dose. Both non-optimized and MV+kV optimized imaging beams delivered, on average, mean dose of approximately 1 cGy per fraction to the target, with peak doses to target of approximately 6 cGy per fraction. Conclusion: When using DAO, MV+kV optimization is shown to Result in improvements to plan quality in terms of skin dose, when compared to the case of MV optimization with non-optimized kV imaging. The combination of DAO and MV+kV optimization may allow for real-time imaging without excessive imaging dose. Financial support for the work has been provided in part by NIH

  13. Chemokines in onchocerciasis patients after a single dose of ivermectin

    PubMed Central

    Fendt, J; Hamm, DM; Banla, M; Schulz-Key, H; Wolf, H; Helling-Giese, G; Heuschkel, C; Soboslay, PT

    2005-01-01

    Ivermectin treatment will effectively diminish microfilariae (Mf) of Onchocerca volvulus in the skin of patients, but therapy is associated with adverse host inflammatory responses. To investigate the association of proinflammatory chemokines with the intensity of infection and clinical adverse reactions, chemokine serum levels were measured in patients following ivermectin treatment (100 µg/kg, 150 µg/kg or 200 µg/kg) or placebo. The density of O. volvulus Mf per mg skin decreased by 85%, 97%, 97% and 90% at day 3, at month 3, month 6 and at 1 year post-ivermectin. The cutaneous T cell-attracting chemokine (CTACK/CCL27) was found highly elevated in onchocerciasis patients compared to infection-free European controls (P = 0·0004) and it did not change following ivermectin or placebo to 1 year post-therapy. The chemokine RANTES/CCL5 (regulated on activated and normally T cell-expressed) was similarly high in onchocerciasis patients and infection-free European controls; the RANTES/CCL5 levels did not change following treatment until 6 months post-therapy but were slightly elevated at 1 year post-therapy (P < 0·02). In contrast, the Th2-type chemoattractants, thymus and activation regulated chemokine (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22), were activated at 3 days post-ivermectin (P < 0·0001) to return to pretreatment or lower levels thereafter. The Th1-type chemoattractants, macrophage inflammatory protein (MIP)-1α/CCL3 and MIP-1β/CCL4 were low before ivermectin treatment, but following clearance of microfilariae of O. volvulus their levels increased from 6 months post-therapy onwards (for both at 12 months post-therapy, P < 0·0001). The adverse reaction scores (RS) in treated patients increased significantly on day 3 (P < 0·02) while it remained unchanged in those who received placebo (P = 0·22); RS interacted with the microfilarial density (P = 0·01), but not with the dose of ivermectin or with the serum levels of MIP-1α/CCL3, MIP-1

  14. Chemokines in onchocerciasis patients after a single dose of ivermectin.

    PubMed

    Fendt, J; Hamm, D M; Banla, M; Schulz-Key, H; Wolf, H; Helling-Giese, G; Heuschkel, C; Soboslay, P T

    2005-11-01

    Ivermectin treatment will effectively diminish microfilariae (Mf) of Onchocerca volvulus in the skin of patients, but therapy is associated with adverse host inflammatory responses. To investigate the association of proinflammatory chemokines with the intensity of infection and clinical adverse reactions, chemokine serum levels were measured in patients following ivermectin treatment (100 microg/kg, 150 microg/kg or 200 microg/kg) or placebo. The density of O. volvulus Mf per mg skin decreased by 85%, 97%, 97% and 90% at day 3, at month 3, month 6 and at 1 year post-ivermectin. The cutaneous T cell-attracting chemokine (CTACK/CCL27) was found highly elevated in onchocerciasis patients compared to infection-free European controls (P = 0.0004) and it did not change following ivermectin or placebo to 1 year post-therapy. The chemokine RANTES/CCL5 (regulated on activated and normally T cell-expressed) was similarly high in onchocerciasis patients and infection-free European controls; the RANTES/CCL5 levels did not change following treatment until 6 months post-therapy but were slightly elevated at 1 year post-therapy (P < 0.02). In contrast, the Th2-type chemoattractants, thymus and activation regulated chemokine (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22), were activated at 3 days post-ivermectin (P < 0.0001) to return to pretreatment or lower levels thereafter. The Th1-type chemoattractants, macrophage inflammatory protein (MIP)-1alpha/CCL3 and MIP-1beta/CCL4 were low before ivermectin treatment, but following clearance of microfilariae of O. volvulus their levels increased from 6 months post-therapy onwards (for both at 12 months post-therapy, P < 0.0001). The adverse reaction scores (RS) in treated patients increased significantly on day 3 (P < 0.02) while it remained unchanged in those who received placebo (P = 0.22); RS interacted with the microfilarial density (P = 0.01), but not with the dose of ivermectin or with the serum levels of MIP-1alpha

  15. Overall measurements of dose to patients in common interventional cardiology procedures.

    PubMed

    Wang, Weipeng; Zhang, Menglong; Zhang, Yi

    2013-12-01

    This study was designed to measure peak skin dose (PSD), dose-area product (DAP), cumulative dose (CD) and fluoroscopy time (FT) for interventional cardiology procedures and to evaluate whether patient doses were higher than that in other published data. Three cardiac procedure types, including coronary angiography (CAG), percutaneous transluminal coronary angioplasty (PTCA) and radio frequency (RF) ablation, were entered into the study. Data of four special metrics (PSD, DAP, CD and FT) for these procedures were collected and measured. A total of 238 patients who underwent interventional radiology procedures participated in this study. For every procedure, data about PSD were resulted from six TLD arrays and DAP, CD and FT were collected from the displayed monitor. The mean, standard deviation (SD), range and third quartile of the distribution of PSD, DAP, CD and FT recorded and measured on spot were calculated for all procedures. High-dose cases were specifically recorded. There was wide variation in the doses observed for different instances of the same procedure. PSD for PTCA and RF ablation ranged from 0.1 Gy to more than 3 Gy. Of 238 instances, there were 22 (9.2 %) with PSDs greater than 2 Gy and 4 (1.7 %) than 3 Gy. The third quartile of the distribution for PTCA had exceeded the DIMOND preliminary reference levels by 41.1 % in DAP and 25.0 % in FT. Mean DAP was in the range of reported values for CAG procedure, but higher than all data obtained in literatures for PTCA. Data from this study are in the range of most reported values for CAG and RF ablation procedure, while higher than that obtained in some literatures for PTCA. In case of a constant delivering of high doses to patient and physician himself, thorough training of interventionalists and staff is necessary, and the legislation has to be revised and set dose constrains especially for the interventional high-dose procedures.

  16. Use of Oritavancin in Acute Bacterial Skin and Skin Structure Infections Patients Receiving Intravenous Antibiotics: A US Hospital Budget Impact Analysis.

    PubMed

    Jensen, Ivar S; Lodise, Thomas P; Fan, Weihong; Wu, Chining; Cyr, Philip L; Nicolau, David P; DuFour, Scott; Sulham, Katherine A

    2016-02-01

    Nearly 10% of all US hospital admissions are attributed to acute bacterial skin and skin structure infections (ABSSSIs). While most antibacterials used to treat these infections require multi-day and multi-dose regimens, a single-dose treatment is now available. The objective of this analysis is to estimate the annual budget impact of using single-dose oritavancin in patients with moderate to severe ABSSSIs receiving intravenous methicillin-resistant Staphylococcus aureus (MRSA)-active antibacterials from a US hospital perspective. A decision-analytic model based on current clinical practice was developed to estimate the economic impact of oritavancin. Utilization of antibacterials and rates of hospital admission were derived from the Premier Research Database. Demographic and clinical data were informed by the published literature and 2014 wholesale drug acquisition costs were used. Other costs were based on the published literature and Medicare National Limitation amounts. All costs were inflated to 2014 US dollars. Two base-case scenarios were considered: one for hospitals with ambulatory services and one for hospitals without ambulatory services. For a US hospital with ambulatory services with 1000 ABSSSI patients receiving intravenous MRSA antibiotics annually, use of oritavancin in 26% of patients is estimated to reduce the total annual budget by 12.9% (US$1.23 million), or approximately US$1234.67 per patient. Total inpatient costs will be reduced by 22.3% (US$1.40 million) and outpatient costs will increase slightly by 1.7% (US$55,310). Pharmaceutical cost increases are offset by savings in the inpatient setting from fewer hospital admissions. Hospitals without ambulatory services are estimated to receive overall cost savings of 9.3% (US$0.63 million). Use of single-dose oritavancin in select ABSSSI patients with suspected or confirmed MRSA involvement is estimated to save US hospitals approximately 9.3-12.9% per year by reducing hospital admissions and

  17. Effect of the reduction of skin contamination on the internal dose of creosote workers exposed to polycyclic aromatic hydrocarbons.

    PubMed

    Van Rooij, J G; Van Lieshout, E M; Bodelier-Bade, M M; Jongeneelen, F J

    1993-06-01

    Ten creosote-exposed workers of a wood impregnation plant participated in this study, which took place in two consecutive weeks on a Monday, after a weekend off. On one of the two days each worker wore Tyvek coveralls underneath his normal workclothes. Dermal contamination measurements (pyrene on exposure pads) and biological monitoring (urinary 1-OH-pyrene) were performed to measure the reduction of both the skin contamination and the internal dose. The total pyrene skin contamination of workers not wearing coveralls ranged between 47 and 1510 micrograms.d-1 (0.2-7.5 mumol.d-1). On the average, the coveralls reduced the pyrene contamination on the workers' skin by about 35 (SD 63)%. The excreted amount of 1-OH-pyrene in urine decreased significantly from 6.6 to 3.2 micrograms (30.2 to 14.7 nmol). Multiple regression analysis showed that skin contamination by polycyclic aromatic hydrocarbons is the main determinant of the internal exposure dose of creosote workers.

  18. Radiation dose enhancement in skin therapy with nanoparticle addition: A Monte Carlo study on kilovoltage photon and megavoltage electron beams

    PubMed Central

    Zheng, Xiao J; Chow, James C L

    2017-01-01

    AIM To investigated the dose enhancement due to the incorporation of nanoparticles in skin therapy using the kilovoltage (kV) photon and megavoltage (MV) electron beams. Monte Carlo simulations were used to predict the dose enhancement when different types and concentrations of nanoparticles were added to skin target layers of varying thickness. METHODS Clinical kV photon beams (105 and 220 kVp) and MV electron beams (4 and 6 MeV), produced by a Gulmay D3225 orthovoltage unit and a Varian 21 EX linear accelerator, were simulated using the EGSnrc Monte Carlo code. Doses at skin target layers with thicknesses ranging from 0.5 to 5 mm for the photon beams and 0.5 to 10 mm for the electron beams were determined. The skin target layer was added with the Au, Pt, I, Ag and Fe2O3 nanoparticles with concentrations ranging from 3 to 40 mg/mL. The dose enhancement ratio (DER), defined as the dose at the target layer with nanoparticle addition divided by the dose at the layer without nanoparticle addition, was calculated for each nanoparticle type, nanoparticle concentration and target layer thickness. RESULTS It was found that among all nanoparticles, Au had the highest DER (5.2-6.3) when irradiated with kV photon beams. Dependence of the DER on the target layer thickness was not significant for the 220 kVp photon beam but it was for 105 kVp beam for Au nanoparticle concentrations higher than 18 mg/mL. For other nanoparticles, the DER was dependent on the atomic number of the nanoparticle and energy spectrum of the photon beams. All nanoparticles showed an increase of DER with nanoparticle concentration during the photon beam irradiations regardless of thickness. For electron beams, the Au nanoparticles were found to have the highest DER (1.01-1.08) when the beam energy was equal to 4 MeV, but this was drastically lower than the DER values found using photon beams. The DER was also found affected by the depth of maximum dose of the electron beam and target thickness. For

  19. Evaluation of a skin protection cream for dry skin in patients undergoing narrow band UVB phototherapy for psoriasis vulgaris.

    PubMed

    Pacifico, A; Leone, G

    2011-06-01

    Severe dry skin is very often associated with chronic skin conditions such as psoriasis vulgaris and can be treated with emollients and moisturizers. The aim of this study was to evaluate the efficacy and tolerability of a new cream containing glycerol, vaseline, and liquid paraffin versus an ointment containing vaseline in patients with severe dry skin and undergoing narrow band UVB phototherapy for moderate psoriasis vulgaris. 54 patients were included in this study (age range, 18-63 years): 26 were randomized to receive treatment with the skin protection cream twice a day; 28 received treatment with a vaseline ointment twice a day. Clinical parameters (erythema, desquamation, and lichenification) were assessed at 3 time points (baseline, after two weeks of treatment, and at the end of the four-week study period). Treatment efficacy and tolerability were assessed by comparing changes in skin hydration as measured by corneometry. At the final assessment, greater improvement in clinical parameters and self-reported questionnaire responses was observed in the cream-treated than in the vaseline-treated group. Improved skin hydration was noted in the cream-treated group already after one week into therapy and the product was well tolerated. The new formulation cream was found to be effective in reducing eythema, flaking and lichenification and to improve skin hydration in patients undergoing narrow band UVB phototherapy for psoriasis vulgaris.

  20. Single-dose oritavancin versus 7-10 days of vancomycin in the treatment of gram-positive acute bacterial skin and skin structure infections: the SOLO II noninferiority study.

    PubMed

    Corey, G Ralph; Good, Samantha; Jiang, Hai; Moeck, Greg; Wikler, Matthew; Green, Sinikka; Manos, Paul; Keech, Richard; Singh, Rajesh; Heller, Barry; Bubnova, Natalia; O'Riordan, William

    2015-01-15

    Oritavancin is a lipoglycopeptide antibiotic with rapid bactericidal activity against gram-positive bacteria. Its concentration-dependent activity and long half-life allow for single-dose treatment. In a randomized, double-blind trial, adults with acute bacterial skin and skin structure infections (ABSSSIs) received either a single intravenous 1200-mg dose of oritavancin or 7-10 days of twice-daily vancomycin. Three efficacy endpoints were tested for noninferiority: (1) primary composite endpoint at 48-72 hours (cessation of spreading or reduction in lesion size, absence of fever, and no rescue antibiotic); (2) investigator-assessed clinical cure 7-14 days after end of treatment; and (3) ≥20% reduction in lesion area at 48-72 hours. A total of 503 and 502 patients comprised the modified intent-to-treat population for oritavancin and vancomycin, respectively. All 3 efficacy endpoints met the 10% noninferiority margin: the primary composite endpoint (80.1% vs 82.9%; 95% confidence interval [CI], -7.5 to 2.0), investigator-assessed clinical cure (82.7% vs 80.5%; 95% CI, -2.6 to 7.0), and proportion of patients attaining ≥20% reduction in lesion area (85.9% vs 85.3%; 95% CI, -3.7 to 5.0) for oritavancin vs vancomycin, respectively. Efficacy outcomes by pathogen, including methicillin-resistant Staphylococcus aureus and the frequency of adverse events, were similar between treatment groups. A single 1200-mg dose of oritavancin was noninferior to 7-10 days of vancomycin in treating ABSSSIs caused by gram-positive pathogens, and was well tolerated. Oritavancin provides a single-dose alternative to multidose therapies for the treatment of ABSSSIs. Clinical Trials Registration. NCT01252732. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  1. [Skin-to-skin caesarean section: a hype or better patient care?

    PubMed

    Korteweg, F J; de Boer, H D; van der Ploeg, J M; Buiter, H D; van der Ham, D P

    2017-01-01

    A caesarean section (CS) is one of the most common surgical procedures performed in the world, for which there are minimal variations in the surgical approach. During the last few years the "skin-to-skin" CS, also coined "natural" or "gentle" CS, is on the rise; parental participation, slow delivery and direct skin-to-skin contact are important aspects. Most Dutch hospitals offer some form of "skin-to-skin" CS but there are local differences in availability and performance of the procedure. Since 2011, the standard procedure in the Martini Hospital in Groningen is the "skin-to-skin" CS (for both elective and emergency CS, 24/7). We describe our method and share our retrospective data, and demonstrate that this procedure does not result in more complications for mother or baby.

  2. Organ doses to adult patients for chest CT

    SciTech Connect

    Huda, Walter; Sterzik, Alexander; Tipnis, Sameer; Schoepf, U. Joseph

    2010-02-15

    Purpose: The goal of this study was to estimate organ doses for chest CT examinations using volume computed tomography dose index (CTDI{sub vol}) data as well as accounting for patient weight. Methods: A CT dosimetry spreadsheet (ImPACT CT patient dosimetry calculator) was used to compute organ doses for a 70 kg patient undergoing chest CT examinations, as well as volume computed tomography dose index (CTDI{sub vol}) in a body CT dosimetry phantom at the same CT technique factors. Ratios of organ dose to CTDI{sub vol} (f{sub organ}) were generated as a function of anatomical location in the chest for the breasts, lungs, stomach, red bone marrow, liver, thyroid, liver, and thymus. Values of f{sub organ} were obtained for x-ray tube voltages ranging from 80 to 140 kV for 1, 4, 16, and 64 slice CT scanners from two vendors. For constant CT techniques, we computed ratios of dose in water phantoms of differing diameter. By modeling patients of different weights as equivalent water cylinders of different diameters, we generated factors that permit the estimation of the organ doses in patients weighing between 50 and 100 kg who undergo chest CT examinations relative to the corresponding organ doses received by a 70 kg adult. Results: For a 32 cm long CT scan encompassing the complete lungs, values of f{sub organ} ranged from 1.7 (thymus) to 0.3 (stomach). Organs that are directly in the x-ray beam, and are completely irradiated, generally had f{sub organ} values well above 1 (i.e., breast, lung, heart, and thymus). Organs that are not completely irradiated in a total chest CT scan generally had f{sub organ} values that are less than 1 (e.g., red bone marrow, liver, and stomach). Increasing the x-ray tube voltage from 80 to 140 kV resulted in modest increases in f{sub organ} for the heart (9%) and thymus (8%), but resulted in larger increases for the breast (19%) and red bone marrow (21%). Adult patient chests have been modeled by water cylinders with diameters between

  3. Cognitive performance in methadone maintenance patients: Effects of time relative to dosing and maintenance dose level

    PubMed Central

    Rass, Olga; Kleykamp, Bethea A.; Vandrey, Ryan G.; Bigelow, George E.; Leoutsakos, Jeannie-Marie; Stitzer, Maxine L.; Strain, Eric; Copersino, Marc L.; Mintzer, Miriam Z.

    2014-01-01

    Given the long-term nature of methadone maintenance treatment, it is important to assess the extent of cognitive side effects. This study investigated cognitive and psychomotor performance in fifty-one methadone maintenance patients (MMP) as a function of time since last methadone dose and maintenance dose level. MMP maintained on doses ranging from 40 to 200 mg (Mean = 97 mg) completed a battery of psychomotor and cognitive measures across two sessions, during peak and trough states, in a double-blind crossover design. Peak sessions were associated with worse performance on measures of sensory processing, psychomotor speed, divided attention, and working memory, compared to trough sessions. The effects of maintenance dose were mixed, with higher dose resulting in worse performance on aspects of attention and working memory, improved performance on executive function, and no effects on several measures. Longer treatment duration was associated with better performance on some measures, but was also associated with increased sensitivity to time since last dose (i.e., worse performance at peak vs. trough) on some measures. The results suggest that cognitive functioning can fluctuate as a function of time since last dose even in MMP who have been maintained on stable doses for an extended time (mean duration in treatment = 4 years), but worsened performance at peak is limited to a subset of functions and may not be clinically significant at these modest levels of behavioral effect. For patients on stable methadone maintenance doses, maintenance at higher doses may not significantly increase the risk of performance impairment. PMID:24548244

  4. Positive impact on heat loss and patient experience of preheated skin disinfection: a randomised controlled trial.

    PubMed

    Wistrand, Camilla; Söderquist, Bo; Nilsson, Ulrica

    2016-11-01

    The aim of this study was to compare the effect of preheated (36 °C) and room-temperature (20 °C) skin disinfectant solution on skin temperature and patients' experience of the skin disinfection process. To prevent surgical site infections, it is important to disinfect skin prior to invasive surgery. In clinical practice, conscious patients often comment on the coldness of the preoperative skin disinfection solution. Evidence is lacking, as to whether preheated skin disinfectant has any positive effects during preoperative skin disinfection. Randomised controlled trial. A total of 220 patients undergoing pacemaker, implantable cardioverter-defibrillator, or cardiac resynchronisation therapy under local anaesthesia were included and randomly allocated to preheated or room-temperature skin disinfection. Skin temperature was assessed before and after skin disinfection at the planned incision site; in addition, three study-specific questions were used to assess how patients experienced the temperature. Patients experienced the skin disinfection process with preheated disinfectant as significantly more pleasant. They felt less cold and reported increased satisfaction with the temperature of the solution compared to patients who were disinfected with room-temperature solution. Skin disinfection with preheated solution also yielded a significantly higher mean skin temperature compared to room-temperature solution. Preoperative skin disinfection with preheated disinfectant may prevent heat loss and contributes to a more pleasant experience for patients. Skin disinfection with preheated skin disinfectant is an easy and inexpensive nursing intervention that has a positive impact on heat loss and on patients' experience of the disinfection process. © 2016 John Wiley & Sons Ltd.

  5. Patient and staff radiation doses from early radiological examinations (1899-1902).

    PubMed

    Kotre, C J; Little, B G

    2006-10-01

    A source of data on radiographic and fluoroscopic examinations, including radiographic technique factors, was used in conjunction with information about cold-cathode X-ray apparatus to estimate patient and staff radiation doses for the years 1899 to 1902 at the Forth Banks Infirmary, Newcastle-upon-Tyne. Physical evidence from representative apparatus of the period was used with a beam spectral simulation program to characterize the X-ray beam, and information about the electrical supply waveform was produced by experimental operation of a contemporary induction coil. Results are given in terms of skin entrance dose, and these are compared with modern values. An estimate of the annual dose received by the radiographer known to have carried out all of the examinations within this period is also given.

  6. EFFECTIVE DOSE TO PATIENTS FROM THORACIC SPINE EXAMINATIONS WITH TOMOSYNTHESIS.

    PubMed

    Svalkvist, Angelica; Söderman, Christina; Båth, Magnus

    2016-06-01

    The purposes of the present work were to calculate the average effective dose to patients from lateral tomosynthesis examinations of the thoracic spine, compare the results with the corresponding conventional examination and to determine a conversion factor between dose-area product (DAP) and effective dose for the tomosynthesis examination. Thoracic spine examinations from 17 patients were included in the study. The registered DAP and information about the field size for each projection radiograph were, together with patient height and mass, used to calculate the effective dose for each projection radiograph. The total effective doses for the tomosynthesis examinations were obtained by adding the effective doses from the 60 projection radiographs included in the examination. The mean effective dose was 0.47 mSv (range 0.24-0.81 mSv) for the tomosynthesis examinations and 0.20 mSv (range 0.07-0.29 mSv) for the corresponding conventional examinations (anteroposterior + left lateral projection). For the tomosynthesis examinations, a conversion factor between total DAP and effective dose of 0.092 mSv Gycm(-2) was obtained. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. DOSE-RESPONSE STUDIES OF SODIUM ARSENITE IN THE SKIN OF K6/ODC TRANSGENIC MOUSE

    EPA Science Inventory

    It has previously been observed that chronic exposure to inorganic arsenic and/or its metabolites increase(s) tumor frequency in the skin of K6/ODC transgenic mice. To identify potential biomarkers and modes of action for this skin tumorigenicity, gene expression profiles w...

  8. DOSE-RESPONSE STUDIES OF SODIUM ARSENITE IN THE SKIN OF K6/ODC TRANSGENIC MOUSE

    EPA Science Inventory

    It has previously been observed that chronic exposure to inorganic arsenic and/or its metabolites increase(s) tumor frequency in the skin of K6/ODC transgenic mice. To identify potential biomarkers and modes of action for this skin tumorigenicity, gene expression profiles w...

  9. Factors influencing skin autofluorescence of patients with peritoneal dialysis.

    PubMed

    Mácsai, Emília; Benke, A; Cseh, A; Vásárhelyi, B

    2012-06-01

    Skin autofluorescence (SAF) measurement is a simple, noninvasive method to assess tissue advanced glycation end products (AGE). In patients with end-stage renal disease and in those on hemodialysis AGE production is increased. Less is known about those treated with peritoneal dialysis (PD). In this study we tested if SAF is influenced by clinical and treatment characteristics in PD patients.This cross-sectional study included 198 PD patients (of those, 128 were on traditional glucose-based solutions and 70 patients were partially switched to icodextrin-based PD). SAF measurements were done with a specific AGE Reader device. The impact of patients' age, gender, current diabetes, duration of PD, cumulative glucose exposure, body mass index, smoking habits and use of icodextrin on SAF values were tested with multiple regression analysis.Our analysis revealed that patients' age, current diabetes and icodextrin use significantly increase patients' SAF values (p = 0.015, 0.012, 0.005, respectively). AGE exposure of PD patients with diabetes and on icodextrin solution is increased. Further investigation is required whether this finding is due to the icodextrin itself or for a still unspecified clinical characteristic of PD population treated with icodextrin.

  10. Survey of patient dose in computed tomography in Syria 2009.

    PubMed

    Kharita, M H; Khazzam, S

    2010-09-01

    The radiation doses to patient in computed tomography (CT) in Syria have been investigated and compared with similar studies in different countries. This work surveyed 30 CT scanners from six different manufacturers distributed all over Syria. Some of the results in this paper were part of a project launched by the International Atomic Energy Agency in different regions of the world covering Asia, Africa and Eastern Europe. The dose quantities covered are CT dose index (CTDI(w)), dose-length product (DLP), effective dose (E) and collective dose. It was found that most CTDI(w) and DLP values were similar to the European reference levels and in line with the results of similar surveys in the world. The results were in good agreement with the UNSCEAR Report 2007. This study concluded a recommendation for national diagnostic reference level for the most common CT protocols in Syria. The results can be used as a base for future optimisation studies in the country.

  11. Dosimetry for quantitative analysis of low dose ionizing radiation effects on humans in radiation therapy patients

    SciTech Connect

    Lehmann, J; Stern, R L; Daly, T P; Schwieter, C W; Jones, G E; Arnold, M L; Hartmann-Siantar, C L; Goldberg, Z

    2004-04-20

    We have successfully developed a practical approach to predicting the location of skin surface dose at potential biopsy sites that receive 1 cGy and 10 cGy, respectively, in support of in vivo biologic dosimetry in humans. This represents a significant technical challenge as the sites lie on the patient surface out side the radiation fields. The PEREGRINE Monte Carlo simulation system was used to model radiation dose delivery and TLDs were used for validation on a phantom and confirmation during patient treatment. In the developmental studies the Monte Carlo simulations consistently underestimated the dose at the biopsy site by approximately 15% for a realistic treatment configuration, most likely due to lack of detail in the simulation of the linear accelerator outside the main beam line. Using a single, thickness-independent correction factor for the clinical calculations, the average of 36 measurements for the predicted 1 cGy point was 0.985 cGy (standard deviation: 0.110 cGy) despite patient breathing motion and other real world challenges. Since the 10 cGy point is situated in the region of high dose gradient at the edge of the field, patient motion had a greater effect and the six measured points averaged 5.90 cGy (standard deviation: 1.01 cGy), a difference that is equivalent to approximately a 6 mm shift on the patient's surface.

  12. A CONCEPTUAL FRAMEWORK FOR MANAGING RADIATION DOSE TO PATIENTS IN DIAGNOSTIC RADIOLOGY USING REFERENCE DOSE LEVELS.

    PubMed

    Almén, Anja; Båth, Magnus

    2016-06-01

    The overall aim of the present work was to develop a conceptual framework for managing radiation dose in diagnostic radiology with the intention to support optimisation. An optimisation process was first derived. The framework for managing radiation dose, based on the derived optimisation process, was then outlined. The outset of the optimisation process is four stages: providing equipment, establishing methodology, performing examinations and ensuring quality. The optimisation process comprises a series of activities and actions at these stages. The current system of diagnostic reference levels is an activity in the last stage, ensuring quality. The system becomes a reactive activity only to a certain extent engaging the core activity in the radiology department, performing examinations. Three reference dose levels-possible, expected and established-were assigned to the three stages in the optimisation process, excluding ensuring quality. A reasonably achievable dose range is also derived, indicating an acceptable deviation from the established dose level. A reasonable radiation dose for a single patient is within this range. The suggested framework for managing radiation dose should be regarded as one part of the optimisation process. The optimisation process constitutes a variety of complementary activities, where managing radiation dose is only one part. This emphasises the need to take a holistic approach integrating the optimisation process in different clinical activities.

  13. Warfarin pharmacogenetics: development of a dosing algorithm for Omani patients.

    PubMed

    Pathare, Anil; Al Khabori, Murtadha; Alkindi, Salam; Al Zadjali, Shoaib; Misquith, Rhea; Khan, Hammad; Lapoumeroulie, Claudine; Paldi, Andras; Krishnamoorthy, Rajagopal

    2012-10-01

    The objective of our present study was to develop a warfarin dosing algorithm for the Omani patients, as performances of warfarin dosing algorithms vary across populations with impact on the daily maintenance dose. We studied the functional polymorphisms of CYP2C9, CYP4F2 and VKORC1 genes to evaluate their impact on the warfarin maintenance dose in an admixed Omani patient cohort with Caucasian, African and Asian ancestries. We observed a 64-fold inter-patient variability for warfarin to achieve stable international normalized ratio in these patients. Univariate analysis revealed that age, gender, weight, atrial fibrillation, deep vein thrombosis/pulmonary embolism and variant genotypes of CYP2C9 and VKORC1 loci were significantly associated with warfarin dose in the studied patient population. However, multiple regression model showed that only the atrial fibrillation, and homozygous CYP2C9 variant genotypes (*2/*3 and *3/*3) and VKORC1 GA and AA genotypes remained significant. A multivariate model, which included demographic, clinical and pharmacogenetic variables together explained 63% of the overall inter-patient variability in warfarin dose requirement in this microgeographically defined, ethnically admixed Omani patient cohort on warfarin. This locally developed model performed much better than the International Warfarin Pharmacogenetics Consortium (IWPC) model as the latter could only explain 34% of the inter-patient variability in Omani patients. VKORC1 3673G>A polymorphism emerged as the single most important predictor of warfarin dose variability, even in this admixed population (partial R(2)=0.45).

  14. Patient Factors and Their Association with Nonmelanoma Skin Cancer Morbidity and the Performance of Self-skin Exams

    PubMed Central

    Amber, Kyle T.; Bloom, Romi; Abyaneh, Mohammad-Ali Yazdani; Falto-Aizpurua, Leyre A.; Viera, Martha; Zaiac, Martin N.; Nouri, Keyvan

    2016-01-01

    Objective: Mohs micrographic surgery is widely utilized for the treatment of nonmelanoma skin cancers with the advantage of tissue sparing and higher cure rate. The preoperative tumor size and post-Mohs micrographic surgery defect size are useful surrogate measures of nonmelanoma skin cancer morbidity. The authors sought to evaluate whether gender, Hispanic ethnicity, socioeconomic status, sun-safe practices and self-skin exams affected tumor size and Mohs micrographic surgery defect size. They also investigated factors associated with self-skin exams. Design: A cross-sectional survey-based study. Setting: Two dermatologic surgery clinics—one academic-associated and the other private. Participants: Patients receiving Mohs surgery for nonmelanoma skin cancers. Measurements: Tumor size and Mohs defect size and their relationship to patient factors ascertained from a survey, as well as the number of patients performing self-skin exams. The authors used t-tests and analysis of variance to compare tumor and defect sizes for each patient factor. Chi-squared tests were used to determine the factors associated with self-skin exams performance. Results: Lower education was associated with greater head and face tumor area (95mm2 vs. 41mm2, P=0.019), but not Mohs micrographic surgery defect size. Other studied patient factors were not associated with an increased morbidity. Hispanics performed self-skin exams at a lower rate than non-Hispanics (27% vs. 46%, p=0.03). Conclusion: This study innovatively uses tumor and Mohs micrographic surgery defect area as a measure of morbidity, allowing for identification of populations at need for improved education and prevention. (J Clin Aesthet Dermatol. 2016;9(9):16–22.) PMID:27878058

  15. Skin Cancer Screening (PDQ®)—Patient Version

    Cancer.gov

    Having a skin exam to screen for skin cancer has not been shown to decrease your chance of dying from skin cancer. Learn about this and other tests that have been studied to detect or screen for skin cancer in this expert reviewed summary.

  16. Evaluation of the stepwise collimation method for the reduction of the patient dose in full spine radiography

    NASA Astrophysics Data System (ADS)

    Lee, Boram; Lee, Sunyoung; Yang, Injeong; Yoon, Myeonggeun

    2014-05-01

    The purpose of this study is to evaluate the dose reduction when using the stepwise collimation method for scoliosis patients undergoing full spine radiography. A Monte Carlo simulation was carried out to acquire dose vs. volume data for organs at risk (OAR) in the human body. While the effective doses in full spine radiography were reduced by 8, 15, 27 and 44% by using four different sizes of the collimation, the doses to the skin were reduced by 31, 44, 55 and 66%, indicating that the reduction of the dose to the skin is higher than that to organs inside the body. Although the reduction rates were low for the gonad, being 9, 14, 18 and 23%, there was more than a 30% reduction in the dose to the heart, suggesting that the dose reduction depends significantly on the location of the OARs in the human body. The reduction rate of the secondary cancer risk based on the excess absolute risk (EAR) varied from 0.6 to 3.4 per 10,000 persons, depending on the size of the collimation. Our results suggest that the stepwise collimation method in full spine radiography can effectively reduce the patient dose and the radiation-induced secondary cancer risk.

  17. [Patient dose optimization in pediatric computerized tomography].

    PubMed

    Verdun, F R; Schnyder, P; Gutièrrez, D; Gudinchet, F

    2006-07-12

    The development of CT applications might become a public health problem if no effort is made on the justification and the optimisation of the examinations. This paper presents some hints to assure that the risk-benefit compromise remains in favour of the patient, especially when one deals with the examinations of young patients. In this context a particular attention has to be made on the justification of the examination. When performing the acquisition one needs to optimise the extension of the volume investigated together with the number of acquisition sequences used. Finally, the use of automatic exposure systems, now available on all the units, and the use of the Diagnostic Reference Levels (DRL) should allow help radiologists to control the exposure of their patients.

  18. Skin dose from neutron-activated soil for early entrants following the A-bomb detonation in Hiroshima: contribution from beta and gamma rays.

    PubMed

    Tanaka, Kenichi; Endo, Satoru; Imanaka, Tetsuji; Shizuma, Kiyoshi; Hasai, Hiromi; Hoshi, Masaharu

    2008-07-01

    Epilation was reported among atomic bomb survivors in Hiroshima and Nagasaki, including "early entrance survivors" who entered the cities after the bombings. The absorbed dose to the skin by neutron-activated soil via beta and gamma rays has been estimated in a preliminary fashion, for these survivors in Hiroshima. Estimation was done for external exposures from activated soil on the ground as well as skin and hair contamination from activated soil particles, using the Monte Carlo radiation transport code MCNP-4C. Assuming 26 mum thickness of activated soil on the skin as an example, the skin dose was estimated to be about 0.8 Gy, for an exposure scenario that includes the first 7 days after the bombing at 1 m above the ground at the hypocenter. In this case, 99% of the total skin dose came from activated radionuclides in the soil, i.e., 0.19 and 0.63 Gy due to beta and gamma rays, respectively. In contrast, contribution to skin dose due to skin contamination with soil particles was found to be about 1%. To make it comparable to the exposure by neutron-activated soil on the ground, a soil thickness on the skin of about 1 mm would be required, which seems to be difficult to keep for a long time. Fifty-five percent of the 7-day skin dose was delivered during the first hour after the bombing. Our estimates of the skin dose are lower than the conventionally reported threshold of 2 Gy for epilation. It should be noted, however, that the possibility of more extreme exposure scenarios for example for entrants who received much heavier soil contamination on their skin cannot be excluded.

  19. The physiological and phenotypic determinants of human tanning measured as change in skin colour following a single dose of ultraviolet B radiation.

    PubMed

    Wong, Terence H; Jackson, Ian J; Rees, Jonathan L

    2010-07-01

    Experimental study of the in vivo kinetics of tanning in human skin has been limited by the difficulties in measuring changes in melanin pigmentation independent of the ultravioletinduced changes in erythema. The present study attempted to experimentally circumvent this issue. We have studied erythemal and tanning responses following a single exposure to a range of doses of ultraviolet B irradiation on the buttock and the lower back in 98 subjects. Erythema was assessed using reflectance techniques at 24 h and tanning measured as the L* spectrophotometric score at 7 days following noradrenaline iontophoresis. We show that dose (P < 0.0001), body site (P < 0.0001), skin colour (P < 0.0001), ancestry (P = 0.0074), phototype (P = 0.0019) and sex (P = 0.04) are all independent predictors of erythema. Quantitative estimates of the effects of these variables are reported, but the effects of ancestry and phototype do not appear solely explainable in terms of L* score. Dose (P < 0.0001), body site (P < 0.0001) and skin colour (P = 0.0365) or, as an alternative to skin colour, skin type (P = 0.0193) predict tanning, with those with lighter skin tanning slightly more to a defined UVB dose. If erythema is factored into the regression, then only dose and body site remain significant predictors of tanning: therefore neither phototype nor pigmentary factors, such as baseline skin colour, or eye or hair colour, predict change in skin colour to a unit erythemal response.

  20. Skin Temperature Changes in Patients With Unilateral Lumbosacral Radiculopathy

    PubMed Central

    Ra, Jong Yun; An, Sun; Lee, Geun-Ho; Kim, Tae Uk; Lee, Seong Jae

    2013-01-01

    Objective To clarify the relationship of skin temperature changes to clinical, radiologic, and electrophysiological findings in unilateral lumbosacral radiculopathy and to delineate the possible temperature-change mechanisms involved. Methods One hundred and one patients who had clinical symptoms and for whom there were physical findings suggestive or indicative of unilateral lumbosacral radiculopathy, along with 27 normal controls, were selected for the study, and the thermal-pattern results of digital infrared thermographic imaging (DITI) performed on the back and lower extremities were analyzed. Local temperatures were assessed by comparing the mean temperature differences (ΔT) in 30 regions of interest (ROIs), and abnormal thermal patterns were divided into seven regions. To aid the diagnosis of radiculopathy, magnetic resonance imaging (MRI) and electrophysiological tests were also carried out. Results The incidence of disc herniation on MRI was 86%; 43% of patients showed electrophysiological abnormalities. On DITI, 97% of the patients showed abnormal ΔT in at least one of the 30 ROIs, and 79% showed hypothermia on the involved side. Seventy-eight percent of the patients also showed abnormal thermal patterns in at least one of the seven regions. Patients who had motor weakness or lateral-type disc herniation showed some correlations with abnormal DITI findings. However, neither pain severity nor other physical or electrophysiological findings were related to the DITI findings. Conclusion Skin temperature change following lumbosacral radiculopathy was related to some clinical and MRI findings, suggesting muscle atrophy. DITI, despite its limitations, might be useful as a complementary tool in the diagnosis of unilateral lumbosacral radiculopathy. PMID:23869333

  1. Quantification of residual dose estimation error on log file-based patient dose calculation.

    PubMed

    Katsuta, Yoshiyuki; Kadoya, Noriyuki; Fujita, Yukio; Shimizu, Eiji; Matsunaga, Kenichi; Matsushita, Haruo; Majima, Kazuhiro; Jingu, Keiichi

    2016-05-01

    The log file-based patient dose estimation includes a residual dose estimation error caused by leaf miscalibration, which cannot be reflected on the estimated dose. The purpose of this study is to determine this residual dose estimation error. Modified log files for seven head-and-neck and prostate volumetric modulated arc therapy (VMAT) plans simulating leaf miscalibration were generated by shifting both leaf banks (systematic leaf gap errors: ±2.0, ±1.0, and ±0.5mm in opposite directions and systematic leaf shifts: ±1.0mm in the same direction) using MATLAB-based (MathWorks, Natick, MA) in-house software. The generated modified and non-modified log files were imported back into the treatment planning system and recalculated. Subsequently, the generalized equivalent uniform dose (gEUD) was quantified for the definition of the planning target volume (PTV) and organs at risks. For MLC leaves calibrated within ±0.5mm, the quantified residual dose estimation errors that obtained from the slope of the linear regression of gEUD changes between non- and modified log file doses per leaf gap are in head-and-neck plans 1.32±0.27% and 0.82±0.17Gy for PTV and spinal cord, respectively, and in prostate plans 1.22±0.36%, 0.95±0.14Gy, and 0.45±0.08Gy for PTV, rectum, and bladder, respectively. In this work, we determine the residual dose estimation errors for VMAT delivery using the log file-based patient dose calculation according to the MLC calibration accuracy. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  2. Dose response evaluation of gene expression profiles in the skin of K6/ODC mice exposed to sodium arsenite

    SciTech Connect

    Ahlborn, Gene J.; Nelson, Gail M.; Ward, William O.; Knapp, Geremy; Allen, James W.; Ouyang Ming; Roop, Barbara C.; Chen Yan; O'Brien, Thomas; Kitchin, Kirk T.; Delker, Don A.

    2008-03-15

    Chronic drinking water exposure to inorganic arsenic and its metabolites increases tumor frequency in the skin of K6/ODC transgenic mice. To identify potential biomarkers and modes of action for this skin tumorigenicity, we characterized gene expression profiles from analysis of K6/ODC mice administered 0, 0.05, 0.25, 1.0 and 10 ppm sodium arsenite in their drinking water for 4 weeks. Following exposure, total RNA was isolated from mouse skin and processed to biotin-labeled cRNA for microarray analyses. Skin gene expression was analyzed with Affymetrix Mouse Genome 430A 2.0 GeneChips (registered) , and pathway analysis was conducted with DAVID (NIH), Ingenuity (registered) Systems and MetaCore's GeneGo. Differential expression of several key genes was verified through qPCR. Only the highest dose (10 ppm) resulted in significantly altered KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, including MAPK, regulation of actin cytoskeleton, Wnt, Jak-Stat, Tight junction, Toll-like, phosphatidylinositol and insulin signaling pathways. Approximately 20 genes exhibited a dose response, including several genes known to be associated with carcinogenesis or tumor progression including cyclin D1, CLIC4, Ephrin A1, STAT3 and DNA methyltransferase 3a. Although transcription changes in all identified genes have not previously been linked to arsenic carcinogenesis, their association with carcinogenesis in other systems suggests that these genes may play a role in the early stages of arsenic-induced skin carcinogenesis and can be considered potential biomarkers.

  3. Optical microscopy of targeted drug delivery and local distribution in skin of a topical minocycline: implications in translational research and guidance for therapeutic dose selection (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hermsmeier, Maiko; Sawant, Tanvee; Lac, Diana; Yamamoto, Akira; Chen, Xin; Huang, Susan Y.; Nagavarapu, Usha; Evans, Conor L.; Chan, Kin Foong; Daniels, AnnaMarie

    2017-02-01

    Acne vulgaris is a chronic inflammatory skin condition commonly resulting in negative aesthetic and social impacts on those affected. Minocycline, currently available as an oral antibiotic for moderate to severe acne, has a known minimum inhibitory concentration (MIC) for the acne-causing bacterium Propionibacterium acnes (P. acnes) in vitro, with its anti-inflammatory properties also eliciting inhibitory effects on pro-inflammatory molecules. A novel topical gel composition containing solubilized minocycline (BPX-01) has been developed to directly deliver the drug to the skin. Because minocycline is a known fluorophore, fluorescence microscopy and concurrent quantitative measurements were performed on excised human facial skin dosed with different concentrations, in order to determine the spatial distribution of the drug and quantification of its local concentration in the epidermis and the pilosebaceous unit where P. acnes generally reside. Local minocycline delivery confirmed achievement of an adequate therapeutic dose to support clinical studies. Subsequently, a 4-week double-blind, randomized, vehicle controlled clinical study was performed to assess the safety and efficacy of 1% minocycline BPX-01 applied daily. No instances of cutaneous toxicity were reported, and a greater than 1 log reduction of P. acnes count was observed at week 4 with statistical significance from baseline and vehicle control. In addition, no detectable amounts of minocycline in the plasma were reported, suggesting the potential of this new formulation to diminish the known systemic adverse effects associated with oral minocycline. Follow-on clinical plans are underway to further establish the safety of BPX-01 and to evaluate its efficacy against inflammatory acne lesions in a 225 patient multi-center dose-finding study.

  4. Accurate Measurements of the Skin Surface Area of the Healthy Auricle and Skin Deficiency in Microtia Patients

    PubMed Central

    van Doremalen, Rob F. M.; Melchels, Ferry P. W.; Kolodzynski, Michail N.; Pouran, Behdad; Malda, Jos; Kon, Moshe; Breugem, Corstiaan C.

    2016-01-01

    Background: The limited cranial skin covering auricular implants is an important yet underrated factor in auricular reconstruction for both reconstruction surgery and tissue engineering strategies. We report exact measurements on skin deficiency in microtia patients and propose an accessible preoperative method for these measurements. Methods: Plaster ear models (n = 11; male:female = 2:1) of lobular-type microtia patients admitted to the University Medical Center Utrecht in The Netherlands were scanned using a micro-computed tomographic scanner or a cone-beam computed tomographic scanner. The resulting images were converted into mesh models from which the surface area could be calculated. Results: The mean total skin area of an adult-size healthy ear was 47.3 cm2, with 49.0 cm2 in men and 44.3 cm2 in women. Microtia ears averaged 14.5 cm2, with 15.6 cm2 in men and 12.6 cm2 in women. The amount of skin deficiency was 25.4 cm2, with 26.7 cm2 in men and 23.1 cm2 in women. Conclusions: This study proposes a novel method to provide quantitative data on the skin surface area of the healthy adult auricle and the amount of skin deficiency in microtia patients. We demonstrate that the microtia ear has less than 50% of skin available compared with healthy ears. Limited skin availability in microtia patients can lead to healing problems after auricular reconstruction and poses a significant challenge in the development of tissue-engineered cartilage implants. The results of this study could be used to evaluate outcomes and investigate new techniques with regard to tissue-engineered auricular constructs. PMID:28293505

  5. Monte Carlo calculation of patient organ doses from computed tomography.

    PubMed

    Oono, Takeshi; Araki, Fujio; Tsuduki, Shoya; Kawasaki, Keiichi

    2014-01-01

    In this study, we aimed to evaluate quantitatively the patient organ dose from computed tomography (CT) using Monte Carlo calculations. A multidetector CT unit (Aquilion 16, TOSHIBA Medical Systems) was modeled with the GMctdospp (IMPS, Germany) software based on the EGSnrc Monte Carlo code. The X-ray spectrum and the configuration of the bowtie filter for the Monte Carlo modeling were determined from the chamber measurements for the half-value layer (HVL) of aluminum and the dose profile (off-center ratio, OCR) in air. The calculated HVL and OCR were compared with measured values for body irradiation with 120 kVp. The Monte Carlo-calculated patient dose distribution was converted to the absorbed dose measured by a Farmer chamber with a (60)Co calibration factor at the center of a CT water phantom. The patient dose was evaluated from dose-volume histograms for the internal organs in the pelvis. The calculated Al HVL was in agreement within 0.3% with the measured value of 5.2 mm. The calculated dose profile in air matched the measured value within 5% in a range of 15 cm from the central axis. The mean doses for soft tissues were 23.5, 23.8, and 27.9 mGy for the prostate, rectum, and bladder, respectively, under exposure conditions of 120 kVp, 200 mA, a beam pitch of 0.938, and beam collimation of 32 mm. For bones of the femur and pelvis, the mean doses were 56.1 and 63.6 mGy, respectively. The doses for bone increased by up to 2-3 times that of soft tissue, corresponding to the ratio of their mass-energy absorption coefficients.

  6. Effective dose to patients from chest examinations with tomosynthesis.

    PubMed

    Båth, Magnus; Svalkvist, Angelica; von Wrangel, Alexa; Rismyhr-Olsson, Heidi; Cederblad, Ake

    2010-01-01

    Chest tomosynthesis, which refers to the principle of collecting low-dose projections of the chest at different angles and using these projections to reconstruct section images of the chest, is an imaging technique recently introduced to health care. The main purpose of the present work was to determine the average effective dose to patients from clinical use of chest tomosynthesis. Exposure data for two chest radiography laboratories with tomosynthesis option (Definium 8000 with VolumeRAD option, GE Healthcare, Chalfont St. Giles, UK) were registered for 20 patients with a weight between 60 and 80 kg (average weight of 70.2 kg). The recorded data were used in the Monte Carlo program PCXMC 2.0 (STUK-Radiation and Nuclear Safety Authority, Helsinki, Finland) to determine the average effective dose for each projection. The effective dose for the chest tomosynthesis examination, including a scout view and the tomosynthesis acquisition, was finally obtained by adding the effective doses from all projections. Using the weighting factors given in ICRP 103, the average effective dose for the examination was found to be 0.13 mSv, whereas the average effective dose for the conventional two-view chest radiography examination was 0.05 mSv. A conversion factor of 0.26 mSv Gy(-1) cm(-2) was found suitable for determining the effective dose from a VolumeRAD chest tomosynthesis examination from the total registered kerma-area product. In conclusion, the effective dose to a standard-sized patient (170 cm/70 kg) from a VolumeRAD chest tomosynthesis examination is ~2 % of an average chest CT and only two to three times the effective dose from the conventional two-view chest radiography examination.

  7. Normal minimal erythema dose responses in patients with suspected photosensitivity disorders.

    PubMed

    Que, Syril Keena T; Brauer, Jeremy A; Soter, Nicholas A; Cohen, David E

    2012-12-01

    Our study identified the most common diagnoses in patients with a history of photosensitivity or with a photodistributed eruption and normal minimal erythema dose (MED) responses. We retrospectively reviewed the diagnoses and phototest results of 319 patients who were phototested at the New York University Photomedicine Section of the Charles C. Harris Skin and Cancer Pavilion from 1993 to 2009. Patients were phototested if they had a history of photosensitivity or had an eruption with a distribution that suggested photosensitivity. The majority of patients with normal MEDs were diagnosed with polymorphous light eruption, followed by contact or photocontact dermatitis, photodistributed dermatitis not otherwise specified (idiopathic), solar urticaria and photoexacerbated atopic dermatitis. The clinical history of photosensitivity and physical findings remain as important metrics in the diagnosis of patients with photodistributed dermatoses and normal MEDs. © 2012 John Wiley & Sons A/S.

  8. Tactile sensitivity on the hands skin in rheumatic patients.

    PubMed

    Kaluga, Elżbieta; Kostiukow, Anna; Samborski, Włodzimierz; Rostkowska, Elżbieta

    2014-06-01

    Clinical symptoms of rheumatic diseases can cause changes in the level of skin tactile sensitivity. To determine the tactile threshold of the hands in female patients with rheumatic diseases. It also attempted to determine correlations between rheumatic patients' tactile sensitivity and the degree of articular movement limitations, the Barthel Index (BI) and Edinburgh Handedness Inventory (EHI) results, the level of disability of the right hand and the left hand as well as age, education and eyesight. Ninety-nine female rheumatic patients aged 19-87 years took part in the study. The control group comprised 45 healthy women aged 23-80 years. The measurement of the tactile threshold was performed using the Touch-Test™ Sensory Evaluators (Semmes-Weinstein Monofilaments Test). The tactile threshold was measured at three sites on the hand: the little finger, the index finger and the metacarpus. The patients' tactile sensitivity ranges were classified as normal, diminished light touch and diminished protective touch. The degree of their disability was correlated with tactile sensitivity. The patients' tactile sensitivity worsens with age, but it is not correlated with the level of education. The lateralization was similar to that of the control group and was not correlated with tactile sensitivity. The worsening eyesight, independent of rheumatic disease, corresponds, however, with decreasing tactile sensitivity. The patients represented a group with a medium level of functional disability and lower tactile sensitivity.

  9. Characterization of a cable-free system based on p-type MOSFET detectors for 'in vivo' entrance skin dose measurements in interventional radiology

    SciTech Connect

    Falco, Maria Daniela; D'Andrea, Marco; Strigari, Lidia; D'Alessio, Daniela; Quagliani, Francesco; Santoni, Riccardo; Bosco, Alessia Lo

    2012-08-15

    Purpose: During radiological interventional procedures (RIP) the skin of a patient under examination may undergo a prolonged x-ray exposure, receiving a dose as high as 5 Gy in a single session. This paper describes the use of the OneDose{sup TM} cable-free system based on p-type MOSFET detectors to determine the entrance skin dose (ESD) at selected points during RIP. Methods: At first, some dosimetric characteristics of the detector, such as reproducibility, linearity, and fading, have been investigated using a C-arc as a source of radiation. The reference setting (RS) was: 80 kV energy, 40 cm Multiplication-Sign 40 cm field of view (FOV), current-time product of 50 mAs and source to skin distance (SSD) of 50 cm. A calibrated PMX III solid state detector was used as the reference detector and Gafchromic{sup Registered-Sign} films have been used as an independent dosimetric system to test the entire procedure. A calibration factor for the RS and correction factors as functions of tube voltage and FOV size have been determined. Results: Reproducibility ranged from 4% at low doses (around 10 cGy as measured by the reference detector) to about 1% for high doses (around 2 Gy). The system response was found to be linear with respect to both dose measured with the PMX III and tube voltage. The fading test has shown that the maximum deviation from the optimal reading conditions (3 min after a single irradiation) was 9.1% corresponding to four irradiations in one hour read 3 min after the last exposure. The calibration factor in the RS has shown that the system response at the kV energy range is about four times larger than in the MV energy range. A fifth order and fourth order polynomial functions were found to provide correction factors for tube voltage and FOV size, respectively, in measurement settings different than the RS. ESDs measured with the system after applying the proper correction factors agreed within one standard deviation (SD) with the corresponding ESDs

  10. Phase I dose escalation trial of feverfew with standardized doses of parthenolide in patients with cancer.

    PubMed

    Curry, Eardie A; Murry, Daryl J; Yoder, Christy; Fife, Karen; Armstrong, Victoria; Nakshatri, Harikrishna; O'Connell, Michael; Sweeney, Christopher J

    2004-08-01

    Feverfew is a botanical product that contains parthenolide. Parthenolide has in vitro and in vivo anti-tumor and anti-angiogenic activity. Feverfew has been used extensively without any formal pharmacokinetic analysis. A Phase I trial was conducted to evaluate the pharmacokinetics and toxicity of parthenolide given as a component of "feverfew." Feverfew (Tanacet trade mark ) was administered as a daily oral tablet in a 28-day cycle. A starting dose of 1 mg per day was explored with subsequent dose escalations to 2, 3, and 4 mg. Assessment of plasma pharmacokinetics was performed on patients accrued to the trial. Solid phase extraction and mass spectroscopy were used to evaluate parthenolide plasma concentrations. The limit of detection for parthenolide in plasma was 0.5 ng/ml. Patients were evaluated for response after every two cycles. Feverfew given on this schedule had no significant toxicity, and the maximum tolerated dose was not reached. When parthenolide was administered at doses up to 4 mg as a daily oral capsule in the feverfew preparation, there was not detectable concentration in the plasma. Because of this, parthenolide pharmacokinetics were not able to be completed. Feverfew, with up to 4 mg of parthenolide, given daily as an oral tablet is well tolerated without dose-limiting toxicity, but does not provide detectable plasma concentrations. Purification of parthenolide for administration of higher doses will be needed.

  11. Stratum corneum hydration and skin surface pH in patients with atopic dermatitis.

    PubMed

    Knor, Tanja; Meholjić-Fetahović, Ajša; Mehmedagić, Aida

    2011-01-01

    Atopic dermatitis (AD) is a chronically relapsing skin disease with genetic predisposition, which occurs most frequently in preschool children. It is considered that dryness and pruritus, which are always present in AD, are in correlation with degradation of the skin barrier function. Measurement of hydration and pH value of the stratum corneum is one of the noninvasive methods for evaluation of skin barrier function. The aim of the study was to assess skin barrier function by measuring stratum corneum hydration and skin surface pH of the skin with lesions, perilesional skin and uninvolved skin in AD patients, and skin in a healthy control group. Forty-two patients were included in the study: 21 young and adult AD patients and 21 age-matched healthy controls. Capacitance, which is correlated with hydration of stratum corneum and skin surface pH were measured on the forearm in the above areas by SM810/CM820/pH900 combined units (Courage AND Khazaka, Germany). The mean value of water capacitance measured in AD patients was 44.1 ± 11.6 AU (arbitrary units) on the lesions, 60.2 ± 12.4 AU on perilesional skin and 67.2 ± 8.8 AU on uninvolved skin. In healthy controls, the mean value was 74.1 ± 9.2 AU. The mean pH value measured in AD patients was 6.13 ± 0.52 on the lesions, 5.80 ± 0.41 on perilesional skin, and 5.54 ± 0.49 on uninvolved skin. In control group, the mean pH of the skin surface was 5.24 ± 0.40. The values of both parameters measured on lesional skin were significantly different (capacitance decreased and pH increased) from the values recorded on perilesional skin and uninvolved skin. The same held for the relation between perilesional and uninvolved skin. According to study results, the uninvolved skin of AD patients had significantly worse values of the measured parameters as compared with control group. The results of this study suggested the skin barrier function to be degraded in AD patients, which is specifically expressed in lesional skin.

  12. Estimating dose to implantable cardioverter-defibrillator outside the treatment fields using a skin QED diode, optically stimulated luminescent dosimeters, and LiF thermoluminescent dosimeters

    SciTech Connect

    Chan, Maria F.; Song, Yulin; Dauer, Lawrence T.; Li Jingdong; Huang, David; Burman, Chandra

    2012-10-01

    The purpose of this work was to determine the relative sensitivity of skin QED diodes, optically stimulated luminescent dosimeters (OSLDs) (microStar Trade-Mark-Sign DOT, Landauer), and LiF thermoluminescent dosimeters (TLDs) as a function of distance from a photon beam field edge when applied to measure dose at out-of-field points. These detectors have been used to estimate radiation dose to patients' implantable cardioverter-defibrillators (ICDs) located outside the treatment field. The ICDs have a thin outer case made of 0.4- to 0.6-mm-thick titanium ({approx}2.4-mm tissue equivalent). A 5-mm bolus, being the equivalent depth of the devices under the patient's skin, was placed over the ICDs. Response per unit absorbed dose-to-water was measured for each of the dosimeters with and without bolus on the beam central axis (CAX) and at a distance up to 20 cm from the CAX. Doses were measured with an ionization chamber at various depths for 6- and 15-MV x-rays on a Varian Clinac-iX linear accelerator. Relative sensitivity of the detectors was determined as the ratio of the sensitivity at each off-axis distance to that at the CAX. The detector sensitivity as a function of the distance from the field edge changed by {+-} 3% (1-11%) for LiF TLD-700, decreased by 10% (5-21%) for OSLD, and increased by 16% (11-19%) for the skin QED diode (Sun Nuclear Corp.) at the equivalent depth of 5 mm for 6- or 15-MV photon energies. Our results showed that the use of bolus with proper thickness (i.e., {approx}d{sub max} of the photon energy) on the top of the ICD would reduce the scattered dose to a lower level. Dosimeters should be calibrated out-of-field and preferably with bolus equal in thickness to the depth of interest. This can be readily performed in clinic.

  13. Estimating dose to implantable cardioverter-defibrillator outside the treatment fields using a skin QED diode, optically stimulated luminescent dosimeters, and LiF thermoluminescent dosimeters.

    PubMed

    Chan, Maria F; Song, Yulin; Dauer, Lawrence T; Li, Jingdong; Huang, David; Burman, Chandra

    2012-01-01

    The purpose of this work was to determine the relative sensitivity of skin QED diodes, optically stimulated luminescent dosimeters (OSLDs) (microStar™ DOT, Landauer), and LiF thermoluminescent dosimeters (TLDs) as a function of distance from a photon beam field edge when applied to measure dose at out-of-field points. These detectors have been used to estimate radiation dose to patients' implantable cardioverter-defibrillators (ICDs) located outside the treatment field. The ICDs have a thin outer case made of 0.4- to 0.6-mm-thick titanium (∼2.4-mm tissue equivalent). A 5-mm bolus, being the equivalent depth of the devices under the patient's skin, was placed over the ICDs. Response per unit absorbed dose-to-water was measured for each of the dosimeters with and without bolus on the beam central axis (CAX) and at a distance up to 20 cm from the CAX. Doses were measured with an ionization chamber at various depths for 6- and 15-MV x-rays on a Varian Clinac-iX linear accelerator. Relative sensitivity of the detectors was determined as the ratio of the sensitivity at each off-axis distance to that at the CAX. The detector sensitivity as a function of the distance from the field edge changed by ± 3% (1-11%) for LiF TLD-700, decreased by 10% (5-21%) for OSLD, and increased by 16% (11-19%) for the skin QED diode (Sun Nuclear Corp.) at the equivalent depth of 5 mm for 6- or 15-MV photon energies. Our results showed that the use of bolus with proper thickness (i.e., ∼d(max) of the photon energy) on the top of the ICD would reduce the scattered dose to a lower level. Dosimeters should be calibrated out-of-field and preferably with bolus equal in thickness to the depth of interest. This can be readily performed in clinic. Copyright © 2012 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  14. Multiple-dose amikacin kinetics in pediatric oncology patients.

    PubMed

    Kramer, W G; Cleary, T; Frankel, L S; Kohl, S; Pickering, L K

    1979-11-01

    Amikacin kinetics was studied in 8 pediatric oncology patients who received the drug by intravenous infusion over 30 or 60 min at a dose of 5 mg/kg every 6 or 8 hr. This regimen is recommended but, due to patient variability, patients should be monitored. Dosing intervals during 1 or 2 and 3 or 4 days of therapy were studied with serum samples collected before and at the end of the infusion and serially to the end of the dosing interval. The data appeared consistent with and were analyzed according to 1-compartment model. An equation describing serum concentration with time for the multiple-dose case was fit to each patient's multiple-interval data with nonlinear regression. Half-life averaged 1.2 hr. volume of distribution 0.24 l/kg, and total body clearance 109 ml/min/1.73 m2 or 2.51 ml/min/kg. The volume of distribution and the clearance are greater than reported for adults and probably account for the larger dose needed to achieve and maintain therapeutic levels. Although the total daily dose was greater than previously reported, there were no signs of toxicity, although therapuetic concentrations were maintained.

  15. IMPLICATIONS OF PATIENT CENTRING ON ORGAN DOSE IN COMPUTED TOMOGRAPHY.

    PubMed

    Kataria, Bharti; Sandborg, Michael; Althén, Jonas Nilsson

    2016-06-01

    Automatic exposure control (AEC) in computed tomography (CT) facilitates optimisation of dose absorbed by the patient. The use of AEC requires appropriate 'patient centring' within the gantry, since positioning the patient off-centre may affect both image quality and absorbed dose. The aim of this experimental study was to measure the variation in organ and abdominal surface dose during CT examinations of the head, neck/thorax and abdomen. The dose was compared at the isocenter with two off-centre positions-ventral and dorsal to the isocenter. Measurements were made with an anthropomorphic adult phantom and thermoluminescent dosemeters. Organs and surfaces for ventral regions received lesser dose (5.6-39.0 %) than the isocenter when the phantom was positioned +3 cm off-centre. Similarly, organ and surface doses for dorsal regions were reduced by 5.0-21.0 % at -5 cm off-centre. Therefore, correct vertical positioning of the patient at the gantry isocenter is important to maintain optimal imaging conditions. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Design and characterization of a new high-dose-rate brachytherapy Valencia applicator for larger skin lesions.

    PubMed

    Candela-Juan, C; Niatsetski, Y; van der Laarse, R; Granero, D; Ballester, F; Perez-Calatayud, J; Vijande, J

    2016-04-01

    large skin lesions simpler, faster, and safer. Also the dose to surrounding healthy tissues is minimal.

  17. Design and characterization of a new high-dose-rate brachytherapy Valencia applicator for larger skin lesions

    SciTech Connect

    Candela-Juan, C.; Niatsetski, Y.; Laarse, R. van der; Granero, D.; Ballester, F.; Perez-Calatayud, J.; Vijande, J.

    2016-04-15

    tool in clinical practice, making treatment of large skin lesions simpler, faster, and safer. Also the dose to surrounding healthy tissues is minimal.

  18. KERMA-based radiation dose management system for real-time patient dose measurement

    NASA Astrophysics Data System (ADS)

    Kim, Kyo-Tae; Heo, Ye-Ji; Oh, Kyung-Min; Nam, Sang-Hee; Kang, Sang-Sik; Park, Ji-Koon; Song, Yong-Keun; Park, Sung-Kwang

    2016-07-01

    Because systems that reduce radiation exposure during diagnostic procedures must be developed, significant time and financial resources have been invested in constructing radiation dose management systems. In the present study, the characteristics of an existing ionization-based system were compared to those of a system based on the kinetic energy released per unit mass (KERMA). Furthermore, the feasibility of using the KERMA-based system for patient radiation dose management was verified. The ionization-based system corrected the effects resulting from radiation parameter perturbations in general radiography whereas the KERMA-based system did not. Because of this difference, the KERMA-based radiation dose management system might overestimate the patient's radiation dose due to changes in the radiation conditions. Therefore, if a correction factor describing the correlation between the systems is applied to resolve this issue, then a radiation dose management system can be developed that will enable real-time measurement of the patient's radiation exposure and acquisition of diagnostic images.

  19. HOSPITAL PHYSICS: Patient radiation doses from diagnostic radiology

    NASA Astrophysics Data System (ADS)

    Hart, D.

    1996-03-01

    X-ray examinations may be of great benefit but they also carry a slight risk. This article explains how doses to patients are measured and describes how different techniques expose patients to differing amounts of ionizing radiation. These figures are compared with other natural and man-made sources.

  20. A feasibility study of low-cost, self-administered skin care interventions in patients with head and neck cancer receiving chemoradiation.

    PubMed

    Mannix, Catherine Marie; Bartholomay, Marian Mahin; Doherty, Carol S; Lewis, Maryellen; Bilodeau, Mary-Liz Connors

    2012-06-01

    Current evidence for the management of radiation skin toxicities demonstrates equivocal outcomes using a variety of interventions, leaving substantial gaps in knowledge. Skin toxicities can lead to treatment delays, infection, pain, and increased costs for the patient. Patients with head and neck cancers receiving chemoradiation (N = 100), a population particularly vulnerable to disruptions in skin integrity, were enrolled into a prospective, descriptive study. Data collection was conducted and photographs were taken at baseline and weekly throughout treatment. Patients received skin care kits, instructions, and a diary to record adherence. Skin toxicity was measured and validated by at least three observers using serial photographs with 100% interrater agreement. Data were analyzed using descriptive statistics, graphs, and bivariate analysis. Adherence to both washing and moisturizing was consistently high. Although a correlation existed between the radiation dose and skin toxicity at week 6, no correlation existed between skin toxicity and adherence. Given the rate of grade 3 toxicities at week 6 and product costs, this proved to be an affordable regimen to which patients could easily adhere. Positive patient outcomes can be promoted through teaching and reinforcement of self-care measures to reduce skin toxicity.

  1. An open label clinical trial assessing the efficacy and safety of Bend Skincare Anti-Aging Formula on minimal erythema dose in skin.

    PubMed

    Morse, Nancy L; Reid, Anna-Jean; St-Onge, Marc

    2017-09-08

    Sunburn and other health risks associated with excess sun exposure place huge economic burdens on societies, and create discomfort and disease within susceptible individuals. Oral supplements that reduce sunburn may be advantageous. This study evaluated the safety and efficacy of Bend Skincare Anti-Aging Formula to ameliorate sunburn induced with a solar simulator. Subjects (n= 28) with Fitzpatrick skin phototypes I, II or III took four capsules daily of the supplement providing 1400 mg of eicosapentaenoic acid (EPA)+ docosahexaenoic acid (DHA), 120 mg of gamma-linolenic acid (GLA), 5 mg of lutein, 2.5 mg of zeaxanthin, and 1000 IU of vitamin D3 for 8 weeks. Skin on each subject's back was exposed to a progressive sequence of timed ultraviolet (UV) radiation exposure doses at baseline, and after 4 and 8 weeks treatment to determine their minimal erythema dose (MED). Results were compared before and after treatment using three paired t-tests and subsequently three linear mixed models. Treatment significantly improved tolerance to UV exposure as evidenced by increased MED at 4 and 8 weeks compared to baseline (p<0.001). This protection increased with prolonged use of Bend Skincare Anti-Aging Formula as demonstrated by progressively increased MED between baseline and 4 weeks, and again between 4 and 8 weeks (p<0.001). Nearly 86% of patients responded to treatment within 4 weeks and 100% of patients responded by the end of the study, resulting in a 39% mean increase in MED at 4 weeks, and an 84% mean increase in MED at 8 weeks compared to baseline. Treatment was well tolerated with no product associated adverse events (AE) and only a few mild and expected side effects. Bend Skincare Anti-Aging Formula safely and effectively provides significant skin photo-protection that increases with continued use. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  2. A New Method for Individualized Digoxin Dosing in Elderly Patients.

    PubMed

    Martin-Suarez, Ana; García González, David; Macías Núñez, Juan F; Ardanuy Albajar, Ramón; Calvo Hernández, M Victoria

    2016-04-01

    Digoxin is a frequently prescribed drug in the elderly population. Estimated glomerular filtration rate is widely used to adjust dosages. The HUGE value is a tool for differentiating the presence or absence of chronic kidney disease in elderly patients. We aimed to investigate the usefulness of the HUGE value to predict the initial dose of digoxin in patients aged older than 70 years. We reviewed retrospectively the medical records of patients aged older than 70 years with serum digoxin concentrations (SDCs) monitored over a 6-month period (63 patients). A linear regression relating the patient's SDC, maintenance dose of digoxin and the HUGE value was estimated to generate a dosage equation. This equation was validated retrospectively (33 patients) and prospectively (35 patients) in comparison with two existing methods based on creatinine clearance. An equation (HUGE_DIG) was generated to calculate the initial digoxin dose to reach a specific target SDC. Thus, to achieve a SDC of 0.8 ng/mL: Digoxin (mg/day) = 0.091 - 0.006 x HUGE. After retrospective validation, the calculated digoxin doses with this equation were administered in the prospective phase and we did not observe statistical differences between measured and desired SDCs. Moreover, the predictive performance of our equation was better than that obtained with the compared methods. We offer a new validated digoxin dosing equation for elderly patients. Our results support the need to perform digoxin dosing in elderly people, bearing in mind the changes in renal physiology secondary to ageing and not merely the estimated glomerular filtration rate.

  3. Patient-specific dose estimation for pediatric chest CT

    PubMed Central

    Li, Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

    2008-01-01

    Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9–18.2kg) were created based on the patients’ actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120kVp, 70 or 75mA, 0.4s gantry rotation period, pitch of 1.375, 20mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7–5.3mSv∕100mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4–12.6mGy∕100mAs and 11.2–13.3mGy∕100mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%–18%) and for partially or indirectly exposed organs (11%–77%). Normalized effective dose correlated weakly with body weight (correlation coefficient:r=−0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=−0.99, heart: r=−0.93); these strong correlation relationships can be used to estimate patient

  4. Analysis of a Low Dose Protocol to Reduce Patient Radiation Exposure During Percutaneous Coronary Interventions.

    PubMed

    Maccagni, Davide; Godino, Cosmo; Latib, Azeem; Azzalini, Lorenzo; Pazzanese, Vittorio; Chieffo, Alaide; Margonato, Alberto; Colombo, Antonio

    2017-01-15

    The cardiac catheterization laboratory is an important source of radiation for patients and operators and it is good practice to limit exposure as much as possible. The purpose of this study was to evaluate the effectiveness and impact of a radiological low dose protocol (LDP) in terms of reduction in patient radiation exposure during percutaneous coronary interventions (PCIs). From November 2014 to October 2015, 906 consecutive patients who underwent PCI were evaluated. Of these, 571 patients (63%) were treated with the standard dose protocol (SDP) of 15 frames per second for cine acquisition and standard settings for fluoroscopy, and 335 patients (37%) with the LDP of 7.5 frames per second for cine acquisition and low-dose settings for fluoroscopy. In the LDP group, we observed a significant reduction of kerma area product (53.3 LDP vs 115 SDP Gycm(2), p <0.0001) and air kerma at interventional reference point (0.79 LDP vs 1.976 SDP Gy, p <0.0001). Marked differences were observed regarding the exceeding of International Commission on Radiological Protection and National Council on Radiation Protection and Measurements' air kerma at interventional reference point trigger level (cutoff for potential skin injuries), which were significantly lower in the LDP group (1.8% vs 7.2%, p <0.0001). Such difference was more relevant in complex PCI. In conclusion, the implementation of LDP allowed a marked reduction in patient dosimetric parameters for PCI and significantly reduced the risk of exceeding the International Commission on Radiological Protection/National Council on Radiation Protection and Measurements trigger levels for potential skin injuries. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Does the fluence map editing in electronic tissue compensator improve dose homogeneity in bilateral field plan of head and neck patients?

    PubMed

    Kinhikar, Rajesh A

    2008-01-01

    The purpose of this study was to evaluate the effect of fluence map editing in electronic tissue compensator (ETC) on the dose homogeneity for head and neck cancer patients. Treatment planning using 6-MV X-rays and bilateral field arrangement employing ETC was carried out on the computed tomography (CT) datasets of 20 patients with head and neck cancer. All the patients were planned in Varian Eclipse three-dimensional treatment planning system (3DTPS) with dynamic multileaf collimator (DMLC). The treatment plans, with and without fluence editing, was compared and the effect of pre-editing and post-editing the fluence maps in the treatment field was evaluated. The skin dose was measured with thermoluminescent dosimeters (TLDs) and was compared with the skin dose estimated by TPS. The mean percentage volume of the tissue receiving at least 107% of the prescription dose was 5.4 (range 1.5-10; SD 2.4). Post-editing fluence map showed that the mean percentage volume of the tissue receiving at least 107% of the prescription dose was 0.47 (range 0.1-0.9; SD 0.3). The mean skin dose measured with TLD was found to be 74% (range 71-80%) of the prescribed dose while the TPS showed the mean skin dose as 85% (range 80-90%). The TPS overestimated the skin dose by 11%. Fluence map editing thus proved to be a potential tool for improving dose homogeneity in head and neck cancer patients planned with ETC, thus reducing the hot spots in the treatment region as well. The treatment with ETC is feasible with DMLC and does not take any additional time for setup or delivery. The method used to edit the fluence maps is simple and time efficient. Manual control over a plan is essential to create the best treatment plan possible.

  6. Increased cis-to-trans urocanic acid ratio in the skin of chronic spontaneous urticaria patients.

    PubMed

    Pham, Duy Le; Lim, Kyung-Min; Joo, Kyung-Mi; Park, Hae-Sim; Leung, Donald Y M; Ye, Young-Min

    2017-05-02

    Increased filaggrin expression was found to be correlated with severity scores in chronic spontaneous urticaria (CSU); however, the role of filaggrin breakdown products (FBPs) in CSU has not been studied. We collected stratum corneum (SC) specimens from the volar forearms of 10 CSU patients, 10 AD patients, and 10 healthy normal controls (NCs) and measured contents of FBPs (pyrrolidone carboxylic acid [PCA] and urocanic acid [UCA]) using UPLC-MS/MS, transepidermal water loss (TEWL) and epidermal pH. Compared to NCs, cis-UCA level was increased in CSU lesions (P < 0.05) and decreased in AD lesions (P < 0.01). The cis-to-trans-UCA ratio in SC specimens from CSU patients was significantly greater than those from AD and NC subjects. AD lesions had lower FBP and PCA contents compared to NC skin (both P < 0.001), and higher TEWL and pH compared to CSU lesions. Moreover, cis-UCA, but not trans-UCA, enhanced the IgE-mediated basophil activation, as well as IgE- and calcium-mediated degranulation of LAD-2 cells, in a dose-dependent manner. These findings suggest that increased cis-to-trans UCA ratio in the epidermis is a distinct feature of CSU, which could enhance mast cell degranulation. Modulation of cis-UCA may be a potential target for skin diseases associated with IgE-mediated mast cell degranulation.

  7. DOSE-RESPONSE FOR UV-INDUCED IMMUNE SUPPRESSION IN PEOPLE OF COLOR: DIFFERENCES BASED ON ERYTHEMAL REACTIVITY RATHER THAN SKIN PIGMENTATION

    EPA Science Inventory

    Ultraviolet radiation (UVR) is known to suppress immune responses in human subjects. The purpose of this study was to develop dose responses across a broad range of skin pigmentation in order to facilitate risk assessment. UVR was administered using FS 20 bulbs. Skin pigmentation...

  8. DOSE-RESPONSE FOR UV-INDUCED IMMUNE SUPPRESSION IN PEOPLE OF COLOR: DIFFERENCES BASED ON ERYTHEMAL REACTIVITY RATHER THAN SKIN PIGMENTATION

    EPA Science Inventory

    Ultraviolet radiation (UVR) is known to suppress immune responses in human subjects. The purpose of this study was to develop dose responses across a broad range of skin pigmentation in order to facilitate risk assessment. UVR was administered using FS 20 bulbs. Skin pigmentation...

  9. SU-E-I-15: Comparison of Radiation Dose for Radiography and EOS in Adolescent Scoliosis Patients

    SciTech Connect

    Schueler, B; Walz-Flannigan, A

    2014-06-01

    Purpose: To estimate patient radiation dose for whole spine imaging using EOS, a new biplanar slot-scanning radiographic system and compare with standard scoliosis radiography. Methods: The EOS imaging system (EOS Imaging, Paris, France) consists of two orthogonal x-ray fan beams which simultaneously acquire frontal and lateral projection images of a standing patient. The patient entrance skin air kerma was measured for each projection image using manufacturer-recommended exposure parameters for spine imaging. Organ and effective doses were estimated using a commercially-available Monte Carlo simulation program (PCXMC, STUK, Radiation and Nuclear Safety Authority, Helsinki, Finland) for a 15 year old mathematical phantom model. These results were compared to organ and effective dose estimated for scoliosis radiography using computed radiography (CR) with standard exposure parameters obtained from a survey of pediatric radiographic projections. Results: The entrance skin air kerma for EOS was found to be 0.18 mGy and 0.33 mGy for posterior-anterior (PA) and lateral projections, respectively. This compares to 0.76 mGy and 1.4 mGy for CR, PA and lateral projections. Effective dose for EOS (PA and lateral projections combined) is 0.19 mSv compared to 0.51 mSv for CR. Conclusion: The EOS slot-scanning radiographic system allows for reduced patient radiation dose in scoliosis patients as compared to standard CR radiography.

  10. Low-dose digital urography in the pregnant patient

    SciTech Connect

    Albert, S.A.; Richter, J.O.; Rosenfield, A.T.

    1987-04-01

    In the pregnant patient when visualization of the ureters is requested, excretory urography is often ordered. We propose the use of digital radiography using single exposure as an alternative to conventional urography. This technique allows significant dose reduction while visualizing the entire urinary tract. It can be performed on most current-generation computerized tomographic scanners. In addition to dose reduction, the ability to manipulate, magnify, and avoid repeat exposures makes this an attractive alternative to the conventional film-screen technique.

  11. Patient specific tube current modulation for CT dose reduction

    NASA Astrophysics Data System (ADS)

    Jin, Yannan; Yin, Zhye; Yao, Yangyang; Wang, Hui; Wu, Mingye; Kalra, Mannudeep; De Man, Bruno

    2015-03-01

    Radiation exposure during CT imaging has drawn growing concern from academia, industry as well as the general public. Sinusoidal tube current modulation has been available in most commercial products and used routinely in clinical practice. To further exploit the potential of tube current modulation, Sperl et al. proposed a Computer-Assisted Scan Protocol and Reconstruction (CASPAR) scheme [6] that modulates the tube current based on the clinical applications and patient specific information. The purpose of this study is to accelerate the CASPAR scheme to make it more practical for clinical use and investigate its dose benefit for different clinical applications. The Monte Carlo simulation in the original CASPAR scheme was substituted by the dose reconstruction to accelerate the optimization process. To demonstrate the dose benefit, we used the CATSIM package generate the projection data and perform standard FDK reconstruction. The NCAT phantom at thorax position was used in the simulation. We chose three clinical cases (routine chest scan, coronary CT angiography with and without breast avoidance) and compared the dose level with different mA modulation schemes (patient specific, sinusoidal and constant mA) with matched image quality. The simulation study of three clinical cases demonstrated that the patient specific mA modulation could significantly reduce the radiation dose compared to sinusoidal modulation. The dose benefits depend on the clinical application and object shape. With matched image quality, for chest scan the patient specific mA profile reduced the dose by about 15% compared to the sinusoid mA modulation; for the organ avoidance scan the dose reduction to the breast was over 50% compared to the constant mA baseline.

  12. Radiation-induced stress response in peripheral blood of breast cancer patients differs between patients with severe acute skin reactions and patients with no side effects to radiotherapy.

    PubMed

    Skiöld, Sara; Naslund, Ingemar; Brehwens, Karl; Andersson, Arja; Wersall, Peter; Lidbrink, Elisabet; Harms-Ringdahl, Mats; Wojcik, Andrzej; Haghdoost, Siamak

    2013-08-30

    The aim of the study was to compare the radiation-induced oxidative stress response in blood samples from breast cancer patients that developed severe acute skin reactions during the radiotherapy, with the response in blood samples from patients with no side effects. Peripheral blood was collected from 12 breast cancer patients showing no early skin reactions after radiotherapy (RTOG grade 0) and from 14 breast cancer patients who developed acute severe skin reactions (RTOG grade 3-4). Whole blood was irradiated with 0, 5 and 2000mGy γ-radiation and serum was isolated. The biomarker for oxidative stress, 8-oxo-dG, was analyzed in the serum by a modified ELISA. While a significant radiation-induced increase of serum 8-oxo-dG levels was observed in serum of the RTOG 0 patients, no increase was seen in serum of the RTOG 3-4 patients. The radiation induced increase in serum 8-oxo-dG levels after 5mGy did not differ significantly from the increase observed for 2000mGy in the RTOG 3-4 cohort, thus no dose response relation was observed. A receiver operating characteristic (ROC) value of 0.97 was obtained from the radiation-induced increase in 8-oxo-dG indicating that the assay could be used to identify patients with severe acute adverse reactions to radiotherapy. The results show that samples of whole blood from patients, classified as highly radiosensitive (RTOG 3-4) based on their skin reactions to radiotherapy, differ significantly in their oxidative stress response to ionizing radiation compared to samples of whole blood from patients with no skin reactions (RTOG 0). Extracellular 8-oxo-dG is primarily a biomarker of nucleotide damage and the results indicate that the patients with severe acute skin reactions differ in their cellular response to ionizing radiation at the level of induction of oxidative stress or at the level of repair or both. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Risk factors for sorafenib-induced high-grade skin rash in Japanese patients with advanced renal cell carcinoma.

    PubMed

    Tsuchiya, Norihiko; Narita, Shintaro; Inoue, Takamitsu; Hasunuma, Naoko; Numakura, Kazuyuki; Horikawa, Yohei; Satoh, Shigeru; Notoya, Takeshi; Fujishima, Naohito; Hatakeyama, Shingo; Ohyama, Chikara; Habuchi, Tomonori

    2013-03-01

    The aim of this study was to evaluate the clinical factors, drug-related genetic polymorphisms, and human leukocyte antigen (HLA) types to determine the association with sorafenib-induced high-grade skin rash (HGSR) in Japanese patients with advanced renal cell carcinoma (RCC). A total of 55 patients with advanced RCC treated with sorafenib were analyzed retrospectively. Of these, 33 patients were subjected to HLA typing and polymorphism analyses of CYP3A5, ABCB1, ABCC2, and UGT1A1, which are involved in the metabolism and membrane transport of sorafenib. Grade 3 or higher SR developed in 12 (22%), and a higher incidence was observed in female patients than in male patients (40 vs. 15%, P=0.046). The initial dose, initial dose per body weight, and initial dose per body surface area in patients with HGSR were significantly higher than those in patients without HGSR. Patients with the ABCC2 -24CC genotype were at a significantly higher risk of SR than those with the CT genotype (35 vs. 0%, P=0.032). HLA-A*24 was significantly associated with the occurrence of HGSR (P=0.049). Our finding suggested that women, higher initial dose per body weight or body surface area, the ABCC2 -24CC genotype, and HLA-A*24 are associated with the risk of sorafenib-induced HGSR in Japanese RCC patients.

  14. Analysis of patient CT dose data using virtualdose

    NASA Astrophysics Data System (ADS)

    Bennett, Richard

    X-ray computer tomography has many benefits to medical and research applications. Recently, over the last decade CT has had a large increase in usage in hospitals and medical diagnosis. In pediatric care, from 2000 to 2006, abdominal CT scans increased by 49 % and chest CT by 425 % in the emergency room (Broder 2007). Enormous amounts of effort have been performed across multiple academic and government groups to determine an accurate measure of organ dose to patients who undergo a CT scan due to the inherent risks with ionizing radiation. Considering these intrinsic risks, CT dose estimating software becomes a necessary tool that health care providers and radiologist must use to determine many metrics to base the risks versus rewards of having an x-ray CT scan. This thesis models the resultant organ dose as body mass increases for patients with all other related scan parameters fixed. In addition to this,this thesis compares a modern dose estimating software, VirtualDose CT to two other programs, CT-Expo and ImPACT CT. The comparison shows how the software's theoretical basis and the phantom they use to represent the human body affect the range of results in organ dose. CT-Expo and ImPACT CT dose estimating software uses a different model for anatomical representation of the organs in the human body and the results show how that approach dramatically changes the outcome. The results categorizes four datasets as compared to the three software types where the appropriate phantom was available. Modeling was done to simulate chest abdominal pelvis scans and whole body scans. Organ dose difference versus body mass index shows as body mass index (BMI) ranges from 23.5 kg/m 2 to 45 kg/m2 the amount of organ dose also trends a percent change from -4.58 to -176.19 %. Comparing organ dose difference with increasing x-ray tube potential from 120 kVp to 140 kVp the percent change in organ dose increases from 55 % to 65 % across all phantoms. In comparing VirtualDose to CT

  15. Dosing celecoxib in pediatric patients with juvenile rheumatoid arthritis.

    PubMed

    Krishnaswami, Sriram; Hutmacher, Matt M; Robbins, Jeffery L; Bello, Akintunde; West, Christine; Bloom, Bradley J

    2012-08-01

    The objective was to derive dosing recommendations for the use of celecoxib in patients with juvenile rheumatoid arthritis (JRA) using pharmacokinetic (PK) and exposure-response data. PK and efficacy data from a randomized, double-blind, 12-week study of celecoxib dosed at 3 and 6 mg/kg twice a day (bid) as an investigational suspension formulation in 152 JRA patients aged 2 to 17 years, PK data from 36 adult RA patients, and relative bioavailability data in healthy adults comparing suspension or capsule sprinkles with the commercial capsule were analyzed. Typical oral clearance (L/h) values were 40% and 24% lower in patients weighing 10 and 25 kg, respectively, compared with a 70-kg patient. Longitudinal, logistic pharmacodynamic models incorporating linear effects of dose/area under the plasma concentration-time curve (AUC) over 0 to 12 hours (AUC(0-12)) suggested that the percentage of responders increased with celecoxib exposure. Systemic exposures (AUC) were similar for the suspension, capsule sprinkles, and intact capsule. Administration of a 50-mg bid capsule (or sprinkles) for patients weighing 10 to 25 kg and 100 mg bid for patients >25 kg was predicted to yield similar exposures and response rates as those observed in the JRA trial. Doses and dosage forms not studied in the JRA trial were approved based on the results of this analysis.

  16. Cortistatin is dysregulated in skin tissue of patients with psoriasis vulgaris and suppresses keratinocyte proliferation in vitro.

    PubMed

    Li, Dai; He, Hui-Lan; Yao, Ming-Zhu; Chen, Ming-Liang; Chen, Xiang

    2015-08-01

    Psoriasis is characterized by the unregulated proliferation of epidermal keratinocytes and increased expression of proinflammatory mediators in the skin. Cortistatin, an endogenous cyclic neuropeptide, inhibits the proliferation of inflammatory cells. We investigated the expression of cortistatin in patients with psoriasis vulgaris and examined its effects on keratinocyte growth in vitro. Serum levels of cortistatin were determined by enzyme-linked immunosorbent assay (ELISA) in 72 patients with psoriasis vulgaris and 76 age-matched healthy volunteers. Cortistatin expression was also examined by immunohistochemistry of skin biopsies from 14 patients and 14 healthy subjects. The effects of cortistatin on the proliferation of primary keratinocytes were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and BrdU incorporation assay. Intracellular levels of cAMP in keratinocytes in the presence or absence of cortistatin were determined by ELISA. Serum levels of cortistatin and expression levels in skin were significantly lower in patients with psoriasis than in healthy subjects. Cortistatin inhibited keratinocyte proliferation in vitro in a dose-dependent manner and substantially reduced intracellular cAMP levels in keratinocytes. Cortistatin is downregulated in the skin of patients with psoriasis vulgaris and suppresses keratinocyte growth in vitro. © 2015 The International Society of Dermatology.

  17. Individualising the dose of allopurinol in patients with gout.

    PubMed

    Kannangara, Diluk R W; Graham, Garry G; Wright, Daniel F B; Stocker, Sophie L; Portek, Ian; Pile, Kevin D; Barclay, Murray L; Williams, Kenneth M; Stamp, Lisa K; Day, Richard O

    2017-09-01

    The aims of the study were to: 1) determine if a plasma oxypurinol concentration-response relationship or an allopurinol dose-response relationship best predicts the dose requirements of allopurinol in the treatment of gout; and 2) to construct a nomogram for calculating the optimum maintenance dose of allopurinol to achieve target serum urate (SU) concentrations. A nonlinear regression analysis was used to examine the plasma oxypurinol concentration- and allopurinol dose-response relationships with serum urate. In 81 patients (205 samples), creatinine clearance (CLCR ), concomitant diuretic use and SU concentrations before (UP ) and during (UT ) treatment were monitored across a range of allopurinol doses (D, 50-700 mg daily). Plasma concentrations of oxypurinol (C) were measured in 47 patients (98 samples). Models (n = 47 patients) and predictions from each relationship were compared using F-tests, r(2) values and paired t-tests. The best model was used to construct a nomogram. The final plasma oxypurinol concentration-response relationship (UT  = UP  - C*(UP  - UR )/(ID50  + C), r(2)  = 0.64) and allopurinol dose-response relationship (UT  = UP  - D(*) (UP  - UR )/(ID50  + D), r(2)  = 0.60) did not include CLCR or diuretic use as covariates. There was no difference (P = 0.87) between the predicted SU concentrations derived from the oxypurinol concentration- and allopurinol dose-response relationships. The nomogram constructed using the allopurinol dose-response relationship for all recruited patients (n = 81 patients) required pretreatment SU as the predict