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Showing papers in "Iranian Journal of Medical Physics in 2014"


Journal ArticleDOI
TL;DR: The average outdoor gamma dose rate for Guilan determined in this study is significantly higher in comparison with values reported by UNSCEAR 2000 from different countries with the mean of 59 nSv although in comparisonWith many provinces of Iran, it is lower.
Abstract: Introduction Guilan is one of the provinces in North of Iran, with population of 2,480,874 and a total area of ​​14,042 square kilometers. This study assesses the outdoor natural gamma dose rates in the air of 49 cities in Guilan and calculates corresponding average annual effective dose. Materials and Methods A total of 260 different sample points measurements were carried out. The results include both terrestrial and cosmic ray components of gamma radiation level. Results The outdoor gamma dose rates range from 65 to 127 nSv h-1 with the mean of 94 ± 24 nSv h-1. Conclusion The average outdoor gamma dose rate for Guilan determined in this study is significantly higher in comparison with values reported by UNSCEAR 2000 from different countries with the mean of 59 nSv although in comparison with many provinces of Iran, it is lower.

13 citations


Journal ArticleDOI
TL;DR: Surveyed apparatuses, both ends of operating range have large errors in therefore it is recommended that these devices should not be used in the mentioned regions.
Abstract: Introduction Using ionization radiation for diagnostic and treatment fields has increased worldwide dramatically. This issue causes an increase in the absorbed and collective doses in society noticeably. With regard to two main principles in radiation protection, i.e., justification and optimization, it is necessary to have imaging process with minimum dose to patients and personnel. For achieving this, it is vital to perform quality control tests regularly. On this topic, many studies have been performed and reported worldwide which show necessities and meaningfulness of QC tests. Materials and Methods In this study, Unfors Mult-O-Meter model 303 is used for surveying accuracy of kVp and time, linearity of exposure with mAs, and reproducibility of exposure. Results According to recommendations of AAPM (2002) and ICRP 103, in this study, 27% of apparatuses in accuracy of kVp, 45% in accuracy of timer, and 30% in accuracy of reproducibility were out of accepted range. Conclusion In surveyed apparatuses, both ends of operating range have large errors in therefore it is recommended that these devices should not be used in the mentioned regions. Performing strict quality control on all radioactive devices is one of the radiation protection priorities that should be done periodically .With regard to the results, repair, substitution or omition of some devices are suggested.

11 citations


Journal ArticleDOI
TL;DR: Considering the significant relationship between skin burn and supraclavicular field, special attention needs to be paid to factors affecting the treatment planning of suprachoice field such as field size and photon energy.
Abstract: Introduction The first medical intervention for many breast cancer patients is breast conserving surgery (BCS) and/or modified radical mastectomy (MRM). Most of these patients undergo radiation therapy, following surgery. The most common side-effect of breast radiotherapy is skin damage. In the present study, the severity of acute skin changes and the underlying causes were investigated in patients undergoing BCS and radiotherapy. Materials and Methods This prospective, cohort study was performed on 31 female patients, undergoing breast surgery therapy at Shahid Rajaie Babolsar Radiotherapy Center from September 2011 to July 2012. A questionnaire was designed, including the patient’s characteristics, details of radiotherapy technique, and skin damage; the questionnaire was completed for each patient. The obtained results were analysed by performing ANOVA and Fisher's exact tests. Complications were graded using the radiation therapy oncology group (RTOG) scale. Results Grade 0 or 4 of skin damage was observed in none of the patients. Among the evaluated patients, 58%, 35.5%, and 6.5% of the patients had grade 1, grade 2, and grade 3 of skin damage, respectively. There was no statistically significant relationship between regional skin burns and factors such as average tangential field size, internal mammary field, chemotherapy, prior history of diseases, tamoxifen use, previous radiotherapy in breast area, or skin type (p>0.05). However, there was a significant relationship between skin burns and presence of supraclavicular field (p=0.05). Conclusion Considering the significant relationship between skin burn and supraclavicular field, special attention needs to be paid to factors affecting the treatment planning of supraclavicular field such as field size and photon energy.

10 citations


Journal ArticleDOI
TL;DR: This article reviews the development of non-invasive optical techniques for determination of blood glucose concentrations in diabetic patients and describes the major optical technologies for noninvasive glucose monitoring and compares their advantages and disadvantages.
Abstract: This article reviews the development of non-invasive optical techniques for determination of blood glucose concentrations in diabetic patients. Early diagnosis and daily management are essential for ensuring the healthy life of diabetic patients. The determination of blood glucose concentration with common devices involves the chemical analysis of blood samples, which are obtained by pricking the finger or extracting blood from the forearm. Pain, discomfort, and inconvenience, associated with current invasive methods, have necessitated the investigation of non-invasive measurement techniques. Non-invasive monitoring of blood glucose level offers several advantages, including absence of pain and biohazard materials, non- exposure to sharp objects, increased testing frequency and consequently, tighter control of glucose concentration. Considering these potential advantages commercialization of non-invasive glucose monitoring devices has become a subject of increasing interest. Several optical technologies have the potential to provide viable noninvasive measuring devices. this review study aimed to describe the major optical technologies for noninvasive glucose monitoring and compare their advantages and disadvantages. second scenario) better than other methods in presence of a typically low false positive rate equal to 3%.

9 citations


Journal ArticleDOI
TL;DR: An accurate delivery of radiation is attainable using these techniques with high precision which leads to dose reduction in critical organs and adjacent normal tissues while delivering the highest dose to tumoral tissue.
Abstract: "Stereotactic" is an exact radiotherapy treatment modality which implements invasive and non-invasive facilities for improving precise dose delivery. Stereotactic refers to three-dimensi onal localization of a specific point in space by a unique set of coordinates that relate to a fixed external reference frame. An accurate delivery of radiation is attainable using these techniques with high precision (1-2 mm) which leads to dose reduction in critical organs and adjacent normal tissues while delivering the highest dose to tumoral tissue. Stereotactic irradiation consists of two techniques of delivery: Stereotactic RadioSurgery (SRS) which is an accurate single fractionated delivery of radiation to intracranial lesions and is attained by converging series of radiation beams on a target from various angles. Stereotactic Radiotherapy (SRT) which is a fractionated irradiation of intra and extra cranial lesions. This review article intends to highlight the radiobiological and physical aspects of these techniques and also introduces three commercially available stereotactic machines systematically and functionally.

8 citations


Journal ArticleDOI
TL;DR: The findings revealed that local DRLs in this study are higher than the corresponding values, recommended by the Commission of European Communities (CEC) and National Radiological Protection Board (NRBP), which were related to the use of low kVp, relatively high mAs in all centers, and use of grid for most of the patients.
Abstract: Introduction Given the fact that children are more sensitive to radiation, compared to adults, special attention needs to be paid to radiation protection in pediatric radiology. Diagnostic reference level (DRL) has been defined to be employed as a practical tool for examining the overall performance of a radiological center in terms of patient dose among a series of similar equipments in an area or an institution as a Local DRL (LDRL). Materials and Methods To establish DRL for diagnostic X-ray examinations of children in KhorasanRazavi province, data were collected from 627 pediatric patients. The average of entrance surface doses (ESDs), arising from chest and abdomen examinations, were examined for three different age groups. Results Local DRL (LDRL) were calculated to be 77, 126, and 138 µGy for chest examinations of <1-month-old, 1-12-month-old, and 1-5-year-old groups, respectively. The corresponding values obtained from abdomen radiographies were 152, 120, and 280 µGy, respectively. Conclusion Our findings revealed that local DRLs in this study are higher than the corresponding values, recommended by the Commission of European Communities (CEC) and National Radiological Protection Board (NRBP). Higher ESDs acquired for chest examination were related to the use of low kVp, relatively high mAs in all centers, and use of grid for most of the patients.

6 citations


Journal ArticleDOI
TL;DR: The proposed enhancement method could be helpful for radiologists to easily detect MCCs; it could also decrease the number of biopsies and reduce the frequency of clinical misdiagnosis and it could be useful prior to segmentation or classification stages.
Abstract: Introduction Breast cancer is one of the most common types of cancer among women. Early detection of breast cancer is the key to reducing the associated mortality rate. The presence of microcalcifications clusters (MCCs) is one of the earliest signs of breast cancer. Due to poor imaging contrast of mammograms and noise contamination, radiologists may overlook some diagnostic signs, specially the presence of MCCs. In order to improve cancer detection, image enhancement methods are often used to aid radiologists. In this paper, a new enhancement method was presented for the accurate and early detection of MCCs in mammograms. Materials and Methods The proposed system consisted of four main steps including: 1) image scaling;2) breast region segmentation;3) noise cancellation using a filter, which is sensitive to MCCs; and 4) contrast enhancement of mammograms using Contrast-Limited Adaptive Histogram Equalization (CLAHE) and wavelet transform. To evaluate this method, 120 clinical mammograms were used. Results To evaluate the performance of the image enhancement algorithm, contrast improvement index (CII) was used. The proposed enhancement method in this research achieved the highest CII in comparison with other methods applied in this study. The Validity of the results was confirmed by an expert radiologist through visual inspection. Conclusion Detection of MCCs significantly improved in contrast-enhanced mammograms. The proposed method could be helpful for radiologists to easily detect MCCs; it could also decrease the number of biopsies and reduce the frequency of clinical misdiagnosis. Moreover, it could be useful prior to segmentation or classification stages.

5 citations


Journal ArticleDOI
TL;DR: The results showed that body coil was the most uniform coil of all; in addition, the head and neck coil was more uniform than the head coil and signal-to-noise ratio (SNR) of the heads and neck coils was higher than that of the body coil.
Abstract: Introduction Signal intensity uniformity in a magnetic resonance (MR) image indicates how well the MR imaging (MRI) system represents an object. One of the major sources of image non-uniformity in high-field MRI scanners is inhomogeneity of radio-frequency coil. The aim of this study was to investigate non-uniformity in head, head and neck, and body coils and compare the obtained results to determine the best clinical coil for future clinical application. Materials and Methods A phantom was designed to investigate the non-uniformity of coils. All evaluations were carried out using a 1.5 T clinical MRI scanner. T1-weighted inversion recovery sequence (linear phase encoding) and turbo fast low angle shot (TurboFLASH) images were used to find non-uniformity in the clinical coils. For testing the uniformity of coils, signal intensity profiles in parts of the coronal image of phantom were measured over X and Y axes. Results The results showed that body coil was the most uniform coil of all; in addition, the head and neck coil was more uniform than the head coil. The results also indicated that signal-to-noise ratio (SNR) of the head and neck coil was higher than the head and body coils. Moreover, SNR of the head coil was higher than that of the body coil. Conclusion In order to accurately find or apply an image signal intensity for measuring organ blood flow or perfusion, coil non-uniformity corrections are required.

5 citations


Journal ArticleDOI
TL;DR: Monitoring blood pressure continuously and without cuff with the designed system can be recommended as a useful method to indicate cardiovascular diseases and used for personal healthcare purposes.
Abstract: Introduction: Blood pressure (BP) is one of the important vital signs that need to be monitored for personal healthcare. Arterial blood pressure is estimated from pulse transit time (PTT). This study uses two pulse sensors to get PTT. The aim of this study was to construct an optical system and to monitor blood pressure continuously and without cuff in people with different ages. Materials and Methods: To measure blood pressure changes, two infrared optical transmitters were used at the distances of 5 mm to the receivers. Output of the optical receivers was inserted in analog circuits. PTT was defined as the time between the two peaks of pulse signals by the software. Signals were measured continuously through a serial network communication. An external personal computer monitored measured waveforms in real time. BP was related to PTT and the relationship coefficients were calculated at different physical activities. After determining the linear correlation coefficients for each individual, blood pressure was measured by the cuff and the PTT method and the results were compared. Results: PTT computed between the two peaks of wave pulses was strongly correlated with systolic blood pressure (R=0.88±0.034) and the diastolic blood pressure (R=0.82±0.058). Systolic blood pressure (SBP) was measured more accurately than the diastolic blood pressure (DBP). The results of SBP showed that the maximum difference and the error percentages between the cuff method and the present method were 7.98±2.88 and 6.33±2.51, respectively. Moreover, the maximum difference and the percentage errors between the cuff method and the present method of DBP were 10.13±3.82 and 10.97±3.89, respectively. Conclusion: Monitoring blood pressure with the designed system can be recommended as a useful method to indicate cardiovascular diseases and used for personal healthcare purposes.

5 citations


Journal ArticleDOI
TL;DR: In this paper, the optical sensitivity of N-isopropyl acrylamide NIPAM and polyacrylamides gelatin and tetrakis hydroxymethyl phosphoniun chloride (PAGAT) polymer gels for different wavelength of visible light spectrum applied in optical computed tomography method was determined.
Abstract: Introduction The purpose of the current study was to determine optical sensitivity of N-isopropyl acrylamide NIPAM and polyacrylamide gelatin and tetrakis hydroxymethyl phosphoniun chloride (PAGAT) polymer gels for different wavelength of visible light spectrum applied in optical computed tomography method. Materials and Methods NIPAM and PAGAT polymer gels with conventional formulations used for polymer gel dosimetry in radiation therapy were prepared. Using a laboratory spectrophotometer, light absorbance against wavelength of light spectrum from 400 to 700 nm was measured. The optical absorbance-dose response curves were obtained for different wavelengths and the results were compared to find the wavelength where the highest sensitivity of polymer gels is occurred. Results The results showed light wavelength dependency for polymer gels optical absorbance-dose sensitivity. The highest sensitivity was seen in the blue part of visible light at wavelengths of 440 and 460 nm for PAGAT and NIPAM, respectively. Moreover, the sensitivity of NIPAM gel was higher than PAGAT for all studied wavelengths. Conclusion The sensitivity of both gels varied considerably with light wavelength and was higher in shorter wavelength of visible light. It is recommended to study optical absorbance-dose sensitivity of polymer gels for selecting the optimum light wavelength for optical measurements and optical computed tomography applications.

5 citations


Journal ArticleDOI
TL;DR: The results illustrated that the system could be utilized for continuous monitoring of interface pressure and temperature for pressure ulcer prevention and a method for detecting different sitting postures was proposed and verified.
Abstract: Introduction Pressure ulcers are tissue damages resulting from blood flow restriction, which occurs when the tissue is exposed to high pressure for a long period of time. These painful sores are common in patients and elderly, who spend extended periods of time in bed or wheelchair. In this study, a continuous pressure and temperature monitoring system was developed for pressure ulcer prevention. Materials and Methods The monitoring system consists of 64 pressure and 64 temperature sensors on a 40×50 cm2 sheet. Pressure and temperature data and the corresponding maps were displayed on a computer in real-time. Risk assessment could be performed by monitoring and recording absolute pressure and temperature values, as well as deviations over time. Furthermore, a posture detection procedure was proposed for sitting posture identification. Information about the patient’s movement history may help caregivers make informed decisions about the patient’s repositioning and ulcer prevention strategies. Results Steady temporal behaviour of the designed system and repeatability of the measurements were evaluated using several particular tests. The results illustrated that the system could be utilized for continuous monitoring of interface pressure and temperature for pressure ulcer prevention. Furthermore, the proposed method for detecting sitting posture was verified using a statistical analysis. Conclusion A continuous time pressure and temperature monitoring system was presented in this study. This system may be suited for pressure ulcer prevention given its feasibility for simultaneous monitoring of pressure and temperature and alarming options. Furthermore, a method for detecting different sitting postures was proposed and verified. Pressure ulcers in wheelchair-bound patients may be prevented using this sitting posture detection method.

Journal ArticleDOI
TL;DR: It can be concluded that AuNPs can significantly increase the absorbed dose in brachytherapy; however, FeNPs do not have a noticeable effect on the absorption dose.
Abstract: Introduction In this study, we aimed to calculate dose enhancement factor (DEF) for gold (Au) and iron (Fe) nanoparticles (NPs) in brachytherapy and teletherapy, using Monte Carlo (MC) method. Materials and Methods In this study, a new algorithm was introduced to calculate dose enhancement by AuNPs and FeNPs for Iridium-192 (Ir-192) brachytherapy and Cobalt-60 (Co-60) teletherapy sources, using the MC method. In this algorithm, the semi-random distribution of NPs was used instead of the regular distribution. Diameters were assumed to be 15, 30, and 100 nm in brachytherapy and 15 and 30 nm in teletherapy. Monte Carlo MCNP4C code was used for simulations, and NP density values were 0.107 mg/ml and 0.112 mg/ml in brachytherapy and teletherapy, respectively. Results AuNPs significantly enhanced the radiation dose in brachytherapy (approximately 60%), and 100 nm diameter NPs showed the most uniform dose distribution. AuNPs had an insignificant effect on teletherapy radiation field, with a dose enhancement ratio of 3% (about the calculation uncertainty) or less. In addition, FeNPs had an insignificant effect on both brachytherapy and teletherapy radiation fields. FeNPs dose enhancement was 3% in brachytherapy and 6% (about the calculation uncertainty) or less in teletherapy. Conclusion It can be concluded that AuNPs can significantly increase the absorbed dose in brachytherapy; however, FeNPs do not have a noticeable effect on the absorbed dose

Journal ArticleDOI
TL;DR: Inhibitory effects of raw garlic may be of particular importance for exposure to environmentally relevant low doses, where RIBE dominates direct radiation effects, and for addressing the limited therapeutic gain of radiotherapy.
Abstract: Introduction Radiation-induced bystander effect (RIBE) is a phenomenon in which radiation signals are transmitted from irradiated cells to non-irradiated ones, inducing radiation effects in these cells. RIBE plays an effective role in radiation response at environmentally relevant low doses and in radiotherapy, given its impact on adjacent normal tissues or those far from the irradiated tumor. Reactive oxygen species contribute to RIBE induction. Therefore, the present study was conducted to investigate the possible inhibitory effects of garlic, as an antioxidant-containing plant, on RIBE. Materials and Methods MCF7 cells, treated with raw garlic extracts, were irradiated by 60Co gamma rays, and their culture medium was transferred to non-irradiated autologous bystander cells. Percentage cell viability and micronucleus formation in both irradiated and bystander cells were examined and compared with corresponding cell groups, not treated with garlic. Results Treatment with garlic extract reduced the number of micronucleus-containing cells in both irradiated and bystander cells. However, it only increased the percentage cell viability in bystander cells, not the irradiated ones. Conclusion RIBE was effectively suppressed by raw garlic extracts. Inhibitory effects of raw garlic may be of particular importance for exposure to environmentally relevant low doses, where RIBE dominates direct radiation effects. They are also partially important for addressing the limited therapeutic gain of radiotherapy, as they may only increase the percentage cell viability of bystander cells, not the directly irradiated tumor cells. However, more comprehensive in-vivo research regarding garlic treatment duration is required to support the obtained results.

Journal ArticleDOI
TL;DR: It was found that images with acceptable quality and reliable detection ability could be obtained using smaller doses of radiation, compared to protocols commonly used by operators.
Abstract: Introduction In computed tomography (CT) technology, an optimal radiation dose can be achieved via changing radiation parameters such as mA, pitch factor, rotation time and tube voltage (kVp) for diagnostic images. Materials and Methods In this study, the brain, abdomen, and thorax scaning was performed using Toshiba 16-slice scannerand standard AAPM and CTDI phantoms. AAPM phantom was used for the measurement of image-related parameters and CTDI phantom was utilized for the calculation of absorbed dose to patients. Imaging parameters including mA (50-400 mA), pitch factor (1 and 1.5) and rotation time (range of 0.5, 0.75, 1, 1.5 and 2 seconds) were considered as independent variables. The brain, abdomen and chest imaging was performed multi-slice and spiral modes. Changes in image quality parameters including contrast resolution (CR) and spatial resolution (SR) in each condition were measured and determined by MATLAB software. Results After normalizing data by plotting the full width at half maximum (FWHM) of point spread function (PSF) in each condition, it was observed that image quality was not noticeably affected by each cases. Therefore, in brain scan, the lowest patient dose was in 150 mA and rotation time of 1.5 seconds. Based on results of scanning of the abdomen and chest, the lowest patient dose was obtained by 100 mA and pitch factors of 1 and 1.5. Conclusion It was found that images with acceptable quality and reliable detection ability could be obtained using smaller doses of radiation, compared to protocols commonly used by operators.

Journal ArticleDOI
TL;DR: It has been shown that the proposed algorithm extracted sperms at least 12% and 18% better than other methods in presence of a typically low false positive rate equal to 3%, better than the minimum acceptable true positive rate of 90%.
Abstract: Introduction The morphologic features of human sperms are key indicators for monitoring fertility problems in men. Therefore, automated analyzing methods via microscopic videos have become the most favorite policy in infertility treatment during the last decades. Materials and Methods In the proposed method, firstly a hypothesis testing framework was defined to distinguish sperms from background. Then, some regions were selected as candidates by minimization of the information distance between the original and processed images. Finally, the correct sperms were extracted from candidates using a watershed-based algorithm. Results The proposed, Watershed Segmentation Algorithm (WSA), Multi Structure Element Segmentation (MSES) and Dynamic Threshold Segmentation (DTS) algorithms achieve true positive rates of 96%, 84%, 81%, and 70%, respectively, versus typically 3% of false positive rate in semen specimens with high density of sperms. The true positive rates of 87%, 69%, 66%, and 52%, respectively, at the same false positive rate were obtained for the semen specimens with high density of sperms. Conclusion Results show that false positive rates of the proposed algorithm were at least 8% (in the first scenario) and 32% (in the second scenario) better than other methods considering the minimum acceptable true positive rate of 90%. Furthermore, it has been shown that the proposed algorithm extracted sperms at least 12% (in the first scenario) and 18% (in the second scenario) better than other methods in presence of a typically low false positive rate equal to 3%.

Journal ArticleDOI
TL;DR: EMG signals of deltoid and pectoralis major muscles are the inputs of the NARX network, which seems to be suitable for dynamic system applications and has the potential to capture the model of nonlinear dynamic systems.
Abstract: Introduction In order to improve the quality of life of amputees, biomechatronic researchers and biomedical engineers have been trying to use a combination of various techniques to provide suitable rehabilitation systems. Diverse biomedical signals, acquired from a specialized organ or cell system, e.g., the nervous system, are the driving force for the whole system. Electromyography(EMG), as an experimental technique,is concerned with the development, recording, and analysis of myoelectric signals. EMG-based research is making progress in the development of simple, robust, user-friendly, and efficient interface devices for the amputees. Materials and Methods Prediction of muscular activity and motion patterns is a common, practical problem in prosthetic organs. Recurrent neural network (RNN) models are not only applicable for the prediction of time series, but are also commonly used for the control of dynamical systems. The prediction can be assimilated to identification of a dynamic process. An architectural approach of RNN with embedded memory is Nonlinear Autoregressive Exogenous (NARX) model, which seems to be suitable for dynamic system applications. Results Performance of NARX model is verified for several chaotic time series, which are applied as input for the neural network. The results showed that NARX has the potential to capture the model of nonlinear dynamic systems. The R-value and MSE are and , respectively. Conclusion EMG signals of deltoid and pectoralis major muscles are the inputs of the NARX network. It is possible to obtain EMG signals of muscles in other arm motions to predict the lost functions of the absent arm in above-elbow amputees, using NARX model.

Journal ArticleDOI
TL;DR: Findings showed that by using carbon ions of 400 MeV/u, the fluence rate of secondary neutrons will be approximately 3.4×1010 n/cm2 in a year, lower than the experimental threshold, and would cause no single event upsets.
Abstract: Introduction Today, there is a growing interest in the use of hadrontherapy as an advanced radiotherapy technique. Hadrontherapy is considered a promising tool for cancer treatment, given its high radiobiological effectiveness and high accuracy of dose deposition due to the physical properties of hadrons. However, new radiation modalities of dose delivery and on-line beam monitoring play crucial roles in a successful treatment. In hadrontherapy, through interactions between the primary beam and patient’s tissue, secondary neutrons are produced. Materials and Methods This study, by using FLUKA Monte Carlo simulations, assessed the level of secondary neutron radiation, produced during patient treatment. In addition, the evaluation included secondary neutron radiation, which was produced while hitting the on-line detectors of beam delivery system by the Italian National Center for Hadrontherapy (CNAO). This study assessed the effects of secondary neutron radiation on an electronics rack (including a data acquisition system, a power supply, and a gas system) and a nozzle, where two monitoring boxes (each one consisting of two or three parallel plate ionization chambers) were installed. Results The resulting neutron energy spectra and radiation doses were used to determine the life performance and the probability of damage to these devices. Findings showed that by using carbon ions of 400 MeV/u, the fluence rate of secondary neutrons will be approximately 3.4×1010 n/cm2 in a year. Conclusion This value is lower than the experimental threshold, which is responsible for less than 1% of changes in electrical characteristics, and would cause no single event upsets.

Journal ArticleDOI
TL;DR: In this paper, the authors found common spectral markers associated with neoplastic changes, associated with normal and cancerous changes, among different tissues, with an accuracy of 84.6, 82.7, and 82.5% in all studied tissues, respectively.
Abstract: Introduction Raman spectroscopy is a vibrational spectroscopic technique, based on inelastic scattering of monochromatic light. This technique can provide valuable information about biomolecular changes, associated with neoplastic transformation. The purpose of this study was to find Raman spectral markers for distinguishing normal samples from cancerous ones in different tissues. Materials and Methods Ten tissue samples from the breast, colon, pancreas, and thyroid were collected. A Raman system was used for Raman spectroscopic measurement of tissues at 532 nm laser excitation. Five to six Raman spectra were acquired from each sample (a total of 52 spectra). Raman spectra were investigated in important bands associated with Amid1, CH2 (scissoring), Amid3, d(NH), n(C-C), and das (CH3) in both normal and cancerous groups. In addition, common spectral markers, which discriminated between normal and cancerous samples in the above tissues, were investigated. Results Common spectral markers among different tissues included intensities of Amid3 and CH2 (scissoring) and intensity ratios of I(Amid1)/I(CH2), I(n(C-C))/I(CH2), and I(d(NH))/I(CH2). This study showed that Amid1-, n(C-C)-, and d(NH)-to-CH2 intensity ratios can discriminate between normal and cancerous samples, with an accuracy of 84.6%, 82.7%, and 82.7% in all studied tissues, respectively. Conclusion This study demonstrates the presence of common spectral markers, associated with neoplastic changes, among different tissues.

Journal ArticleDOI
TL;DR: Assessment of absorbed doses in eyes and various tumors found in the area of sclera and choroid and the adjacent tissues in radiotherapy while changing most important proton therapy parameters shows the amount of absorbed dose in tumoral cells is noticeable.
Abstract: Introduction Proton therapy is used to treat malignant tumors such as melanoma inside the eye. Proton particles are adjusted according to various parameters such as tumor size and position and patient’s distance from the proton source. The purpose of this study was to assess absorbed doses in eyes and various tumors found in the area of sclera and choroid and the adjacent tissues in radiotherapy while changing most important proton therapy parameters such as moderators thickness (1.5-1.9 cm), exposure radius (0.5-0.8 cm), and proton energy beam (53.5-65 MeV). Materials and Methods A proton therapy system of Laboratori Nazionali del Sud-INFNwas simulated by Monte Carlo method. Moreover, the eye and its components were simulated using concentric spheres. To obtain a more accurate results, real density of eye components such as cornea and lens, were applied for simulation. Then, the absorbed dose of eye and eye tumor, in choroid and sclera areas, were calculated by Monte Carlo method. Results The absorbed dose in tumoral region of eye was calculated to be about 12.5 ±0.006Gy in one day with energy 62 MeV for a therapy session, which is suitable for treatment. However, normal eye cells received at most 11.01 Gy which is high. Conclusion The amount of absorbed dose in tumoral cells is noticeable. Therefore, accurate treatment planning, patient immobility and fine calibration of proton-therapy system and its simulator are very important to reduce the absorbed dose of healthy cells.

Journal ArticleDOI
TL;DR: Normalized LV twist or LV torsion values were comparable for both imaging techniques (TDI and VVI methods) and suggest that these methods may be interchanged for serial assessment, but needs additional studies and preferably larger populations to confirm it.
Abstract: Introduction Left ventricular (LV) twist is believed to store potential energy and plays an important role in generating diastolic suction Recent advances in echocardiography techniques have allowed quantification of LV twist The aim of the present study was to compare LV twist and torsion in healthy human subjects determined by velocity vector imaging (VVI) and tissue Doppler imaging (TDI) at rest Materials and Methods All volunteers (72 healthy subjects) underwent complete echocardiographic study and LV torsional parameters were assessed using VVI or TDI methods LV rotation at apical and basal short-axis levels was calculated throughout cardiac cycle and LV twist was defined as net difference between rotation angles of the two levels The LV torsion was calculated as the LV twist divided by the LV end-diastolic length Results Twist degree was significantly lower in the VVI group than the TDI group (114±24o vs141±30o, p<0001), but when LV twist was normalized by LV end-diastolic length, there was no statistically significant difference between the two groups (19±07 o/cm vs 21±06 o/cm, p=0142) Conclusion Normalized LV twist or LV torsion values were comparable for both imaging techniques (TDI and VVI methods) Results suggest that these methods may be interchanged for serial assessment, but needs additional studies and preferably larger populations to confirm it

Journal ArticleDOI
TL;DR: It is confirmed that using magnetic field can alter the dose deposition patterns and as a result can produce dose enhancement as well as dose reduction in the medium using high-energy electron beams.
Abstract: Introduction Magnetic fields are capable of altering the trajectory of electron beams andcan be used in radiation therapy.Theaim of this study was to produce regions with dose enhancement and reduction in the medium. Materials and Methods The NdFeB permanent magnets were arranged on the electron applicator in several configurations. Then, after the passage of the electron beams (9 and 15 MeV Varian 2100C/D) through the non-uniform magnetic field, the Percentage Depth Dose(PDDs) on central axis and dose profiles in three depths for each energy were measured in a 3D water phantom. Results For all magnet arrangements and for two different energies, the surface dose increment and shift in depth of maximum dose (dmax) were observed. In addition, the pattern of dose distribution in buildup region was changed. Measurement of dose profile showed dose localization and spreading in some other regions. Conclusion The results of this study confirms that using magnetic field can alter the dose deposition patterns and as a result can produce dose enhancement as well as dose reduction in the medium using high-energy electron beams. These effects provide dose distribution with arbitrary shapes for use in radiation therapy.

Journal ArticleDOI
TL;DR: A fast, robust, vision-based approach for blink detection that was faster than other systems, which use normalized correlation coefficient (NCC) for eye tracking, since time complexity of SSD is lower than that of NCC.
Abstract: Introduction “Blink” is defined as closing and opening of the eyes in a small duration of time. In this study, we aimed to introduce a fast, robust, vision-based approach for blink detection. Materials and Methods This approach consists of two steps. In the first step, the subject’s face is localized every second and with the first blink, the system detects the eye’s location and creates an open-eye template image. In the second step, the eye is tracked, using sum of squared differences (SSD). This system can classify the state of the eyes as open, closed, or lost, using the SSD-based classifier. If the eyes are closed as in usual blinking, the blink will be detected. To classify eyes as closed or open, two adaptive thresholds were proposed; therefore, factors such as the subject’s distance from the camera or environment illumination did not affect the system performance. In addition, in order to improve system performance, a new feature, called "peak-to-neighbors ratio", was proposed. Results The accuracy of this system was 96.03%, based on the evaluation on Zhejiang University (ZJU) dataset, and 98.59% in our own dataset. Conclusion The present system was faster than other systems, which use normalized correlation coefficient (NCC) for eye tracking, since time complexity of SSD is lower than that of NCC. The achieved processing rate for ZJU dataset was 35 fps.

Journal ArticleDOI
TL;DR: The results showed that using 32P applicator is a cost-effective method for pterygium treatment, which indicated that it could deliver higher doses to a target, located within a close distance from the surface, compared to 90Sr and 106Ru.
Abstract: Introduction Pterygium is a wing-shaped, vascular, fleshy growth that originates from the conjunctiva and can spread into the corneal limbus and beyond Beta irradiation after bare sclera surgery of primary pterygium is a simple, effective, and safe treatment, which reduces the risk of local recurrence Materials and Methods Dosimetric components of strontium-90 (90Sr), phosphorous-32 (32P), and ruthenium-106 (106Ru), in form of ophthalmic applicators, were evaluated, using the Monte Carlo method Results The obtained results indicated that 32P applicator could deliver higher doses (about 10 Gy) to a target, located within a close distance from the surface, compared to 90Sr and 106Ru; it also delivered a lower dose to normal tissues Conclusion The risk of pterygium has increased given the geographical location and climate of Iran Spread of dust in the country over the past few years has also contributed to the rising rate of this condition Our results showed that using 32P applicator is a cost-effective method for pterygium treatment

Journal ArticleDOI
TL;DR: Considering the results and sclera tolerance, it was concluded that the thickness of Silastic must not exceed 0.5 mm, because increasing the Silastic thickness from this area, increases absorbed dose by healthy tissues and also the treatment time.
Abstract: Introduction In order to treat uveal Melanoma , first, radioactive seeds are laid on a silicone- made substance which is called Silastic after that they are inserted in the plaque, and finally, this plaque containing silicone-made substance is stitched to the sclera surface. The dose gradient within the tumor and healthy tissues can be varied due to changing the Silastic thickness between sclera surface and radioactive seeds. In turn, this leads to difference in the amount of absorbed dose of tumor and healthy tissues. Present study is to investigate the optimum Silastic thickness in uveal Melanoma brachytherapy. Materials and Methods To measure changes of depth dose of the plaque in a sphere with a radius of 12 mm, MCNP4C code was applied. Exact specifications of a 20-mm Collaborative Ocular Melanoma Study (COMS) plaque, Silastic and three I-125 seed sources, 6711 model were integrated in simulation. Dose calculations were performed using F6 tally in spheres with a radius of 0.2 mm. Results By measuring the changes of dose rate of plaque in distances of 0.2 to 18 mm from the sclera surface and having the prescribed dose for the absolute treatment of eye melanoma, final absorbed doses by tumor and healthy tissues for each different Silastic thicknesses of 0, 0.5, 1, 1.5, and 2 were calculated. Conclusion Considering the results and sclera tolerance, it was concluded that the thickness of Silastic must not exceed 0.5 mm, because increasing the Silastic thickness from this area, increases absorbed dose by healthy tissues and also the treatment time.