Purpose: The risk effect of long-term occupational exposure to extremely low- frequency electromagnetic fields (ELF-EMFs) has been studied extensively. However, due to several experimental issues such as exposure measurement error and the lack of standard ELF-EMFs exposing devices, the obtained results are controversial. The inconsistent reported results preclude clear conclusions on the evidence of an association between EMF exposure and the disorders reported. To assist with resolving these issues, a digital–low cost ELF-EMFs generator to produce EMFs with desired magnitude and frequency is proposed.
Methods: A sinusoidal waveform with adjustable amplitude and frequency controlled by a microprocessor is generated and then is applied to a coil with a U-shape core. To increase the accuracy of the instrument, three coils with 250 turns; 500 turns; and 1200 turns were designed and used in the instrument. The amplitude and frequency of the voltage delivered to each of these coil are controlled by turning off and on TRIAC transistors controlled by a microprocessor–based system.
Results: The designed instrument provided EMF with magnitude of 0.55 mTesla to 1.56 mTesla with error rate < 5.9% and frequency of 10 Hz to 50 Hz with error rate <1%. The provided EMF was sufficiently homogeneous over a given volume and was stable over time.

Purpose: Proton magnetic resonance spectroscopy (1H-MRS) is a non-invasive method with the capability to correctly lateralize the seizure foci in patients with Temporal Lobe Epilepsy (TLE), with the first evidence published in 1993. One major drawback of this modality is that the MRS data is naturally high dimensional. This, along with the time-consuming post-processing and quantification procedures such as spectral fitting, have made MRS impractical for clinical use. Dimension reduction techniques eliminate undesired properties of high-dimensional spaces, suggesting simple and feasible analysis techniques in comparison with quantification procedures.
Methods: In this study, we use two dimension reduction techniques so-called Isomap and Diffusion maps to quantify MRS data obtained from TLE patients for localization seizure foci. Then, we evaluate the results by comparison with obtained ratio of NAA/(Cr+Cho) from the quantification method.
Results: Our results show that the proposed methodology has the ability to localize and/or to lateralize the seizure foci in such patients, while it maintains minimal required amount of computations and time (Sensitivity= 60%, Specificity= 82.81%).
Conclusion: We are hoping that this method broadens new horizons to explore the informative yet complicated MRS modality into Epileptic diagnosis.

Purpose: The physical and mechanical properties of resin composites are highly affected by the extent of conversion obtained by polymerization. The hardness test can be used as an indirect method to evaluate degree of conversion.The purpose of this study was to evaluate the effect of three preheating temperatures on microhardness of three different nanohybrid resin based composites.
Methods: The 30 specimens for each commercial resin composite [Grandio (Voco), Simile (Pentron) and Tetric N-Ceram (Ivoclar Vivadent)] were randomly subdivided in 3 subgroups which 10 specimens were used for each one {subgroup 1 = preheating at room temperature 21˚ C, subgroup 2 = preheating temperature 37˚ C and subgroup 3 = preheating temperature 54˚ C}. The specimens were photopolimerized with QTH light- curing unit for 20 s following the preheating process. Vickers microhardness test was performed for the top and bottom surfaces of each specimen. Three random indentations were taken for each surface and a mean value was calculated.
Results: The microhardness values in Grandio group were significantly different between all three subgroups (p value ≤ 0.001). In Simile group the only significant difference was between 21˚ C and 54˚ C (p value ≤ 0.005) and in Tetric N-Ceram group the difference between 21˚ C and 54˚ C (p value ≤ 0.001) and also between 21˚ C and 37˚ C (p value ≤ 0.01) were considered as statistically significant. 
Conclusion: Regardless of the resin composite material used, surface hardness was considerably improved by increasing temperature. The microhardness values were influenced significantly by resin-based composite brand

Purpose: The complex geometry of breast tissue, variable shape, size of breasts, their lack of homogeneity and other organs at risk like the heart and lungs make dose distribution difficult, especially for cases involving large breasts. Assessment of breast dosimetry includes homogeneity dose distribution with complete target coverage and the avoidance of organs at risk as much as possible. The aim of this study is to assess dose distribution and coverage of the target by TLD dosimeter in slab breast phantoms.
Methods: This study used a slab anatomical phantom with lung inhomogenity for two different breast sizes, large and small. Exposure was done with 6 MV, utilized PTW reader, oven LTM to annulling conventional methods were carried out with a hand generated contour, 3D treatment planning used RT Dose Plan software.
Results: There were areas with lower than 95 percent reference dose in 3D methods decreased in compare of conventional methods. This result for large breasts was remarkable. Received area of target for both size more than 105 percent reference dose reduce to some extent, therefore getting more homogeneity also better coverage for target volume for large breast.
Conclusion: This study has shown that conventional methods are not suitable to assessment of dose distribution and coverage in target volume, especially for large breast. Also there was not sufficient dose distribution for small breast a as result of the 3D method, and so can it be useful for crowded hospitals with restricted facility centers because they can use conventional methods with nearly the same results as the 3D method.

Purpose: In cataract surgery, the defected lens is replaced with an artificial intraocular lens (IOL). The refraction power of this lens is specified by ophthalmologists before the surgery. There are different formulas that propose the IOL power based on corneal power and axial length. Six common formulas is used in this study and the one which minimizes the postoperative error for a specific patient have to be selected.
Methods: Refraction is measured three times at most, during six month after surgery and the best result is considered as postoperative refraction for each patient. A Support Vector Machine (SVM) is used to classify the data to two groups based on axial length and corneal power. Each class needs a formula with a specific tendency toward stronger or weaker IOL lenses according to the feature vector.
Results: Experimental tests lead to a nearly diagonal confusion matrix which supports the performance of the proposed method strongly. Mean Absolute Error (MAE) is 0.47 which shows 6% decrease in postoperative refraction error compared to the best reported result.
Conclusions: In calculating IOL power, we expect stronger IOL powers for eyes having shorter axial length or weaker corneal power. In the contrary, a weaker IOL power is expected for longer axial length and stronger corneal power. But experimental results show that for the first group, formulas proposing weaker powers win the race for decreased postoperative refraction error while for the second group, formulas leading to stronger powers perform better. This shows that these formulas overestimate and underestimate for marginal cases.

Purpose: Patient setup optimization has been required to fill the gap between individual treatment and uncertainty in the external beam radiotherapy at each of the treatment sessions. This uncertainty error consists of patient body misalignments and patient body displacement between different fractions.
Methods: In this study, the patient geometrical set-up has been simulated comprehensively by 4D XCAT anthropomorphic phantom where the XCAT phantom was used to access 4D modeling of dynamic organs motion. All of the possible roto-translation displacement parameters that were effective on instigate patient position before re-alignment were considered. While the data set was assembled from XCAT phantom including 2D translation and 2D rotation, the parallelisms of the dada set between position of the external markers and reference point (patient couch) were considered. Moreover, the experimental validation models for further investigation were considered. For this aim, the captured data from XCAT phantom was extended to four real patients. In some clinically available strategies, the corrective models have been implemented to estimate patient displacement of patient setup. In this study, four intelligent models were proposed for set-up, realignment, and continuous tracking of the patient positioning.
Results: Final results illustrate that Adaptive Neuro Fuzzy Interference System with all markers can estimate the true patient position with less error.
Conclusion: In this study, the four intelligent models were demonstrated to investigate the robustness of various intelligent models in re-alignment and patient set-up at external beam radiotherapy. Finally, our correlation model “ANFIS” can estimate the true patient position with less error.

Purpose: The most general form to report dose in Multislice CT is the CTDI and DLP which are computed for several slices. The goal of the current study was to estimate actual doses and dose distribution during CT examinations in a head and neck anthropomorphic phantom.
Methods: After construction of the head and neck phantom using natural bone and paraffin wax with NaCl as impurity, several places were considered in different sites to fill with badges of Gafchromic film. These places include brain, Parotid, Thyroid and Lens of eye. Phantom was scanned at CT Angio and Spiral protocols with 10 and 256 slice scanners.
Results: Our findings showed that in 10 slice scanner, selected organ doses were in the range of 0.09-23.1 mSv while in the 256 slice scanner, it was in the range of 0.14-18.01 mSv. The CT Angio protocol has a higher organ dose at all.
Conclusion: In CT Angio protocol, organ dose (except for the lens of eye) is lower in 10 slice compared to 256 slice CT; the brain dose in both protocols has no difference statistically. In the spiral protocol, the dose in 256 slice scanner is lower than the 10 slice scanner which might be due to higher number of detector arrays in 256 slice scanner.Thyroid dose is mainly due to scattered radiation and because of strict beam collimation; it has a small value in all protocols.

Purpose: Virtual reality based minimally invasive surgical trainers have been proved to be highly effective for training of surgical residents before clinical practice. In this article we introduce the SinaSim, a low-cost laparoscopic surgery simulator based on virtual reality environment.
Methods: The most important part in developing a virtual reality system is to making the virtual reality software of a surgical practice and modeling the physical properties and reaction of soft tissues in real time. At SinaSim we used a newly developed graphical engine to minimize the cost and maximize the widespread usage of this system.
Results: Screenshots of the final graphical view of each training task as well as graphical user interface which provides the trainees with necessary information about their learning progress, are included in this report.
Conclusion: The preliminary results of this study shows that the performance of both hardware and software of the SinaSim laparoscopic surgery simulator are comparable with a commercial virtual reality based trainer in spite of its lower final price.