فهرست مطالب m. farzin

We aimed to assess the effect of the DIBH plan on cardiac and other organs at risk received dose during radiotherapy in left breast cancer patients.

The study was carried out on 30 patients with left breast cancer with a history of mastectomy/lumpectomy surgery who were referred to the radiotherapy department of the Cancer Institute of Iran. Each patient underwent computed tomography (CT) simulations in two respiratory phases, including deep inspiration breath-hold (DIBH) and free-breathing (FB). In addition, the dose-volume histograms (DVHs) of the heart, lung, spinal cord, and breast of each respiratory phase were compared.

We observed a significantly higher mean of heart dose in FB in both lumpectomy and mastectomy groups (P value<0.05). We also compared the means of V25 and V30 heart between FB and DIBH—for both, the received dose was statistically higher in FB than DIBH. The mean dose received by the lung and spinal cord was higher in FB than DIHB. However, the observed difference was only significant in the lumpectomy group (P value<0.05).

The DIBH is a viable method that could be suggested to reduce the mean dose of the heart during left breast cancer radiotherapy.

Low cutting forces can significantly reduce damage risk on sensitive tissues adjacent to the bone. Applying an ultrasound tool in bone cutting is an interest among surgeons due to its better control in an incision, low cutting force, and reduced postoperative complications. In this study, by applying a full factorial design of experiments, the effects of changes in cutting tool geometry, ultrasonic power, bone-cutting direction, and tool speed on the cutting forces of cortical bone are assessed simultaneously. The analyses of variance and regression are run on experimental data, and the influence of each factor and interactions of the elements on the cutting forces are discussed. The adjusted coefficient of determination (R2adj.) of the statistical models is 91.49% and 91.15% in the main cutting force and cutting resistant force, respectively. Both the blade geometry and ultrasonic power, together with their interactions, are the most influential factors in cutting forces with 82.2% and 86.6% contribution therein, respectively. Creating teeth in the cutting edge improves the cutting process and reduces the cutting force by about 40%. The ultrasonic-powered toothed edge blade with a 1 mm pitch, low vertical velocity, and high longitudinal speed is recommended for high efficiency and low cutting force.

Radiation therapy (RT) is one of the common and successful treatments for brain malignancies and benign disorders. In spite of its irrefutable merits, it is associated with a number of complications caused by radiation damage to the important Organs at Risks (OARs), which is strongly correlated with the radiation dose during RT. This study aimed to determine the range of radiation dose to Hippocampus and certain OARs in the brain.

Thirty-two patients with primary brain cancer, undergoing RT, were selected retrospectively. The selected OARs were contoured using the RT Treatment Planning Software through assessing the images from the computed tomography and magnetic resonance imaging (MRI). Dose parameters, namely maximum dose (Dmax) and median dose (Dmedian), to OARs (optic nerves, chiasm, retinas, lenses, orbits, lachrymal glands, brainstem, hippocampi, etc.) were assessed.

The mean age of the patients was 37.8±14.3 years (from 5 to 60 years), and 19 patients (59%) were male. Glioblastoma multiforme and astrocytoma were the most common tumors. The maximum dose received by the brainstem, lenses, and eye ranged between 32-62 Gy, 0.75-40 Gy, 1.5-65 Gy, respectively. The maximum dose received by the hippocampi was 62.7 Gy.

Important OARs can tolerate the received doses which were lower than the threshold level of serious complications. However, the maximum dose received by the hippocampi was higher than the recommended tolerated radiation dose; therefore, it is recommended to conduct more studies in this regard.

The aim of this study was to determine, analyze and predict changes in LC/LU and the destruction trend of natural resources due to the growth of urbanization around Yasouj city. For this purpose, first, Landsat 5 and 8 satellite data were downloaded in August 1989, 1999, 2009 and 2009 from the Geological Survey of the United States. With performing the required radiometric and atmospheric corrections, the data layers were prepared. After, by creating a data set, the land cover/land use classification maps were prepared. Then, the coverage / user map in 1408 was predicted and prepared using the Markov automatic cell model. The results showed that the area of the range and forest in 1989 and 2019 has decreased from 22087 to 12381 and 16095 to 15332 hectares, respectively. The highest destruction of ranges and forests occurred between 1999 and 2009, and in contrast, the area of follow, residential, and construction areas has increased. The kappa coefficient and overall accuracy percentage values of the likelihood classification algorithm (0.77, 0.91, 0.89 and 0.9, and 84.4, 93.9, 91.9 and 92.5 percent, in 1989, 1999, 2009, and 2019, respectively) show that the classification model is appropriate to determine the classes. Based on the prediction map in 2029 using Markov’s Cellular Automata algorithm, the process of destroying and altering range and forest will continue over the next 10 years and agricultural and construction areas will be increasing in future.

Online Monte Carlo (MC) treatment planning is very crucial to increase the precision of intraoperative radiotherapy (IORT). However, the performance of MC methods depends on the geometries and energies used for the problem under study.

This study aimed to compare the performance of MC N-Particle Transport Code version 4c (MCNP4c) and Electron Gamma Shower, National Research Council/easy particle propagation (EGSnrc/Epp) MC codes using similar geometry of an INTRABEAM® system.

This simulation study was done by increasing the number of particles and compared the performance of MCNP4c and EGSnrc/Epp simulations using an INTRABEAM® system with 1.5 and 5 cm diameter spherical applicators. A comparison of these two codes was done using simulation time, statistical uncertainty, and relative depth-dose values obtained after doing the simulation by each MC code.

The statistical uncertainties for the MCNP4c and EGSnrc/Epp MC codes were below 2% and 0.5%, respectively. 1e9 particles were simulated in 117.89 hours using MCNP4c but a much greater number of particles (5e10 particles) were simulated in a shorter time of 90.26 hours using EGSnrc/Epp MC code. No significant deviations were found in the calculated relative depth-dose values for both in the presence and absence of an air gap between MCNP4c and EGSnrc/Epp MC codes. Nevertheless, the EGSnrc/Epp MC code was found to be speedier and more efficient to achieve accurate statistical precision than MCNP4c.

Therefore, in all comparisons criteria used, EGSnrc/Epp MC code is much better than MCNP4c MC code for simulating an INTRABEAM® system.

Awake surgery usually used for eloquent region gliomas, however it may be associated with neuropsychological distress. In this study we evaluate the level of anxiety and depression before and after awake craniotomy.

Twenty-eight patients (Mean age = 39.25±11.09, 78.5% males vs. 21.5% females) who were awake craniotomy candidate, were enrolled in this longitudinal study. The level of anxiety and depression were assessed using Hospital Anxiety and Depression Scale (HADS) questionnaire before awake craniotomy and 1, 6 months after it. Patients were categorized as having depressive/anxiety symptoms or not if they scored ≥ 8 or ≤ 7 on the HADS, respectively. Information pertaining to histological diagnosis, extent of resection and adjuvant therapies were obtained from medical records.

17 patients were diagnosed with high grade glioma and 11 patients with low grade glioma. Depressive and anxiety symptoms were diagnosed in 50% and 25% of patients respectively. The mean preoperative despressive and anxiety score were 4.89±5.03 and 7.71±5.85 respectively. One month after surgery they were 6±4.96 and 7.39±16 and in 6 months’ follow-up they were 5.54±5.16 and 5.38 ±4.23 respectively. There was no significant variation between none of the times mentioned above. However, preoperative anxiety (P &lt; 0.001) and depressive (P: 0.001) mean score is significantly higher amongs women. In addition, there is a significant difference between preoperative anxiety (P: 0.017) mean score in patients with high grade glioma in comparison to low grade group, whereas there is no difference between preoperative depressive (P: 0.30) mean score in high / low grade glioma patients.

Depressive and anxiety symptoms are common in glioma patients. In this study it has been showed despite an increase in depressive and a decrease in anxiety mean score during the follow-up period, there is no difference between anxiety and depressive symptoms before and after surgery.