Zobrazení zdroje stránky Crowellbland6654

Background Electroporation has become a routine technique for rapid drug delivery for the treatment of cancer. Because of its simplicity and wide range of application, it has been applied for the transfer of gold-nanoparticles and can facilitate entry into target cancer cells. Objective The aim of this study is finding optimal conditions in order to obtain high GNPs- uptake and cell viability by means of electroporation. Materials and Methods In this in vitro study, exponential electrical pulse with electric field intensity ranging from 0.2 -2 kV/cm, pulse length of 100 µs and the pulse number of 2 was used. Electroporated cell viability was investigated using MTS assay and GNPs-cellular uptake was assayed using graphite furnace atomic absorption spectrometry (GFAAS). Finally, electroporation results were compared with passive method. Results The maximum uptake occurred at 1.2 to 2 kV/cm and passive method happened. The cell viability of 1.2 kV/cm and passive method was about 90%, while the cell viability in 2 kV/cm drastically decreased to 50%. The findings showed that using two pulses of 1.2 kV/cm and 100 µs is a convenient way and surrogate of passive method for internalizing GNPs into cells. Conclusion It is concluded that the electroporation-GNPs method could create an opportunistic context for colon cancer therapy. This type of treatment is especially attractive for highly immunogenic types of cancers in patients who are otherwise not surgical candidates or whose tumors are unresectable. Copyright © Journal of Biomedical Physics and Engineering.Background Neutron contamination is produced in electron beams of linac when tooth or dental materials are located in the path of beam. Objective This study aims to determine the neutron dose contamination from different dental restoration materials in electron mode of a linac. Material and Methods In this experimental study, the neutron dose contamination was calculated in the presence of tooth and tooth restored by Ceramco C3 veneer, Eclipse or amalgam. The electron mode included 8, 12, and 14 MeV electron beams of Siemens Primus linac at different depths before and after tooth. MCNPX code was used to simulate the linear accelerator and dental restoration materials. Tooth and tooth restoration materials were located in the beams' central axis and the neutron dose was scored in 3 × 3 × 1 cm3 voxels at different depths before and after the tooth. Results The highest neutron dose contamination was observed for the combination of the tooth and Eclipse in 12 and 14 MeV beams and the maximum calculated relative neutron dose was 1.53 for tooth and Eclipse for 14 MeV electron beam. Conclusion Tooth and dental materials lead to neutron dose contamination production, therefore, in order to avoid having harmful effects on normal tissues due to the neutron beam in head and neck cancer, it is recommended that treatment planning performed should not place tooth with dental restoration materials in the path of the beam and lower energy electron beams be used. Copyright © Journal of Biomedical Physics and Engineering.Background Diazinon is one of the most common pesticides in the world playing a similar role to radiation and it could cause DNA breaks and genetic effects. Objective In this study, radiosensitivity of a lymphoblastic cell line pretreated by Diazinon was investigated. Material and Methods In this case-control study, the human lymphoblastic T-cell line was divided into 6 groups based on receiving radiation or/and Diazinon. [https://www.selleckchem.com/products/FK-506-(Tacrolimus).html mTOR inhibitor] After that, the DNA damage, in all of the groups, were counted by cytokinesis-block micronuclei assay using different indices. Results The mean frequency of micronuclei, nuclear bridges and nuclear buds in cell groups exposed by both Diazinon and radiation were remarkably higher than the other groups which just received radiation or Diazinon alone. The interaction between radiation and Diazinon treatment was statistically significant for NBUDS index. Conclusion The results indicated that the Diazinon contamination could affect the radiosensitivity index of cancerous cells while further molecular and in-vivo studies are needed to investigate genetic and toxic effects of Diazinon on DNA and its repair system. Copyright © Journal of Biomedical Physics and Engineering.Background Intracavitary brachytherapy plays a major role in management of cervical carcinoma. Assessment of dose received by OAR's therefore becomes crucial for the estimation of radiation toxicities in HDR brachytherapy. Objective Purpose of this study is to evaluate the role of in vivo dosimetry in HDR brachytherapy and to compare actual doses delivered to OAR' s with those calculated during treatment planning. Material and Methods In this retrospective study, 50 patients of cervical carcinoma were treated by Microselectron HDR. Out of 50 patients, 26 were treated with a dose of 7 Gy and 24 with a dose of 9 Gy, prescribed to point A. Brachytherapy planning and evaluation of dose to bladder and rectum was done on TPS &amp; in vivo dosimetry was performed using portable MOSFET. Results Calibration factors calculated for both dosimeters are almost equal and are 0.984 cGy/mV and 1.0895 cGy/mV. For bladder, dose deviation was found to be within ± 5% in 28 patients, ± 5-10% in 14 patients, ± 10-15% in 4 patients. Deviation between TPS-calculated dose and dose measured by MOSFET for rectum was within ± 5% in 31 patients, ± 5-10% in 8 patients, and ± 10-15% in 7 patients. Conclusion TPS calculated doses were slightly higher than that measured by MOSFET. The use of small size MOSFET dosimeter is an efficient method for accurately measuring doses in high-dose gradient fields typically seen in brachytherapy. Therefore, to reduce the risk of large errors in dose delivery, in vivo dosimetry can be done in addition to TPS computations. Copyright © Journal of Biomedical Physics and Engineering.Background Hysterosalpingography (HSG) is an indispensable tool for diagnosing infertility in females. The procedure exposes female reproductive organs to ionizing radiation as the genitals are irradiated during the process. Investigating patient absorbed dose during the procedures is essential for effective radiological protection of the patient. Objective This study aims to investigate the radiation dose received by patient during HSG examination in the study environment in order to enhance optimization of procedures and the associated dose, thereby minimizing radiation risks. Material and Methods The prospective pilot study, was conducted in four tertiary healthcare institutions in Southwest Nigeria. Thermoluminescence dosimeter (TLD 100) was used to determine the Entrance Surface Dose (ESD) of 80 patients presented for HSG investigation. The corresponding effective dose, ovary, uterus and urinary bladder doses were evaluated using PCXMC software. Results The mean entrance surface doses (ESD) obtained from the four centers were 18.