Introduction With regards to the use of ionisation radiation in the computed tomography (CT), optimal parameters should be used to reduce the risk of incidence of secondary cancers in patients who are constantly exposed to X-rays. The aim of this study was to optimise the parameters used in CT scan of cervical vertebrae and neck soft tissue with minimal loss of image quality in emergency patients. Materials and methods In this study, the patients were divided into two groups. The first group consisted of patients scanned with default parameters and the second group scanned with optimised parameters. All the study has been implemented in emergency settings. The cases included cervical vertebrae and soft tissue protocols. Common CT dose descriptors including weighted computed tomography dose index (CTDIw), volumetric CTDI (CTDIvol), dose length product (DLP), effective dose (ED) and image noise were measured for each group. The ImpactDose program was used to estimate the organs doses. Statistical analysis was performed using Kruskal-Wallis test using SPSS software. Results There was no significant quality reduction in the optimised images. Decreasing in radiation dose parameters for the soft tissue was: kVp=16.7%, mAs=64.3% and pitch=24.1%, and for the cervical vertebrae was: kVp=16.7%, mAs=54.2% and pitch=48.3%. Consequently, decreasing these parameters reduced CTDIw=81.0%, CTDIvol=90.0% and DLP = 90.2% in the cervical vertebral protocol, as well as CTDIw=75.5%, CTDIvol=81.3% and DLP = 81.4% in the soft tissue protocol. Conclusion Regarding the results, the optimised parameters in the mentioned organ scan reduce the radiation dose in the target area and the organs surrounding. Therefore, these protocols can be used for reducing the risk of cancer.

Introduction: Due to use of ionization radiation in the computed tomography (CT), optimal parameters should be used to reduce the risk of incidence of secondary cancers in patients who are constantly exposed to x-rays. To reduce the dose delivered to patients in each scan, CT technologists can change the image acquisition parameters. However, this reduces image quality. The present study aimed to optimize and reduce radiation dose in a CT of the paranasal sinuses while minimizing deterioration of image quality. Methods: In this study patients were divided in two groups: Group A was scanned axially and coronally using default parameters, while Group B was scanned axially and coronally using new parameters. Common CT dose descriptors including weighted computed tomography dose index (CTDIw), volumetric CTDI (CTDIvol), dose length product (DLP), effective dose (ED) and image noise were measured for each group. The patients' organ doses were estimated using the ImPACT CT patient Dosimetry Calculator. The tube voltage, tube current, pitch, rotation time, and other parameters were then reduced and optimized. After reconstruction and analysis, all of the images were of good diagnostic quality in both groups Results: Using the new parameters, good agreement was found between the direct and reconstructed images. The CT parameters were reduced by the following proportions: kVp-16.6%, mA-75%, rotation time-20%, and mAs-80%. However, these reductions did not obscure any anatomical landmarks. These parameters reduced the CTDIw, CTDIvol and DLP by 88.2%, 91.3%, and 91.3% respectively. Conclusion: The results suggest that the use of a Bone algorithm reduces the total amount of radiation used during CT of the sinuses. We recommend using these parameters in children, in the evaluation of facial trauma, and in emergency CT of the paranasal sinuses. RECEIVED

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Limb salvage for management of osteosarcoma of the lower extremity has become the mainstay of treatment for patients with malignant bony and soft tissue tumors. The knee has become a special area of concern for the reconstructive surgeon due to the high rate of wound complications and difficulties of soft tissue reconstruction. With the availability of new prosthetic implants, the advancement of surgical soft tissue techniques and introduction of adjuvant and neoadjuvant chemotherapy, resection and reconstruction has become the standard approach for patients presenting to St. Jude Children's Research Hospital. The pediatric plastic surgeon's role usually requires handling of wound complications in these reconstructive procedures. This article will discuss the authors' approach to dealing with wound complications in this difficult patient population and their interaction with the orthopedic oncologic service in obtaining primary resection and soft tissue coverage.

IntroductionMonte Carlo calculation method is considered to be the most accurate method for dose calculation in radiotherapy. The purpose of this research is comparison between 6 MV Primus LINAC simulation output with commissioning data using EGSnrc and build a Monte Carlo geometry of 6 MV Primus LINAC as realistically as possible. The BEAMnrc and DOSXYZnrc (EGSnrc package) Monte Carlo model of the LINAC head was used as a benchmark.MethodsIn the first part, the BEAMnrc was used for the designing of the LINAC treatment head. In the second part, dose calculation and for the design of 3D dose file were produced by DOSXYZnrc. The simulated PDD and beam profile obtained were compared with that calculated using commissioning data. Good agreement was found between calculated PDD (1·1%) and beam profile using Monte Carlo simulation and commissioning data. After validation, TPR20,10, TMR and Spvalues were calculated in five different field.ResultsGood agreement was found between calculated values by using Monte Carlo simulation and commissioning data. Average differences for five field sizes in this approach is about 0·83% for Sp. for TPR20,10differences for field sizes 10×10 cm2is 0·29% and for TMR in five field sizes, the average value is ~1·6%.ConclusionIn conclusion, the BEAMnrc and DOSXYZnrc codes package have very good accuracy in calculating dose distribution for 6 MV photon beam and it can be considered as a promising method for patient dose calculations and also the Monte Carlo model of primus linear accelerator built in this study can be used as method to calculate the dose distribution for cancer patients.