Siham S. Abdullah

Bio: Siham S. Abdullah is an academic researcher from Nahrain University. The author has contributed to research in topics: Range (aeronautics) & Imaging phantom. The author has an hindex of 2, co-authored 10 publications receiving 6 citations.

The Correlation of Total MU Number and Percentage Dosimetric Error in Step and Shoot IMRT with Gamma Passing Rate Using OCTAVIUS 4D-1500 Detector Phantom

Abstract: Background: Step and shoot (SS) IMRT treatment technique is one of the modern planning techniques used in radiotherapy. It conforms to the dose to the possible minimum as to the OARs. Dosimetric error calculations used to estimate the sensitivity of reading and the dose difference between TPS and phantom detector. Monitor units (MUs) are measured by monitor chambers, which are ionization chambers that measure the dose delivered by a beam and are built into the treatment head of radiotherapy linear accelerators. Material and Method: Thirty cases of two regions (25 HN and 5 pelvic cases) performed with SS IMRT using MONACO5.1 Treatment Planning System (TPS). Then the QA tested using OCTAVIUS 4D-1500 phantom in Baghdad Center for Radiotherapy and Nuclear Medicine, Baghdad, Iraq. Gamma index and %GP calculated index by comparing the actual QA (using Octavius) with virtual QA (using MONACO TPS). Dosimetric error percentage with global and local %GP and the total Monitor Unit (MU) correlation with global and local %GP were measured. Results: The %GP was ≥95%, where 20% for local %GP for all cases and 73.3 % for global passing rate. A significant correlation found between the %DEs resulted in the %GP for both local and global. There was a correlation between the total MUs for global %GP. For a local %GP, it was statistically not correlated with MUs. Conclusion: There is a correlation found between dosimetric error percentage (%DE) and %GP for both local and global. There is a correlation between the total Monitor Unit (MU) and global %GP but not with local.

Electron Beam Profile Assessment of Linear Accelerator Using Startrack Quality Assurance Device

Abstract: Electron beam therapy using linear accelerator done for patients with superficial cancerous tumors. Daily quality assurance is preferable to assess a good treatment for the patients. This study focuses on penumbra, flatness, and symmetry determination for four types of an electron beam using StarTrack 2D array for quality assurance. Eelectron beam with energies: 6MeV, 9MeV, 12 MeV, and 15MeV for both in-plane (x-axis) and cross-plane (y-axis) using Elekta synergy linac exposed to StarTrack 2D array readings during 16 weeks for testing the performance and stability of StarTrack. The testing protocol used is IEC.The beam profile estimation of variation, when compared with standard values of penumbra, flatness, and symmetry of electron beam energy at the time of commissioning, reveals that all had a variation but these variations are within the limits. It is concluded that StarTrack 2D array detector is favourable in the QA process. Their implementation is not only easy, but gives information about the beam’s temporal stability and is particularly suitable for beam steering mounting.

Impact of Extracorporeal Shock Wave Therapy on Spastic HandFunction with Assistive Devices in Children with Cerebral Palsy

Abstract: Abstract Background: The spastic cerebral palsy isconsidered the most common of cerebral palsy types. Spasticity of upper limbs is major problem in children that affected on hand function during grasping and through using assistive devices as walker and canes. Shock wave treatment on spastic muscles of upper limbs in stroke patients performed a significant decrease in muscle tone.The aim of current study was to determine the impact of extracorporeal shock wave therapy (ESWT) on spastic muscle of hand in children with spastic cerebral palsy.Methods:Thirty twohemiplegic spastic cerebral palsy patients from both sexes were recruited in this study.The children were divided randomly into two groups equal in number; GroupӀ(control)consisted of 16 children(7 boys and 9 girls) with mean±standard deviation age of 6.68±2.63years received exercises program only (3sessions/week for two months, GroupӀӀ(experimental)included (10 boys and 6 girls)with mean±standard deviation age of 6.37±1.44 years received the same exercises program in addition to sessions by extracorporeal shock wave therapy(BTL-6000WT) with energy flux(0.003mJ/mm2),frequency (10Hz)and (one session/week) for 8 weeks .The two groups were evaluated before and after therapy by Modified Ashworth Scale (MAS) and Modified House function Classification (MHC).Results:The results showed a statistically significant improvement in spasticity and hand function post treatment.Conclusion:We concluded that the ESWT is effective in decreasingspasticity(muscle tone) of upper extremities and enhancinghand function for patients with spastic cerebral palsyto help those children become independent and participate in different daily activities as grasping of walker or canes.

Effect of Annealing on the Transformation Behavior of NiTi Shape Memory Alloy

Abstract: Shape memory alloys (SMAs) have enormous potential for a wide variety of applications. Therefore there has been a wide concern for studying the properties of those alloys. In this study polycrystalline alloys from shape memory alloy have been prepared successfully by thermal plasma spray in a wire form of 3 mm diameter in a graphite cast with three different ratios Ni50Ti50, Ni50.5Ti49.5 and Ni51Ti49. Its structure has been tested by means of X-ray diffraction technique. It has been noticed that annealing at 500° C helps to transform part of the material from an austenite phase into a martensite phase .It has also been noticed that increasing Ni proportion more than 50% to Ti in the alloy increases the martensite phase. The temperature of phase transformation as a function to the temperature of NiTi was calculated by using Differential Scanning Calorimeter (DSC) at a temperature between 100°C and -80.0°C in a scan rate of 10°C/min. The charts show that transformation from an austenite phase into martensite phase is done through an intermediate phase called (R-phase) which means there is no direct transformation, while transformation from martensite into austenite in heating cycle is direct. An exception to that is annealing Ni50Ti50 at a temperature of 400°Cwhere the transformation cycle is in two stages.

Dosimetric assessment of IMRT treatment planning for unilateral breast cancer patient using Octavius phantom detector

Abstract: The goal of this research was to study the widely used criteria in Iraq and the suggested criteria from the American association of physics in medicine (AAPM). The breast cancer patients treated at Al-Andalus private hospital underwent a CT simulation. The data were exported to Monaco 5.1 treatment planning system for planning purposes using the intensity-modulated radiation therapy technique with X-ray energies of 6 or 10 MV. The planning was transferred to Agility linear accelerator for irradiation to Octavius-4D phantom detector for pre-treatment verification. The results show that there is no significant difference between the prescribed and measured point dose. In addition, the dose difference is acceptable and there was no significant correlation between the dose error and the result of gamma passing rates for all criteria. A high significant difference appeared between the 3%/2 mm and 3%/3 mm criteria for both local and global gamma passing rates at the two studied thresholds 5% and 10%. All the values of 10% thresholds were highly significant than 5% in local %GP but not significant for the global %GP. The number of segments and the total number of monitor units show an inverse relationship with gamma passing rates. The results clearly show that criteria and thresholds depend on the situation and health of the patient. This means the criteria are to be set at 3%/2 mm for plans which use high doses to organs at risk, while 3%/3 mm may be used for simpler plans with lower doses to organs at risk.

The Effects of Temperature and Time of Heat Treatment on Thermo-Mechanical Properties of Custom-Made NiTi Orthodontic Closed Coil Springs

Abstract: Nickel-Titanium (NiTi) springs have been increasingly used in orthodontics; however, no optimum condition of heat treatment has been reported. Therefore, this research was conducted to determine the optimum heat-treatment temperature and duration for the fabrication of NiTi-closed coil springs by investigating their effects on thermo-mechanical properties. As-drawn straight NiTi wires of 0.2 mm diameter were used to fabricate closed coil springs of 0.9 mm lumen diameter. The springs were heat-treated at three different temperatures (400, 450, and 500 °C) with three different durations (20, 40, and 60 min). Electron Probe Micro-Analysis (EPMA) and Differential Scanning Calorimetry (DSC) were used to investigate element composition and thermo-mechanical properties, respectively. Custom-made NiTi closed coil springs composed of 49.41%-Ti and 50.57%-Ni by atomic weight, where their DSC curves of 500 °C presented the obvious endothermic and exothermic peaks, and the austenite finish temperature (Af) were approximately 25 °C. With increasing temperature, deactivation curves presented decreased plateau slopes generating higher superelastic ratios (SE ratios). At 500 °C, closed coil springs showed superelastic tendency with lower stress hysteresis. The thermo-mechanical properties were significantly influenced by heat-treatment temperature rather than duration. The optimum parameter appeared to be 500 °C for 40 min to produce appropriate force delivery levels, relatively low plateau slope, and lower hysteresis for orthodontic use.

Prevalence of distinct types of hardware failures related to deep brain stimulation.

Abstract: Deep brain stimulation (DBS) is an effective treatment of several types of neurological conditions, including Parkinson’s disease, essential tremor, dystonia, and epilepsy. Despite technological progress in the past 10 years, the number of studies reporting side effects of DBS has increased, mainly due to hardware failures. This review investigated studies published between 2017 and 2021 to identify the prevalence of distinct types of hardware failures related to DBS. In total, fifteen studies were selected for the estimate of the prevalence of five distinct types of hardware failures: high impedance, fracture or failure of the lead or other parts of the implant, skin erosion and infection, lead malposition or migration, and implantable pulse generator (IPG) malfunction. The quality evaluation of the studies suggests a need to report results including populations from distinct regions of the world so that results can be generalized. The objective analysis of the prevalence of hardware failures showed that skin erosion and infection presented the highest prevalence in relation to other hardware failures. Despite the sophistication of the surgical technique of DBS over time, there is a considerable complication rate, about 7 per 100 individuals ( $$\mathrm{prevalence}=6.67\%, CI = [2.26\%,12.49\%]$$ , in which CI is the confidence interval). Future research can also include correlation analysis with the aim of understanding the correlation between distinct hardware failures and variables such as gender, type of disorder, and age.