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This article provides a summary of the clinical spectrum of no obstructive coronary arteries. We describe the pathologies, invasive and noninvasive assessment, and management strategies., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: N.R.S. is a consultant for Abbott and Philips and has received honoraria for speaking from Abbott, Philips, and Zoll. None of the other authors have any relevant disclosures., (© 2024 The Authors.)

Introduction: Psoriasis is a prevalent, complex, immune-mediated illness. There is some evidence in the literature supporting the involvement of the Wnt signaling pathway in psoriasis. No previous studies have focused on the association between the Wnt signaling pathway and vitamin D receptor (VDR) expression in psoriasis. This study investigates the expression of VDR and mediators of the canonical (β-catenin) and non-canonical (Wnt5a) Wnt signaling pathway in psoriatic lesional skin biopsy specimens compared to controls., Methods: A cross-sectional study conducted on skin punch biopsy specimens from 42 psoriasis patients were stained with VDR, β-catenin, and Wnt5a and compared with 42 control biopsies. Patients' demographics, clinical data, and serum vitamin D levels were recorded., Results: VDR showed nuclear localization with significant downregulation in the psoriasis specimens compared to controls. β-catenin (membranous) and Wnt5a (cytoplasmic) showed significant upregulation in the psoriasis specimens. When the expressions of VDR, β-catenin, and Wnt5a were compared based on disease severity, no differences were found between mild, moderate, and severe subgroups of the disease. Late-onset psoriasis patients had lower VDR and Wnt5a histoscores compared to the early-onset group. A trend toward a positive correlation was observed between the histoscores of VDR and Wnt5a., Conclusion: Our findings confirm the significance of VDR signaling in the pathophysiology of psoriasis and strengthen the relationship between this disease and the Wnt signaling pathway. There was evidence that there is an association between VDR status and Wnt5a expression.

Introduction: Hashimoto thyroiditis is the most common cause of chronic inflammation of the thyroid gland. Ultrasound is the modality for detection, while fine needle aspiration is the gold standard method for diagnosis. Serologic markers, such as antithyroidal peroxidase antibody (TPO) and antithyroglobulin antibody (TG), are usually elevated., Aim: The main objective is to appraise the incidence of neoplasms on a background of Hashimoto thyroiditis. Our second objective is to recognize the different sonographic appearances of Hashimoto thyroiditis, to focus on its nodular and focal patterns, and to measure the sensitivity of the ACR TIRAD system (2017) when interpreted on patients with Hashimoto thyroiditis., Methods: A single-center retrospective cross-sectional study. We studied 137 cases diagnosed cytologically as Hashimoto thyroiditis from January 2013-December 2019. The data collected were analyzed using SPSS (26th edition), and ultrasounds were reviewed by a single board-certified radiologist. The ACR thyroid imaging and Data System 2017 (ACR TI-RADs 2017) and the Bethesda System for reporting thyroid cytology 2017 (BSRTC 2017) were used for reporting ultrasound and cytology, respectively., Results: The mean age was 44.66 years and the female : male was 9 : 1. Serologically, anti-Tg was high in 22 cases (38%), while anti-TPO was positive in all of the 60 cases studied. Histologically, 11 cases were diagnosed with papillary thyroid carcinoma (8%) and a single case with follicular adenoma (0.7%). Ultrasonographically, 50% of the cases showed diffuse pattern, in which 13% of them showed micronodules. 32.2% were macronodular, and 17.7% were a focal nodular pattern. 45 nodules were interpreted with the ACR TIRAD system (2017), in which 22.2% were TR2, 26.6% were TR3, 17.7% were TR4, and 33.3% were TR5., Conclusion: Hashimoto thyroiditis is a risk factor for developing thyroid neoplasms, which necessitate a proper assessment of the cytological material studied and a correlation with the clinical and radiological features. Recognizing the different types of Hashimoto thyroiditis and its variable appearances is significantly important in performing and interpreting thyroid ultrasound imaging. Microcalcification is the most sensitive parameter to discriminate between PTC and nodular type of Hashimoto thyroiditis. The TIRAD system (2017) is a useful tool for risk stratification; however, it might create unnecessary FNA studies in the setting of Hashimoto thyroiditis because of its variable appearances on ultrasound. A modified TIRAD system for patients with Hashimoto thyroiditis is important to alleviate this confusion. Finally, anti-TPO is a sensitive marker for detecting Hashimoto thyroiditis, which could be used for future referencing of newly diagnosed cases., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2023 Sayed Ali Almahari et al.)

The coronavirus disease of 2019 (COVID-19) pandemic has resulted in an unprecedented circumstance that has never previously occurred. This has caused the Saudi Arabian people to recognize the necessity of preventive measures and explore alternative systems, such as using natural products (NPs), for treating their infection. Therefore, the specific objectives of this study were to explore the factors that influence the selection of NPs for COVID-19 management and to know the outcome of using NPs in COVID-19 infection management. This observational cross-sectional study was conducted in Saudi Arabia between February and April 2022. The validated pretested questionnaire was distributed among different regions of the country via a purposive snowball sampling procedure. Both descriptive statistics and stepwise regression analyses were carried out to evaluate the parameters related to the use of medicinal plants for the prevention of COVID-19 and the treatment of respiratory symptoms during the pandemic. The data obtained were statistically analyzed using IBM SPSS Statistics for Windows, version 25 (IBM Corp., Armonk, NY, USA). Of the 677 participants, 65% reported using NPs for themselves or family members during COVID-19. Utilizing NPs is always given priority by a significant ( p < 0.001) percentage of survey respondents. Further, a highly significant ( p < 0.001) percentage of participants felt that using NPs reduced their COVID-19 symptoms without having any remarkable ( p < 0.001) adverse effects. Family and friends (59%) were the most frequent sources of information about utilizing NPs, followed by personal experience (41%). Honey (62.7%) and ginger (53.8%) were the most utilized NP among participants. Moreover, black seeds, garlic and turmeric were used by 40.5%, 37.7% and 26.3% of the surveyors, respectively. Those who used NPs before COVID-19 were 72.9% more likely to use them during COVID-19. NPs are more likely to be used by 75% of people who live in the central part of the country and whose families prefer it. This is true even if other factors are considered, such as the practice of using NPs along with traditional therapies and the fact that some participants' families prefer it. Our findings show that NPs were commonly used to treat COVID-19 infection among Saudi Arabian residents. Close friends and family members mainly encouraged the use of NPs. Overall, the use of NPs was high among those who participated in our study; such practices are strongly impacted by society. It is essential to promote extensive studies to improve the recognition and accessibility of these products. Authorities should also educate the people about the benefits and risks of using commonly used NPs, especially those reported in this study.

Objectives Epidural anesthesia (EA) is one of the most popular and efficient techniques for labor pain relief. Women's preferences and awareness about EA have been investigated worldwide through various studies. The level of awareness varies from region to region in Saudi Arabia. Consequently, the aim of this study is to understand the views of women regarding EA in the eastern region of Saudi Arabia and how this affects decision-making with regard to EA. Methods This cross-sectional study was conducted in the eastern region of Saudi Arabia from July-September, 2021, through a self-administered online questionnaire. The study included Saudi females aged 18 years and older living in the eastern region of Saudi Arabia. Data were analyzed using IBM SPSS Statistics for Windows, Version 25.0 (Released 2017; IBM Corp., Armonk, New York, United States). A p-value less than 0.05 was considered statistically significant. Results A total of 499 participants were included in the study. Nearly half of them were between the age of 25-35 years (46.9%, n = 234). The mean of the awareness score was 3.66 with SD = 1.491. It was observed that age was related to awareness. Women older than 45 years of age were found to be less aware. Additionally, the number of children these women had further affected their awareness; those who had four children or more tended to be less aware. The effect of regular antenatal care visits was clear, as pregnant women who maintained regular antenatal care visits showed more awareness. As for income, there was a notable increase in awareness with an increase in income. Participants who had had a previous delivery with EA were found to be more aware. Likewise, educational status also impacted their awareness. Women with a high school certificate or below were found to be less aware. Lastly, it was observed that a majority of the participants chose not to request an EA upon their next delivery (60.5%, n = 302). Conclusion The results demonstrated that awareness of EA in the study area is acceptable. The most important predictors for awareness about EA were age, educational status, income, number of children, regular antenatal visits, and previous delivery with EA. It was concluded that women who were aware were more likely to take EA., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2022, Al Mousa et al.)

Background: Cord-blood and heel-prick TSH levels are essential in diagnosing and preventing the serious complications of congenital hypothyroidism, which mainly include intellectual disability. The study aimed to compare between cord-blood and heel-prick TSH sensitivity and specificity in detecting congenital hypothyroidism (CH) among newborn screened babies., Method: The study included 21,012 newborn screened babies for congenital hypothyroidism starting from September 2013 until March 2019. Both cord-blood and heel-prick TSH were collected from each newborn. Heel prick and cord-blood TSH cutoff values of >21 μU/ml and >30 mIU/L respectively were considered positive., Results: Out of the total screened newborns, 12 were confirmed for having primary congenital hypothyroidism. Nine cases were positive for cord-blood TSH (Sensitivity 75%, specificity 99.9%, and a recall rate of 0.004%), while 139 cases were positive for heel-prick blood TSH (Sensitivity of 100%, specificity of 99.3%, and a recall rate of 0.60%)., Conclusion: For the screening of CH, heel prick is considered a superior method, but cord blood remains a practical option due to its cost-effectiveness, immediate action, and lower recall rate. Therefore, whenever recall is difficult and/or early discharge is the practice, cord blood is an alternative method to heel prick but not with cases of prematurity., (© 2021 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

Introduction: New onset atrial fibrillation leads to worse outcomes in patients with sepsis. The association between new onset atrial fibrillation (AF) in COVID19 patients with COVID19 outcomes are lacking. This study aims to determine whether new onset atrial fibrillation in COVID19 patients admitted in the ICU is a risk factor for death or requirement of mechanical ventilation (MV)., Methods: This is a retrospective study conducted in a cohort of COVID-19 patients admitted to Bahrain Defence Force COVID19 Field ICU between April 2020 to November 2020. Data were extracted from the electronic medical records. The patients who developed new onset AF during admission were compared to patients who remained in sinus rhythm. Multivariate logistic regression models were used to control for confounders and estimate the effect of AF on the outcomes of these patients., Results: Our study included a total of 492 patients out of which 30 were diagnosed with new onset AF. In the AF group, the primary outcome occurred in 66.7% of patients (n = 20). In the control group, 17.1% (n = 79) developed the primary outcome. Upon adjusting for the confounders in the multivariate regression model, AF had an odds ratio of 3.96 (95% CI: 1.05-14.98; p = 0.042) for the primary outcome., Conclusion: Our results indicate that new onset AF is a risk factor for worse outcomes in patients admitted with COVID19 in the ICU., Competing Interests: Conflict of interest The authors have declared that no conflict of interest exists., (© 2021 Saudi Heart Association.)

Background: Heavy menstrual bleeding (HMB) is a common clinical problem. However, seeking medical advice might be delayed until patients develop several clinical consequences., Aim: To assess the prevalence and awareness of HMB among the Saudi female population and measures that are commonly used to control the bleeding., Method: This is a cross-sectional study where a trained study team member carried out a survey. The survey includes patient demographics and medications history, comorbidities, blood transfusion, and patient perception about her period. HMB was defined as bleeding lasting >7 days, flooding or changing protection more than every 2 hours, and passing clots >1 in. in diameter., Results: Four hundred and thirty-one women were evaluated for HMB with a median age of 27.72 ± 7.75. Out of the total number, 281 (65.2%) females were identified to have HMB. Among these 281 females, only 35.6% were aware of having HMB, whereas 64.4% either unaware or unsure about having it. For those who were aware of having HMB, only 32% seek medical advice, particularly gynecology clinic though 46.6% were not satisfied with offered management. On the other hand, 28% and 3.9% of those unaware of having HMB did required iron supplementation and blood transfusion, respectively., Conclusion: HMB is a major clinical problem though awareness about having HMB lacks regardless of the age and education level. Raising awareness and a multidisciplinary approach may result in early diagnosis, early intervention, and reduction of clinical consequences., Competing Interests: The authors declare no conflicts of interest., (© 2021 The Authors. Health Science Reports published by Wiley Periodicals LLC.)

Introduction: When the baseline anatomical syntax score-I (SxSI) is more than or equal to 33, percutaneous coronary intervention (PCI) of unprotected left main (UPLM) is discouraged and considered as high-risk of adverse cardiac events. We designed this study to compare the outcomes of UPLM-PCI between the low to intermediate-syntax score (SxSI low / int .) group (defined as SxSI <33) and the high-syntax score (SxSI high ) group (defined as SxSI more than or equal 33) with a subanalysis to explore the predictive role of intravascular images (IVI)., Methods: The study is a retrospective observational analysis in a prospective cohort. The prospectively gathered data of consecutive patients, who were enrolled from January 2018 to December 2018, were analyzed at 1-year regarding the primary outcome of major adverse cardiovascular and cerebrovascular events (MACCE). An independent committee calculated the SxSI and reviewed all the events., Results: Baseline data of 2144 patients were considered for analysis. 1245 underwent PCI and 32 (2.57%) had PCI of UPLM; of these, 24 (75%) were in SxSI low / int. group and 8 (25%) in SxSI high group. The mean SxSI was 20.3 ± 6.5 and 37.1 ± 4.9 for SxSI low / int. and SxSI high groups, respectively. Compared with patients in the SxSI low / int. , patients in SxSI high group had a greater syntax score-II (<0.0001), which reflects the expected 4-year mortality after PCI by combining the SxSI and clinical variables.Interestingly, despite the fact that the proportion of subjects who sustained MACCE was almost three times more among the SxSIhigh compared to their SxSIlow/int. counterparts [1 (12.5%) vs. 1 (4.2%), P = 0.444], this difference was not statistically significant.It was noted that a higher proportion of patients in whom intravascular imaging (IVI) was not used to guide PCI sustained MACCE compared with that in whom IVI was utilized (2 [50%] vs. [0%], P = 0.012). There is a strong, negative, statistically significant association between the use of IVI and the occurrence of MAACE (Phi=-0.681), which reflects that the use of imaging is associated with significantly lower probability of developing MACCE., Conclusion: As demonstrated in this real-world cohort, PCI of UPLM provides excellent outcome at one year regardless of the initial anatomical syntax score. Furthermore, it appears that IVI utilization during the index PCI procedure of UPLM is a potent and independent predictor of MACCE., Competing Interests: There are no conflicts of interest., (Copyright: © 2021 Heart Views.)

Background: Body fluid cytology (BFC) is an important tool in the diagnosis and staging of malignancy and is aided by the judicious use of immunohistochemistry (IHC). The aim of this study was to determine the usage rates of IHC stains in BFC, their type and indications, and their diagnostic impact. We also attempted to estimate the optimal rate of IHC use in BFC by comparing the entire laboratory's and each individual cytopathologist's IHC use rates with their respective indeterminate and malignant diagnosis rates., Methods: We conducted a retrospective study of IHC stain use in BFC during a 5.5-year interval (2013-2018) and determined the laboratory's and each individual cytopathologist's IHC usage patterns according to the final diagnosis, site, and indications for their use., Results: A total of 477 out of 4144 (11.5%) BFC cases had 2128 individual immunostains performed, with an average of 4.5 immunostains per case. Individual cytopathologists used IHC stains on 6.7% to 22% of their BFC cases. Pathologists with higher rates of IHC stain use than the laboratory's mean were less experienced and had higher rates of indeterminate but not of malignant diagnoses. The most common indication for the use of IHC stains was differentiating mesothelial from malignant cells. MOC31, calretinin, Ber-EP4, CD68, and D2-40 were the most commonly used of the 67 different IHC stains used in BFC., Conclusions: The laboratory's mean may represent the optimal IHC use rate, as higher IHC use rates did not lead to more diagnostic certainty or higher pickup rates of malignant cells., (© 2020 American Cancer Society.)

Background: Thyroid gland nodules are common and fine-needle aspiration (FNA) is the gold standard for screening those nodules. The Bethesda system for reporting thyroid cytolopathology standardized reporting thyroid nodules aspirations, but atypia of undetermined significance or follicular lesion of undetermined significance (Bethesda category III) was the most controversial category. The aim of our study is to review our institutional experience and analyze the clinical implications of making a diagnosis of AUS/FLUS (Bethesda category III)., Methods: This is a retrospective study of an 889 thyroid FNAs from 825 patients in Salmaniya Medical Complex, during (January 2013-December 2017)., Results: The most common cause for designating cases as AUS/FLUS (Bethesda category III) was the presence of features suggestive of papillary thyroid carcinoma, but not quite fulfilling the criteria for such diagnosis. Ninety-six cases were diagnosed as AUS/FLUS (10.7%), in which 26 (27%) patients underwent surgery without repeating the FNA, 25 (26%) underwent a second FNA and 43 (44.7%) patients were followed up by ultrasound. On repeating the FNA, 1 (4%) was unsatisfactory, 13 (52%) were benign, 10 (40%) were AUS/FLUS, and only 1 (4%) was categorized as malignant. Thirty cases were surgically excised, in which 4 (13.3%) were diagnosed as follicular adenoma, 2 (6.6%) as Hurthle cell adenoma, 9 (30%) as multinodular goiter, 5 (16.6%) as multinodular goiter with Hashimoto thyroiditis, 1 (3.3%) as colloid nodule with Hashimoto thyroiditis, and 9 (30%) as papillary thyroid carcinoma. Among all the cases diagnosed initially as AUS/FLUS (Bethesda category III), 9 (9.3%) cases were diagnosed as papillary thyroid carcinoma., Conclusion: Diagnostically, we almost meet the international standards of designating cases with AUS/FLUS (Bethesda category III) and approximate the risk of malignancy. However, the clinical management's guidelines should be followed to decrease the risk of unnecessary surgeries and their complications. There is a statistically significant correlation between the age and gender with the final histopathology report, respectively., Competing Interests: The authors declare that they have no competing interests., (Copyright: © 2019 Almahari, et al.; Licensee Cytopathology Foundation Inc.)

Purpose: The aim of this work was to evaluate the use of an angularly independent silicon detector (edgeless diodes) developed for dosimetry in megavoltage radiotherapy for Cyberknife in a phantom and for patient quality assurance (QA)., Method: The characterization of the edgeless diodes has been performed on Cyberknife with fixed and IRIS collimators. The edgeless diode probes were tested in terms of basic QA parameters such as measurements of tissue-phantom ratio (TPR), output factor and off-axis ratio. The measurements were performed in both water and water-equivalent phantoms. In addition, three patient-specific plans have been delivered to a lung phantom with and without motion and dose measurements have been performed to verify the ability of the diodes to work as patient-specific QA devices. The data obtained by the edgeless diodes have been compared to PTW 60016, SN edge, PinPoint ionization chamber, Gafchromic EBT3 film, and treatment planning system (TPS)., Results: The TPR measurement performed by the edgeless diodes show agreement within 2.2% with data obtained with PTW 60016 diode for all the field sizes. Output factor agrees within 2.6% with that measured by SN EDGE diodes corrected for their field size dependence. The beam profiles' measurements of edgeless diodes match SN EDGE diodes with a measured full width half maximum (FWHM) within 2.3% and penumbra widths within 0.148 mm. Patient-specific QA measurements demonstrate an agreement within 4.72% in comparison with TPS., Conclusion: The edgeless diodes have been proved to be an excellent candidate for machine and patient QA for Cyberknife reproducing commercial dosimetry device measurements without need of angular dependence corrections. However, further investigation is required to evaluate the effect of their dose rate dependence on complex brain cancer dose verification., (© 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.)

Background: Fine-needle aspiration cytology (FNAC) of thyroid is the initial screening test for thyroid nodules. The Bethesda system classifies thyroid FNAC into six categories. Each category is linked to a malignancy risk and has a recommended clinical management. The aim of this study is to analyze the thyroid cytology smears by Bethesda system and to correlate the diagnosis of cytopathology with histopathology, whenever surgery was done., Materials and Methods: This study presents our experience with the Bethesda system in 681 thyroid FNAs from 632 patients in the period between January 2013 and December 2016., Results: Categories were as follows: 10.1% were Category I (nondiagnostic), 68.8% Category II (benign), 12.4% were Category III (atypia of undetermined significance), 2.9% were Category IV (suspicious for follicular neoplasm), 2.6% were Category V (suspicious for malignancy), and 4.1% were Category VI (malignant). Surgery was done on 126 nodules from 119 patients with an overall rate of malignancy of 27.8% (35/126 nodules)., Conclusion: The Bethesda System for Reporting Thyroid Cytopathology proved to be an excellent reporting system.

The purpose of this study is to compare performance of several dosimetric meth-ods in heterogeneous phantoms irradiated by 6 and 18 MV beams. Monte Carlo (MC) calculations were used, along with two versions of Acuros XB, anisotropic analytical algorithm (AAA), EBT2 film, and MOSkin dosimeters. Percent depth doses (PDD) were calculated and measured in three heterogeneous phantoms. The first two phantoms were a 30 × 30 × 30 cm3 solid-water slab that had an air-gap of 20× 2.5 × 2.35 cm3. The third phantom consisted of 30 × 30 × 5 cm3 solid water slabs, two 30 × 30 × 5 cm3 slabs of lung, and one 30 × 30 × 1 cm3 solid water slab. Acuros XB, AAA, and MC calculations were within 1% in the regions with particle equilibrium. At media interfaces and buildup regions, differences between Acuros XB and MC were in the range of +4.4% to -12.8%. MOSkin and EBT2 measurements agreed to MC calculations within ~ 2.5%, except for the first cen-timeter of buildup where differences of 4.5% were observed. AAA did not predict the backscatter dose from the high-density heterogeneity. For the third, multilayer lung phantom, 6 MV beam PDDs calculated by all TPS algorithms were within 2% of MC. 18 MV PDDs calculated by two versions of Acuros XB and AAA differed from MC by up to 2.8%, 3.2%, and 6.8%, respectively. MOSkin and EBT2 each differed from MC by up to 2.9% and 2.5% for the 6 MV, and by -3.1% and ~2% for the 18 MV beams. All dosimetric techniques, except AAA, agreed within 3% in the regions with particle equilibrium. Differences between the dosimetric techniques were larger for the 18 MV than the 6 MV beam. MOSkin and EBT2 measurements were in a better agreement with MC than Acuros XB calculations at the interfaces, and they were in a better agreement to each other than to MC. The latter is due to their thinner detection layers compared to MC voxel sizes.

Purpose: Silicon diode arrays are commonly implemented in radiation therapy quality assurance applications as they have a number of advantages including: real time operation (compared to the film) and high spatial resolution, large dynamic range and small size (compared to ionizing chambers). Most diode arrays have detector pitch that is too coarse for routine use in small field applications. The goal of this work is to characterize the two-dimensional monolithic silicon diode array named "MagicPlate-512" (MP512) designed for QA in stereotactic body radiation therapy (SBRT) and stereotactic radio surgery (SRS)., Methods: MP512 is a silicon monolithic detector manufactured on ap-type substrate. An array contains of 512 pixels with size 0.5×0.5 mm2 and pitch 2 mm with an overall dimension of 52×52 mm2. The MP512 monolithic detector is wire bonded on a printed circuit board 0.5 mm thick and covered by a thin layer of raisin to preserve the silicon detector from moisture and chemical contamination and to protect the bonding wires. Characterization of the silicon monolithic diode array response was performed, and included pixels response uniformity, dose linearity, percent depth dose, output factor, and beam profiling for beam sizes relevant to SBRT and SRS and depth dose response in comparison with ionization chamber., Results: MP512 shows a good dose linearity (R2=0.998) and repeatability within 0.2%. The measured depth dose response for field size of 10×10 cm2 agreed to within 1.3%, when compared to a CC13 ionization chamber for depths in PMMA up to 30 cm. The output factor of a 6 MV Varian 2100EX medical linac beam measured by MP512 at the isocenter agrees to within 2% when compared to PTW diamond, Scanditronix point EDD-2 diode and MOSkin detectors for field sizes down to 1×1 cm2. An over response of 4% was observed for square beam size smaller than 1 cm when compared to EBT3 films, while the beam profiles (FWHM) of MP512 match to within 2% the data measured by radiochromic film., Conclusions: The response of the 2D detector array, MP512, has been evaluated. The properties of the array demonstrated suitability for use as in phantom dosimeter for QA in SRS and SBRT. Although MP512 matches film measurements down to 1×1 cm2 well, it showed a discrepancy of 4% in the determination of output factors of beams smaller than 0.5×0.5 cm2 due to the field perturbation generated by the large amount of silicon surrounding the central diode. MP512 is highly capable of measuring beam size (FWHM) and has a discrepancy of less than 1.3% when compared to EBT3 film. A reduction in the detector pitch to less than 2 mm would improve the penumbra reconstruction accuracy at the cost readout electronics complexity.

Contemporary radiation therapy (RT) is complicated and requires sophisticated real-time quality assurance (QA). While 3D real-time dosimetry is most preferable in RT, it is currently not fully realised. A small, easy to use and inexpensive point dosimeter with real-time and in vivo capabilities is an option for routine QA. Such a dosimeter is essential for skin, in vivo or interface dosimetry in phantoms for treatment plan verification. The metal-oxide-semiconductor-field-effect-transistor (MOSFET) detector is one of the best choices for these purposes, however, the MOSFETs sensitivity and its signal stability degrade after essential irradiation which limits its lifespan. The accumulation of positive charge on the gate oxide and the creation of interface traps near the silicon-silicon dioxide layer is the primary physical phenomena responsible for this degradation. The aim of this study is to investigate MOSFET dosimeter recovery using two proposed annealing techniques: direct current (DC) and pulsed current (PC), both based on hot charged carrier injection into the gate oxide of the p-MOSFET dosimeter. The investigated MOSFETs were reused multiple times using an irradiation-annealing cycle. The effect of the current-annealing parameters was investigated for the dosimetric characteristics of the recovered MOSFET dosimeters such as linearity, sensitivity and initial threshold voltage. Both annealing techniques demonstrated excellent results in terms of maintaining a stable response, linearity and sensitivity of the MOSFET dosimeter. However, PC annealing is more preferable than DC annealing as it offers better dose response linearity of the reused MOSFET and has a very short annealing time.

The purpose of this study was to examine the accuracy of AcurosXB and AAA algorithms near low and high density heterogeneities of different densities using EBT2 film, MOSFET detector "MOSkin" and Monte Carlo calculations using BEAMnrc/DOSXYZnrc. Three different interfaces were used that included a solid water phantom with 2×2×30cm 3 rectangular air gap, rectangular steel insert, and a slab of water embedded between two slabs of lung material. 6MV photon beam with field size of 10×10cm 2 was used for the first two geometries and a 3×3cm 2 -field was used for the third. Percentage Depth Doses were measured and calculated at the beam central axis. Calculation voxel of 0.1×0.1×0.1cm 3 was used by all three algorithms. For all configurations, AcurosXB and AAA agreed to within ±1.3% with MC before the inhomogeneity. The PDD measurements using MOSkin and EBT2 in water, apart from 0.2cm layer near heterogeneity, agreed with the MC within ±2.2%. Within 0.1cm before the water-air interface AcurosXB and AAA overestimated the dose by 4.7% and 1.6%, respectively. Whereas, in the 0.1cm beyond the air-water interface, AcurosXB and AAA overestimated the dose by 2.4% and 16.2% respectively. In the 0.1cm before the water-steel interface, AcurosXB overestimated the dose by 4.7% and AAA underestimated the dose by 9.5%; beyond the steel-water interface AcurosXB and AAA overestimated the dose by 3.6% and 7.7% respectively. For the lung phantom configuration, AcurosXB and AAA were in agreement with MC within 2% throughout the phantom. These results demonstrate improved performance of AcurosXB as compared to AAA in considered conditions., (© 2012 American Association of Physicists in Medicine.)