Repository@USM
Welcome to closed access digital repository of Universiti Sains Malaysia (USM).
This repository contains multiple types of scholarly materials, especially USM theses and exam papers.
To access the full text, please log in with your USM email account.
Research outputs
3557
Projects
0
People
0
Recent Additions
- PublicationImpact of BPL penalty functions and PSF models in PET/CT radial spatial resolution recovery(2024-07)Introduction: A conventional three-point source method adhering to NEMA NU 2-2018 has been introduced where three-point sources are placed at 1 cm, 10 cm, and 20 cm within the PET/CT FOV to evaluate impact of radial distance on spatial resolution. Advanced reconstruction algorithms like TOF, BPL, and PSF models, along with OSEM have shown spatial resolution enhancements based on the FWHM measured. Combining OSEM with TOF improves event localization, and PSF modelling mitigates parallax effects. However, OSEM often struggles with full convergence, necessitating BPL with smooth penalty functions (β values) for regularized iterative reconstruction. Since National Cancer Institute (NCI) currently practice OSEM+TOF+PSF+BPL (β 450) as the in-house protocol, this study explores alternative BPL and PSF functions in OSEM to enhance spatial resolution and determine optimal β values for NCI's routine clinical use. Methods: In-house spatial resolution phantom acquisition was conducted using single F-18 point source method with activity > 5mCi/cc. A capillary tube was used to draw the selected drop, creating the point source with volume 1 mm3. Tubes filled were placed at 5 cm intervals from the center towards the PET/CT FOV's periphery. Scans were done with default settings of scout view, followed by CT axial slice scan and subsequently PET scan with 1 minute per bed position. PET data was then reconstructed with OSEM+TOF, OSEM+TOF+PSF, and OSEM+TOF+PSF+BPL (β 200,400,450, 600,800,1000 and 1200). Tangential and radial FWHM of the point source at different radial distances and locations were calculated by using Xeleris Functional Imaging Workstation Version 4.1. Radial distance effects on spatial resolution under the NCI protocol (OSEM+TOF+PSF+BPL with β450) and varying BPL β values (β 200-1200) were evaluated using fitted function slopes. Additionally, different reconstruction algorithms' impact on spatial resolution within PET/CT FOV was assessed using standard deviation calculations and plotting error bars to show spreading of the data around the mean as well as to determine the significant difference between the FWHM measured using different types of reconstruction. Result: The tangential FWHM at Location D was the only measurement that aligned with the theoretical prediction, increasing linearly with the increment of the radial distance from 1.10 mm to 1.76 mm (R2 = 0.8602). Additionally, OSEM+TOF+PSF+BPL provided greatest spatial resolution compared to OSEM+TOF and OSEM+TOF+PSF, where BPL with β200 reduced FWHM measurements closed to actual size of point source. Conclusion: OSEM+TOF+PSF+BPL (β200) reconstruction algorithms is suggested to be the optimum reconstruction algorithm that can be practiced by NCI in clinical setting due to best radial spatial resolution recovery even with increased of radial distances.
- PublicationInvestigation of gamma index parameters in patient specific quality assurance (PSQA) for radiotherapy treatment planning technique: retrosective study(2024-06)The patient specific quality assurance (PSQA) is a pre-treatment procedure performed to evaluate the validity of the inversed treatment plans, before the actual radiotherapy (RT) treatment delivery, to ensure the patient’s safety. The current method applied for the PSQA assessment in Hospital Universiti Sains Malaysia (HUSM) department is the ArcCHECK phantom based measurement using 3%/3mm gamma index (GI) analysis and currently, there is no standard procedure to perform the PSQA assessment. The aim of this study is to investigate the GI parameters (3%/3mm, 3%/2mm, 2%/2mm, 2%/1mm and 1%/1mm) in Volumetric modulated arc therapy (VMAT), intensity-modulated radiation therapy (IMRT) and Stereotactic body radiation therapy (SBRT) across various treatment regions retrospectively. The gamma passing rate (GPR) of 95% is the universal tolerance limit provide by the American Association of Physicist in Medicine Task Group 218 (AAPM TG-218). The GPR result indicated the PSQA cases were able to fulfill the 95% limit when 3%/3mm 3%/2mm and 2%/2mm GI parameter were applied with the result of 92.5% (99 cases), 100% (29 cases) and 87.5% (14 cases) for 3%/3mm, 82 cases (82.8%),18 cases (62.1%) and 8 cases (57.1%) for 3%/2mm, meanwhile for 2%/2mm, 46 cases (46.5%), 6 cases (20.7%) and 6 cases (42.9%) respectively for VMAT, IMRT and SBRT. Consequently, the GPR tolerance limit were also evaluated and reflected that 3%/2mm (≥95%), and 2%/2mm (>90%) is applicable for IMRT, VMAT and SBRT as the tolerance limit aligns with the suggestion by the previous study. Subsequently, The GPR tolerance limit for different treatment technique indicates a significant difference (p<0.05) in tolerance limit between IMRT and VMAT when applied using 3%/2mm (≥97.19%) and (≥94.85%), 2%/2mm (≥93.74%) and (≥90.39%). Moreover, The GPR tolerance limit for different treatment region reflect a significant different (p<0.05) when VMAT 3%/2mm is applied for HN (≥97 %), Pelvic (≥ 96%) and Chest (≥ 98%). In conclusion this study proves that apart from 3%/3mm (≥95%), 3%/2mm (≥95%) and 2%/2mm (>90%) are suitable for IMRT, VMAT and SBRT cases for all treatment region to be applied in HUSM, except for IMRT and VMAT when applied on HN region, as well as for VMAT when applied on HN, pelvic and chest region using 3%/2mm.
- PublicationPerancangan Pembangunan Tanaman Makanan Asasi Di Aceh, Indonesia: Analisis Dari Perspektif Perancangan Pembangunan Tanaman Makanan Asasi Nabi Yusuf A.s.(2020-09)Perancangan pembangunan tanaman makanan asasi adalah unsur penting dalam menjamin kualiti kehidupan masyarakat dunia hari ini. Membicarakan tentang keselamatan makanan di peringkat global bukanlah perkara baru. Peningkatan penduduk dunia telah menjadikan perancangan pembangunan tanaman makanan asasi di negara maju dan negara membangun sebagai fokus utama. Kajian ini melihat bahawa asas dalam perancangan pembangunan tanaman makanan asasi yang diamalkan oleh Nabi Yusuf A.S. harus dirungkai secara sistematik dalam melihat keberkesanan penerapan amalan yang dilaksanakan di sesebuah kawasan. Berdasarkan isu tersebut, Aceh merupakan salah satu daerah autonomi yang melaksanakan syariat Islam di Indonesia dan mempunyai pengeluaran hasil tanaman makanan asasi yang melebihi keperluan domestik. Perancangan pembangunan daerah juga telah mensasarkan Aceh menjadi salah satu daerah atau kawasan bekalan makanan untuk Indonesia walaupun sering berhadapan dengan bencana alam, perubahan iklim atau cuaca yang tidak menentu. Sehubungan itu, kajian ini dilakukan untuk mencapai tiga objektif kajian. Pertama, mengenal pasti perancangan pembangunan tanaman makanan asasi Nabi Yusuf A.S. menerusi tafsiran ulama tafsir. Kedua, menganalisis perancangan pembangunan tanaman makanan asasi di Aceh dari segi strategi dan program pembangunan. Ketiga, menganalisis perancangan pembangunan tanaman makanan asasi di Aceh, Indonesia dari perspektif amalan dalam perancangan pembangunan tanaman makanan asasi Nabi Yusuf A.S. Kajian ini merupakan kajian kualitatif yang melibatkan temu bual tidak berstruktur dengan 10 orang informan kajian. Analisis kandungan juga dilakukan dengan menganalisis kitab-kitab tafsir yang dipilih dan dokumen perancangan pembangunan yang berkaitan. Hasil kajian mempamerkan tiga dapatan utama. Pertama, perancangan pembangunan tanaman makanan asasi Nabi Yusuf A.S. merupakan perancangan pembangunan yang komprehensif. Kedua, perancangan pembangunan tanaman makanan asasi di Aceh dipertanggungjawabkan oleh tiga agensi utama iaitu Badan Perencanaan Pembangunan Daerah (BAPPEDA) Aceh, Dinas Pertanian Tanaman Pangan Aceh dan Badan Urusan Logistik (BULOG) Aceh. Ketiga, wujud keselarian antara kedua-dua perancangan pembangunan tanaman makanan asasi berdasarkan penekanan amalan perancangan pembangunan tanaman makanan asasi Nabi Yusuf A.S. dalam perancangan pembangunan di Aceh.
- PublicationThe effects of CT-based attenuation correction on the accuracy of 99mtc SPECT/CT quantification(2024-08)This study focuses on how CT- based attenuation correction affects the precision of quantification using Technetium-99m (99mTc) single-photon emission computed tomography/computed tomography (SPECT/CT). Functional and anatomical imaging are combined in SPECT/CT in nuclear medicine which is essential for precise diagnosis and therapy planning. To reduce patient exposure while retaining the image quality, CT scan radiation doses must be lowered. Therefore, this study investigates how varying CT current (mA) affects 99mTc SPECT/CT image quality overall and photon attenuation correction accuracy. In terms of methodology, the study used NEMA 2012/IEC 2008 phantoms filled with 99mTc and the GE Discovery NM/CT 670 Pro SPECT/CT system, using tumor-to-background ratios (TBR) of 4:1 and 10:1. The effects of various mA levels (30, 60, 90, 100, and 120 mA) on quantification accuracy and image quality were investigated. Image quantification and reconstruction were made easier using the Q.Metrix software and the Xeleris workstation, respectively. To evaluate the quality of the images, important metrics like contrast, signal-to-noise ratio (SNR) and coefficient of variation (COV) were examined. Recovery coefficients (RC) were utilised for quantitative analysis. According to the findings, low-dose CT which is accomplished by reducing the tube current can generate images with sufficient quality for precise quantification in 99mTc SPECT/CT. The study supports the ALARA (As Low As Reasonably Achievable) principle by showing that radiation exposure to patients can be decreased without sacrificing diagnostic accuracy. The significance of these findings lies in their potential to improve patient safety by lowering radiation doses while maintaining accurate and trustworthy diagnostic imaging.
- PublicationEvaluation of patient dose during multi-catheter insertion in CT-guided interstitial liver brachytherapy(2024-07)Introduction: Brachytherapy is a type of cancer treatment that involves placing an encapsulated radioactive source either near or directly into the tumour. Liver brachytherapy has been practiced in institutions where multiple catheters are inserted into the liver under CT-guidance. Numerous studies have acknowledged the dose received during brachytherapy, however, the dose received during CT-guided multi-catheter insertion lacks in discussion, hence, the optimisation of the procedure is presented by investigating various aspects of the procedure. Objectives: This study aims to evaluate the patient dose received from multi-catheter insertion during interstitial liver brachytherapy, to determine the association between number of catheters with the CT dose values (𝐶𝑇𝐷𝐼𝑣𝑜𝑙 and total DLP) and to evaluate the organ dose for the patients undergoing multi-catheter insertion in CT-guided interstitial liver brachytherapy using IndoseCT software as well. Methods: This study involved a retrospective survey on 18 patients who undergone CT-guided multi-catheter insertion for liver brachytherapy for evaluation of the patient dose received from the procedure. Patients’ demographic information (age and gender), CT data (number of catheters, number of CT phases, exposure settings – kVp, mAs, pitch and scan length (in cm)), patient dose data (𝐶𝑇𝐷𝐼𝑣𝑜𝑙(in mGy) and total DLP (in mGy.cm)), volume of lesion (in cm3) and diameter of lesion (in cm) were retrieved from CT workstation and recorded for further analysis. Besides that, the axial CT images of patients were obtained and retrieved from the Picture Archiving and Communication System (PACS) for further analysis. The collected CT images were uploaded in the IndoseCT software (Version 20b) to estimate the organ dose (developed by Anam et al., 2021). Result: Number of catheters showed weak correlation with CT dose indices (CTDIvol and total DLP) and number of CT phases while number of catheters had strong correlation with volume and diameter of lesion. Furthermore, the organ that received the highest dose for patient undergone RTP Abdomen HCT 3 mm protocol was heart with 755.79 mGy, while kidneys received the highest dose (964.79 mGy) for patients underwent RTP Abdo/Pelvis HCT 3 mm protocol. Conclusion: The examination of association between variables used in the procedures is extremely important to further optimise the procedure as well as provide insight on accurate decision making for future advancements.
Most viewed
- ItemDevelopment Of Selective Extraction For Cd(II), Cu(II) And Ni(II) Ions Using Dual Flat Sheet Supported Liquid Membrane System(Universiti Sains Malaysia, 2021-05)Wastewater produced from washing out the mixtures and massive discharge of used acids usually have large mass of diverse metallic ions. In electroplating industry, treating the wastewater with various metals is a complex process whereby unwanted metallic ions are often discarded and only metals with high commercial values are separated for recovery. In fact, most of the existing wastewater treatments are non-selective and some are limited for removal of single metal. Due to close similarities in chemistry, metallic ions usually coexist and compete with each other to be selectively separated. Therefore, multiple metal ions could be separated from industrial effluent. Supported liquid membrane (SLM) allows heavy metals separation with the advantages include simultaneous extraction and stripping in a single step, supported with polymer with minimal usage of extractants and low energy use. Dual Flat Sheet Supported Liquid Membrane (DFSSLM) applies two separated SLMs to selectively recover not just one but three types of metal ions at the end of the system. This research aims to study the efficiency of DFSSLM in selective extraction of Cd(II) and Cu(II) over Ni(II) ions from aqueous mixture and electroplating wastewater. The effects of feed pH and carrier concentration for selective extraction of Cd(II) and Cu(II) over Ni(II) were investigated. The effects of pH, carrier concentration and masking agent concentration for separation of Cd(II) over Cu(II) were optimized. Operating parameters for DFSSLM were selected based on screening experiments: Feed phase containing 100 mg/L of Cd(II), Cu(II) and Ni(II) with pHeq 4.6, first membrane soaked with 100 mM di(2-ethylhexyl) phosphoric acid and 50 mM tributyl phosphate in kerosene, second membrane soaked with 99.64 mM trioctylmethylammonium chloride and 50 mM tributyl phosphate in toluene, and 1 M sulfuric acid in Intermediate phase and 48.86 mM ethylenediaminetetraacetic acid in the Strip phase. After 48 hours of stirring at 500 rpm, 98.79% of Ni(II) were found in Feed, 91.32% of Cu(II) in Intermediate, and 91.04% of Cd(II) in Strip compartment of DFSSLM. Competitive transportation between Cd(II) and Cu(II) was justified with the flux changes and kinetic studies of Cd(II) and Cu(II). Treatment using DFSSLM yielded high output/input ratios for recovered Cd(II), Cu(II) and Ni(II). 89.09% of Cd(II) recovered in Strip, 90.87% of Cu(II) in Intermediate, 97.61% of Ni(II) remained in Feed and most of the other heavy metals were eliminated. This study concluded that DFSSLM is efficient for separation and recovery of Cd(II), Cu(II) and Ni(II) from complex mixture.
- ItemStress analysis of stretchable thermal(2017-06)This paper present a summary of the performance of modelling for stretchable circuit. For this new technology, the stretchable board can achieve mechanically bendable and stretchable by using the elastomer based substrate and interconnect. Hence, the study on mechanical properties of substrate effect on design of interconnect is important on the fatigue lifetime and reliability of circuit. Nowadays, the reliability of stretchable circuit is still an existing issue when it continuously supplied by cyclic stresses which will cause the elastic strain deformation during stretch and compress. The purpose of this paper is to present the stress and strain deformation on the interconnect design and reliability of stretchable circuit. By using the Finite Element Method (FEM), it enables to define a more reliable design and suitable material of the stretchable circuit. The stretchability performance can be evaluated on the strain and stress applied to the interconnect and substrate. Suitable material properties of substrate able to offer the less damage during elongation. PDMS and TPU are chosen as material of substrates because of its high elongation before break and it allows high stretchability. This study demonstrates the effect of stress and strain deformation on new design of stretchable board by using proposed material for the substrates at different elongation.
- ItemThe Effects Of The Museums’ Circulation Design On The Elderly Visitors’ Satisfaction In Peninsular Malaysia(Universiti Sains Malaysia, 2011-06)The study examines how elderly visitors‘ expectations, interior circulation design quality, and satisfaction are related in the context of interior design of museums. This study explores a theoretical as well as practical key issue in interior circulation design in museums in Peninsular Malaysia. The research intends to investigate the interior circulation design that interacts with the interior environment and space planning in museums. This is to fully understand the relationship between elderly visitors‘ satisfaction and interior circulation design. This study plans to answer critical questions; what is interior circulation design? How does the interior circulation design relate to the elderly visitors‘ satisfaction? And what is the relationship between elderly visitors‘ expectation, design quality and elderly satisfaction? This study is one of the few studies focus on elderly people in Malaysia. Quantitative approaches as well as qualitative approach were adopted in this study. This research methodology was dealt also with the qualitative data which came in the form of field notes, personal interviews and the visitors' verbal responses, site investigations and observations. The empirical analysis was carried out on 509 of elderly visitors in 21 museums in Peninsular Malaysia to allow us to confirm that the quality of interior circulation design is a direct determinant of elderly satisfaction. The results also reveal that there is a significant relationship between elderly satisfaction, design quality and pre-expectation. This study finds that interior circulation design quality appears to be multidimensional and consisting of different dimensions. The dimensions are horizontal circulation design, vertical circulation design, and interior environment design of museums. The study reveals that the interior circulation design affects positively or negatively the level of satisfaction of elderly visitors in museums and the elderly visitors are somewhat dissatisfied with the interior circulation design of museums in Peninsular Malaysia.
- PublicationKetum (Mitragyna Speciosa Korth.) Consumption, Lipid Profile And Electrocardiogram (Ecg) Abnormalities(2023-07)Ketum (Mitragyna speciosa Korth.) a native medicinal plant of Southeast Asia, has been used in Malaysia for decades for its unique curative properties. Given its broad therapeutic properties and increasing utility, ketum’s long-term safety profile, especially on its cardiotoxicity risk remains poorly investigated in regular ketum users. Given this research limitation, this study aims to evaluate the electrocardiogram (ECG) abnormalities and lipid profile between regular ketum users and healthy control subjects. A total of 200 respondents (n=100 regular ketum users and n=100 healthy control subjects) were recruited through convenience sampling from the northern peninsular state of Penang for this clinical, cross-sectional study. All were required to undergo an ECG evaluation, and blood samples were also drawn to characterize the respondent’s lipid profile. All males, a majority were Malays (97%, n=194/200), and the samples mean age in this study was 33 years (SD=6.7), while ketum users mean duration of ketum use was 6.4 years (SD=4.31). Ketum users mean systolic and diastolic blood pressure rates were 132.9 beats per minute (SD=17.3) and 77.1 beats per minute (SD=11.1), respectively.
- ItemUsage Of Dental General Anesthesia And Assessment Of Fear Among Special Needs And Non-Special Needs Children In Kota Bharu, Kelantan(Universiti Sains Malaysia, 2009-03)Introduction: Dental general anesthesia (DGA) is widely used to facilitate the provision of safe and effective treatment for patients with physical, mental and medically compromising conditions and anxious patients who fail to respond to behavior modification techniques. This study aims to determine types of dental treatment and assess perceived level of fear among study subjects.0 Materials and methods: A comparative retrospective record review study of 193 special needs and 193 non-special needs subjects aged less than 18 years was undertaken at two tertiary centers in Kota Bharu, Kelantan from 2001-2006 to explore the utilization of DGA. Postal Child Fear Survey Schedule-Dental Subscale (CFSS-DS) was used to describe dental anxiety and fear. Results: Mean age was 7.4 (4.11) years. Medical problems among special needs children were cardiovascular, respiratory, syndromes, endocrine, bleeding, craniofacial anomalies, neurology, multi-system disorders, autism, myopathy, metabolic and HIV. Dental treatment provided was restorations and extractions. GIC was mostly used followed by a combination of GIC and fissure sealants. More extractions of primary teeth were done for special needs patients followed by restorations. More restoration of primary teeth was done for non-special needs patients followed by extractions. Common surgical treatment for special needs was cleft lip and palate repair. The most common surgical dental procedures for non-special needs patients was removal of impacted teeth, treatment of dento-alveolar abscess, and anomalies.