Seng Boh Lim
YOU?
Author Swipe
View article: AAPM MEDICAL PHYSICS PRACTICE GUIDELINE 10.b: Scope of practice for clinical medical physics
AAPM MEDICAL PHYSICS PRACTICE GUIDELINE 10.b: Scope of practice for clinical medical physics Open
The American Association of Physicists in Medicine (AAPM) is a nonprofit professional society whose mission is “Advancing medicine through excellence in the science, education and professional practice of medical physics.” The AAPM has rou…
View article: Dosimetric commissioning of a high-resolution CMOS 2D detector array for patient-specific QA of single-isocenter multi-target VMAT stereotactic radiosurgery
Dosimetric commissioning of a high-resolution CMOS 2D detector array for patient-specific QA of single-isocenter multi-target VMAT stereotactic radiosurgery Open
Stereotactic radiosurgery (SRS) using the single-isocenter-multiple-target (SIMT) technique by volumetric modulated arc therapy is increasingly popular for treating multiple brain metastases. However, the complex nature of SIMT SRS necessi…
View article: Standardization of scan protocols for RT CT simulator from different vendors using quantitative image quality technique
Standardization of scan protocols for RT CT simulator from different vendors using quantitative image quality technique Open
Objective To investigate the feasibility of standardizing RT simulation CT scanner protocols between vendors using target‐based image quality (IQ) metrics. Method and materials A systematic assessment process in phantom was developed to st…
View article: An automated technique for global noise level measurement in CT image with a conjunction of image gradient
An automated technique for global noise level measurement in CT image with a conjunction of image gradient Open
Automated assessment of noise level in clinical computed tomography (CT) images is a crucial technique for evaluating and ensuring the quality of these images. There are various factors that can impact CT image noise, such as statistical n…
View article: Resolving signal drift in the wall‐mounted camera of the RGSC system
Resolving signal drift in the wall‐mounted camera of the RGSC system Open
Purpose To present a modified calibration method to reduce signal drift due to table sagging in Respiratory Gating for Scanner (RGSC) systems with a wall‐mounted camera. Materials and Methods Approximately 70 kg of solid water phantoms wer…
View article: A retrospective bilateral breast proton pencil beam scanning and photon volumetric arc therapy planning comparison
A retrospective bilateral breast proton pencil beam scanning and photon volumetric arc therapy planning comparison Open
PBS provides better sparing of heart and lungs compared to VMAT in whole breast, chest wall and expander patients. Further study with more patients is required to validate these conclusions.
View article: Regular supervised exercise training improves endothelial function, early atherosclerosis, arterial stiffness and endothelial progenitor cells in PCI patients
Regular supervised exercise training improves endothelial function, early atherosclerosis, arterial stiffness and endothelial progenitor cells in PCI patients Open
Backgrounds A disrupted balance between endothelial injury and repair induces endothelial dysfunction and endothelial progenitor cells (EPC) augment vascular repair. So, exercise improves endothelial function through increased numbers of E…
View article: Technical note: Energy dependence of the Gafchromic EBT4 film: Dose‐response curves for 70 kV, 6 MV, 6 MV FFF, 10 MV FFF, and 15 MV x‐ray beams
Technical note: Energy dependence of the Gafchromic EBT4 film: Dose‐response curves for 70 kV, 6 MV, 6 MV FFF, 10 MV FFF, and 15 MV x‐ray beams Open
Background EBT4 was newly released for radiotherapy quality assurance to improve the signal‐to‐noise ratio in radiochromic film dosimetry. It is important to know its dose‐response characteristics before its use in the clinic. Purpose This…
View article: Evaluation of OrthoChromic OC-1 films for photon radiotherapy application
Evaluation of OrthoChromic OC-1 films for photon radiotherapy application Open
A new film dosimetry system consists of the new OrthoChromic™ OC-1 film, and a novel calibration procedure was evaluated. Two films, C1 and C2, were exposed simultaneously using the 6FFF beam with a step-wedge pattern of five steps ranging…
View article: Comparative study of SRS end‐to‐end QA processes of a diode array device and an anthropomorphic phantom loaded with GafChromic XD film
Comparative study of SRS end‐to‐end QA processes of a diode array device and an anthropomorphic phantom loaded with GafChromic XD film Open
Purpose End‐to‐end testing (E2E) is a necessary process for assessing the readiness of the stereotactic radiosurgery (SRS) program and annual QA of an SRS system according to the AAPM MPPG 9a. This study investigates the differences betwee…
View article: Integration of an Independent Monitor Unit Check for High-Magnetic-Field MR-Guided Radiation Therapy System
Integration of an Independent Monitor Unit Check for High-Magnetic-Field MR-Guided Radiation Therapy System Open
Purpose Commercial independent monitor unit (IMU) check systems for high-magnetic-field MR-guided radiation therapy (RT) systems are lacking. We investigated the feasibility of adopting an existing treatment planning system (TPS) as an IMU…
View article: Dosimetric Effect of Cobalt-Chrome Stabilization Hardware in Paraspinal Radiation Treatments
Dosimetric Effect of Cobalt-Chrome Stabilization Hardware in Paraspinal Radiation Treatments Open
High density materials are assigned with an apparent density of 3.2 g/cm3 in 12-bit CT images due to saturation. This is often ignored in planning for spine tumors with titanium (density 4.40 g/cm3) spinal hardware. However, new cobalt-chr…
View article: Dosimetric evaluation of irradiation geometry and potential air gaps in an acrylic miniphantom used for external audit of absolute dose calibration for a hybrid 1.5 T MR‐linac system
Dosimetric evaluation of irradiation geometry and potential air gaps in an acrylic miniphantom used for external audit of absolute dose calibration for a hybrid 1.5 T MR‐linac system Open
Introduction To investigate the impact of partial lateral scatter (LS), backscatter (BS) and presence of air gaps on optically stimulated luminescence dosimeter (OSLD) measurements in an acrylic miniphantom used for dosimetry audit on the …
View article: Longitudinal assessment of quality assurance measurements in a 1.5T MR‐linac: Part I—Linear accelerator
Longitudinal assessment of quality assurance measurements in a 1.5T MR‐linac: Part I—Linear accelerator Open
Purpose To describe and report longitudinal quality assurance (QA) measurements for the mechanical and dosimetric performance of an Elekta Unity MR‐linac during the first year of clinical use in our institution. Materials and methods The m…
View article: An investigation of using log‐file analysis for automated patient‐specific quality assurance in MRgRT
An investigation of using log‐file analysis for automated patient‐specific quality assurance in MRgRT Open
Objective Adaptive radiation therapy (ART) is an integral part of MR‐guided RT (MRgRT), requiring a new RT plan for each treatment fraction and resulting in a significant increase in patient‐specific quality assurance (PSQA). This study in…
View article: Commissioning of optical surface imaging systems for cranial frameless stereotactic radiosurgery
Commissioning of optical surface imaging systems for cranial frameless stereotactic radiosurgery Open
Purpose This study aimed to evaluate and compare different system calibration methods from a large cohort of systems to establish a commissioning procedure for surface‐guided frameless cranial stereotactic radiosurgery (SRS) with intrafrac…
View article: A novel quality assurance procedure for trajectory log validation using phantom‐less real‐time latency corrected EPID images
A novel quality assurance procedure for trajectory log validation using phantom‐less real‐time latency corrected EPID images Open
The use of trajectory log files for routine patient quality assurance is gaining acceptance. Such use requires the validation of the trajectory log itself. However, the accurate localization of a multileaf collimator (MLC) leaf while it is…
View article: Machine QA for the Elekta Unity system: A Report from the Elekta MR‐linac consortium
Machine QA for the Elekta Unity system: A Report from the Elekta MR‐linac consortium Open
Over the last few years, magnetic resonance image‐guided radiotherapy systems have been introduced into the clinic, allowing for daily online plan adaption. While quality assurance (QA) is similar to conventional radiotherapy systems, ther…
View article: Can the Risk of Dysphagia in Head and Neck Radiation Therapy Be Predicted by an Automated Transit Fluence Monitoring Process During Treatment? A First Comparative Study of Patient Reported Quality of Life and the Fluence-Based Decision Support Metric
Can the Risk of Dysphagia in Head and Neck Radiation Therapy Be Predicted by an Automated Transit Fluence Monitoring Process During Treatment? A First Comparative Study of Patient Reported Quality of Life and the Fluence-Based Decision Support Metric Open
Purpose/Objective(s): The additional personnel and imaging procedures required for Adaptive Radiation Therapy (ART) pose a challenge for a broad implementation. We hypothesize that a change in transit fluence during the treatment course is…
View article: Risk Management of Clinical Reference Dosimetry of a Large Hospital Network Using Statistical Process Control
Risk Management of Clinical Reference Dosimetry of a Large Hospital Network Using Statistical Process Control Open
Managing TG-51 reference dosimetry in a large hospital network can be a challenging task. The objectives of this study are to investigate the effectiveness of using Statistical Process Control (SPC) to manage TG-51 workflow in such a netwo…
View article: A dosimetry study of post‐mastectomy radiation therapy with AeroForm tissue expander
A dosimetry study of post‐mastectomy radiation therapy with AeroForm tissue expander Open
Purpose To evaluate the dosimetric effects of the AeroForm TM (AirXanpders®, Palo Alto, CA) tissue expander in‐situ for breast cancer patients receiving post‐mastectomy radiation therapy. Methods and Materials A film phantom (P1) was const…
View article: Commissioning and Evaluation of a Third-Party 6 Degrees-of-Freedom Couch Used in Radiotherapy
Commissioning and Evaluation of a Third-Party 6 Degrees-of-Freedom Couch Used in Radiotherapy Open
Purposes: The newly released Protura 6 degrees-of-freedom couch (CIVCO) has limited quality assurance protocols and pertinent publications. Herein, we report our experiences of the Protura system acceptance, commissioning, and quality assu…
View article: Investigation of a Novel Decision Support Metric for Head and Neck Adaptive Radiation Therapy Using a Real-Time <i>In Vivo</i> Portal Dosimetry System
Investigation of a Novel Decision Support Metric for Head and Neck Adaptive Radiation Therapy Using a Real-Time <i>In Vivo</i> Portal Dosimetry System Open
In adaptive radiation therapy of head and neck cancer, any significant anatomical changes observed are used to adapt the treatment plan to maintain target coverage without elevating the risk of xerostomia. However, the additional resources…
View article: Institutional experience with SRS VMAT planning for multiple cranial metastases
Institutional experience with SRS VMAT planning for multiple cranial metastases Open
Background and Purpose This study summarizes the cranial stereotactic radiosurgery (SRS) volumetric modulated arc therapy (VMAT) procedure at our institution. Materials and Methods Volumetric modulated arc therapy plans were generated for …