Radiation Medicine Commons^™

Feasibility Of Using Ring-Mounted Halcyon Linac For Single-Isocenter/Two-Lesion Lung Stereotactic Body Radiation Therapy, Damodar Pokhrel, Aaron Webster, Richard Mallory, Justin Visak, Mark E. Bernard, Ronald C. Mcgarry, Mahesh Kudrimoti

Radiation Medicine Faculty Publications

PURPOSE: To demonstrate the plan quality and delivery efficiency of volumetric-modulated arc therapy (VMAT) with the Halcyon Linac ring delivery system (RDS) in the treatment of single-isocenter/two-lesion lung stereotactic body radiation therapy (SBRT).

MATERIALS/METHODS: Sixteen previously treated non-coplanar VMAT single-isocenter/two-lesion lung SBRT plans delivered with SBRT-dedicated C-arm TrueBeam Linac were selected. Prescribed dose was 50 Gy to each lesion over five fractions with treatment delivery every other day and AcurosXB algorithm as the final dose calculation algorithm. TrueBeam single-isocenter plans were reoptimized for Halcyon Linac with coplanar geometry. Both TrueBeam and Halcyon plans were normalized for identical combined target coverage …

Multi-Center Planning Study Of Radiosurgery For Intracranial Metastases Through Automation (Mc-Prima) By Crowdsourcing Prior Web-Based Plan Challenge Study, M K H Chan, T Gevaert, N Kadoya, J Dorr, R Leung, S Alheet, A Toutaoui, R Farias, M Wong, C Skourou, M Valenti, I Farré, C Otero-Martínez, D O'Doherty, J Waldron, S Hanvey, M Grohmann, Haisong Lui

Department of Radiation Oncology Faculty Papers

Background: Planning radiosurgery to multiple intracranial metastases is complex and shows large variability in dosimetric quality among planners and treatment planning systems (TPS). This project aimed to determine whether autoplanning using the Muliple Brain Mets (AutoMBM) software can improve plan quality and reduce inter-planner variability by crowdsourcing results from prior international planning study.

Methods: Twenty-four institutions autoplanned with AutoMBM on a five metastases case from a prior international planning competition from which population statistics (means and variances) of 23 dosimetric metrics and resulting composite plan score (maximum score = 150) of other TPS (Eclipse, Monaco, RayStation, iPlan, GammaPlan, MultiPlan) were …

What After Bcg Fails In Non-Muscle Invasive Bladder Cancer?, M Hammad Ather

Section of Urology

No abstract provided.

Chronoradiobiology Of Breast Cancer: The Time Is Now To Link Circadian Rhythm And Radiation Biology, Nicolas Nelson, Joseph Lombardo, Lauren Matlack, Alexandria Smith, Kamryn Hines, Wenyin Shi, Nicole L Simone

Department of Radiation Oncology Faculty Papers

Circadian disruption has been linked to cancer development, progression, and radiation response. Clinical evidence to date shows that circadian genetic variation and time of treatment affect radiation response and toxicity for women with breast cancer. At the molecular level, there is interplay between circadian clock regulators such as PER1, which mediates ATM and p53-mediated cell cycle gating and apoptosis. These molecular alterations may govern aggressive cancer phenotypes, outcomes, and radiation response. Exploiting the various circadian clock mechanisms may enhance the therapeutic index of radiation by decreasing toxicity, increasing disease control, and improving outcomes. We will review the body’s natural circadian …

Corrigendum To: Impact Of Lymphopenia On Survival For Elderly Patients With Glioblastoma: A Secondary Analysis Of The Cctg Ce.6 (Eortc 26062-22061, Trog 08.02) Randomized Clinical Trial., Andrew J Song, Keyue Ding, Iyad Alnahhas, Normand J Laperriere, James Perry, Warren P Mason, Chad Winch, Chris J O'Callaghan, Johan J Menten, Alba A Brandes, Claire Phillips, Michael F Fay, Ryo Nishikawa, David Osoba, J Gregory Cairncross, Wilson Roa, Wolfgang Wick, Wenyin Shi

Department of Radiation Oncology Faculty Papers

[This corrects the article DOI: 10.1093/noajnl/vdab153.].

Radiation Exposure Determination In A Secure, Cloudbased Online Environment, Ben C. Shirley, Eliseos J. Mucaki, Joan H.M. Knoll, Peter Rogan

Biochemistry Publications

Rapid sample processing and interpretation of estimated exposures will be critical for triaging exposed individuals after a major radiation incident. The dicentric chromosome (DC) assay assesses absorbed radiation using metaphase cells from blood. The Automated Dicentric Chromosome Identifier and Dose Estimator System (ADCI) identifies DCs and determines radiation doses. This study aimed to broaden accessibility and speed of this system, while protecting data and software integrity. ADCI Online is a secure web-streaming platform accessible worldwide from local servers. Cloud-based systems containing data and software are separated until they are linked for radiation exposure estimation. Dose estimates are identical to ADCI …

The Use Of Nuclear Medicine In Detecting And Treating Mental Health Diseases, Jena Simmons, Gina Capitano, Walter Kierzkowski

Medical Imaging Senior Posters

Mental health disorders affect over 792 million people around the world, and a leading cause for disability. Mental health disorders include a plethora of conditions that affect mood, thinking and behavior, including but not limited to, depression, dementia, anxiety, autism, and schizophrenia. The most common method of diagnosis is a psychological evaluation, which can lack accuracy if performed as the only method of diagnosis. Nuclear Medicine helps aid in diagnosis of these disorders in conjunction with psychological testing. Brain scans can help determine if there is a pathogenic cause for the symptoms. Brain scans are done utilizing Positron Emission Tomography …

Development Of End-To-End Test Phantom For Stereotactic Radiosurgery Using Alanine Dosimeter, Aungsumalin Intang

Chulalongkorn University Theses and Dissertations (Chula ETD)

Alanine dosimeters are generally used in high-dose dosimetry, while accurate and precise dose delivery verification procedures are important in stereotactic radiosurgery (SRS). Hence, an end-to-end test is required. In addition, no end-to-end SRS test employing an alanine dosimeter has been established in Thailand. The objective of this study was to determine the dose accuracy of SRS VMAT plans in end-to-end test phantom using alanine dosimeter. The electron paramagnetic resonance (EPR) parameters were optimized in the 1-2000 cGy dose range. Following that, suitable parameters were used to investigate the alanine characteristics and estimate the uncertainty in radiation therapy dose range. The …

Investigating The Uncertainties In Ct Non-Small Cell Lung Cancer Radiomics, Gary Ge

Theses and Dissertations--Radiation Medicine

Radiomics is a technique that extracts quantitative features, termed radiomic features, from medical images using data-characterization algorithms. These radiomic features can be used to identify tissue characteristics and radiologic phenotyping that are not observable by clinicians in a non-invasive, low-cost manner, potentially generating image biomarkers for clinical decision. To date, there are still many uncertainties involved in radiomics which limit its clinical implementation. Herein, we propose to explore the impact of each component in the radiomics pipeline on predicting clinical outcomes. In Chapter II, we conduct a thorough review of CT lung cancer radiomics studies to examine the typical feature …

A Method For Predicting Dose Changes For Hn Treatment Using Surface Imaging, Sarah E. Holler

Theses and Dissertations

Head and neck cancer is commonly treated with a six- to seven-week course of radiotherapy, during which a patient’s anatomy may change substantially, due to target reduction or weight loss. Anatomical changes lead to reduction in treatment quality due to decreased setup reproducibility and altered dose deposition compared to the original plan. Few clinics have developed a standard method for triggering resimulation and replan due to anatomic changes. This work investigates a new method for determining when to resimulate and replan HNC patients by utilizing their topographic anatomical changes to predict differences in planned versus delivered dose distributions. The first …

Identification Of Biomarkers For The Prediction Of Radiation Toxicity In Prostate Cancer Patients, Daniel Cullen

Doctoral

The success of radiotherapy in tumour control depends on the total dose given. However, the tolerance of the normal tissues surrounding the tumour limits this dose. It is not known why some patients develop radiation toxicity and, currently, it is not possible to predict before treatment which patients will experience adverse effects. Thus, there is an unmet clinical need for a new test to identify patients at risk of radiation toxicity. The aim of this study was to determine if spectral variations in blood lymphocytes from PCa patients may suggest Raman spectral bands that could be used in future research …

Three-Dimensional (3d) Anatomic Location, Extension, And Timing Of Severe Osteoradionecrosis Of The Mandible, Lucas G Sapienza, Justin J Thomas, Weiyuan Mai, Alexander N Hanania, Sandeep Hunjan, Vlad C Sandulache, Albert C Chen

Faculty, Staff and Students Publications

BACKGROUND: The purpose of this study was to describe the topography, extension (volume), and timing of severe osteoradionecrosis (ORN) that required mandible resection in patients previously treated for head and neck cancer at a high-volume Veterans Affairs Medical Center.

MATERIALS AND METHODS: The records from a reference hyperbaric oxygen clinic were retrospectively analyzed (n = 50, 2018-2021). Inclusion criteria were: I) severe ORN defined as progressive ORN that required resection; II) pathologic confirmation of ORN; and III) availability of pre-operative CT-imaging. Using a radiotherapy (RT) imaging software, we performed a detailed volumetric (3D) analysis of the bone involvement by ORN. …

Comparison Of Radiation Dose And Image Quality Between Fast Kvp Switching Dual-Energy Ct And Routine Single-Energy Ct For Whole Abdomen At King Chulalongkorn Memorial Hospital, Chanthawan Khemkhangboon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Abdominal computed tomography (CT) using a single energy protocol is a common imaging procedure in hospitals. As CT technology has continued to evolve, dual-energy protocols (DECT) have emerged as a new option. A spectral CT scanner with fast kVp switching was installed at King Chulalongkorn Memorial Hospital in 2017, and its clinical utility in emergency patients has not yet been studied. This study aims to compare the radiation dose and image quality between DECT and SECT in abdominal CT for emergency patients. The study retrospectively collected CT data from 130 standard-sized adult patients who underwent contrast-enhanced using the 256-slice MDCT. …

In Vivo Dosimetry Of 3d Gynecological Brachytherapy Using The Glass Dosimeter: A Phantom Study, Itsaraporn Konlak

Chulalongkorn University Theses and Dissertations (Chula ETD)

Brachytherapy can deliver high doses to the target while sparing healthy tissues due to its steep dose gradient property. However, treatment was only performed according to the dose calculated by a treatment planning system without verification of the dose due to the characteristics. Therefore, the aim of this study was to design the in-house phantom to evaluate the dosimetric differences of gynecological brachytherapy under clinical conditions between calculation by the treatment planning system and measurement by the RPLGDs. An in-house phantom consisting of the glass dosimeter holder and the holder of the applicator was created. This holder was designed to …

Effect Of Inter-Observer Delineation Variability On Radiomics Features In Nasopharyngeal Cancer, Pongpitch Panyura

Chulalongkorn University Theses and Dissertations (Chula ETD)

Nasopharyngeal cancer (NPC) is a type of head and neck cancer that is prevalent in China and Southeast Asia. The standard treatment for NPC is radiation therapy (RT), which requires accurate target volume delineation (TVD) to ensure an effective radiation dose while minimizing damage to surrounding healthy tissues. However, TVD is subject to intra- and inter-observer variability, which can affect the accuracy of RT and lead to unstable results in radiomics analysis. Radiomics is a technique that extracts quantitative data from medical images, but it is currently limited by the manual process of tumor delineation. This study aims to investigate …

Dosimetric Differences Between Scheduled And Adapted Plans Generated From Ethos Adaptive Radiotherapy For Patients With Prostate Cancer, Sarita Suvira

Chulalongkorn University Theses and Dissertations (Chula ETD)

Prostate is one of the organs that can easily move or change during the treatment fractions. Adaptive radiotherapy can help to reduce the uncertainty of interfraction and decrease the side effects produced from the radiation given to the patients. The objective of this study was to provide evidence of the efficiency of adaptive radiotherapy for prostate cancer patients by investigating the dosimetric differences between the scheduled and adapted plans generated from Ethos. The treatment data of 100 fractions of prostate cancer patients who had previously been treated on Ethos daily adaptive radiotherapy were collected. The treatment data in each fraction …

Accuracy In Classification Of Liver Lesion Ultrasound Using Artificial Intelligence, Sutthirak Tangruangkiat

Chulalongkorn University Theses and Dissertations (Chula ETD)

B-mode ultrasound imaging is the standard method for hepatocellular carcinoma (HCC) screening. If a lesion has a unique appearance, a conventional detector can be applied. However, if the lesion shares its appearance with other lesion, a large training dataset is required, which may be unavailable. Therefore, a two-stage method is proposed. In the first stage, lesions are detected but not differentiated into any particular class. The detected lesions are then classified in the second stage using a conventional convolutional neural network (CNN). The aims of the dissertation are to design an artificial intelligent system model and to investigate the most …

Accuracy Of Small-Field High Energy Photon Using Plastic Scintillation Detector In Heterogenous Media Compared With Model-Based Algorithm Calculation, Thanat Kaewsuksri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Some radiotherapy techniques such as stereotactic body radiotherapy (SBRT) has the challenges in small field dosimetry in heterogenous media. This study aims at evaluating the accuracy of W2 plastic scintillation detector (PSD) compared with the calculation from algorithms for small-field high energy photon in heterogenous media. The characteristics of W2-PSD were studied. The percentage depth dose (PDD) of 6 FFF and 10 FFF with various field sizes ranging from 1x1 to 4x4 cm2 were measured in solid water phantom with low-density inhomogeneities slabs of air (Styrofoam) and lung (cork) and high-density inhomogeneity slab of aluminum. The characteristics of W2 plastic …

Validation Of Independent Software-Based Calculation In Patient-Specific Quality Assurance, Yasmine Joy Labagnoy

Chulalongkorn University Theses and Dissertations (Chula ETD)

The Mobius3D software addresses limitations lacking in measurement-based methods in patient-specific QA. The objective of this study is to validate its dosimetric performance against conventionally used portal dose measurements using gamma analysis and confidence limits. First, a total of 240 patient-specific QA plans for the Varian Halcyon linear accelerator were collected. Then, the EPID was characterized and the Mobius3D software commissioned through plan verification. Then all patient-specific plans underwent QA using the Portal Dosimetry software and the Mobius3D. The EPID exhibited high reproducibility, dose linearity, and stable dose rate, gantry speed, and MLC speed responses. QA data were assessed using …

Comparative Dosimetry Between 2d Planar-Based And Hybrid-Based Method For Personalized 177 Lu-Psma I&T And 177lu-Dotatate Therapy, Wuri Handayani

Chulalongkorn University Theses and Dissertations (Chula ETD)

Targeted radionuclide therapy (TRT) uses unsealed radiation sources that are accumulated in the target tissues to deliver a damaging radiation dose to the cancerous cells, and a part of the radiopharmaceutical will end up in non-targeted tissues. To avoid treatment-related side effects, dosimetry is mandatory for TRT for each treatment cycle. This study aimed to evaluate and compare the feasibility of 2D planar-based dosimetry and hybrid-based dosimetry for 177Lu-PSMA I&T and 177Lu-DOTATATE therapy. Whole-body planar images and SPECT/CT images were acquired from 27 treatment cycles, 18 patients (13 patients for 177Lu-PSMA I&T and 5 patients for 177Lu-DOTATATE treatment) at immediately, …