Radiation Medicine Commons^™

A Model-Based Method For Assessment Of Salivary Gland And Planning Target Volume Dosimetry In Volumetric-Modulated Arc Therapy Planning On Head-And-Neck Cancer., H. Zhang, Y. Cao, J. Antone, A. C. Riegel, M. Ghaly, L. Potters, A. Jamshidi

Journal Articles

This study examined the relationship of achievable mean dose and percent volumetric overlap of salivary gland with the planning target volume (PTV) in volumetric-modulated arc therapy (VMAT) plan in radiotherapy for a patient with head-and-neck cancer. The aim was to develop a model to predict the viability of planning objectives for both PTV coverage and organs-at-risk (OAR) sparing based on overlap volumes between PTVs and OARs, before the planning process. Forty patients with head-and-neck cancer were selected for this retrospective plan analysis. The patients were treated using 6 MV photons with 2-arc VMAT plan in prescriptions with simultaneous integrated boost …

Dna Damage And Cytokine Production In Non-Target Irradiated Lymphocytes, Jane Bryant, Laura Shields, Christopher Hynes, Orla L. Howe, Brendan Mcclean, Fiona Lyng

Articles

In advanced radiotherapy, treatment of the tumor with high-intensity modulated fields is balanced with normal tissue sparing. However, the non-target dose delivered to surrounding healthy tissue within the irradiated volume is a potential cause for concern. Whether the effects observed are caused after exposure to out-of-field radiation or bystander effects through neighboring irradiated cells is not fully understood. The goal of this study was to determine the effect of exposure to out-of-field radiation in lymphocyte cell lines and primary blood cells. The role of cellular radiosensitivity in altering bystander responses in out-of-field exposed cells was also investigated. Target cells were …

Dosimetric Performance And Planning/Delivery Efficiency Of A Dual-Layer Stacked And Staggered Mlc On Treating Multiple Small Targets: A Planning Study Based On Single-Isocenter Multi-Target Stereotactic Radiosurgery (Srs) To Brain Metastases., Taoran Li, Peyton Irmen, Haisong Lui, Wenyin Shi, Michelle Alonso-Basanta, Wei Zou, Boon-Keng Kevin Teo, James M. Metz, Lei Dong

Department of Radiation Oncology Faculty Papers

Purpose: To evaluate the dosimetric performance and planning/delivery efficiency of a dual-layer MLC system for treating multiple brain metastases with a single isocenter.

Materials and Methods: 10 patients each with 6-10 targets with volumes from 0.11 to 8.57 cc, and prescription doses from 15 to 24 Gy, were retrospectively studied. Halcyon has only coplanar delivery mode. Halcyon V1 MLC modulates only with the lower layer at 1 cm resolution, whereas V2 MLC modulates with both layers at an effective resolution of 0.5 cm. For each patient five plans were compared varying MLC and beam arrangements: the clinical plan using multi-aperture …

A Custom Radiopaque Thermoresponsive Chemotherapy-Loaded Hydrogel For Intratumoural Injection: An In Vitro And Ex Vivo Assessment Of Imaging Characteristics And Material Properties, Seóna M. Rossi, Timothy E. Murray, John Cassidy, Michael J. Lee, Helena M. Kelly

Articles

Purpose Thermoresponsive hydrogels are gels which have different properties at varying temperatures. The objective of this study was to assess the material characteristics, imaging properties and chemotherapeutic drug release profile of a novel radiopaque thermoresponsive hydrogel in vitro, which is liquid at room temperature but solidifies at body temperature, to determine potential suitability for intratumoural delivery. Materials and Methods An iodinated radiopaque thermoresponsive hydrogel was formulated using iodixanol at a range of concentrations and assessed for sol–gel transition, radiopacity and imaging using CT and US. A lead formulation containing iodixanol at a concentration of 9.22% weight by weight (w/w, g …

Recent Advances In The Vibrational Spectroscopic Diagnosis Of Non-Small Cell Lung Cancer, Declan O'Dea, Fiona Lyng, Siobhan Nicholson, Finbar O'Connell, Aoife Maguire, Alison Malkin

Articles

Lung cancer is the leading cause of cancer deaths worldwide accounting for 1.69 million deaths in 2015. Studies have indicated a 5 year survival rate of 8%–15% in western countries, although a survival rate as low as 1% has been demonstrated for late stage diagnosis. With the advent of targeted therapies, it is imperative to accurately differentiate non-small cell lung cancer (NSCLC) subtypes in order to ensure efficacy of treatment for patients. Immunohistochemistry and molecular techniques for the diagnosis of NSCLC are increasingly part of the diagnostic algorithm and clinical work-up of lung cancer patients, however due to the limitation …

Measurement Of The Whole Body, Eye Lens And Extremity Occupational Exposures In Nuclear Medicine Staff At King Chulalongkorn Memorial Hospital, Siriwan Sisai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Due to the epidemiology evidence of cataract and eye lens opacity, ICRP Publication 118 in 2012, recommended the new eye lens dose limit of occupational exposure at 20 mSv/year, averaged over 5-year periods, no single year exceeding 50 mSv. For the public eye lens dose limit is 15 mSv/year. After ICRP changed the eye lens dose limit, many reports on eye lens dose measurement using thermoluminescent dosimeter (TLD) from interventional radiologists and interventional cardiologists were published. Few reports on eye lens dose measurement in nuclear medicine (NM) personnel were found. The primary objective of this study is to measure whole …

A Feasibility Study Of Diffusion Weighted Imaging And Parametric Response Map Analysis For Treatment Response Prediction In Nasopharyngeal Cancer, Titiya Jirawatwanith

Chulalongkorn University Theses and Dissertations (Chula ETD)

Diffusion-weighted imaging (DWI) is an MRI technique which provides functional information of tissue by detecting microscopic motion of water molecules. The change of apparent diffusion coefficient (ADC) derived from DWI was used as an imaging biomarker for treatment response prediction in cancers. However, it was based on whole-tumor analysis which did not reflect heterogeneity within the tumor. To overcome this limitation, a new method called parametric response map (PRM) analysis was proposed to evaluate response by quantifying voxel-wise changes in ADC. Here we investigated the use of PRM analysis on ADC from DWI as an imaging biomarker for treatment response …

Dosimetric Comparison Between Single And Double Isocenters Volumetric Arc Therapy For Stereotactic Radiotherapy With Multiple Targets, Wai Lwin Lwin Kyaw

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this study was to evaluate the dosimetric effects between single isocenter (SI) and double isocenters (DI) VMAT SRT of multiple brain metastases. There are two parts of study, which were experimental for energy selection, technique comparison and clinical part to use appropriate technique. As the first part, three lesions with 3 cm distance apart and 1 cm size for all lesions were created as standard plan by varying energy. Twelve VMAT SRT plans by varying energy with 6 MV, 10 MV, 6 FFF and 10 FFF were planned on simulated three lesions of CT image. 18 VMAT …

Effect Of Neoadjuvant Chemoradiation On Preoperative Pulmonary Physiology, Postoperative Respiratory Complications And Quality Of Life In Patients With Oesophageal Cancer, J. A. Elliott, L. O'Byrne, G. Foley, C. F. Murphy, Suzanne Doyle, S. King, E. M. Guinan, N. Ravi, V. Reynolds

Articles

Background: It remains controversial whether neoadjuvant chemoradiation (nCRT) for oesophageal cancer influences operative morbidity, in particular pulmonary, and quality of life. This study combined clinical outcome data with systematic evaluation of pulmonary physiology to determine the impact of nCRT on pulmonary physiology and clinical outcomes in locally advanced oesophageal cancer.

Methods: Consecutive patients treated between 2010 and 2016 were included. Three-dimensional conformal radiation was standard, with a lung dose–volume histogram of V20 less than 25 per cent, and total radiation between 40 and 41⋅4Gy. Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and diffusion capacity …

An Ensemble Of Flexible Conformations Underlies Mechanotransduction By The Cadherin–Catenin Adhesion Complex, Martin Bush, Bashir M. Alhanshali, Shuo Qian, Christopher B. Stanley, William T. Heller, Tsutomu Matsui, Thomas M. Weiss, Iain D. Nicholl, Thomas Walz, David J. E. Callaway, Zimei Bu

Publications and Research

The cadherin–catenin adhesion complex is the central component of the cell–cell adhesion adherens junctions that transmit mechanical stress from cell to cell. We have determined the nanoscale structure of the adherens junction complex formed by the α-catenin•β-catenin•epithelial cadherin cytoplasmic domain (ABE) using negative stain electron microscopy, small-angle X-ray scattering, and selective deuteration/small-angle neutron scattering. The ABE complex is highly pliable and displays a wide spectrum of flexible structures that are facilitated by protein-domain motions in α- and β-catenin. Moreover, the 107-residue intrinsically disordered N-terminal segment of β-catenin forms a flexible “tongue” that is inserted into α-catenin and participates in the …

Spaceoar To Improve Dosimetric Outcomes For Monotherapy High-Dose-Rate Prostate Implantation In A Patient With Ulcerative Colitis., Michael Trager, Benjamin Greenberger, Amy S. Harrison, James Keller, Robert B. Den

Department of Radiation Oncology Faculty Papers

High-dose-rate (HDR) brachytherapy is an attractive option for patients receiving definitive radiation therapy for prostate cancer with decreased overall dose to the pelvis. However, ulcerative colitis increases rectal toxicity risk and may be a contraindication. A synthetic hydrogel, SpaceOAR (Augmentix Inc., Waltham, MA, USA), can facilitate the use of HDR brachytherapy for patients where rectal toxicity is a limiting factor. SpaceOAR gel (13.19 cc) was utilized in a monotherapy HDR prostate treatment with Ir-192 under transrectal ultrasound guidance, with the intention of decreasing rectal dose. SpaceOAR gel was inserted transperineally into the patient 18 days prior to the procedure. The …

Challenges Faced By Pakistani Healthcare System: Clinician's Perspective, Faran Khalid, Ahmed Nadeem Abbasi

Department of Radiation Oncology

Abstract are not provided by the author/publisher

Clinical Audit To Assess Delays In Chemotherapy Administration At Daycare Oncology Center At A Tertiary Care Hospital In Karachi, Pakistan, Arifa Arifa Aziz, Zarka Samoon, Afsheen Feroz, Nadia Ayoub, Safia Awan, Madhia Beg

Department of Radiation Oncology

Aim: There were delays reported by patients in chemotherapy administration in daycare oncology. Therefore, we decided to audit all processes which are involved in chemotherapy administration. The objective was to improve our service by decreasing the time between admission and initiation of chemotherapy and identify the reasons for delays. Materials and Methods: The audit was conducted in three parts. In Review I, audit tool was developed and information documented of 109 patients receiving chemotherapy at daycare center from April 14 to May 13, 2015. Five processes were assessed out of which delay in initial assessment by the nurse was the …

Development And Validation Of A Prostate Cancer Genomic Signature That Predicts Early Adt Treatment Response Following Radical Prostatectomy., R. Jeffrey Karnes, Vidit Sharma, Voleak Choeurng, Hussam Al-Deen Ashab, Nicholas Erho, Mohammed Alshalalfa, Bruce Trock, Ashley Ross, Kasra Yousefi, Harrison Tsai, Shuang G. Zhao, Jeffrey J. Tosoian, Zaid Haddad, Mandeep Takhar, S. Laura Chang, Daniel E. Spratt, Firas Abdollah, Robert B. Jenkins, Eric A. Klein, Paul L. Nguyen, Adam P. Dicker, Robert B. Den, Elai Davicioni, Felix Y. Feng, Tamara L. Lotan, Edward M. Schaeffer

Department of Radiation Oncology Faculty Papers

Purpose: Currently, no genomic signature exists to distinguish men most likely to progress on adjuvant androgen deprivation therapy (ADT) after radical prostatectomy for high-risk prostate cancer. Here we develop and validate a gene expression signature to predict response to postoperative ADT.

Experimental Design: A training set consisting of 284 radical prostatectomy patients was established after 1:1 propensity score matching metastasis between adjuvant-ADT (a-ADT)-treated and no ADT–treated groups. An ADT Response Signature (ADT-RS) was identified from neuroendocrine and AR signaling–related genes. Two independent cohorts were used to form three separate data sets for validation (set I, n = 232; set II, …

Prognostic Factors For Elderly Patients Treated With Stereotactic Body Radiation Therapy For Pancreatic Adenocarcinoma, Philip A. Sutera, Mark E. Bernard, Hong Wang, Dwight E. Heron

Radiation Medicine Faculty Publications

Introduction: Pancreatic ductal adenocarcinoma (PDAC) commonly presents later in life with a median age at diagnosis of 70 years. Unfortunately, elderly patients are significantly underrepresented in clinical trials. Stereotactic body radiation therapy (SBRT) is a promising treatment modality in this population as it has demonstrated excellent local control with minimal toxicity. We aimed to determine prognostic factors associated with outcomes in elderly patients treated with SBRT.

Materials and Methods: Elderly patients older than 70 treated with SBRT for PDAC at our institution, from 2004 to 2014 were included. Our primary endpoints included overall survival (OS) and local-progression-free survival (LPFS). Secondary …

Impact Of The Spop Mutant Subtype On The Interpretation Of Clinical Parameters In Prostate Cancer., Deli Liu, Mandeep Takhar, Mohammed Alshalalfa, Nicholas Erho, Jonathan Shoag, Robert B. Jenkins, R. Jeffrey Karnes, Ashley E. Ross, Edward M. Schaeffer, Mark A. Rubin, Bruce Trock, Eric A. Klein, Robert B. Den, Scott A. Tomlins, Daniel E. Spratt, Elai Davicioni, Andrea Sboner, Christopher E. Barbieri

Department of Radiation Oncology Faculty Papers

Purpose: Molecular characterization of prostate cancer, including The Cancer Genome Atlas, has revealed distinct subtypes with underlying genomic alterations. One of these core subtypes, SPOP (speckle-type POZ protein) mutant prostate cancer, has previously only been identifiable via DNA sequencing, which has made the impact on prognosis and routinely used risk stratification parameters unclear.

Methods: We have developed a novel gene expression signature, classifier (Subclass Predictor Based on Transcriptional Data), and decision tree to predict the SPOP mutant subclass from RNA gene expression data and classify common prostate cancer molecular subtypes. We then validated and further interrogated the association of prostate …

Open Book Testing In Health Science Education: Student Perceptions And Outcomes In Ultrasound Physics, Kim Michael, Tanya M. Custer

Posters and Presentations: Medical Imaging & Therapeutic Sciences

Objectives: The purpose of this study was to investigate the use of open book exams (OBE) in the education of imaging students and to assess the beliefs and perceptions of the students in regard to the use of open book testing.

Subjects & Methods: Study participants included twenty-seven sonography students enrolled in an academic health sciences center. OBE was implemented in two ultrasound physics courses. Data was collected through focus groups & exam outcomes. Creswell’s procedure for data analysis & representation was followed.

Results: Overall outcomes showed no statistically significant difference between exam grades for the different cohorts with the …

Discriminating Radiation Injury From Recurrent Tumor With [18f]Parpi And Amino Acid Pet In Mouse Models, Patrick L. Donabedian, Susanne Kossatz, John A. Engelbach, Stephen A. Jannetti, Brandon Carney, Robert J. Young, Wolfgang A. Weber, Joel R. Garbow, Thomas Reiner

Publications and Research

Background

Radiation injury can be indistinguishable from recurrent tumor on standard imaging. Current protocols for this differential diagnosis require one or more follow-up imaging studies, long dynamic acquisitions, or complex image post-processing; despite much research, the inability to confidently distinguish between these two entities continues to pose a significant dilemma for the treating clinician. Using mouse models of both glioblastoma and radiation necrosis, we tested the potential of poly(ADP-ribose) polymerase (PARP)-targeted PET imaging with [¹⁸F]PARPi to better discriminate radiation injury from tumor.

Results

In mice with experimental radiation necrosis, lesion uptake on [¹⁸F]PARPi-PET was similar to …

Tmsotf Assisted Synthesis Of 2’-Deoxy-2’-[18f] Fluoro-Β-D-Arabinofuranosylcytosine ([18f] Fac), Kishore K. Gangangari, John L. Humm, Steven M. Larson, Naga Vara Kishore Pillarsetty

Publications and Research

[¹⁸F]FAC (2’-deoxy-2’-[¹⁸F]fluoro-β-D-arabinofuranosylcytosine, 1) is a versatile probe for imaging deoxycytidine kinase (dCK) expression levels in vivo. dCK is responsible for phosphorylation of deoxycytidine (dC, 2) and other nucleoside analogs, plays a key role in immune activation and has demonstrated to be one of the key enzymes in activating nucleoside based drugs including gemcitabine. Reported synthesis of [¹⁸F]FAC is high yielding but is quite challenging requiring bromination using HBr and careful drying of excess HBr which is critical for successful synthesis. Here in we report a simplified trimethylsilyl trifluoromethanesulfonate (TMSOTf) assisted synthesis …

Analysis Of Clinical Data To Determine The Minimum Number Of Sensors Required For Adequate Skin Temperature Monitoring Of Superficial Hyperthermia Treatments., Akke Bakker, Rebecca Holman, Dario B. Rodrigues, Hana Dobšíček Trefná, Paul R. Stauffer, Geertjan Van Tienhoven, Coen R.N. Rasch, Hans Crezee

Department of Radiation Oncology Faculty Papers

PURPOSE: Tumor response and treatment toxicity are related to minimum and maximum tissue temperatures during hyperthermia, respectively. Using a large set of clinical data, we analyzed the number of sensors required to adequately monitor skin temperature during superficial hyperthermia treatment of breast cancer patients.

METHODS: Hyperthermia treatments monitored with >60 stationary temperature sensors were selected from a database of patients with recurrent breast cancer treated with re-irradiation (23 × 2 Gy) and hyperthermia using single 434 MHz applicators (effective field size 351-396 cm²). Reduced temperature monitoring schemes involved randomly selected subsets of stationary skin sensors, and another subset …

Bezoar: Imaging Findings & Case Study Of A Rare Pathology, Tanya M. Custer, Kim Michael

Posters and Presentations: Medical Imaging & Therapeutic Sciences

A bezoar is a hard, indigestible mass of material that forms within the alimentary canal, most commonly the stomach.1 Bezoars are classified according to composition. The most common type of bezoar is a phytobezoar composed of indigestible food fibers that occur in fruits & vegetables, including celery, pumpkin, prunes, raisins, & sunflower-seed shells. Other common types of bezoars include trichobezoars, composed of hair, & pharmacobezoars, made of undissolved medications.

A number of risk factors have been associated with bezoar development. Patients who have undergone gastric surgery, such as partial gastrectomy, are at an increased risk of developing a bezoar due …

Antibody-Drug Conjugates For Cancer Therapy: Chemistry To Clinical Implications, Nirnoy Dan, Saini Setua, Vivek K. Kashyap, Sheema Khan, Meena Jaggi, Murali M. Yallapu, Subhash C. Chauhan

School of Medicine Publications

Chemotherapy is one of themajor therapeutic options for cancer treatment. Chemotherapy is often associated with a low therapeutic window due to its poor specificity towards tumor cells/tissues. Antibody-drug conjugate (ADC) technology may provide a potentially new therapeutic solution for cancer treatment. ADC technology uses an antibody-mediated delivery of cytotoxic drugs to the tumors in a targeted manner, while sparing normal cells. Such a targeted approach can improve the tumor-to-normal tissue selectivity and specificity in chemotherapy. Considering its importance in cancer treatment, we aim to review recent efforts for the design and development of ADCs. ADCs are mainly composed of an …

Therapeutic Challenge With A Cdk 4/6 Inhibitor Induces An Rb-Dependent Smac-Mediated Apoptotic Response In Non-Small Cell Lung Cancer., Thangavel Chellappagounder, Boopathi Ettickan, Yi Liu, Christopher Mcnair, Alex Haber, Maryna Perepelyuk, Anshul Bhardwaj, Sankar Addya, Adam Ertel, Sunday Shoyele, Ruth Birbe, Joseph M. Salvino, Adam P. Dicker, Karen E. Knudsen, Robert B. Den

Department of Radiation Oncology Faculty Papers

Purpose: The retinoblastoma tumor suppressor (RB), a key regulator of cell-cycle progression and proliferation, is functionally suppressed in up to 50% of non-small cell lung cancer (NSCLC). RB function is exquisitely controlled by a series of proteins, including the CyclinD-CDK4/6 complex. In this study, we interrogated the capacity of a CDK4/6 inhibitor, palbociclib, to activate RB function.

Experimental Design and Results: We employed multiple isogenic RB-proficient and -deficient NSCLC lines to interrogate the cytostatic and cytotoxic capacity of CDK 4/6 inhibition in vitro and in vivo We demonstrate that while short-term exposure to palbociclib induces cellular senescence, prolonged exposure results …

Pdz-Rhogef Is A Signaling Effector For Troy-Induced Glioblastoma Cell Invasion And Survival, Z. Ding, H. Dhruv, A. Kwiatkowska-Piwowarczyk, R. Ruggieri, J. Kloss, M. Symons, P. Pirrotte, J. M. Eschbacher, N. L. Tran, J. C. Loftus

Journal Articles

© 2018 The Authors Glioblastoma multiforme (GBM) is the most common type of malignant brain tumors in adults and has a dismal prognosis. The highly aggressive invasion of malignant cells into the normal brain parenchyma renders complete surgical resection of GBM tumors impossible, increases resistance to therapeutic treatment, and leads to near-universal tumor recurrence. We have previously demonstrated that TROY (TNFRSF19) plays an important role in glioblastoma cell invasion and therapeutic resistance. However, the potential downstream effectors of TROY signaling have not been fully characterized. Here, we identified PDZ-RhoGEF as a binding partner for TROY that potentiated TROY-induced nuclear factor …

Restricted Single Isocenter For Multiple Targets Dynamic Conformal Arc (Rsimt Dca) Technique For Brain Stereotactic Radiosurgery (Srs) Planning., J. Chang, A. G. Wernicke, S. C. Pano

Journal Articles

In stereotactic radiosurgery (SRS), the multiple isocenters for multiple targets dynamic conformal arc (MIMT DCA) technique is traditionally used to treat multiple brain metastases, with one isocenter for each target. The single isocenter for multiple targets (SIMT) technique has recently been adopted to reduce the treatment time at the cost of plan quality. The objective of this study was to develop a restricted single isocenter for multiple targets DCA (RSIMT DCA) technique that can significantly reduce the treatment time but still maintain similar plan quality as the MIMT DCA technique.Treating multiple brain metastases with a single isocenter poses a challenge …

Reducing Seed Waste And Increasing Value Of Dynamic Intraoperative Implantation Of Pd-103 Seeds In Prostate Brachytherapy, P. K. Taylor, A, C. Riegel

Journal Articles

© 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine. Several nomograms exist for ordering palladium-103 seeds for permanent prostate seed implants (PSI). Excess seeds from PSIs pose additional radiation safety risks and increase the cost of care. This study compared five nomograms to clinical data from dynamic modified-peripheral intraoperative PSI to determine (a) the cause of excess seeds and (b) the optimal nomogram for our institution. Pre- and intraoperative patient data were collected for monotherapy PSIs and compiled into a clinical database. All patients were …

Intermediate-Risk Meningioma: Initial Outcomes From Nrg Oncology Rtog 0539, L. Rogers, P. Zhang, M. A. Vogelbaum, A. Perry, L. S. Ashby, J. M. Modi, A. M. Alleman, J. Galvin, J. P. S. Knisely, M. P. Mehta, +5 Additional Authors

Journal Articles

No abstract provided.

Implementation And Utilization Of Hypofractionation For Breast Cancer, P. Gilbo, L. Potters, L. Lee

Journal Articles

© 2018 The Authors Purpose: Hypofractionation (HF) of whole breast irradiation has become a standard treatment regimen because randomized trials continue to demonstrate equivalence in survival and local control compared with conventional fractionation. In 2011, the American Society for Radiation Oncology (ASTRO) adopted clinical guidelines on the proper selection of HF. Nevertheless, utilization remains lower than predicted. We evaluate the effects of clinical directives that serve as default treatment decisions and prospective contouring rounds on the implementation of HF in a large, multicenter radiation oncology department. Methods and materials: In 2010, we implemented consensus-driven and evidence-based clinical directives to guide …

Dosimetric Comparison Between Using Daily Cone Beam Ct And Planning Ct In Volumetric Modulated Arc Therapy Technique For Prostate Cancer Therapy, Julaluck Chanayota

Chulalongkorn University Theses and Dissertations (Chula ETD)

The variations of shape and size of organs inside, especially bladder and rectum, in prostate cancer patient are mainly factors of external beam radiation therapy that may impact to disease control and normal tissue toxicity. The purpose of this study was to investigate the dosimetric comparison between using daily CBCT and planning CT in Volumetric modulated arc therapy (VMAT) technique for prostate cancer therapy. The HU and electron density between CBCT and planning CT were verified by using Catphan® 600 phantom. Treatment planning system was verified by dose distribution comparison between plans on CBCT and planning CT images of Anthropomorphic …

The Measurement Of Transverse Relaxation Time (T2) Using Histogram From Roi Setting In Muscle Activity Study At 1.5 Tesla Mri, Kannikar Kanyakham

Chulalongkorn University Theses and Dissertations (Chula ETD)

Muscle functional MRI (mfMRI) is the method to evaluate the muscle activity before and immediately after the muscle exercise by the magnetic resonance images. Exercise of skeletal muscles enhances image contrast in T2-weighted magnetic resonance (MR) images. In previous studies, the exercised physiology used multiple-spin-echo (MSE) sequences for calculating transverse relaxation time (T2) with several small regions of interest (ROI) within the target tissue. Such a method may not represent all properties of the target tissue. The purpose of this study is to measure T2 in rest and exercise muscle at 1.5 Tesla MRI using average mode values in histogram …