Medicine and Health Sciences Commons^™

Mobilising Expertise And Resources To Close The Radiotherapy Gap In Cancer Care., D Rodin, J Longo, T Sherertz, M M Shah, O Balagun, N Wendling, Jacob Van Dyk, C N Coleman, M J Xu, S Grover

Oncology Publications

Closing the gap in cancer care within low- and middle-income countries and in indigenous and geographically isolated populations in high-income countries requires investment and innovation. This is particularly true for radiotherapy, for which the global disparity is one of the largest in healthcare today. New models and paradigms and non-traditional collaborations have been proposed to improve global equity in cancer control. We describe recent initiatives from within the radiation oncology community to increase access to treatment, build the low- and middle-income countries' radiation oncology workforce, mobilise more professionals from within high-income countries and raise awareness of the global need for …

Analysis Of Global Radiotherapy Needs And Costs By Geographic Region And Income Level., E Zubizarreta, Jacob Van Dyk, Y Lievens

Oncology Publications

Recent years have seen various reviews on the lack of access to radiotherapy often based on geographic regions of the world such as Africa, Asia Pacific, Europe, Latin America and North America. Countries are often defined by their national income per capita levels based on World Bank definitions of high income, upper middle income, lower middle income and low income. Within the world regions, there are significant variations in gross national income (GNI) per capita among the different countries, and even within similar income levels, large variations exist. This report presents the actual status of radiotherapy and analyses the current …

Accuracy Requirements And Uncertainties In Radiotherapy: A Report Of The International Atomic Energy Agency., Debbie Van Der Merwe, Jacob Van Dyk, Brendan Healy, Eduardo Zubizarreta, Joanna Izewska, Ben Mijnheer, Ahmed Meghzifene

Oncology Publications

BACKGROUND: Radiotherapy technology continues to advance and the expectation of improved outcomes requires greater accuracy in various radiotherapy steps. Different factors affect the overall accuracy of dose delivery. Institutional comprehensive quality assurance (QA) programs should ensure that uncertainties are maintained at acceptable levels. The International Atomic Energy Agency has recently developed a report summarizing the accuracy achievable and the suggested action levels, for each step in the radiotherapy process. Overview of the report: The report seeks to promote awareness and encourage quantification of uncertainties in order to promote safer and more effective patient treatments. The radiotherapy process and the radiobiological …

Radiation Oncology Quality And Safety Considerations In Low Resource Settings: A Medical Physics Perspective, Jacob Van Dyk, Ahmed Meghzifene

Oncology Publications

The last few years have seen a significant growth of interest in the global radiation therapy crisis. Various organizations have quantified the need and are providing aid in support of addressing the shortfalls existing in many low-to-middle income countries (LMICs). With the tremendous demand for new facilities, equipment and personnel, it is very important to recognize the quality and safety challenges and to address them directly. An examination of publications on quality and safety in radiation therapy indicates a consistency in a number of the recommendations; however, these authoritative reports were generally based on input from high-resourced contexts. Here we …

Global Access To Radiation Therapy For Cervical Cancer: The Cost Of Inaction, Jacob Van Dyk, D Rodin, Timothy Paul Hanna, E Burger, Eduardo Zubizarreta, Mei Ling Yap, Michael Barton, Rifat Atun, Felicia Marie Knaul, Y Lievens, Mary K. Gospodarowicz, D A. Jaffray, M Milosevic

Oncology Publications

No abstract provided.

Exploiting High-Throughput Cell Line Drug Screening Studies To Identify Candidate Therapeutic Agents In Head And Neck Cancer, Anthony C Nichols, Morgan Black, John Yoo, Nicole Pinto, Andrew Fernandes, Benjamin Haibe-Kains, Paul C Boutros, John W Barrett

Oncology Publications

BACKGROUND: There is an urgent need for better therapeutics in head and neck squamous cell cancer (HNSCC) to improve survival and decrease treatment morbidity. Recent advances in high-throughput drug screening techniques and next-generation sequencing have identified new therapeutic targets in other cancer types, but an HNSCC-specific study has not yet been carried out. We have exploited data from two large-scale cell line projects to clearly describe the mutational and copy number status of HNSCC cell lines and identify candidate drugs with elevated efficacy in HNSCC.

METHODS: The genetic landscape of 42 HNSCC cell lines including mutational and copy number data …

Has The Use Of Computers In Radiation Therapy Improved The Accuracy In Radiation Dose Delivery?, Jacob Van Dyk, Jerry J. Battista Dr.

Oncology Publications

Purpose: It is well recognized that computer technology has had a major impact on the practice of radiation oncology. This paper addresses the question as to how these computer advances have specifically impacted the accuracy of radiation dose delivery to the patient. Methods: A review was undertaken of all the key steps in the radiation treatment process ranging from machine calibration to patient treatment verification and irradiation. Using a semi-quantitative scale, each stage in the process was analysed from the point of view of gains in treatment accuracy. Results: Our critical review indicated that computerization related to digital medical imaging …

Medical Physics Staffing For Radiation Oncology: A Decade Of Experience In Ontario, Canada., Jerry J. Battista Dr., Brenda G Clark, Michael S Patterson, Luc Beaulieu, Michael B Sharpe, L John Schreiner, Miller S Macpherson, Jacob Van Dyk

Oncology Publications

The January 2010 articles in The New York Times generated intense focus on patient safety in radiation treatment, with physics staffing identified frequently as a critical factor for consistent quality assurance. The purpose of this work is to review our experience with medical physics staffing, and to propose a transparent and flexible staffing algorithm for general use. Guided by documented times required per routine procedure, we have developed a robust algorithm to estimate physics staffing needs according to center-specific workload for medical physicists and associated support staff, in a manner we believe is adaptable to an evolving radiotherapy practice. We …

Optimal Slice Thickness For Cone-Beam Ct With On-Board Imager., Kyt Seet, A Barghi, Slav Yartsev, Jacob Van Dyk

Oncology Publications

PURPOSE: To find the optimal slice thickness (Δτ) setting for patient registration with kilovoltage cone-beam CT (kVCBCT) on the Varian On Board Imager (OBI) system by investigating the relationship of slice thickness to automatic registration accuracy and contrast-to-noise ratio.

MATERIALS AND METHOD: Automatic registration was performed on kVCBCT studies of the head and pelvis of a RANDO anthropomorphic phantom. Images were reconstructed with 1.0 ≤ Δτ (mm) ≤ 5.0 at 1.0 mm increments. The phantoms were offset by a known amount, and the suggested shifts were compared to the known shifts by calculating the residual error. A uniform cylindrical phantom …

Schedule For Ct Image Guidance In Treating Prostate Cancer With Helical Tomotherapy., G Beldjoudi, S Yartsev, G Bauman, Jerry J. Battista Dr., Jacob Van Dyk

Oncology Publications

The aim of this study was to determine the effect of reducing the number of image guidance sessions and patient-specific target margins on the dose distribution in the treatment of prostate cancer with helical tomotherapy. 20 patients with prostate cancer who were treated with helical tomotherapy using daily megavoltage CT (MVCT) imaging before treatment served as the study population. The average geometric shifts applied for set-up corrections, as a result of co-registration of MVCT and planning kilovoltage CT studies over an increasing number of image guidance sessions, were determined. Simulation of the consequences of various imaging scenarios on the dose …

A Review Of Autoimmune Diseases Associated With Cancer, Patricia Tai, Edward Yu, Kurian Joseph, Thomas Miale

Oncology Publications

The focus of this review is on the relationships between autoimmune diseases and cancer from two closely related perspectives: 1.Those autoimmune diseases which are often associated with malignancies. 2.Those prevalent cancers which may increase the risks of developing autoimmune disorders. The review concludes with a brief discussion of some selected innovative approaches to cancer immunotherapy.

The Effects Of Field-Of-View And Patient Size On Ct Numbers From Cone-Beam Computed Tomography., Katrina Y T Seet, Arvand Barghi, Slav Yartsev, Jacob Van Dyk

Oncology Publications

Cone-beam computed tomography (CBCT) is used for patient alignment before treatment and is ideal for use in adaptive radiotherapy to account for tumor shrinkage, organ deformation and weight loss. However, CBCT images are prone to artifacts such as streaking and cupping effects, reducing image quality and CT number accuracy. Our goal was to determine the optimum combination of cone-beam imaging options to increase the accuracy of image CT numbers. Several phantoms with and without inserts of known relative electron densities were imaged using the Varian on-board imaging system. It was found that CT numbers are most influenced by the selection …

Effects Of Genistein Following Fractionated Lung Irradiation In Mice., Andrea E Para, Andrea Bezjak, Ivan W T Yeung, Jacob Van Dyk, Richard P Hill

Oncology Publications

BACKGROUND AND PURPOSE: This study investigated protection of lung injury by genistein following fractionated doses of radiation and its effect on tumor response.

MATERIAL AND METHODS: C3H/HeJ mice were irradiated (100 kVp X-rays) with 9 fractions of 3.1 Gy over 30 days (approximately equivalent to 10 Gy single dose) and were maintained on a genistein diet ( approximately 10mg/kg). Damage was assessed over 28 weeks in lung cells by a cytokinesis block micronucleus (MN) assay and by changes in breathing rate and histology. Tumor protection was assessed using a colony assay to determine cell survival following in situ irradiation of …

Adaptive Radiation Therapy For Localized Mesothelioma With Mediastinal Metastasis Using Helical Tomotherapy., James Renaud, Slav Yartsev, A Rashid Dar, Jacob Van Dyk

Oncology Publications

The purpose of this study was to compare 2 adaptive radiotherapy strategies with helical tomotherapy. A patient having mesothelioma with mediastinal nodes was treated using helical tomotherapy with pretreatment megavoltage CT (MVCT) imaging. Gross tumor volumes (GTVs) were outlined on every MVCT study. Two alternatives for adapting the treatment were investigated: (1) keeping the prescribed dose to the targets while reducing the dose to the OARs and (2) escalating the target dose while maintaining the original level of healthy tissue sparing. Intensity modulated radiotherapy (step-and-shoot IMRT) and 3D conformal radiotherapy (3DCRT) plans for the patient were generated and compared. The …

Consistency Check Of Planned Adaptive Option On Helical Tomotherapy., M Schirm, S Yartsev, G Bauman, Jerry J. Battista Dr., Jacob Van Dyk

Oncology Publications

This study aims to evaluate a new Planned Adaptive software (TomoTherapy Inc., Madison, WI) of the helical tomotherapy system by retrospective verification and adaptive re-planning of radiation treatment. Four patients with different disease sites (brain, nasal cavity, lungs, prostate) were planned in duplicate using the diagnostic planning kVCT data set and MVCT studies of the first treatment fraction with the same optimization parameters for both plan types. The dosimetric characteristics of minimum, maximum, and mean dose to the targets as well as to organs at risk were compared. Both sets of plans were used for calculation of dose distributions in …

Quality Assurance Of Radiation Therapy Planning Systems: Current Status And Remaining Challenges., Jacob Van Dyk

Oncology Publications

Computerized radiation therapy planning systems (RTPSs) are pivotal for treatment planning. The acceptance, commissioning, and quality control of RTPSs are uniquely complex and are described in the American Association of Physicists in Medicine Task Group Report 53 (1998) and International Atomic Energy Agency Technical Report Series No. 430 (2004). The International Atomic Energy Agency also developed a document and data package for use by vendors and purchasers to aid with acceptance testing of RTPSs. This document is based on International Electrotechnical Commission standard 62083 (2000) and describes both "type" tests to be performed in the factory and "site" tests to …

Adaptive Radiotherapy Planning On Decreasing Gross Tumor Volumes As Seen On Megavoltage Computed Tomography Images., Curtis Woodford, Slav Yartsev, R. Dar, Glenn Bauman, Jacob Van Dyk

Oncology Publications

PURPOSE: To evaluate gross tumor volume (GTV) changes for patients with non-small-cell lung cancer by using daily megavoltage (MV) computed tomography (CT) studies acquired before each treatment fraction on helical tomotherapy and to relate the potential benefit of adaptive image-guided radiotherapy to changes in GTV.

METHODS AND MATERIALS: Seventeen patients were prescribed 30 fractions of radiotherapy on helical tomotherapy for non-small-cell lung cancer at London Regional Cancer Program from Dec 2005 to March 2007. The GTV was contoured on the daily MVCT studies of each patient. Adapted plans were created using merged MVCT-kilovoltage CT image sets to investigate the advantages …

Esophageal Cancer, Edward Yu

Oncology Publications

No abstract provided.