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Pai H.H.,Cancer Agency Vancouver Island Center | Lau F.,University of Victoria | Barnett J.,Cancer Agency Vancouver Island Center | Jones S.,Flinders University
Current Oncology | Year: 2013

Background There is interest in the use of health information technology in the form of personal health record (PHR) systems to support patient needs for health information, care, and decision-making, particularly for patients with distressing, chronic diseases such as prostate cancer (PCa). We sought feedback from PCa patients who used a PHR. Methods For 6 months, 22 PCa patients in various phases of care at the BC Cancer Agency (BCCA) were given access to a secure Web-based PHR called PROVIDER, which they could use to view their medical records and use a set of support tools. Feedback was obtained using an end-of-study survey on usability, satisfaction, and concerns with PROVIDER. Site activity was recorded to assess usage patterns. Results Of the 17 patients who completed the study, 29% encountered some minor difficulties using PROVIDER. No security breaches were known to have occurred. The two most commonly accessed medical records were laboratory test results and transcribed doctor's notes. Of survey respondents, 94% were satisfied with the access to their medical records, 65% said that PROVIDER helped to answer their questions, 77% felt that their privacy and confidentiality were preserved, 65% felt that using PROVIDER helped them to communicate better with their physicians, 83% found new and useful information that they would not have received by talking to their health care providers, and 88% said that they would continue to use PROVIDER. Conclusions Our results support the notion that phrs can provide cancer patients with timely access to their medical records and health information, and can assist in communication with health care providers, in knowledge generation, and in patient empowerment. © 2013 Multimed Inc.

Matthews Q.,University of Victoria | Brolo A.G.,University of Victoria | Lum J.,Cancer Agency Vancouver Island Center | Duan X.,Cancer Agency Vancouver Island Center | Jirasek A.,University of Victoria
Physics in Medicine and Biology | Year: 2011

This work investigates the capability of Raman spectroscopy (RS) to study the effects of ionizing radiation on single human tumour cells. Prostate tumour cells (cell line DU145) are cultured in vitro and irradiated to doses between 15 and 50 Gy with single fractions of 6 MV photons. Single-cell Raman spectra are acquired from irradiated and unirradiated cultures up to 5 days post-irradiation. Principal component analysis is used to distinguish the uniquely radiation-induced spectral changes from inherent sources of spectral variability arising from cell cycle differences and other known factors. We observe uniquely radiation-induced spectral changes which are correlated with both the irradiated dose and the incubation time post-irradiation. The spectral changes induced by radiation arise from biochemical differences in lipids, nucleic acids, amino acids and conformational protein structures between irradiated and unirradiated cells. To our knowledge, this study is the first use of RS to observe radiation-induced biochemical differences in single cells, and is the first use of vibrational spectroscopy to observe uniquely radiation-induced biochemical differences in single cells independent of concurrent cell-cycle- or cell-death-related processes. © 2011 Institute of Physics and Engineering in Medicine.

Nesslinger N.J.,Cancer Agency Vancouver Island Center | Ng A.,Cancer Agency Vancouver Island Center | Tsang K.-Y.,U.S. National Cancer Institute | Ferrara T.,U.S. National Cancer Institute | And 5 more authors.
Clinical Cancer Research | Year: 2010

Purpose: We previously reported a randomized phase II clinical trial combining a poxvirus-based vaccine encoding prostate-specific antigen (PSA) with radiotherapy in patients with localized prostate cancer. Here, we investigate whether vaccination against PSA induced immune responses to additional tumor-associated antigens and how this influenced clinical outcome. Experimental Design: Pretreatment and posttreatment serum samples from patients treated with vaccine + external beam radiation therapy (EBRT) versus EBRT alone were evaluated by Western blot and serologic screening of a prostate cancer cDNA expression library (SEREX) to assess the development of treatment-associated autoantibody responses. Results: Western blotting revealed treatment-associated autoantibody responses in 15 of 33 (45.5%) patients treated with vaccine + EBRT versus 1 of 8 (12.5%) treated with EBRT alone. SEREX screening identified 18 antigens, which were assembled on an antigen array with 16 previously identified antigens. Antigen array screening revealed that 7 of 33 patients (21.2%) treated with vaccine + EBRT showed a vaccine-associated autoantibody response to four ubiquitously expressed self-antigens: DIRC2, NDUFS1, MRFAP1, and MATN2. These responses were not seen in patients treated with EBRT alone, or other control groups. Patients with autoantibody responses to this panel of antigens had a trend toward decreased biochemical-free survival. Conclusions: Vaccine + EBRT induced antigen spreading in a large proportion of patients. A subset of patients developed autoantibodies to a panel of four self-antigens and showed a trend toward inferior outcomes. Thus, cancer vaccines directed against tumor-specific antigens can trigger autoantibody responses to self-proteins, which may influence the efficacy of vaccination. ©2010 AACR.

Zavgorodni S.,Cancer Agency Vancouver Island Center | Zavgorodni S.,University of Victoria | Alhakeem E.,Cancer Agency Vancouver Island Center | Alhakeem E.,University of Victoria | And 2 more authors.
Physics in Medicine and Biology | Year: 2014

Linac backscattered radiation (BSR) into the monitor chamber affects the chamber's signal and has to be accounted for in radiotherapy dose calculations. In Monte Carlo (MC) calculations, the BSR can be modelled explicitly and accounted for in absolute dose. However, explicit modelling of the BSR becomes impossible if treatment head geometry is not available. In this study, monitor backscatter factors (MBSFs), defined as the ratio of the charge collected in the monitor chamber for a reference field to that of a given field, have been evaluated experimentally and incorporated into MC modelling of linacs with either known or unknown treatment head geometry. A telescopic technique similar to that by Kubo (1989 Med. Phys. 16 295-98) was used. However, instead of lead slits, a 1.8 mm diameter collimator and a small (2 mm diameter) detector positioned at extended source to detector distance were used. This setup provided a field of view to the source of less than 3.1 mm and allowed for MBSF measurements of open fields from 1 × 1 to 40 × 40 cm2. For the fields with both X and Y dimensions exceeding 15 cm, a diode detector was used. A pinpoint ionization chamber was used for smaller fields. MBSFs were also explicitly modelled in MC calculations using BEAMnrc and DOSXYZnrc codes for 6 and 18 MV beams of a Varian 21EX linac. A method for deriving the values that are used in MC absolute dose calculations was demonstrated. These values were derived from measured MBSFs for two 21EX and four TrueBeam energies. MBSFs were measured for 6 and 18 MV beams from Varian 21EX, and for 6 MV, 10 MV-FFF, 10 MV, and 15 MV beams from Varian TrueBeam linacs. For the open field sizes modelled in this study for the 21EX, the measured MBSFs agreed with MC calculated values within combined statistical (0.4%) and experimental (0.2%) uncertainties. Variation of MBSFs across field sizes was about a factor of two smaller for the TrueBeam compared to 21EX Varian linacs. Measured MBSFs and the derived factors allow for the incorporation of the BSR effect into accurate radiotherapy dose calculations without explicit backscatter modelling. © 2014 Institute of Physics and Engineering in Medicine.

Jirasek A.,University of Victoria | Hilts M.,Cancer Agency Vancouver Island Center | McAuley K.B.,Queen's University
Physics in Medicine and Biology | Year: 2010

A primary limitation of current x-ray CT polymer gel dosimetry is the low contrast, and hence poor dose resolution, of dose images produced by the system. The low contrast is largely due to the low-dose sensitivity of current formulations of polymer gel for x-ray CT imaging. This study reports on the investigation of new dosimeter formulations with improved dose sensitivity for x-ray CT polymer gel dosimetry. We incorporate an isopropanol co-solvent into an N-isopropylacrylamide-based gel formulation in order to increase the total monomer/crosslinker concentration %T) within the formulation. It is shown that gels of high %T exhibit enhanced dose sensitivity and dose resolutions over traditional formulations. The gels are shown to be temporally stable and reproducible. A single formulation 16%T) is used to demonstrate the capabilities of the x-ray CT polymer gel dosimetry system in measuring known dose distributions. A 1 L gel volume is exposed to three separate irradiations: a single-field percent depth dose, a two-field 'cross' and a three-field 'test case'. The first two irradiations are used to generate a dose calibration curve by which images are calibrated. The calibrated images are compared with treatment planning predictions and it is shown that the x-ray CT polymer gel dosimetry system is capable of capturing spatial and dose information accurately. The proposed new gel formulation is shown to be sensitive, stable and to improve the dose resolution over current formulations so as to provide a feasible gel for clinical applications of x-ray CT polymer gel dosimetry. © 2010 Institute of Physics and Engineering in Medicine.

Johnston H.,University of Victoria | Hilts M.,University of Victoria | Hilts M.,Cancer Agency Vancouver Island Center | Carrick J.,University of Victoria | Jirasek A.,University of Victoria
Physics in Medicine and Biology | Year: 2012

This article reports on the dosimetric properties of a new N-isopropylacrylamide, high %T, polymer gel formulation (19.5%T, 23%C), optimized for x-ray computed tomography (CT) polymer gel dosimetry (PGD). In addition, a new gel calibration technique is introduced together with an intensity-modulated radiation therapy (IMRT) treatment validation as an example of a clinical application of the new gel dosimeter. The dosimetric properties investigated include the temporal stability, spatial stability, batch reproducibility and dose rate dependence. The polymerization reaction is found to stabilize after 15 h post-irradiation. Spatial stability investigations reveal a small overshoot in response for gels imaged later than 36 h post-irradiation. Based on these findings, it is recommended that the new gel formulation be imaged between 1536 h after irradiation. Intra- and inter-batch reproducibility are found to be excellent over the entire range of doses studied (028 Gy). A significant dose rate dependence is found for gels irradiated between 100600 MUmin 1. Overall, the new gel is shown to have promising characteristics for CT PGD, however the implication of the observed dose rate dependence for some clinical applications remains to be determined. The new gel calibration method, based on pixel-by-pixel matching of dose and measured CT numbers, is found to be robust and to agree with the previously used region of interest technique. Pixel-by-pixel calibration is the new recommended standard for CT PGD. The dose resolution for the system was excellent, ranging from 0.20.5 Gy for doses between 020 Gy and 0.30.6 Gy for doses beyond 20 Gy. Comparison of the IMRT irradiation with planned doses yields excellent results: gamma pass rate (3%, 3 mm) of 99.3% at the isocentre slice and 93.4% over the entire treated volume. © 2012 Institute of Physics and Engineering in Medicine.

Jirasek A.,University of Victoria | Carrick J.,University of Victoria | Hilts M.,Cancer Agency Vancouver Island Center
Physics in Medicine and Biology | Year: 2012

In this study a new x-ray CT polymer gel dosimetry (PGD) filtering technique is presented for the removal of (i) remnant ring and streak artefacts, and (ii) structured noise in the form of minute, intrinsic gel density fluctuations. It is shown that the noise present within x-ray CT PGD images is not purely stochastic (pixel by pixel) in nature, but rather is structured, and hence purely stochastic-based noise-removal filters fail in removing this significant, unwanted noise component. The remnant artefact removal (RAR) technique is based on a class of signal stripping (i.e. baseline-estimation) algorithms typically used in the estimation of unwanted non-uniform baselines underlying spectral data. Here the traditional signal removal algorithm is recast, whereby the signal that is removed is the structured noise and remnant artefacts, leaving the desired polymer gel dose distribution. The algorithm is extended to 2D and input parameters are optimized for PGD images. RAR filter results are tested on (i) synthetic images with measured gel background images added, in order to accurately represent actual noise present in PGD images, and (ii) PGD images of a three-field gel irradiation. RAR results are compared to a top-performing noise filter (adaptive mean, AM), used in previous x-ray CT PGD studies. It is shown that, in all cases, the RAR filter outperforms the AM filter, particularly in cases where either (i) a low-dose gel image has been acquired or (ii) the signal-to-noise ratio of the PG image is low, as in the case when a low number of image averages are acquired within a given experiment. Guidelines for the implementation of the RAR filter are given. © 2012 Institute of Physics and Engineering in Medicine.

Han K.,Odette Cancer Center | Cheung P.,Odette Cancer Center | Basran P.S.,Cancer Agency Vancouver Island Center | Poon I.,Odette Cancer Center | And 2 more authors.
Radiotherapy and Oncology | Year: 2010

Purpose: This study aims to compare the efficacy, efficiency and comfort level of two immobilization systems commonly used in lung stereotactic body radiation therapy (SBRT): the Bodyfix and the abdominal compression plate (ACP). Materials and methods: Twenty-four patients undergoing SBRT for medically inoperable stage I lung cancer or pulmonary metastases were entered on this prospective randomized study. All underwent 4DCT simulation with free breathing, the Bodyfix, and the ACP to assess respiratory tumor motion. After CT simulation, patients were randomly assigned to immobilization with either the Bodyfix or the ACP for the actual SBRT treatment. Cone beam CTs (CBCTs) were acquired before and after each treatment to assess intrafraction tumor motion. Setup time and patient comfort were recorded. Results: There were 16 upper lobe, two middle lobe and seven lower-lobe lesions. Both the Bodyfix and the ACP significantly reduced the superior-inferior (SI) and overall respiratory tumor motion compared to free breathing (4.6 and 4.0 vs 5.3 mm; 5.3 and 4.7 vs 6.1 mm, respectively, p < 0.05). The ACP further reduced the SI and overall respiratory tumor motion compared to the Bodyfix (p < 0.05). The mean overall intrafraction tumor motion was 2.3 mm with the Bodyfix and 2.0 mm with the ACP (p > 0.05). The ACP was faster to set up and rated more comfortable by patients than the Bodyfix (p < 0.05). Conclusions: While there is no significant difference between the Bodyfix and ACP in reducing intrafraction tumor motion, the ACP is more comfortable, faster to set up, and superior to the Bodyfix in reducing SI and overall respiratory tumor motion. © 2010 Elsevier Ireland Ltd. All rights reserved.

Whelan T.J.,McMaster University | Olivotto I.A.,Tom Baker Cancer Center | Olivotto I.A.,Cancer Agency Vancouver Island Center | Parulekar W.R.,Queen's University | And 20 more authors.
New England Journal of Medicine | Year: 2015

Background Most women with breast cancer who undergo breast-conserving surgery receive wholebreast irradiation. We examined whether the addition of regional nodal irradiation to whole-breast irradiation improved outcomes. Methods We randomly assigned women with node-positive or high-risk node-negative breast cancer who were treated with breast-conserving surgery and adjuvant systemic therapy to undergo either whole-breast irradiation plus regional nodal irradiation (including internal mammary, supraclavicular, and axillary lymph nodes) (nodalirradiation group) or whole-breast irradiation alone (control group). The primary outcome was overall survival. Secondary outcomes were disease-free survival, isolated locoregional disease-free survival, and distant disease-free survival. Results Between March 2000 and February 2007, a total of 1832 women were assigned to the nodal-irradiation group or the control group (916 women in each group). The median follow-up was 9.5 years. At the 10-year follow-up, there was no significant between-group difference in survival, with a rate of 82.8% in the nodal-irradiation group and 81.8% in the control group (hazard ratio, 0.91; 95% confidence interval [CI], 0.72 to 1.13; P = 0.38). The rates of disease-free survival were 82.0% in the nodal-irradiation group and 77.0% in the control group (hazard ratio, 0.76; 95% CI, 0.61 to 0.94; P = 0.01). Patients in the nodal-irradiation group had higher rates of grade 2 or greater acute pneumonitis (1.2% vs. 0.2%, P = 0.01) and lymphedema (8.4% vs. 4.5%, P = 0.001). Conclusions Among women with node-positive or high-risk node-negative breast cancer, the addition of regional nodal irradiation to whole-breast irradiation did not improve overall survival but reduced the rate of breast-cancer recurrence. © 2015 Massachusetts Medical Society.

Vlachaki M.T.,Cancer Agency Vancouver Island Center
Journal of applied clinical medical physics / American College of Medical Physics | Year: 2010

Radiation therapy for advanced Hodgkin's disease often requires large fields and may result in significant exposure of normal tissues to ionizing radiation. In long-term survivors, this may increase the risk for late toxicity including secondary malignancies. 3DCRT has been successfully used to treat this disease but treatment delivery is often complex requiring matching of photon with electron beams, utilization of field-in-field techniques and of partial transmission blocks. HT is an arc-rotational intensity modulated radiation therapy technique proven to achieve superior target dose conformality and sharp dose gradients around critical normal tissues. HT however, has also been associated with higher volumes of low dose regions in normal tissues and therefore, higher integral dose. The present study was undertaken to compare the dosimetry of 3DCRT to HT in a pediatric patient with advanced HD. Clinical target volume (CTV) included bilateral lower cervical and supraclavicular areas, mediastinum, bilateral hili, left axilla and bilateral diaphragmatic lymph nodes. The planning target volume (PTV) was derived by circumferentially expanding the CTV by 1 cm. Whole lung and heart irradiation was also planned due to bilateral pleural and pericardial effusions. The prescribed radiation dose was 21 Gy to the PTV and 10.5 Gy to the whole lung and heart. Target coverage was comparable for both plans. The minimum, maximum and mean PTV doses were 18.61 Gy, 22.45 Gy and 21.52 Gy with 3DCRT and 19.85 Gy, 22.36 Gy and 21.39 Gy with HT, respectively. HT decreased mean normal tissue dose by 21.6% and 20.07% for right and left breast, 20.40% for lung, 30.78% for heart and 22.74% for the thyroid gland. Integral dose also decreased with HT by 46.50%. HT results in significant dosimetric gain related to normal tissue sparing compared to 3DCRT. Further studies are warranted to evaluate clinical applications of HT in patients with HD.

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