Grand River Regional Cancer Center

Kitchener, Canada

Grand River Regional Cancer Center

Kitchener, Canada
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Chow J.,Princess Margaret Hospital | Jiang R.,Grand River Regional Cancer Center
Medical Physics | Year: 2013

Purpose: This study compared the dosimetric impact between prostate intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) when patient weight loss occurs, which resulted in a reduction of external contour in the course of treatment. Methods: Six prostate patients were planned by the 7‐beam IMRT and VMAT technique using the same set of target and critical organ dose‐volume criteria and prescription dose per fraction (79 Gy per 39 fractions). Based on the original plan, doses in IMRT and VMAT plans were recalculated with the external contour of the patient reduced by 0.5–2 cm anteriorly and laterally to mimic the patient size reduction. Dose coverage and dose‐volume points of the targets and critical organs (rectum, bladder and femoral heads) were compared between IMRT and VMAT. Results: It is found in IMRT plans that increases of the D99% (target volume having 99% of the prescription dose) in PTV and CTV were 4.0 +/− 0.1% per cm of the reduced depth, which were higher than those in VMAT plans (2.7 +/−0.24% per cm). For increases of the D30% in rectum and bladder, 4.0 +/− 0.2% per cm and 3.5 +/− 0.5% per cm were found in IMRT plans, which were higher than those of VMAT (2.2 +/− 0.2% per cm and 2.0 +/−0.6% per cm), respectively. The increase of the D5% in right femoral head for IMRT (3.7 +/− 0.1% per cm) was also found higher than VMAT (3.3 +/− 0.1% per cm). Conclusion: For increases of dose‐volume criteria of critical organs in IMRT plans, it is concluded that VMAT would be preferred to IMRT in prostate radiotherapy, when a patient has potentials to have weight loss in the treatment. © 2013, American Association of Physicists in Medicine. All rights reserved.

Knight G.,Grand River Regional Cancer Center | Earle C.C.,Odette Cancer Center | Cosby R.,McMaster University | Coburn N.,Odette Cancer Center | And 3 more authors.
Gastric Cancer | Year: 2013

Background: Gastric cancer is a global health problem accounting for 10% of all new cancer cases and 12% of all cancer deaths worldwide. Many clinical trials and meta-analyses have explored the value of neoadjuvant or adjuvant chemotherapy and radiation therapy in gastric cancer; however, these studies have produced conflicting results. The purpose of this guidance document was to determine whether patients with resectable gastric cancer should receive neoadjuvant or adjuvant therapy in addition to surgery. Outcomes of interest were overall survival, disease-free survival, and adverse events. Methods: A systematic review was undertaken to inform recommendations regarding neoadjuvant and adjuvant therapy in resectable gastric cancer in Ontario, Canada. MEDLINE and EMBASE databases, as well as American Society of Clinical Oncology (ASCO) annual meeting proceedings and American Society for Therapeutic Radiology and Oncology (ASTRO) proceedings were systematically searched from 2002 to 2010. Oral fluoropyrimidine trials were excluded owing to the unavailability of these agents in North America. Results: Overall, 22 randomized controlled trials (RCTs), 13 meta-analyses, and two secondary analyses were included. The systematic review informed the development of a clinical practice guideline with the following recommendations. Postoperative 5-fluorouracil-based chemoradiotherapy based on the Macdonald approach or perioperative ECF (epirubicin, cisplatin, fluorouracil) chemotherapy based on the Cunningham/MAGIC (Medical Research Council Adjuvant Gastric Infusional Chemotherapy) approach are both acceptable standards of care in North America. Choice of treatment should be made on a case-by-case basis. Adjuvant chemotherapy is a reasonable option for those patients for whom the Macdonald and MAGIC protocols are contraindicated. All patients with resectable gastric cancer should undergo a pretreatment multidisciplinary assessment to determine the best plan of care. Conclusions: Overall survival in patients with resectable gastric cancer is significantly improved with the use of either postoperative chemoradiation (Macdonald approach) or perioperative ECF (MAGIC protocol). © 2012 The International Gastric Cancer Association and The Japanese Gastric Cancer Association.

Crump M.,University of Toronto | Herst J.,Northeastern Ontario Regional Cancer Center | Baldassarre F.,McMaster University | Sussman J.,Juravinski Cancer Center | And 3 more authors.
Blood | Year: 2015

Case 1. Anne is a 23-year-old nursing student who presents with bilateral cervical, left supraclavicular, and left axillary adenopathy. Computed tomography (CT) scan of the thorax reveals a 6-cm anterior mediastinal mass. Biopsy of the left supraclavicular lymph node reveals classical nodular sclerosis Hodgkin lymphoma. A complete blood count is normal and the erythrocyte sedimentation rate (ESR) is 25 mm/h. CT scan of the abdomen/pelvis show normal liver and spleen and no evidence of abdominal lymphadenopathy. You are asked to advise her on the role of radiation therapy in her treatment plan. Case 2. John is a 48-year-old teacher who presents with chest pain following a hockey game. A chest radiograph reveals mediastinal widening, and a contrast-enhancedCT scan shows a 7.5-cm anterior mediastinalmass, with enlarged paratracheal and right hilar lymph nodes. Image-guided core biopsy of the mediastinal mass is diagnostic for classical Hodgkin lymphoma. The hemoglobin is 130 g/L, white blood cell count and platelets are normal, and the ESR is 35 mm/h. John asks you about the role of radiotherapy in the management of his lymphoma. © 2015 by The American Society of Hematology.

Gao X.,University of Waterloo | Kang Q.S.,University of Waterloo | Yeow J.T.W.,University of Waterloo | Barnett R.,University of Waterloo | Barnett R.,Grand River Regional Cancer Center
Nanotechnology | Year: 2010

The extraordinary physical properties of quantum dot (QD) materials such as high radiation sensitivity and good radiation resistivity indicate their potential for use in the fabrication of radiation sensors. This paper reports the design and fabrication of two kinds of radiation sensors based on ZnO and CdTe QDs. Both sensors are characterized using a Gulmay Medical D3000DXR unit for superficial x-ray irradiation with source photon energies that range from 36.9 to 64.9keV. The QD radiation sensors exhibit excellent linearity with respect to different photon energy doses, radiation source to device surface distances, and field sizes. The effects of the electrode separation and the area density of the QD layer are also investigated. All sensors characterized show an outstanding repeatability under photon irradiation, with a signal variation less than 1%. © 2010 IOP Publishing Ltd.

Nambiar S.,University of Waterloo | Osei E.K.,University of Waterloo | Osei E.K.,Grand River Regional Cancer Center | Yeow J.T.W.,University of Waterloo
Journal of Applied Polymer Science | Year: 2013

Lead is commonly used in medical radiology departments as a shielding material. Lead-based protective materials are also used by clinical personnel during X-ray image-guided interventional radiology (IVR) procedures. However, lead is extremely toxic and prolonged exposure to it can result in serious health concerns. Polymer composites, on the other hand, can be designed to be lead-free in addition to being lightweight, conformable, cost effective, and potentially capable of significantly attenuating X-rays. Nanomaterials have unique material properties that can be exploited to develop novel lead-free radiation-protection materials. In this study, polydimethylsiloxane (PDMS) nanocomposites were fabricated using different weight percentages (wt %) of bismuth oxide (BO) nanopowder. The attenuation properties of the nanocomposites were characterized using diagnostic X-ray energies from 40 to 150 kV tube potential and were compared to the attenuation characteristics of 0.25-mm-thick pure lead sheet. The PDMS/BO nanocomposite (44.44 wt% of BO and 3.73-mm thick) was capable of attenuating all the scattered X-rays generated at a tube potential of 60 kV, which is the beam energy commonly employed in IVR. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013 Copyright © 2012 Wiley Periodicals, Inc.

Chow J.C.L.,University of Toronto | Jiang R.,Grand River Regional Cancer Center | Jiang R.,University of Waterloo
Reports of Practical Oncology and Radiotherapy | Year: 2013

Aim: This study compared the dosimetric impact between prostate IMRT and VMAT due to patient's weight loss. Background: Dosimetric variation due to change of patient's body contour is difficult to predict in prostate IMRT and VMAT, since a large number of small and irregular segmental fields is used in the delivery. Materials and methods: Five patients with prostate volumes ranging from 32.0 to 86.5cm3 and a heterogeneous pelvis phantom were used for prostate IMRT and VMAT plans using the same set of dose-volume constraints. Doses in IMRT and VMAT plans were recalculated with the patient's and phantom's body contour reduced by 0.5-2cm to mimic size reduction. Dose coverage/criteria of the PTV and CTV and critical organs (rectum, bladder and femoral heads) were compared between IMRT and VMAT. Results: In IMRT plans, increases of the D99% for the PTV and CTV were equal to 4.0 ± 0.1% per cm of reduced depth, which were higher than those in VMAT plans (2.7 ± 0.24% per cm). Moreover, increases of the D30% of the rectum and bladder per reduced depth in IMRT plans (4.0 ± 0.2% per cm and 3.5 ± 0.5% per cm) were higher than those of VMAT (2.2 ± 0.2% per cm and 2.0 ± 0.6% per cm). This was also true for the increase of the D5% for the right femoral head in a patient or phantom with size reduction due to weight loss. Conclusions: VMAT would be preferred to IMRT in prostate radiotherapy, when a patient has potential to suffer from weight loss during the treatment. © 2013.

Ahmadi M.,University of Waterloo | Osei E.K.,University of Waterloo | Osei E.K.,Grand River Regional Cancer Center | Yeow J.T.W.,University of Waterloo
Sensors and Actuators, B: Chemical | Year: 2012

Bacteriorhodopsin is a proton-pump protein in the cell membrane of Halobacterium salinarium. Unlike many other biomaterials, bacteriorhodopsin keeps most of its physical, chemical and electrical properties in the dry thin film form. This makes bacteriorhodopsin an excellent candidate for fabrication of electro-mechanical devices in the scale of micrometer and possibly nanometer. In this paper, we report on employing a film of dry oriented bacteriorhodopsin for sensing kilovoltage (kV) energy X-ray beam. © 2012 Elsevier B.V. All rights reserved.

Chow J.C.L.,University of Toronto | Jiang R.,Grand River Regional Cancer Center | Jiang R.,University of Waterloo
Medical Dosimetry | Year: 2013

This study investigated the dosimetric variations of the target and critical organs of patients who had weight loss associated with prostate volumetric-modulated arc therapy (VMAT). Five patients with prostate volumes ranging from 32-86.5 cm3 were selected from a group of 30 patients. Prostate VMAT plans were carried out on each patient using the 6-MV photon beam with a single 360° arc. Decrease of patient size as a result of weight loss was mimicked by contracting the patient's external contour in the anterior, left, and right directions with depths from 0.5-2 cm. Soft tissue excluded by the contracted external contour was replaced by air and the dose distribution was recalculated using the same beam geometry and dose prescription. Dose-volume histograms and dose-volume points such as D99% and D5% for the planning target volume (PTV), clinical target volume (CTV), rectum, bladder, and femoral heads were calculated with variations of reduced depth. In addition, the minimum, maximum, and mean doses for the target and critical organs were determined. PTV and CTV D99% were found to have increased 2.86 ± 0.30% per cm and 2.75 ± 0.38% per cm of reduced depth ranging from 0.5-2 cm. Moreover, the rectal and bladder D30% increased 2.20 ± 0.20% per cm and 2.31 ± 0.83% per cm, and the femoral head D5% increased 3.30 ± 0.11% per cm of reduced depth. Results from variations of the minimum, maximum, and mean doses of the PTV, CTV, rectum, bladder, and femoral heads showed that there was a >5% increase of dose when the reduced depth reached 2 cm. This study provided dosimetry estimation for radiation oncology staff to justify dose variations of the target and critical organs when patients' weight loss occurred in prostate VMAT. Dose variations >5% were seen when the patients' reduced depth was equal to 2 cm. © 2013 American Association of Medical Dosimetrists.

Gu C.-S.,Hamilton Health Sciences | Law C.H.,Sunnybrook Health science Center and Odette Cancer Center | Tandan V.R.,Hamilton Health Sciences | Hart R.,St Josephs Health Center | And 10 more authors.
JAMA - Journal of the American Medical Association | Year: 2014

IMPORTANCE: Patients with colorectal cancer with liver metastases undergo hepatic resection with curative intent. Positron emission tomography combined with computed tomography (PET-CT) could help avoid noncurative surgery by identifying patients with occult metastases. OBJECTIVES: To determine the effect of preoperative PET-CT vs no PET-CT (control) on the surgical management of patients with resectable metastases and to investigate the effect of PET-CT on survival and the association between the standardized uptake value (ratio of tissue radioactivity to injected radioactivity adjusted by weight) and survival. DESIGN, SETTING, AND PARTICIPANTS: A randomized trial of patients older than 18 years with colorectal cancer treated by surgery, with resectable metastases based on CT scans of the chest, abdomen, and pelvis within the previous 30 days, and with a clear colonoscopy within the previous 18 months was conducted between 2005 and 2013, involving 21 surgeons at 9 hospitals in Ontario, Canada, with PET-CT scanners at 5 academic institutions. INTERVENTIONS: Patients were randomized using a 2 to 1 ratio to PET-CT or control. MAIN OUTCOMES AND MEASURES: The primary outcomewas a change in surgical management defined as canceled hepatic surgery, more extensive hepatic surgery, or additional organ surgery based on the PET-CT. Survival was a secondary outcome. RESULTS: Of the 263 patients who underwent PET-CT, 21 had a change in surgical management (8.0%; 95% CI, 5.0%-11.9%). Specifically, 7 patients (2.7%) did not undergo laparotomy, 4 (1.5%) had more extensive hepatic surgery, 9 (3.4%) had additional organ surgery (8 of whom had hepatic resection), and the abdominal cavity was opened in 1 patient but hepatic surgery was not performed and the cavity was closed. Liver resection was performed in 91% of patients in the PET-CT group and 92%of the control group. After a median follow-up of 36 months, the estimated mortality rate was 11.13 (95% CI, 8.95-13.68) events/1000 person-months for the PET-CT group and 12.71 (95% CI, 9.40-16.80) events/1000 person-months for the control group. Survival did not differ between the 2 groups (hazard ratio, 0.86 [95% CI, 0.60-1.21]; P = .38). The standardized uptake value was associated with survival (hazard ratio, 1.11 [90% CI, 1.07-1.15] per unit increase; P < .001). The C statistic for the model including the standardized uptake value was 0.62 (95% CI, 0.56-0.68) and without it was 0.50 (95% CI, 0.44-0.56). The difference in C statistics is 0.12 (95% CI, 0.04-0.21). The low C statistic suggests that the standard uptake value is not a strong predictor of overall survival. CONCLUSIONS AND RELEVANCE: Among patients with potentially resectable hepatic metastases of colorectal adenocarcinoma, the use of PET-CT compared with CT alone did not result in frequent change in surgical management. These findings raise questions about the value of PET-CT scans in this setting. Copyright 2014 American Medical Association. All rights reserved.

Chow J.C.L.,University of Toronto | Chow J.C.L.,Ryerson University | Jiang R.,Grand River Regional Cancer Center | Leung M.K.K.,University of Toronto
Journal of Applied Clinical Medical Physics | Year: 2011

Although there are many works on evaluating dose calculations of the anisotropic analytical algorithm (AAA) using various homogeneous and heterogeneous phantoms, related work concerning dosimetry due to tangential photon beam is lacking. In this study, dosimetry predicted by the AAA and collapsed cone convolution (CCC) algorithm was evaluated using the tangential photon beam and phantom geometry. The photon beams of 6 and 15 MV with field sizes of 4 × 4 (or 7 × 7), 10 × 10 and 20 × 20 cm 2, produced by a Varian 21 EX linear accelerator, were used to test performances of the AAA and CCC using Monte Carlo (MC) simulation (EGSnrc-based code) as a benchmark. Horizontal dose profiles at different depths, phantom skin profiles (i.e., vertical dose profiles at a distance of 2 mm from the phantom lateral surface), gamma dose distributions, and dose-volume histograms (DVHs) of skin slab were determined. For dose profiles at different depths, the CCC agreed better with doses in the air-phantom region, while both the AAA and CCC agreed well with doses in the penumbra region, when compared to the MC. Gamma evaluations between the AAA/CCC and MC showed that deviations of 2D dose distribution occurred in both beam edges in the phantom and air-phantom interface. Moreover, the gamma dose deviation is less significant in the air-phantom interface than the penumbra. DVHs of skin slab showed that both the AAA and CCC underestimated the width of the dose drop-off region for both the 6 and 15MV photon beams. When the gantry angle was 0°, it was found that both the AAA and CCC overestimated doses in the phantom skin profiles compared to the MC, with various photon beam energies and field sizes. The mean dose differences with doses normalized to the prescription point for the AAA and CCC were respectively: 7.6%±2.6% and 2.1% ± 1.3% for a 10 × 10 cm 2 field, 6 MV; 16.3%± 2.1% and 6.7% ± 2.1% for a 20 × 20 cm 2 field, 6 MV; 5.5% ± 1.2% and 1.7% ± 1.4% for a 10 × 10 cm 2, 15 MV; 18.0% ± 1.3% and 8.3% ± 1.8% for a 20×20 cm 2, 15 MV. However, underestimations of doses in the phantom skin profile were found with small fields of 4 × 4 and 7 × 7 cm 2 for the 6 and 15 MV photon beams, respectively, when the gantry was turned 5° anticlockwise. As surface dose with tangential photon beam geometry is important in some radiation treatment sites such as breast, chest wall and sarcoma, it is found that neither of the treatment planning system algorithms can predict the dose well at depths shallower than 2 mm. The dosimetry data and beam and phantom geometry in this study provide a better knowledge of a dose calculation algorithm in tangential-like irradiation.

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