Time filter

Source Type

Brigham City, United States

Arvold N.D.,Dana Farber Brigham Womens Cancer Center | Heidari P.,Massachusetts General Hospital | Kunawudhi A.,Massachusetts General Hospital | Sequist L.V.,Massachusetts General Hospital | Mahmood U.,Massachusetts General Hospital
Technology in Cancer Research and Treatment | Year: 2016

Hypoxia is associated with resistance to radiotherapy and chemotherapy. Functional imaging of hypoxia in non-small cell lung cancer (NSCLC) could allow early assessment of tumor response and guide subsequent therapies. Epidermal growth factor receptor (EGFR) inhibition with erlotinib reduces hypoxia in vivo. [18F]-Fluoromisonidazole (FMISO) is a radiolabeled tracer that selectively accumulates in hypoxic cells. We sought to determine whether FMISO positron emission tomography (FMISO-PET) could detect changes in hypoxia in vivo in response to EGFR-targeted therapy. In a preclinical investigation, nude mice with human EGFR-mutant lung adenocarcinoma xenografts underwent FMISO-PET scans before and 5 days after erlotinib or empty vehicle initiation. Descriptive statistics and analysis of variance (ANOVA) tests were used to analyze changes in standardized uptake value (SUV), with pooled analyses for the mice in each group (baseline, postvehicle, and posterlotinib). In a small correlative pilot human study, patients with EGFR-mutant metastatic NSCLC underwent FMISO-PET scans before and 10 to 12 days after erlotinib initiation. Changes in SUV were compared to standard chest computed tomography (CT) scans performed 6 weeks after erlotinib initiation. The mean (±standard error of the mean; SUVmean) of the xenografts was 0.17 ± 0.014, 0.14 ± 0.008, and 0.06 ± 0.004 for baseline, postvehicle, and posterlotinib groups, respectively, with lower SUVmean among the posterlotinib group compared to other groups (P <.05). Changes on preclinical PET imaging were striking, with near-complete disappearance of FMISO uptake after erlotinib initiation. Two patients were enrolled on the pilot study. In the first patient, SUVmean increased by 21% after erlotinib, with progression on 6-week chest CT followed by death after 4.8 months. In the second patient, SUVmean decreased by 7% after erlotinib, with regression on 6-week chest CT accompanied by clinical improvement; the patient had stable disease at 14.5 months. In conclusion, we observed that FMISO-PET can detect changes in hypoxia levels after EGFR-directed therapy in EGFR-mutant NSCLC. Further study is warranted to determine its utility as an imaging biomarker of early response to EGFR-directed therapy. © 2015, © The Author(s) 2015. Source

Killoran J.H.,Dana Farber Brigham Womens Cancer Center
Journal of applied clinical medical physics / American College of Medical Physics | Year: 2011

For PET/CT, fast CT acquisition time can lead to errors in attenuation correction, particularly at the lung/diaphragm interface. Gated 4D PET can reduce motion artifacts, though residual artifacts may persist depending on the CT dataset used for attenuation correction. We performed phantom studies to evaluate 4D PET images of targets near a density interface using three different methods for attenuation correction: a single 3D CT (3D CTAC), an averaged 4D CT (CINE CTAC), and a fully phase matched 4D CT (4D CTAC). A phantom was designed with two density regions corresponding to diaphragm and lung. An 8 mL sphere phantom loaded with 18F-FDG was used to represent a lung tumor and background FDG included at an 8:1 ratio. Motion patterns of sin(x) and sin4(x) were used for dynamic studies. Image data was acquired using a GE Discovery DVCT-PET/CT scanner. Attenuation correction methods were compared based on normalized recovery coefficient (NRC), as well as a novel quantity "fixed activity volume" (FAV) introduced in our report. Image metrics were compared to those determined from a 3D PET scan with no motion present (3D STATIC). Values of FAV and NRC showed significant variation over the motion cycle when corrected by 3D CTAC images. 4D CTAC- and CINE CTAC-corrected PET images reduced these motion artifacts. The amount of artifact reduction is greater when the target is surrounded by lower density material and when motion was based on sin4(x). 4D CTAC reduced artifacts more than CINE CTAC for most scenarios. For a target surrounded by water equivalent material, there was no advantage to 4D CTAC over CINE CTAC when using the sin(x) motion pattern. Attenuation correction using both 4D CTAC or CINE CTAC can reduce motion artifacts in regions that include a tissue interface such as the lung/diaphragm border. 4D CTAC is more effective than CINE CTAC at reducing artifacts in some, but not all, scenarios. Source

Court L.,Dana Farber Brigham Womens Cancer Center
Journal of applied clinical medical physics / American College of Medical Physics | Year: 2011

The purpose was to evaluate the effect of dose rate on discrepancies between expected and delivered dose caused by the interplay effect. Fifteen separate dynamic IMRT plans and five hybrid IMRT plans were created for five patients (three IMRT plans and one hybrid IMRT plan per patient). The impact of motion on the delivered dose was evaluated experimentally for each treatment field for different dose rates (200 and 400 MU/min), and for a range of target amplitudes and periods. The maximum dose discrepancy for dynamic IMRT fields was 18.5% and 10.3% for dose rates of 400 and 200 MU/min, respectively. The maximum dose discrepancy was larger than this for hybrid plans, but the results were similar when weighted by the contribution of the IMRT fields. The percentage of fields for which 98% of the target never experienced a 5% or 10% dose discrepancy increased when the dose rate was reduced from 400 MU/min to 200 MU/min. For amplitudes up to 2 cm, reducing the dose rate to 200 MU/min is effective in keeping daily dose discrepancies for each field within 10%. Source

Baldini E.H.,Brigham and Womens Hospital | Bosch W.,Washington University in St. Louis | Kane J.M.,Roswell Park Cancer Institute | Abrams R.A.,Rush University Medical Center | And 11 more authors.
Annals of Surgical Oncology | Year: 2015

Purpose: Curative intent management of retroperitoneal sarcoma (RPS) requires gross total resection. Preoperative radiotherapy (RT) often is used as an adjuvant to surgery, but recurrence rates remain high. To enhance RT efficacy with acceptable tolerance, there is interest in delivering “boost doses” of RT to high-risk areas of gross tumor volume (HR GTV) judged to be at risk for positive resection margins. We sought to evaluate variability in HR GTV boost target volume delineation among collaborating sarcoma radiation and surgical oncologist teams. Methods: Radiation planning CT scans for three cases of RPS were distributed to seven paired radiation and surgical oncologist teams at six institutions. Teams contoured HR GTV boost volumes for each case. Analysis of contour agreement was performed using the simultaneous truth and performance level estimation (STAPLE) algorithm and kappa statistics. Results: HRGTV boost volume contour agreement between the seven teams was “substantial” or “moderate” for all cases. Agreement was best on the torso wall posteriorly (abutting posterior chest abdominal wall) and medially (abutting ipsilateral para-vertebral space and great vessels). Contours varied more significantly abutting visceral organs due to differing surgical opinions regarding planned partial organ resection. Conclusions: Agreement of RPS HRGTV boost volumes between sarcoma radiation and surgical oncologist teams was substantial to moderate. Differences were most striking in regions abutting visceral organs, highlighting the importance of collaboration between the radiation and surgical oncologist for “individualized” target delineation on the basis of areas deemed at risk and planned resection. © 2015, Society of Surgical Oncology. Source

Motzer R.J.,Sloan Kettering Cancer Center | Jonasch E.,University of Texas M. D. Anderson Cancer Center | Agarwal N.,University of Utah | Beard C.,Dana Farber Brigham Womens Cancer Center | And 28 more authors.
JNCCN Journal of the National Comprehensive Cancer Network | Year: 2015

Germ cell tumors (GCTs) account for 95% of testicular cancers. Testicular GCTs constitute the most common solid tumor in men between the ages of 20 and 34 years, and the incidence of testicular GCTs has been increasing in the past 2 decades. Testicular GCTs are classified into 2 broad groups - pure seminoma and nonseminoma - which are treated differently. Pure seminomas, unlike nonseminomas, are more likely to be localized to the testis at presentation. Nonseminoma is the more clinically aggressive tumor associated with elevated serum concentrations of alphafetoprotein (AFP). The diagnosis of a seminoma is restricted to pure seminoma histology and a normal serum concentration of AFP. When both seminoma and elements of a nonseminoma are present, management follows that for a nonseminoma. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Testicular Cancer outline the diagnosis, workup, risk assessment, treatment, and follow-up schedules for patients with both pure seminoma and nonseminoma. © JNCCN - Journal of the National Comprehensive Cancer Network. Source

Discover hidden collaborations