118 research outputs found
Radiation Therapy for Esophageal Cancer
Esophageal cancer develops in the mucosa of the esophagus and spreads toward the muscle layer. The nonsurgical treatment for localized, deeply invasive esophageal cancer has been external beam radiation therapy (EBRT) and concurrent chemotherapy. Recently, intraluminal brachytherapy showed a strong potential for the improvement of the therapeutic ratio. It was found that the fractionated high dose rate (HDR) brachytherapy offered beneficial palliation for a longer period of time with more durable symptom control. A similar was concluded for advanced unresectable esophageal cancer in previously irradiated patients. HDR brachytherapy may be a useful salvage treatment option for inoperable patients diagnosed with local esophageal cancer. Although better local control can be achieved with higher brachytherapy dose, this increases the risk of acute morbidity and late morbidity, especially in the setting of recurrence cancer. It was found that the moderate dose of EBRT and HDR brachytherapy could give a better local response than EBRT alone
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High-dose-rate Interstitial Brachytherapy Boost with a Pedicled Latissimus Dorsi Myocutaneous Flap for Myxofibrosarcoma of the Arm
Summary: A 71-year-old man was found to have a 7.4 × 2.9 × 7.0 cm myxofibrosarcoma of the right medial arm close to neurovascular structures. He received 50 Gray (Gy) of preoperative external beam radiation. Radical resection resulted in a 15 × 10 cm defect. Nine brachytherapy catheters were placed, and a pedicled latissimus dorsi myocutaneous flap was used in reconstruction. Final pathology confirmed myxofibrosarcoma, high grade. The tumor was <1 mm from 2 margins. A total of 17.5 Gy of brachytherapy was delivered to the surgical bed from postoperative days 7 to 9. The flap developed fat necrosis distally which eventually required surgical debridement on postoperative day 58. It subsequently healed well and maintained good function of the limb. The patient remains under surveillance without evidence of recurrence
Galaxy Cluster Pressure Profiles as Determined by Sunyaev Zel'dovich Effect Observations with MUSTANG and Bolocam I: Joint Analysis Technique
We present a technique to constrain galaxy cluster pressure profiles by
jointly fitting Sunyaev-Zel'dovich effect (SZE) data obtained with MUSTANG and
Bolocam for the clusters Abell 1835 and MACS0647. Bolocam and MUSTANG probe
different angular scales and are thus highly complementary. We find that the
addition of the high resolution MUSTANG data can improve constraints on
pressure profile parameters relative to those derived solely from Bolocam. In
Abell 1835 and MACS0647, we find gNFW inner slopes of and , respectively when
and are constrained to 0.86 and 4.67 respectively. The fitted
SZE pressure profiles are in good agreement with X-ray derived pressure
profiles.Comment: 12 pages, 12 figures. Submitted to Ap
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Dose volume histogram analysis of normal structures associated with accelerated partial breast irradiation delivered by high dose rate brachytherapy and comparison with whole breast external beam radiotherapy fields
<p>Abstract</p> <p>Purpose</p> <p>To assess the radiation dose delivered to the heart and ipsilateral lung during accelerated partial breast brachytherapy using a MammoSite™ applicator and compare to those produced by whole breast external beam radiotherapy (WBRT).</p> <p>Materials and methods</p> <p>Dosimetric analysis was conducted on patients receiving MammoSite breast brachytherapy following conservative surgery for invasive ductal carcinoma. Cardiac dose was evaluated for patients with left breast tumors with a CT scan encompassing the entire heart. Lung dose was evaluated for patients in whom the entire lung was scanned. The prescription dose of 3400 cGy was 1 cm from the balloon surface. MammoSite dosimetry was compared to simulated WBRT fields with and without radiobiological correction for the effects of dose and fractionation. Dose parameters such as the volume of the structure receiving 10 Gy or more (V10) and the dose received by 20 cc of the structure (D20), were calculated as well as the maximum and mean doses received.</p> <p>Results</p> <p>Fifteen patients were studied, five had complete lung data and six had left-sided tumors with complete cardiac data. Ipsilateral lung volumes ranged from 925–1380 cc. Cardiac volumes ranged from 337–551 cc. MammoSite resulted in a significantly lower percentage lung V30 and lung and cardiac V20 than the WBRT fields, with and without radiobiological correction.</p> <p>Conclusion</p> <p>This study gives low values for incidental radiation received by the heart and ipsilateral lung using the MammoSite applicator. The volume of heart and lung irradiated to clinically significant levels was significantly lower with the MammoSite applicator than using simulated WBRT fields of the same CT data sets.</p> <p>Trial registration</p> <p>Dana Farber Trial Registry number 03-179</p
Inherent change in MammoSite applicator three-dimensional geometry over time
Accelerated partial breast irradiation is commonly done with the MammoSite applicator, which requires symmetry to treat the patient. This paper describes three cases that were asymmetric when initially placed and became symmetric over time, without manipulation
Src-Mediated EGF Receptor Activation Regulates Ozone-Induced Interleukin 8 Expression in Human Bronchial Epithelial Cells
Background:Human exposure to ozone (O3) results in pulmonary function decrements and airway inflammation. The mechanisms underlying these adverse effects remain unclear. Epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of lung inflammation.ObjectiveWe examined the role of EGFR activation in O3-induced expression of the chemokine interleukin 8 (IL-8) in human bronchial epithelial cells (HBEC).MethodsWe detected phosphorylated EGFR using immunoblotting. EGFR dimerization was examined through cross-linking reaction and immunoblotting, and levels of IL-8 protein were measured using ELISA.ResultsExposure to O3 (0.25–1.0 ppm) induced rapid and marked increase in EGFR phosphorylation at the autophosphorylation site Y1068 and the transphosphorylation site Y845, implicating the involvement of Src kinase. Further investigation showed that O3 stimulation induced phosphorylation of Src at Y416, indicative of Src activation. Pharmacological inhibition of Src kinase activity abrogated O3-induced EGFR phosphorylation at tyrosines 1068 and 845. Moreover, pretreatment of BEAS-2B cells with inhibitor of either EGFR or Src kinase activities significantly blocked O3-induced IL-8 expression.ConclusionConclusion: O3 exposure increased IL-8 expression through Src-mediated EGFR transactivation in HBEC.Citation>Wu W, Wages PA, Devlin RB, Diaz-Sanchez D, Peden DB, Samet JM. 2015. Src-mediated EGF receptor activation regulates ozone-induced interleukin 8 expression in human bronchial epithelial cells. Environ Health Perspect 123:231–236; http://dx.doi.org/10.1289/ehp.130737
MUSTANG 3.3 Millimeter Continuum Observations of Class 0 Protostars
We present observations of six Class 0 protostars at 3.3 mm (90 GHz) using
the 64-pixel MUSTANG bolometer camera on the 100-m Green Bank Telescope. The
3.3 mm photometry is analyzed along with shorter wavelength observations to
derive spectral indices (S_nu ~ nu^alpha) of the measured emission. We utilize
previously published dust continuum radiative transfer models to estimate the
characteristic dust temperature within the central beam of our observations. We
present constraints on the millimeter dust opacity index, beta, between 0.862
mm, 1.25 mm, and 3.3 mm. Beta_mm typically ranges from 1.0 to 2.4 for Class 0
sources. The relative contributions from disk emission and envelope emission
are estimated at 3.3 mm. L483 is found to have negligible disk emission at 3.3
mm while L1527 is dominated by disk emission within the central beam. The
beta_mm^disk <= 0.8 - 1.4 for L1527 indicates that grain growth is likely
occurring in the disk. The photometry presented in this paper may be combined
with future interferometric observations of Class 0 envelopes and disks.Comment: 19 pages, 3 figures, AJ accepted, in pres
A Multi-wavelength Study of the Sunyaev-Zel'dovich Effect in the Triple-Merger Cluster MACS J0717.5+3745 with MUSTANG and Bolocam
We present 90, 140, and 268GHz sub-arcminute resolution imaging of the
Sunyaev-Zel'dovich effect (SZE) in MACSJ0717.5+3745. Our 90GHz SZE data result
in a sensitive, 34uJy/bm map at 13" resolution using MUSTANG. Our 140 and
268GHz SZE imaging, with resolutions of 58" and 31" and sensitivities of 1.8
and 3.3mJy/beam respectively, was obtained using Bolocam. We compare these maps
to a 2-dimensional pressure map derived from Chandra X-ray observations. Our
MUSTANG data confirm previous indications from Chandra of a pressure
enhancement due to shock-heated, >20keV gas immediately adjacent to extended
radio emission seen in low-frequency radio maps. The MUSTANG data also detect
pressure substructure that is not well-constrained by the X-ray data in the
remnant core of a merging subcluster. We find that the small-scale pressure
enhancements in the MUSTANG data amount to ~2% of the total pressure measured
in the 140GHz Bolocam observations. The X-ray template also fails on larger
scales to accurately describe the Bolocam data, particularly at the location of
a subcluster known to have a high line of sight optical velocity (~3200km/s).
Our Bolocam data are adequately described when we add an additional component -
not described by a thermal SZE spectrum - coincident with this subcluster.
Using flux densities extracted from our model fits, and marginalizing over the
temperature constraints for the region, we fit a thermal+kinetic SZE spectrum
to our data and find the subcluster has a best-fit line of sight proper
velocity of 3600+3440/-2160km/s. This agrees with the optical velocity
estimates for the subcluster. The probability of velocity<0 given our
measurements is 2.1%. Repeating this analysis using flux densities measured
non-parametrically results in a 3.4% probability of a velocity<=0. We note that
this tantalizing result for the kinetic SZE is on resolved, subcluster scales.Comment: 10 Figures, 18 pages. this version corrects issues with the previous
arXiv versio
Galaxy Cluster Pressure Profiles as Determined by Sunyaev Zel’dovich Effect Observations with MUSTANG and Bolocam. II. Joint Analysis of 14 Clusters
We present pressure profiles of galaxy clusters determined from high
resolution Sunyaev-Zel'dovich (SZ) effect observations of fourteen clusters,
which span the redshift range . The procedure simultaneously
fits spherical cluster models to MUSTANG and Bolocam data. In this analysis, we
adopt the generalized NFW parameterization of pressure profiles to produce our
models. Our constraints on ensemble-average pressure profile parameters, in
this study , , and , are consistent with those in
previous studies, but for individual clusters we find discrepancies with the
X-ray derived pressure profiles from the ACCEPT2 database. We investigate
potential sources of these discrepancies, especially cluster geometry, electron
temperature of the intracluster medium, and substructure. We find that the
ensemble mean profile for all clusters in our sample is described by the
parameters: , for cool core clusters: , and for disturbed
clusters: . Four of the fourteen clusters have
clear substructure in our SZ observations, while an additional two clusters
exhibit potential substructure.Comment: 22 pages, 9 figures, accepted to Ap
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Variability in MRI vs. ultrasound measures of prostate volume and its impact on treatment recommendations for favorable-risk prostate cancer patients: a case series
Background: Prostate volume can affect whether patients qualify for brachytherapy (desired size ≥20 mL and ≤60 mL) and/or active surveillance (desired PSA density ≤0.15 for very low risk disease). This study examines variability in prostate volume measurements depending on imaging modality used (ultrasound versus MRI) and volume calculation technique (contouring versus ellipsoid) and quantifies the impact of this variability on treatment recommendations for men with favorable-risk prostate cancer. Methods: We examined 70 patients who presented consecutively for consideration of brachytherapy for favorable-risk prostate cancer who had volume estimates by three methods: contoured axial ultrasound slices, ultrasound ellipsoid (height × width × length × 0.523) calculation, and endorectal coil MRI (erMRI) ellipsoid calculation. Results: Average gland size by the contoured ultrasound, ellipsoid ultrasound, and erMRI methods were 33.99, 37.16, and 39.62 mLs, respectively. All pairwise comparisons between methods were statistically significant (all p < 0.015). Of the 66 patients who volumetrically qualified for brachytherapy on ellipsoid ultrasound measures, 22 (33.33%) did not qualify on ellipsoid erMRI or contoured ultrasound measures. 38 patients (54.28%) had PSA density ≤0.15 ng/dl as calculated using ellipsoid ultrasound volumes, compared to 34 (48.57%) and 38 patients (54.28%) using contoured ultrasound and ellipsoid erMRI volumes, respectively. Conclusions: The ultrasound ellipsoid and erMRI ellipsoid methods appeared to overestimate ultrasound contoured volume by an average of 9.34% and 16.57% respectively. 33.33% of those who qualified for brachytherapy based on ellipsoid ultrasound volume would be disqualified based on ultrasound contoured and/or erMRI ellipsoid volume. As treatment recommendations increasingly rely on estimates of prostate size, clinicians must consider method of volume estimation
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