185 research outputs found
Radiotherapy in prostate cancer after kidney transplant: review of the literature and report of 6 cases
Background: Patients who received a kidney transplant (KT) are described in literature as a group with a higher incidence of malignant neoplasms compared to the general population. Cancer development after KT has become a major issue, as a remarkable percentage of patients are diagnosed with cancer. Treatment of prostate cancer (PCa) in renal transplant recipients (RTRs) is a challenging issue that has been discussed by many authors over the years, but evidence is sparse and often includes conflicting reports. Among the therapeutic options for PCa in these patients, prostate irradiation represents a valuable alternative to surgery or other systemic therapies, as RTRs are often ineligible for these treatments. Objective: To report six cases treated at our institution between 1998 and 2017 and discuss the available literature. Methods: Patients’ characteristics were reported along with biochemical status at diagnosis, type of immunosuppressive treatment, radiation therapy technique, and dose to transplanted kidney. Results: Overall, prostate irradiation was delivered respecting the dose constraints and patients showed good tolerance with no reports of acute or late transplanted kidney injury. Conclusions: Our experience confirms that prostate radiotherapy for RTRs is feasible and effective and represents a valid option that should be considered by the multidisciplinary team
Morphology, dynamics and plasma parameters of plumes and inter-plume regions in solar coronal holes
Coronal plumes, which extend from solar coronal holes (CH) into the high
corona and - possibly - into the solar wind (SW), can now continuously be
studied with modern telescopes and spectrometers on spacecraft, in addition to
investigations from the ground, in particular, during total eclipses. Despite
the large amount of data available on these prominent features and related
phenomena, many questions remained unanswered as to their generation and
relative contributions to the high-speed streams emanating from CHs. An
understanding of the processes of plume formation and evolution requires a
better knowledge of the physical conditions at the base of CHs, in plumes and
in the surrounding inter-plume regions (IPR). More specifically, information is
needed on the magnetic field configuration, the electron densities and
temperatures, effective ion temperatures, non-thermal motions, plume
cross-sections relative to the size of a CH, the plasma bulk speeds, as well as
any plume signatures in the SW. In spring 2007, the authors proposed a study on
"Structure and dynamics of coronal plumes and inter-plume regions in solar
coronal holes" to the International Space Science Institute (ISSI) in Bern to
clarify some of these aspects by considering relevant observations and the
extensive literature. This review summarizes the results and conclusions of the
study. Stereoscopic observations allowed us to include three-dimensional
reconstructions of plumes. Multi-instrument investigations carried out during
several campaigns led to progress in some areas, such as plasma densities,
temperatures, plume structure and the relation to other solar phenomena, but
not all questions could be answered concerning the details of plume generation
process(es) and interaction with the SW.Comment: To appear on: The Astronomy and Astrophysics Review. 72 pages, 30
figure
A Far-Ultraviolet Spectroscopic Survey of Luminous Cool Stars
FUSE ultraviolet spectra of 8 giant and supergiant stars reveal that high
temperature (3 X 10^5 K) atmospheres are common in luminous cool stars and
extend across the color-magnitude diagram from Alpha Car (F0 II) to the cool
giant Alpha Tau (K5 III). Emission present in these spectra includes
chromospheric H-Lyman Beta, Fe II, C I, and transition region lines of C III, O
VI, Si III, Si IV. Emission lines of Fe XVIII and Fe XIX signaling temperatures
of ~10^7 K and coronal material are found in the most active stars, Beta Cet
and 31 Com. A short-term flux variation, perhaps a flare, was detected in Beta
Cet during our observation. Stellar surface fluxes of the emission of C III and
O VI are correlated and decrease rapidly towards the cooler stars, reminiscent
of the decay of magnetically-heated atmospheres. Profiles of the C III (977A)
lines suggest that mass outflow is underway at T~80,000 K, and the winds are
warm. Indications of outflow at higher temperatures (3 X 10^5K) are revealed by
O VI asymmetries and the line widths themselves. High temperature species are
absent in the M-supergiant Alpha Ori. Narrow fluorescent lines of Fe II appear
in the spectra of many giants and supergiants, apparently pumped by H Lyman
Alpha, and formed in extended atmospheres. Instrumental characteristics that
affect cool star spectra are discussed.Comment: Accept for publication in The Astrophysical Journal; 22 pages of
text, 23 figures and 8 table
RHESSI images and spectra of two small flares
We studied the evolution of two small flares (GOES class C2 and C1) that
developed in the same active region with different morphological
characteristics: one is extended and the other is compact. We analyzed the
accuracy and the consistency of different algorithms implemented in RHESSI
software to reconstruct the image of the emitting sources, for energies between
3 and 12 keV. We found that all tested algorithms give consistent results for
the peak position whil the other parameters can differ at most by a factor 2.
Pixon and Forward-fit generally converge to similar results but Pixon is more
reliable for reconstructing a complex source. We investigated the spectral
characteristics of the two flares during their evolution in the 3--25 keV
energy band. We found that a single thermal model of the photon spectrum is
inadequate to fit the observations and we needed to add either a non-thermal
model or a hot thermal one.The non-thermal and the double thermal fits are
comparable. If we assume a non-thermal model, the non-thermal energy is always
higher than the thermal one.Only during the very final decay phase a single
thermal model fits fairly well the observed spectrum.Comment: 26 pages, 11 figures, accepted by Solar Physic
Management of prostate cancer radiotherapy during the COVID-19 pandemic: A necessary paradigm change
Purpose: To adapt the management of prostate malignancy in response to the COVID-19 pandemic. Methods: In according to the recommendations of the European Association of Urology, we have developed practical additional document on the treatment of prostate cancer. Results: Low-Risk Group Watchful Waiting should be offered to patients >75 years old, with a limited life expectancy and unfit for local treatment. In Active Surveillance (AS) patients re-biopsy, PSA evaluation and visits should be deferred for up to 6 months, preferring non-invasive multiparametric-MRI. The active treatment should be delayed for 6–12 months. Intermediate-Risk Group AS should be offered in favorable-risk patients. Short-course neoadjuvant androgen deprivation therapy (ADT) combined with ultra-hypo-fractionation radiotherapy should be used in unfavorable-risk patients. High-Risk Group Neoadjuvant ADT combined with moderate hypofractionation should be preferred. Whole-pelvis irradiation should be offered to patients with positive lymph nodes in locally advanced setting. ADT should be initiated if PSA doubling time is < 12 months in radio-recurrent patients, as well as in low priority/low volume of metastatic hormone sensitive prostate cancer. If radiotherapy cannot be delayed, hypo-fractionated regimens should be preferred. In high priority class metastatic disease, treatment with androgen receptor-targeted agents should be offered. When palliative radiotherapy for painful bone metastasis is required, single fraction of 8 Gy should be offered. Conclusions: In Covid-19 Era, the challenge should concern a correct management of the oncologic patient, reducing the risk of spreading the virus without worsening tumor prognosis
2D and 3D Polar Plume Analysis from the Three Vantage Positions of STEREO/EUVI A, B, and SOHO/EIT
Polar plumes are seen as elongated objects starting at the solar polar
regions. Here, we analyze these objects from a sequence of images taken
simultaneously by the three spacecraft telescopes STEREO/EUVI A and B, and
SOHO/EIT. We establish a method capable of automatically identifying plumes in
solar EUV images close to the limb at 1.01 - 1.39 R in order to study their
temporal evolution. This plume-identification method is based on a multiscale
Hough-wavelet analysis. Then two methods to determined their 3D localization
and structure are discussed: First, tomography using the filtered
back-projection and including the differential rotation of the Sun and,
secondly, conventional stereoscopic triangulation. We show that tomography and
stereoscopy are complementary to study polar plumes. We also show that this
systematic 2D identification and the proposed methods of 3D reconstruction are
well suited, on one hand, to identify plumes individually and on the other
hand, to analyze the distribution of plumes and inter-plume regions. Finally,
the results are discussed focusing on the plume position with their
cross-section area.Comment: 22 pages, 10 figures, Solar Physics articl
Radiotherapy is effective in the management of rare penile metastases: Two case reports
Penile metastasization is an uncommon condition, mostly derived from primitive advanced abdominal cancers, with disabling symptoms. Palliative treatment, in reason of poor prognosis patients, is frequently surgical with destructive management. We report two cases of penile metastasis, from primitive prostatic adenocarcinoma and primitive urothelial carcinoma, effectively managed with radiation treatment at our institution. A three-dimensional conformal radiation therapy with 42 Gy to the planning target volume in 14 fractions was delivered. Radiation treatment was safely delivered, with low toxicity profile and achieved adequate symptoms control without compromising genitourinary functions. Radiation therapy should be considered in management of rare penile metastases
LEMUR: Large European Module for solar Ultraviolet Research. European contribution to JAXA's Solar-C mission
Understanding the solar outer atmosphere requires concerted, simultaneous
solar observations from the visible to the vacuum ultraviolet (VUV) and soft
X-rays, at high spatial resolution (between 0.1" and 0.3"), at high temporal
resolution (on the order of 10 s, i.e., the time scale of chromospheric
dynamics), with a wide temperature coverage (0.01 MK to 20 MK, from the
chromosphere to the flaring corona), and the capability of measuring magnetic
fields through spectropolarimetry at visible and near-infrared wavelengths.
Simultaneous spectroscopic measurements sampling the entire temperature range
are particularly important.
These requirements are fulfilled by the Japanese Solar-C mission (Plan B),
composed of a spacecraft in a geosynchronous orbit with a payload providing a
significant improvement of imaging and spectropolarimetric capabilities in the
UV, visible, and near-infrared with respect to what is available today and
foreseen in the near future.
The Large European Module for solar Ultraviolet Research (LEMUR), described
in this paper, is a large VUV telescope feeding a scientific payload of
high-resolution imaging spectrographs and cameras. LEMUR consists of two major
components: a VUV solar telescope with a 30 cm diameter mirror and a focal
length of 3.6 m, and a focal-plane package composed of VUV spectrometers
covering six carefully chosen wavelength ranges between 17 and 127 nm. The
LEMUR slit covers 280" on the Sun with 0.14" per pixel sampling. In addition,
LEMUR is capable of measuring mass flows velocities (line shifts) down to 2
km/s or better.
LEMUR has been proposed to ESA as the European contribution to the Solar C
mission.Comment: 35 pages, 14 figures. To appear on Experimental Astronom
Explosive events - swirling transition region jets
In this paper, we extend our earlier work to provide additional evidence for
an alternative scenario to explain the nature of so-called `explosive events'.
The bi-directed, fast Doppler motion of explosive events observed
spectroscopically in the transition region emission is classically interpreted
as a pair of bidirectional jets moving upward and downward from a reconnection
site. We discuss the problems of such a model. In our previous work, we focused
basically on the discrepancy of fast Doppler motion without detectable motion
in the image plane. We now suggest an alternative scenario for the explosive
events, based on our observations of spectral line tilts and bifurcated
structure in some events. Both features are indicative of rotational motion in
narrow structures. We explain the bifurcation as the result of rotation of
hollow cylindrical structures and demonstrate that such a sheath model can also
be applied to explain the nature of the puzzling `explosive events'. We find
that the spectral tilt, the lack of apparent motion, the bifurcation, and a
rapidly growing number of direct observations support an alternative scenario
of linear, spicular-sized jets with a strong spinning motion.Comment: 9 pages, 3 figures, accepted for publication in Solar Physic
In-flight validation of Metis Visible-light Polarimeter Coronagraph on board Solar Orbiter
Context. The Metis coronagraph is one of the remote-sensing instruments of
the ESA/NASA Solar Orbiter mission. Metis is aimed at the study of the solar
atmosphere and solar wind by simultaneously acquiring images of the solar
corona at two different wavelengths; visible-light (VL) within a band ranging
from 580 nm to 640 nm, and in the HI Ly-alpha 121.6 +/- 10 nm ultraviolet (UV)
light. The visible-light channel includes a polarimeter with electro-optically
modulating Liquid Crystal Variable Retarders (LCVRs) to measure the linearly
polarized brightness of the K-corona to derive the electron density.
Aims. In this paper, we present the first in-flight validation results of the
Metis polarimetric channel together with a comparison to the on-ground
calibrations. It is the validation of the first use in deep space (with hard
radiation environment) of an electro-optical device: a liquid crystal-based
polarimeter.
Methods. We used the orientation of the K-corona's linear polarization vector
during the spacecraft roll maneuvers for the in-flight calibration.
Results. The first in-flight validation of the Metis coronagraph on-board
Solar Orbiter shows a good agreement with the on-ground measurements. It
confirms the expected visible-light channel polarimetric performance. A final
comparison between the first pB obtained by Metis with the polarized brightness
(pB) obtained by the space-based coronagraph LASCO and the ground-based
coronagraph KCor shows the consistency of the Metis calibrated results.Comment: 8 pages, 13 figures, 3 tables, pape
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