122 research outputs found
Early imaging and molecular changes with neoadjuvant bevacizumab in stage ii/iii breast cancer
This prospective, phase II study evaluated novel biomarkers as predictors of response to bevacizumab in patients with breast cancer (BC), using serial imaging methods and gene expression analysis. Patients with primary stage II/III BC received bevacizumab 15 mg/kg (cycle 1; C1), then four cycles of neoadjuvant docetaxel doxorubicin, and bevacizumab every 3 weeks (C2–C5). Tumour proliferation and hypoxic status were evaluated using18F-fluoro-3'-deoxy-3'-L-fluorothymidine (FLT)-and18F-fluoromisonidazole (FMISO)-positron emission tomography (PET) at baseline, and during C1 and C5. Pre-and post-bevacizumab vascular changes were evaluated using dynamic contrastenhanced magnetic resonance imaging (DCE-MRI). Molecular biomarkers were assessed using microarray analysis. A total of 70 patients were assessed for treatment efficacy. Significant decreases from baseline in tumour proliferation (FLT-PET), vascularity, and perfusion (DCE-MRI) were observed during C1 (p = 0.001), independent of tumour subtype. Bevacizumab treatment did not affect hypoxic tumour status (FMISO-PET). Significant changes in the expression of 28 genes were observed after C1. Changes in vascular endothelial growth factor receptor (VEGFR)-2p levels were observed in 65 patients, with a > 20% decrease in VEGFR-2p observed in 13/65. Serial imaging techniques. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
Impact of the dosimetry approach on the resulting 90Y radioembolization planned absorbed doses based on 99mTc-MAA SPEC T-CT: is there agreement between dosimetry methods?
Background: Prior radioembolization, a simulation using 99mTc-macroaggregated
albumin as 90Y-microspheres surrogate is performed. Gamma scintigraphy images
(planar, SPECT, or SPECT-CT) are acquired to evaluate intrahepatic 90Y-microspheres
distribution and detect possible extrahepatic and lung shunting. These images may
be used for pre-treatment dosimetry evaluation to calculate the 90Y activity that
would get an optimal tumor response while sparing healthy tissues.
Several dosimetry methods are available, but there is still no consensus on the best
methodology to calculate absorbed doses. The goal of this study was to
retrospectively evaluate the impact of using different dosimetry approaches on the
resulting 90Y-radioembolization pre-treatment absorbed dose evaluation based on 99mTc-MAA images.
Methods: Absorbed doses within volumes of interest resulting from partition model
(PM) and 3D voxel dosimetry methods (3D-VDM) (dose-point kernel convolution and
local deposition method) were evaluated. Additionally, a new “Multi-tumor Partition
Model” (MTPM) was developed. The differences among dosimetry approaches were
evaluated in terms of mean absorbed dose and dose volume histograms within the
volumes of interest.
Results: Differences in mean absorbed dose among dosimetry methods are higher
in tumor volumes than in non-tumoral ones. The differences between MTPM and
both 3D-VDM were substantially lower than those observed between PM and any
3D-VDM. A poor correlation and concordance were found between PM and the
other studied dosimetry approaches.
DVH obtained from either 3D-VDM are pretty similar in both healthy liver and
individual tumors. Although no relevant global differences, in terms of absorbed
dose in Gy, between both 3D-VDM were found, important voxel-by-voxel differences
have been observed. Conclusions: Significant differences among the studied dosimetry approaches for 90Y-radioembolization treatments exist. Differences do not yield a substantial impact
in treatment planning for healthy tissue but they do for tumoral liver.
An individual segmentation and evaluation of the tumors is essential. In patients with
multiple tumors, the application of PM is not optimal and the 3D-VDM or the new
MTPM are suggested instead. If a 3D-VDM method is not available, MTPM is the best
option. Furthermore, both 3D-VDM approaches may be indistinctly used
Disminución de la reserva de flujo coronario en pacientes con insuficiencia cardíaca no isquémica
Introduction and objectives. Coronary flow reserve
(CFR) is impaired not only in ischemic heart disease, but
also in cardiac diseases that may or may not course with
heart failure. The aim of the present study was to determine
if the severity of heart failure can influence CFR impairment.
Methods. Forty patients with non-ischemic heart disease
and heart failure were studied 41 times. Four groups
were established: 1. 10 patients in functional class III-IV;
2. 10 patients in functional class II not taking beta-blockers;
3. 11 patients in class II treated with carvedilol, and 4.
10 patients in class I. These patients had a history of heart
failure and systolic dysfunction. Myocardial blood flow
(MBF) was measured with positron emission tomography
(PET) and N-13 ammonia at rest (r) and during adenosine
triphosphate (ATP) infusion.
Results. MBF and CFR were significantly higher in
group 4 (1.95 ± 0.58 and 2.40 ± 0.95 ml/min/g) than in
group 1 (1.02 ± 0.52 and 1.46 ± 0.48 ml/min/g). CFR tended
to be higher in groups 2 (1.73 ± 0.72), and 3 (1.89 ±
0.75) vs group 1. No significant correlation was found between
CFR and the following variables: age, systolic blood
pressure, ventricular mass index, ventricular volume indexes,
and ejection fraction.
Conclusions. Coronary microvascular function is impaired
in non-ischemic heart failure, and the impairment is
related to functional class, regardless of the underlying
responsible heart disease
The milliarcsecond-scale radio structure of AB Doradus A
Context. The fast rotator, pre-main sequence star AB Dor A is a strong and persistent radio emitter. The extraordinary coronal flaring activity is thought to be the origin of compact radio emission and other associated phenomena, such as large slingshot prominences.
Aims. We aim to investigate the radio emission mechanism and the milliarcsecond radio structure around AB Dor A.
Methods. We performed phase-referenced VLBI observations at 22.3 GHz, 8.4 GHz, and 1.4 GHz over more than one decade using the Australian VLBI array.
Results. Our 8.4 GHz images show a double core-halo morphology, similar at all epochs, with emission extending at heights between 5 and 18 stellar radii. Furthermore, the sequence of the 8.4 GHz maps shows a clear variation of the source structure within the observing time. However, images at 1.4 GHz and 22.3 GHz are compatible with a compact source. The phase-reference position at 8.4 GHz and 1.4 GHz are coincident with those expected from the well-known milliarcsecond-precise astrometry of this star, meanwhile the 22.3 GHz position is 4σ off the prediction in the north-west direction. The origin of this offset is still unclear.
Conclusions. We have considered several models to explain the morphology and evolution of the inner radio structure detected in AB Dor A. These models include emission from the stellar polar caps, a flaring, magnetically-driven loop structure, and the presence of helmet streamers. We also investigated a possible close companion to AB Dor A. Our results confirm the extraordinary coronal magnetic activity of this star, capable of producing compact radio structures at very large heights that have so far only been seen in binary interacting systems.J.B.C., R.A., J.C.G., and J.M.M. were partially supported
by the Spanish MINECO projects AYA2012-38491-C02-01, AYA2015-63939-
C2-2-P, PGC2018-098915-B-C22 and by the Generalitat Valenciana projects
PROMETEO/2009/104 and PROMETEOII/2014/05
Evaluation of spacial resolution of a PET scanner through the simulation and experimental measurement of the Recovery coefficient
Purpose: In order to measure spatial resolution of a PET tomograph in clinical conditions, this study describes and
validates a method based on the recovery coefficient, a factor required to compensate underestimation in measured
radioactivity concentration for small structures.
Methods: In a PET image, the recovery factors of radioactive spheres were measured and their comparison with
simulated recovery coefficients yielded the tomographic spatial resolution. Following this methodology, resolution was
determined in different surrounding media and several conditions for reconstruction, including clinical conditions for brain
PET studies. All spatial resolution values were compared with those obtained using classical methods with point and
line sources.
Results: In each considered condition, spatial resolution of the PET image estimated using the recovery coefficient
showed good agreement with classical methods measurements, validating the procedure.
Conclusion: Measurement of the recovery coefficient provides an assessment of tomographic spatial resolution,
particularly in clinical studies conditions
Autologous intramyocardial injection of cultured skeletal muscle-derived stem cells in patients with non-acute myocardial infarction
AIM: Experimental animal studies suggest that the use of skeletal myoblast in patients with myocardial infarction may result in improved cardiac function. The aim of the study was to assess the feasibility and safety of this therapy in patients with myocardial infarction.
METHODS AND RESULTS: Twelve patients with old myocardial infarction and ischaemic coronary artery disease underwent treatment with coronary artery bypass surgery and intramyocardial injection of autologous skeletal myoblasts obtained from a muscle biopsy of vastus lateralis and cultured with autologous serum for 3 weeks. Global and regional cardiac function was assessed by 2D and ABD echocardiogram. 18F-FDG and 13N-ammonia PET studies were used to determine perfusion and viability. Left ventricular ejection fraction (LVEF) improved from 35.5+/-2.3% before surgery to 53.5+/-4.98% at 3 months (P=0.002). Echocardiography revealed a marked improvement in regional contractility in those cardiac segments treated with skeletal myoblast (wall motion score index 2.64+/-0.13 at baseline vs 1.64+/-0.16 at 3 months P=0.0001). Quantitative 18F-FDG PET studies showed a significant (P=0.012) increased in cardiac viability in the infarct zone 3 months after surgery. No statistically significant differences were found in 13N-ammonia PET studies. Skeletal myoblast implant was not associated with an increase in adverse events. No cardiac arrhythmias were detected during early follow-up.
CONCLUSIONS: In patients with old myocardial infarction, treatment with skeletal myoblast in conjunction with coronary artery bypass is safe and feasible and is associated with an increased global and regional left ventricular function,improvement in the viability of cardiac tissue in the infarct area and no induction of arrhythmias
Recommendations by the Spanish Society of Hospital Pharmacy, the Spanish Society of Oncology Nursing and the Spanish Society of Medical Oncology for the safe management of antineoplastic medication in cancer patients
Aim: To define recommendations that permit safe management of antineoplastic medication, minimise medication errors and improve the safety of cancer patients undergoing treatment.
Methods: By reviewing the literature and consulting the websites of various health organisations and agencies, an expert committee from the Spanish Society of Hospital Pharmacy and the Spanish Society of Medical Oncology defined a set of safe practices covering all stages of providing cancer therapy to patients. The Spanish Society of Oncology Nursing revised and endorsed the final list.
Results: In total, 68 recommendations arranged in five sections were defined. They include issues concerning the training of health professionals, the technological resources needed, treatment planning, informing the patient and his/her family, the processes of prescribing, preparing, dispensing and administering cancer therapy (orally, parenterally or intrathecally), assessing patient adherence and treatment toxicity.
Conclusions: It is essential for healthcare establishments to implement specific measures designed to prevent medication errors, in order to ensure the safety of cancer patients treated with antineoplastic medication
Utilización de un ciclotrón para la producción de radionucleidos emisores de positrones
The experience acquired by our center during the first two years of using cyclotron 18/9 (IBA) dedicated to the production of clinical positron emission radionuclides is described. The cyclotron performance characteristics, production yields, quality control and synthesized radiotracers are analyzed. Cyclotron makes it possible to produce up to 3,300 mCi of 18F-, 270 mCi of 18F2, 3,100 mCi of 11C, 502 mCi of 13N (in 120, 60, 35 and 20 minutes respectively) and 540 mCi/min of 15O. In our center, about 85% of the PET studies are performed with 18F-FDG, whereas the remaining are done with 15O-water, 11C-bicarbonate, 11C-methionine, 13N-ammonia or 18F-. Cyclotron is included in the Radiopharmacy Unit of our PET facility and is subjected to a global quality control program. Follow-up of the bombardment parameters and periodic verifications of the cyclotron performance have made it possible to prevent equipment functioning problems, increase mean time between stoppage and decrease downtime. We conclude that cyclotron has high production capabilities and allows enough flexibility for a clinical and research positron emission tomography center; furthermore, it can also be used for regional distribution of 18F-FDG to satellite PET centers
Abnormalities on 1q and 7q are associated with poor outcome in sporadic Burkitt's lymphoma. A cytogenetic and comparative genomic hybridization study
Comparative genomic hybridization (CGH) studies have demonstrated a high incidence of chromosomal imbalances in non-Hodgkin's lymphoma. However, the information on the genomic imbalances in Burkitt's Lymphoma (BL) is scanty. Conventional cytogenetics was performed in 34 cases, and long-distance PCR for t(8;14) was performed in 18 cases. A total of 170 changes were present with a median of four changes per case (range 1-22). Gains of chromosomal material (143) were more frequent than amplifications (5) or losses (22). The most frequent aberrations were gains on chromosomes 12q (26%), Xq (22%), 22q (20%), 20q (17%) and 9q (15%). Losses predominantly involved chromosomes 13q (17%) and 4q (9%). High-level amplifications were present in the regions 1q23-31 (three cases), 6p12-p25 and 8p22-p23. Upon comparing BL vs Burkitt's cell leukemia (BCL), the latter had more changes (mean 4.3 +/- 2.2) than BL (mean 2.7 +/- 3.2). In addition, BCL cases showed more frequently gains on 8q, 9q, 14q, 20q, and 20q, 9q, 8q and 14q, as well as losses on 13q and 4q. Concerning outcome, the presence of abnormalities on 1q (ascertained either by cytogenetics or by CGH), and imbalances on 7q (P=0.01) were associated with a short survival
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