Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
1.
Phys Med ; 118: 103209, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38281410

RESUMO

In-beam PET (Positron Emission Tomography) is one of the most precise techniques for in-vivo range monitoring in hadron therapy. Our objective was to demonstrate the feasibility of a short irradiation run for range verification before a carbon-ion treatment. To do so a PMMA target was irradiated with a 220 MeV/u carbon-ion beam and annihilation coincidences from short-lived positron emitters were acquired after irradiations lasting 0.6 s. The experiments were performed at the synchrotron-based facility CNAO (Italian National Center of Oncological Hadrontherapy) by using the INSIDE in-beam PET detector. The results show that, with 3·107 carbon ions, the reconstructed positron emitting nuclei distribution is in good agreement with the predictions of a detailed FLUKA Monte Carlo study. Moreover, the radio-nuclei production is sufficiently abundant to determine the average ion beam range with a σ of 1 mm with a 6 s measurement of the activity distribution. Since the data were acquired when the beam was off, the proposed rapid calibration method can be applied to hadron beams extracted from accelerators with very different time structures.


Assuntos
Elétrons , Radioterapia com Íons Pesados , Tomografia por Emissão de Pósitrons/métodos , Carbono/uso terapêutico , Síncrotrons , Método de Monte Carlo
2.
Phys Med Biol ; 68(23)2023 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-37827167

RESUMO

Objective. The performance of silicon detectors with moderate internal gain, named low-gain avalanche diodes (LGADs), was studied to investigate their capability to discriminate and count single beam particles at high fluxes, in view of future applications for beam characterization and on-line beam monitoring in proton therapy.Approach. Dedicated LGAD detectors with an active thickness of 55µm and segmented in 2 mm2strips were characterized at two Italian proton-therapy facilities, CNAO in Pavia and the Proton Therapy Center of Trento, with proton beams provided by a synchrotron and a cyclotron, respectively. Signals from single beam particles were discriminated against a threshold and counted. The number of proton pulses for fixed energies and different particle fluxes was compared with the charge collected by a compact ionization chamber, to infer the input particle rates.Main results. The counting inefficiency due to the overlap of nearby signals was less than 1% up to particle rates in one strip of 1 MHz, corresponding to a mean fluence rate on the strip of about 5 × 107p/(cm2·s). Count-loss correction algorithms based on the logic combination of signals from two neighboring strips allow to extend the maximum counting rate by one order of magnitude. The same algorithms give additional information on the fine time structure of the beam.Significance. The direct counting of the number of beam protons with segmented silicon detectors allows to overcome some limitations of gas detectors typically employed for beam characterization and beam monitoring in particle therapy, providing faster response times, higher sensitivity, and independence of the counts from the particle energy.


Assuntos
Terapia com Prótons , Radiometria , Radiometria/métodos , Prótons , Silício , Ciclotrons
3.
Med Phys ; 50(9): 5817-5827, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37493525

RESUMO

BACKGROUND: The beam energy is one of the most significant parameters in particle therapy since it is directly correlated to the particles' penetration depth inside the patient. Nowadays, the range accuracy is guaranteed by offline routine quality control checks mainly performed with water phantoms, 2D detectors with PMMA wedges, or multi-layer ionization chambers. The latter feature low sensitivity, slow collection time, and response dependent on external parameters, which represent limiting factors for the quality controls of beams delivered with fast energy switching modalities, as foreseen in future treatments. In this context, a device based on solid-state detectors technology, able to perform a direct and absolute beam energy measurement, is proposed as a viable alternative for quality assurance measurements and beam commissioning, paving the way for online range monitoring and treatment verification. PURPOSE: This work follows the proof of concept of an energy monitoring system for clinical proton beams, based on Ultra Fast Silicon Detectors (featuring tenths of ps time resolution in 50 µm active thickness, and single particle detection capability) and time-of-flight techniques. An upgrade of such a system is presented here, together with the description of a dedicated self-calibration method, proving that this second prototype is able to assess the mean particles energy of a monoenergetic beam without any constraint on the beam temporal structure, neither any a priori knowledge of the beam energy for the calibration of the system. METHODS: A new detector geometry, consisting of sensors segmented in strips, has been designed and implemented in order to enhance the statistics of coincident protons, thus improving the accuracy of the measured time differences. The prototype was tested on the cyclotron proton beam of the Trento Protontherapy Center (TPC). In addition, a dedicated self-calibration method, exploiting the measurement of monoenergetic beams crossing the two telescope sensors for different flight distances, was introduced to remove the systematic uncertainties independently from any external reference. RESULTS: The novel calibration strategy was applied to the experimental data collected at TPC (Trento) and CNAO (Pavia). Deviations between measured and reference beam energies in the order of a few hundreds of keV with a maximum uncertainty of 0.5 MeV were found, in compliance with the clinically required water range accuracy of 1 mm. CONCLUSIONS: The presented version of the telescope system, minimally perturbative of the beam, relies on a few seconds of acquisition time to achieve the required clinical accuracy and therefore represents a feasible solution for beam commission, quality assurance checks, and online beam energy monitoring.


Assuntos
Terapia com Prótons , Calibragem , Terapia com Prótons/normas , Fatores de Tempo , Humanos
4.
Nutrients ; 15(13)2023 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-37447210

RESUMO

Prolonged fatigue is associated with non-pathological causes and lacks an established therapeutic approach. The current study is aimed at assessing the efficacy of a new food supplement (Improve™) based on a chemically characterized pomegranate extract and hydro-soluble vitamins (B complex and C). UHPLC-HRMS analysis of pomegranate extract showed the presence of 59 compounds, with gallotannins and ellagitannins being the most abundant phytochemicals. For the clinical study, 58 subjects were randomized into two groups, 1 and 2 (n = 29, each), which received either the food supplement or placebo. The effects of the food supplement against fatigue were assessed via validated questionnaires, recorded at time intervals t0 (at baseline), t1 (after 28 days), t2 (56 days), and t3 (after follow-up) in combination with the analysis of biochemical markers at t0 and t2. Fatigue severity scale (FSS) questionnaire scores were significantly decreased at the t2 and t3 time intervals in subjects treated with the food supplements, while the effect of the food supplement on a 12-Item Short Form Survey (SF-12) was not considerable. Moreover, the food supplement did not significantly affect biochemical parameters associated with fatigue and stress conditions. This study shows that the food supplement tested reduces prolonged fatigue following two months of supplementation in healthy subjects with mild prolonged fatigue.


Assuntos
Punica granatum , Vitaminas , Humanos , Suplementos Nutricionais , Fadiga/tratamento farmacológico , Vitamina A/uso terapêutico , Vitamina K/uso terapêutico , Método Duplo-Cego
5.
Biomed Pharmacother ; 156: 113930, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36411659

RESUMO

Depression is one of the most serious chronic psychiatric disorders affecting people worldwide. Subthreshold depression (SD) is a form of subclinical depression with increased risk of major depressive disorder (MDD). Patients diagnosed with SD may not be eligible for antidepressant drugs and, particularly in the case of MDD, these antidepressants may have adverse effects which outweigh their therapeutic effects, leading to discontinuation of therapy. Food supplements could provide an alternative strategy. The aim of this study is to demonstrate the efficacy of a food supplement based on a combination of S-adenosyl methionine (SAMe, 200 mg/day) and probiotics (Lactobacillus helveticus Rosell®-52, Bifidobacterium longum Rosell®-175, 3 ×109 CFU/day) in reducing depression symptoms in a monocentric, randomised, double-blind, placebo-controlled, cross-over clinical trial. 80 Subjects were recruited and offered the food supplement or placebo daily for three months, according to a cross-over clinical trial design, followed by a six-week follow-up period. The efficacy of the food supplement was measured by means of the "Hamilton Depression Rating Scale" (HAM-D) and "Patient Health Questionnaire-9" (PHQ-9), using a mixed analysis of variance model, with random intercept, for statistical analysis. The food supplement showed a significant decrease of PHQ-9 and HAM-D scores resulting in reduced SD and MDD symptoms as compared to placebo. In conclusion, the daily intake of the food supplement based on SAMe and probiotic strains for a period of three months is effective in improving the quality of life of SD subjects who are not eligible for antidepressant therapies, and patients suffering from mild-to-moderate depression who are not sensitive or cannot tolerate conventional drugs.


Assuntos
Transtorno Depressivo Maior , Probióticos , Humanos , Transtorno Depressivo Maior/tratamento farmacológico , Depressão/tratamento farmacológico , Qualidade de Vida , Suplementos Nutricionais , Probióticos/efeitos adversos , S-Adenosilmetionina/uso terapêutico , Método Duplo-Cego
6.
Nutrients ; 14(13)2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35807931

RESUMO

Depression is a common and serious health issue affecting around 280 million people around the world. Suicidal ideation more frequently occurs in people with moderate to severe depression. Psychotherapy and pharmacological drugs are the mainstay of available treatment options for depressive disorders. However, pharmacological options do not offer complete cure, especially in moderate to severe depression, and are often seen with a range of adverse events. S-adenosyl methionine (SAMe) supplementation has been widely studied, and an impressive collection of literature published over the last few decades suggests its antidepressant efficacy. Probiotics have gained significant attention due to their wide array of clinical uses, and multiple studies have explored the link between probiotic species and mood disorders. Gut dysbiosis is one of the risk factors in depression by inducing systemic inflammation accompanied by an imbalance in neurotransmitter production. Thus, concomitant administration of probiotics may be an effective treatment strategy in patients with depressed mood, particularly in resistant cases, as these can aid in dysbiosis, possibly resulting in the attenuation of systemic inflammatory processes and the improvement of the therapeutic efficacy of SAMe. The current review highlights the therapeutic roles of SAMe and probiotics in depression, their mechanistic targets, and their possible synergistic effects and may help in the development of food supplements consisting of a combination of SAMe and probiotics with new dosage forms that may improve their bioavailability.


Assuntos
Disbiose , Probióticos , Depressão/tratamento farmacológico , Suplementos Nutricionais , Disbiose/tratamento farmacológico , Humanos , Probióticos/uso terapêutico , S-Adenosilmetionina/uso terapêutico
7.
Biomed Pharmacother ; 138: 111414, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33765581

RESUMO

Benign prostatic hyperplasia (BPH) is a common condition in adult men. Especially in Europe, increasing attention has been focused on E. angustifolium extracts (EAEs), which are widely used for their positive effects on the symptoms of BPH, although human clinical trials are limited. The aim of this monocentric, randomized, double-blind, placebo-controlled clinical trial is to evaluate if a daily intake of hard, gastric-resistant capsules containing a chemically characterized EAE (500 mg) for 6 months may allow a significant improvement in symptoms in subjects with BPH. This study was conducted in 128 adult men, randomly assigned to receive either EAE food supplement (N = 70) or placebo (N = 58), who underwent four visits (baseline = t0, after 15 days = t1, after 2 months = t2 and after 6 months = t3) in an outpatient setting to evaluate post-void residual (PVR) and prostate volume (PV) by means of prostate ultrasound, prostate-specific antigen (PSA) and neutrofile/lymphocyte ratio (N/L), nocturia before the clinical visits and International Prostate Specific Score (IPSS) registered by the physicians. EAE food supplement induced a significant decrease in the PVR and consequently nocturia improving the quality of life as suggested by the decrease of IPSS. No subjects reported adverse effects related to oral intake of EAE food supplement. Moreover, EAE food supplement did not show hepatic or renal toxicity. In conclusion, EAE food supplements can be used in subjects with BPH, to improve their quality of life and general renal function.


Assuntos
Epilobium , Taninos Hidrolisáveis/uso terapêutico , Onagraceae , Extratos Vegetais/uso terapêutico , Próstata/efeitos dos fármacos , Hiperplasia Prostática/tratamento farmacológico , Idoso , Método Duplo-Cego , Humanos , Taninos Hidrolisáveis/isolamento & purificação , Taninos Hidrolisáveis/farmacologia , Masculino , Pessoa de Meia-Idade , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Próstata/metabolismo , Próstata/patologia , Hiperplasia Prostática/sangue , Hiperplasia Prostática/patologia
8.
Intern Emerg Med ; 16(5): 1297-1305, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33428110

RESUMO

The most relevant manifestation of coronavirus disease 2019 (COVID-19) is interstitial pneumonia. Several lung ultrasound (US) protocols for pneumonia diagnosis are used in clinical practice, but none has been proposed for COVID-19 patients' screening in the emergency department. We adopted a simplified 6-scan lung US protocol for COVID-19 pneumonia diagnosis (LUSCOP) and compared its sensitivity with high resolution computed tomography (HRCT) in patients suspected for COVID-19, presenting to one Emergency Department from February 21st to March 15th, 2020, during the outbreak burst in northern Italy. Patients were retrospectively enrolled if both LUSCOP protocol and HRCT were performed in the Emergency Department. The sensitivity of LUSCOP protocol and HRCT were compared. COVID-19 pneumonia's final diagnosis was based on real-time reverse-transcription polymerase chain reaction from nasal-pharyngeal swab and on clinical data. Out of 150 suspected COVID-19 patients, 131 were included in the study, and 130 had a final diagnosis of COVID-19 pneumonia. The most frequent lung ultrasonographic features were: bilateral B-pattern in 101 patients (77%), B-pattern with subpleural consolidations in 26 (19.8%) and lung consolidations in 2 (1.5%). LUSCOP Protocol was consistent with HRCT in correctly screening 130 out of the 131 COVID-19 pneumonia cases (99.2%). In one case COVID-19 pneumonia was excluded by both HRCT and lung US. LUSCOP protocol showed optimal sensitivity and can be proposed as a simple screening tool for COVID-19 pneumonia diagnosis in the context of outbreak burst areas where prompt isolation of suspected patients is crucial for patients' and operators' safety.


Assuntos
COVID-19/complicações , Pulmão/diagnóstico por imagem , Pneumonia/diagnóstico por imagem , Pneumonia/etiologia , Ultrassonografia/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19/diagnóstico por imagem , Serviço Hospitalar de Emergência/organização & administração , Serviço Hospitalar de Emergência/estatística & dados numéricos , Feminino , Humanos , Pulmão/fisiopatologia , Masculino , Programas de Rastreamento/métodos , Programas de Rastreamento/estatística & dados numéricos , Pessoa de Meia-Idade , Pneumonia/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase em Tempo Real/estatística & dados numéricos , Estudos Retrospectivos , Ultrassonografia/tendências
9.
Phytomedicine ; 80: 153368, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33091857

RESUMO

BACKGROUND: The most common symptoms of mild upper respiratory tract infections (URTIs) are sore throat, muffled dysphonia, and swelling and redness of the throat, which result from the inflammation process following acute bacterial or viral infection. HYPOTHESIS/PURPOSE: As propolis is a natural resinous substance traditionally used to maintain oral cavity and upper respiratory tract health due to its antimicrobial and anti-inflammatory properties, the aim of this study is to evaluate the efficacy of an oral spray based on poplar-type propolis extract with a known and standardized polyphenol content, on the remission of the symptoms associated with mild uncomplicated URTIs. STUDY DESIGN: A monocentric, randomized, double-blind, placebo-controlled clinical trial was performed. METHODS: This study was conducted in 122 healthy adults who had perceived mild upper respiratory tract infections. Participants, randomly assigned to receive either propolis oral spray (N = 58) or placebo (N = 64), underwent four visits (baseline = t0, after 3 days = t1 and after 5 days = t2 and after a follow-up of 15 days = t3) in an outpatient setting. Propolis oral spray total polyphenol content was 15 mg/ml. The dosage was 2-4 sprays three times/day (corresponding to 12-24 mg of polyphenols/day), for five days. The duration of the study was 8 weeks. RESULTS: After 3 days of treatment, 83% of subjects treated with propolis oral spray had remission of symptoms, while 72% of subjects in the placebo group had at least one remaining symptom. After five days, all subjects had recovered from all symptoms. This means that resolution from mild uncomplicated URTIs took place two days earlier, instead of taking place in five days as recorded in the control group. There was no relationship between the ingestion of propolis oral spray or placebo and adverse reactions. CONCLUSION: Propolis oral spray can be used to improve both bacterial and viral uncomplicated URTI symptoms in a smaller number of days without the use of pharmacological treatment, leading to a prompt symptom resolution.


Assuntos
Faringite/tratamento farmacológico , Polifenóis/uso terapêutico , Própole/uso terapêutico , Infecções Respiratórias/tratamento farmacológico , Administração Oral , Adolescente , Adulto , Idoso , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Placebos , Polifenóis/análise , Polifenóis/normas , Própole/administração & dosagem , Própole/química , Infecções Respiratórias/etiologia , Resultado do Tratamento , Adulto Jovem
10.
Med Phys ; 47(4): 1468-1480, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31971612

RESUMO

PURPOSE: A retrospective analysis of the dose delivery system (DDS) performances of the initial clinical operation at CNAO (Centro Nazionale di Adroterapia Oncologica) is reported, and compared with the dose delivery accuracy following the implementation of a position feedback control. METHODS: Log files and raw data of the DDS were analyzed for every field of patients treated with protons and carbon ions between January 2012 and April 2013 (~3800 fields). To investigate the DDS accuracy, the spot positions and the number of particles per spot measured by the DDS and prescribed by the treatment planning system were compared for each field. The impact of deviations on dose distributions was studied by comparing, through the gamma-index method, 2 three-dimensional (3D) physical dose maps (one for prescribed, one for measured data), generated by a validated dose computation software. The maximum gamma and the percentage of points with gamma ≤ 1 (passing volume) were studied as a function of the treatment day, and correlated with the deviations from the prescription in the measured number of particles and spot positions. Finally, delivered dose distributions of same treatment plans were compared before and after the implementation of a feedback algorithm for the correction of small position deviations, to study the effect on the delivery quality. A double comparison of prescribed and measured 3D maps, before and after feedback implementation, is reported and studied for a representative treatment delivered in 2012, redelivered on a polymethyl methacrylate (PMMA) block in 2018. RESULTS: Systematic deviations of spot positions, mainly due to beam lateral offsets, were always found within 1.5 mm, with the exception of the initial clinical period. The number of particles was very stable, as possible deviations are exclusively related to the quantization error in the conversion from monitor counts to particles. For the chosen representative patient treatment, the gamma-index evaluation of prescribed and measured dose maps, before and after feedback implementation, showed a higher variability of maximum gamma for the 2012 irradiation, with respect to the reirradiation of 2018. However, the 2012 passing volume is >99.8% for the sum of all fields, which is comparable to the value of 2018, with the exception of one day with 98.2% passing volume, probably related to an instability of the accelerating system. CONCLUSIONS: A detailed retrospective analysis of the DDS performances in the initial period of CNAO clinical activity is reported. The spot position deviations are referable to beam lateral offset fluctuations, while almost no deviation was found in the number of particles. The impact of deviations on dose distributions showed that the position feedback implementation and the increased beam control capability acquired after the first years of clinical experience led to an evident improvement in the DDS stability, evaluated in terms of gamma-index as a measure of the impact on dose distributions. However, the clinical effect of the maximum gamma variability found in the 2012 representative irradiation is mitigated by averaging along the number of fractions, and the high percentage of passing volumes confirmed the accuracy of the delivery even before the feedback implementation.


Assuntos
Doses de Radiação , Radioterapia Assistida por Computador/métodos , Radioterapia com Íons Pesados , Humanos , Terapia com Prótons , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Estudos Retrospectivos
11.
Sci Rep ; 9(1): 8412, 2019 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-31182789

RESUMO

Colour polymorphism occurs when two or more genetically-based colour morphs permanently coexist within an interbreeding population. Colouration is usually associated to other life-history traits (ecological, physiological, behavioural, reproductive …) of the bearer, thus being the phenotypic marker of such set of genetic features. This visual badge may be used to inform conspecifics and to drive those decision making processes which may contribute maintaining colour polymorphism under sexual selection context. The importance of such information suggests that other communication modalities should be recruited to ensure its transfer in case visual cues were insufficient. Here, for the first time, we investigated the potential role of proteins from femoral gland secretions in signalling colour morph in a polymorphic lizard. As proteins are thought to convey identity-related information, they represent the ideal cues to build up the chemical modality used to badge colour morphs. We found strong evidence for the occurrence of morph-specific protein profiles in the three main colour-morphs of the common wall lizard, which showed both qualitative and quantitative differences in protein expression. As lizards are able to detect proteins by tongue-flicking and vomeronasal organ, this result support the hypothesis that colour polymorphic lizards may use a multimodal signal to inform about colour-morph.


Assuntos
Estruturas Animais/metabolismo , Lagartos/anatomia & histologia , Lagartos/metabolismo , Pigmentação , Proteínas/metabolismo , Sequência de Aminoácidos , Animais , Eletroforese em Gel Bidimensional , Masculino , Espectrometria de Massas , Peptídeos/química , Peptídeos/metabolismo
12.
Breast ; 45: 64-69, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30884340

RESUMO

PURPOSE: The evaluation of the surgical margin in breast conservative surgery is a matter of general interest as such treatments are subject to the critical issue of margin status as positive surgical margins can undermine the effectiveness of the procedure. The relatively unexplored ability of millimeter-wave (mm-wave) spectroscopy to provide insight into the dielectric properties of breast tissues was investigated as a precursor to their possible use in assessment of surgical margins. METHODS: We assessed the ability of a mm-wave system with a roughly hemispherical sensitive volume of ∼3 mm radius to distinguish malignant breast lesions in prospectively and consecutively collected tumoral and non-tumoral ex-vivo breast tissue samples from 91 patients. We characterized the dielectric properties of 346 sites in these samples, encompassing malignant, fibrocystic disease and normal breast tissues. An expert pathologist subsequently evaluated all measurement sites. RESULTS: At multivariate analysis, mm-wave dielectric properties were significantly correlated to histologic diagnosis and fat content. Further, using 5-fold cross-validation in a Bayesian logistic mixed model that considered the patient as a random effect, the mm-wave dielectric properties of neoplastic tissues were significantly different from normal breast tissues, but not from fibrocystic tissue. CONCLUSION: Reliable discrimination of malignant from normal, fat-rich breast tissue to a depth compatible with surgical margin assessment requirements was achieved with mm-wave spectroscopy.


Assuntos
Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Espectroscopia Dielétrica/estatística & dados numéricos , Margens de Excisão , Mastectomia Segmentar , Adulto , Idoso , Idoso de 80 Anos ou mais , Teorema de Bayes , Mama/patologia , Mama/cirurgia , Espectroscopia Dielétrica/métodos , Feminino , Doença da Mama Fibrocística/patologia , Doença da Mama Fibrocística/cirurgia , Humanos , Modelos Logísticos , Pessoa de Meia-Idade , Análise Multivariada , Estudos Prospectivos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
13.
Radiother Oncol ; 128(2): 203-208, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29279241

RESUMO

BACKGROUND AND PURPOSE: To compare RECIST 1.1 with volume modifications in patients with sacral chordoma not suitable for surgery treated with carbon ions radiotherapy (CIRT) alone. To evaluate patients pain before and after CIRT. To detect if baseline Apparent Diffusion Coefficient values (ADC) from Diffusion Weighted sequences could predict response to treatment. MATERIAL AND METHODS: Patients included had one cycle of CIRT and underwent MRI before and after treatment. For each MRI, lesion maximum diameter and volume were obtained, and ADC values were analyzed within the whole lesion volume. Patients pain was evaluated with Numerical Rating Scale (NRS), considering the upper tumor level at baseline MRIs. RESULTS: 39 patients were studied (mean follow-up 18 months). Considering RECIST 1.1 there was not a significant reduction in tumor diameters (p = 0.19), instead there was a significant reduction in tumor volume (p < 0.001), with a significant reduction in pain (p = 0.021) if the tumors were above vertebrae S2-S3 at baseline MRIs. The assessment of baseline ADC maps demonstrated higher median values and more negative skewness values in progressive disease (PD) patients versus both partial response (PR) and stable disease (SD). CONCLUSIONS: Lesion volume measurement is more accurate than maximum diameter to better stratify the response of sacral chordoma treated with CIRT. Preliminary results suggest that baseline ADC values could be predictive of response to CIRT.


Assuntos
Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/radioterapia , Cordoma/diagnóstico por imagem , Cordoma/radioterapia , Radioterapia com Íons Pesados/métodos , Imageamento por Ressonância Magnética/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Região Sacrococcígea/diagnóstico por imagem , Carga Tumoral
14.
Med Phys ; 44(4): 1577-1589, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28130821

RESUMO

PURPOSE: Advanced ion beam therapeutic techniques, such as hypofractionation, respiratory gating, or laser-based pulsed beams, have dose rate time structures which are substantially different from those found in conventional approaches. The biological impact of the time structure is mediated through the ß parameter in the linear quadratic (LQ) model. The aim of this study was to assess the impact of changes in the value of the ß parameter on the treatment outcomes, also accounting for noninstantaneous intrafraction dose delivery or fractionation and comparing the effects of using different primary ions. METHODS: An original formulation of the microdosimetric kinetic model (MKM) is used (named MCt-MKM), in which a Monte Carlo (MC) approach was introduced to account for the stochastic spatio-temporal correlations characteristic of the irradiations and the cellular repair kinetics. A modified version of the kinetic equations, validated on experimental cell survival in vitro data, was also introduced. The model, trained on the HSG cells, was used to evaluate the relative biological effectiveness (RBE) for treatments with acute and protracted fractions. Exemplary cases of prostate cancer irradiated with different ion beams were evaluated to assess the impact of the temporal effects. RESULTS: The LQ parameters for a range of cell lines (V79, HSG, and T1) and ion species (H, He, C, and Ne) were evaluated and compared with the experimental data available in the literature, with good results. Notably, in contrast to the original MKM formulation, the MCt-MKM explicitly predicts an ion and LET-dependent ß compatible with observations. The data from a split-dose experiment were used to experimentally determine the value of the parameter related to the cellular repair kinetics. Concerning the clinical case considered, an RBE decrease was observed, depending on the dose, ion, and LET, exceeding up to 3% of the acute value in the case of a protraction in the delivery of 10 min. The intercomparison between different ions shows that the clinical optimality is strongly dependent on a complex interplay between the different physical and biological quantities considered. CONCLUSIONS: The present study provides a framework for exploiting the temporal effects of dose delivery. The results show the possibility of optimizing the treatment outcomes accounting for the correlation between the specific dose rate time structure and the spatial characteristic of the LET distribution, depending on the ion type used.


Assuntos
Modelos Biológicos , Método de Monte Carlo , Doses de Radiação , Planejamento da Radioterapia Assistida por Computador , Linhagem Celular Tumoral , Humanos , Cinética , Radiometria , Dosagem Radioterapêutica , Eficiência Biológica Relativa , Processos Estocásticos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA