ABSTRACT
Purpose: Purpose: Subtotal skin electron beam therapy may be an option for patients with cutaneous lymphoma receiving radiation therapy to treat large areas of their skin but may benefit from sparing specific areas that may have had previous radiation therapy, are of specific cosmetic concern, and/or show no evidence of disease. We report here on the design, implementation, and dosimetric characteristics of a reusable and transparent customizable shield for use with the large fields used to deliver total skin electron beam therapy at extended distance with a conventional linear accelerator. Methods and Materials: A shield was designed and manufactured consisting of acrylic blocks that can be mounted on a steel frame to allow patient-specific shielding. The dosimetry of the device was measured using radiochromic film. Results: The shield is easy to use and well-tolerated for patient treatment, providing minimal electron transmission through the shield with a sharp penumbra at the field edge, with no increase in x-ray dose. We report on the dosimetry of a commercial device that has been used to treat more than 30 patients to date. Conclusions: The customizable shield is well suited to providing patient-specific shielding for subtotal skin electron beam therapy.
ABSTRACT
Objetive: Evaluate an Ozone Generating System (OGS) through of the microorganisms count and identificated in the air of the sanitary environments of the National Institute of Health (INS) from Peru. These were The study:exposed to OGS for 1 min per m2, air samples were collected at volumes of 200L, 500Land 1000Lby impaction, pre and post exposure to OGS, cultures were obtained on Plate Count Agar (PCA) and Oxytetracycline Glucose Agar (OGA) grown at 35°C±2°C for 48 hours and 25°C ± 2°C for 5 days.Adecrease Findings:in the count of fungi after exposure to OGS, the difference being statistically significant for the volumes of 200L(p=0.047) and 1000 L(p<0.005); Aspergillus spp. species were identified in most cultures, in bacteria no significant difference was observed.The OGS is a method that inhibits the Conclusions:growth of most fungi in sanitary environments.
Objetivo: Evaluar un Sistema Generador de Ozono (SGO) a través del recuento e identificación de microorganismos en el aire de los ambientes sanitarios del Instituto Nacional de Salud (INS) del Perú. El estudio: Los ambientes fueron expuestos a SGO por 1 min por m2, se recolectaron muestras de aire en volúmenes de 200L, 500L y 1000L por impactación, pre y post exposición a SGO; los cultivos se obtuvieron en Plate Count Agar (PCA) y Oxitetracicline Glucose Agar (OGA) cultivados a 35 °C ± 2 °C durante 48 horas y 25 °C ± 2 °C durante 5 días. Hallazgos: Disminución del recuento de hongos post exposición a SGO, la diferencia fue estadísticamente significativa para los volúmenes de 200L (p=0.047) y 1000 L (p<0.005); especies de Aspergillus spp. fueron identificados en la mayoría de los cultivos; en bacterias no se observaron diferencias significativas. Conclusiones: El SGO es un método que inhibe el crecimiento de la mayoría de hongos en ambientes sanitarios.
ABSTRACT
RESUMEN El presente estudio, tuvo por objetivo evaluar una intervención psicoterapéutica con base en psicodrama para el personal de salud de un hospital que atiende pacientes con COVID-19 en la ciudad de Apodaca, Nuevo León, México. Se estudió a una población con ansiedad y/o depresión, midiendo sus síntomas con el Test de Goldberg. Se trató a los sujetos mediante sesiones de psicodrama y se lograron disminuir significativamente síntomas como preocupación, nerviosismo, irritabilidad; se consiguió además, aumentar la energía y el interés por las cosas en los participantes.
RESUMO O presente estudo teve como objetivo avaliar uma intervenção psicoterapêutica baseada no psicodrama para os profissionais de saúde de um hospital que atende pacientes com COVID-19 na cidade de Apodaca, Nuevo León, México. Foi estudada uma população com ansiedade e/ou depressão, mensurando seus sintomas com o teste de Goldberg. Os indivíduos tratados em sessões de psicodrama mostram sintomas como preocupação, nervosismo e irritabilidade significativamente reduzidos. Também foi possível aumentar a energia e o interesse pelas coisas nos participantes.
ABSTRACT The present study aimed to provide a psychotherapeutic alternative based on psychodrama for the health personnel of a hospital that treats patients with COVID-19 in the city of Apodaca, Nuevo León, Mexico. The population with anxiety and/or depression was detected, measuring their symptoms with the Goldberg test. Subjects were treated through psychodrama sessions and symptoms such as worry, nervousness, irritability were significantly reduced; It was also possible to increase the energy and interest in things in the participants.
ABSTRACT
BACKGROUND: Minibeam radiation therapy is an experimental radiation therapy utilizing an array of parallel submillimeter planar X-ray beams. In preclinical studies, minibeam radiation therapy has been shown to eradicate tumors and cause significantly less damage to normal tissue compared to equivalent radiation doses delivered by conventional broadbeam radiation therapy, where radiation dose is uniformly distributed. METHODS: Expanding on prior studies that suggested minibeam radiation therapy increased perfusion in tumors, we compared a single fraction of minibeam radiation therapy (peak dose:valley dose of 28 Gy:2.1 Gy and 100 Gy:7.5 Gy) and broadbeam radiation therapy (7 Gy) in their ability to enhance tumor delivery of PEGylated liposomal doxorubicin and alter the tumor microenvironment in a murine tumor model. Plasma and tumor pharmacokinetic studies of PEGylated liposomal doxorubicin and tumor microenvironment profiling were performed in a genetically engineered mouse model of claudin-low triple-negative breast cancer (T11). RESULTS: Minibeam radiation therapy (28 Gy) and broadbeam radiation therapy (7 Gy) increased PEGylated liposomal doxorubicin tumor delivery by 7.1-fold and 2.7-fold, respectively, compared to PEGylated liposomal doxorubicin alone, without altering the plasma disposition. The enhanced tumor delivery of PEGylated liposomal doxorubicin by minibeam radiation therapy is consistent after repeated dosing, is associated with changes in tumor macrophages but not collagen or angiogenesis, and nontoxic to local tissues. Our study indicated that the minibeam radiation therapy's ability to enhance the drug delivery decreases from 28 to 100 Gy peak dose. DISCUSSION: Our studies suggest that low-dose minibeam radiation therapy is a safe and effective method to significantly enhance the tumor delivery of nanoparticle agents.
ABSTRACT
PURPOSE: To identify key dosimetric parameters that have close associations with tumor treatment response and body weight change in SFRT treatments with a large range of spatial-fractionation scale at dose rates of several Gy/min. METHODS: Six study arms using uniform tumor radiation, half-tumor radiation, 2mm beam array radiation, 0.3mm minibeam radiation, and an untreated arm were used. All treatments were delivered on a 320kV x-ray irradiator. Forty-two female Fischer 344 rats with fibrosarcoma tumor allografts were used. Dosimetric parameters studied are peak dose and width, valley dose and width, peak-to-valley-dose-ratio (PVDR), volumetric average dose, percentage volume directly irradiated, and tumor- and normal-tissue EUD. Animal survival, tumor volume change, and body weight change (indicative of treatment toxicity) are tested for association with the dosimetric parameters using linear regression and Cox Proportional Hazards models. RESULTS: The dosimetric parameters most closely associated with tumor response are tumor EUD (R2 = 0.7923, F-stat = 15.26*; z-test = -4.07***), valley (minimum) dose (R2 = 0.7636, F-stat = 12.92*; z-test = -4.338***), and percentage tumor directly irradiated (R2 = 0.7153, F-stat = 10.05*; z-test = -3.837***) per the linear regression and Cox Proportional Hazards models, respectively. Tumor response is linearly proportional to valley (minimum) doses and tumor EUD. Average dose (R2 = 0.2745, F-stat = 1.514 (no sig.); z-test = -2.811**) and peak dose (R2 = 0.04472, F-stat = 0.6874 (not sig.); z-test = -0.786 (not sig.)) show the weakest associations to tumor response. Only the uniform radiation arm did not gain body weight post-radiation, indicative of treatment toxicity; however, body weight change in general shows weak association with all dosimetric parameters except for valley (minimum) dose (R2 = 0.3814, F-stat = 13.56**), valley width (R2 = 0.2853, F-stat = 8.783**), and peak width (R2 = 0.2759, F-stat = 8.382**). CONCLUSIONS: For a single-fraction SFRT at conventional dose rates, valley, not peak, dose is closely associated with tumor treatment response and thus should be used for treatment prescription. Tumor EUD, valley (minimum) dose, and percentage tumor directly irradiated are the top three dosimetric parameters that exhibited close associations with tumor response.
Subject(s)
Dose Fractionation, Radiation , Fibrosarcoma/radiotherapy , Animals , Body Weight/radiation effects , Disease Models, Animal , Female , Fibrosarcoma/pathology , Radiometry , Rats , Rats, Inbred F344 , Treatment Outcome , Tumor Burden/radiation effectsABSTRACT
[This corrects the article DOI: 10.7150/thno.19703.].
ABSTRACT
Cancer affects 39.6% of Americans at some point during their lifetime. Solid tumor microenvironments are characterized by a disorganized, leaky vasculature that promotes regions of low oxygenation (hypoxia). Tumor hypoxia is a key predictor of poor treatment outcome for all radiotherapy (RT), chemotherapy and surgery procedures, and is a hallmark of metastatic potential. In particular, the radiation therapy dose needed to achieve the same tumor control probability in hypoxic tissue as in normoxic tissue can be up to 3 times higher. Even very small tumors (<2-3 mm3) comprise 10-30% of hypoxic regions in the form of chronic and/or transient hypoxia fluctuating over the course of seconds to days. We investigate the potential of recently developed lipid-stabilized oxygen microbubbles (OMBs) to improve the therapeutic ratio of RT. OMBs, but not nitrogen microbubbles (NMBs), are shown to significantly increase dissolved oxygen content when added to water in vitro and increase tumor oxygen levels in vivo in a rat fibrosarcoma model. Tumor control is significantly improved with OMB but not NMB intra-tumoral injections immediately prior to RT treatment and effect size is shown to depend on initial tumor volume on RT treatment day, as expected.
Subject(s)
Fibrosarcoma/radiotherapy , Microbubbles/therapeutic use , Oxygen/therapeutic use , Animals , Female , Fibrosarcoma/metabolism , Humans , Oxygen/administration & dosage , Oxygen/metabolism , Rats , Rats, Inbred F344 , Sarcoma, Experimental/metabolism , Sarcoma, Experimental/radiotherapy , Translational Research, Biomedical , Tumor Hypoxia/drug effectsABSTRACT
Measuring changes in tumor volume using anatomical imaging weeks to months post radiation therapy (RT) is currently the clinical standard for indicating treatment response to RT. For patients whose tumors do not respond successfully to treatment, this approach is suboptimal as timely modification of the treatment approach may lead to better clinical outcomes. We propose to use tumor microvasculature as a biomarker for early assessment of tumor response to RT. Acoustic angiography is a novel contrast ultrasound imaging technique that enables high-resolution microvascular imaging and has been shown to detect changes in microvascular structure due to cancer growth. Data suggest that acoustic angiography can detect longitudinal changes in the tumor microvascular environment that correlate with RT response. Methods: Three cohorts of Fisher 344 rats were implanted with rat fibrosarcoma tumors and were treated with a single fraction of RT at three dose levels (15 Gy, 20 Gy, and 25 Gy) at a dose rate of 300 MU/min. A simple treatment condition was chosen for testing the feasibility of our imaging technique. All tumors were longitudinally imaged immediately prior to and after treatment and then every 3 days after treatment for a total of 30 days. Both acoustic angiography (using in-house produced microbubble contrast agents) and standard b-mode imaging was performed at each imaging time point using a pre-clinical Vevo770 scanner and a custom modified dual-frequency transducer. Results: Results show that all treated tumors in each dose group initially responded to treatment between days 3-15 as indicated by decreased tumor growth accompanied with decreased vascular density. Untreated tumors continued to increase in both volume and vascular density until they reached the maximum allowable size of 2 cm in diameter. Tumors that displayed complete control (no tumor recurrence) continued to decrease in size and vascular density, while tumors that progressed after the initial response presented an increase in tumor volume and volumetric vascular density. The increase in tumor volumetric vascular density in recurring tumors can be detected 10.25 ± 1.5 days, 6 ± 0 days, and 4 ± 1.4 days earlier than the measurable increase in tumor volume in the 15, 20, and 25 Gy dose groups, respectively. A dose-dependent growth rate for tumor recurrence was also observed. Conclusions: In this feasibility study we have demonstrated the ability of acoustic angiography to detect longitudinal changes in vascular density, which was shown to be a potential biomarker for tumor response to RT.
Subject(s)
Fibrosarcoma/diagnostic imaging , Microbubbles , Microvessels/diagnostic imaging , Ultrasonography/methods , Animals , Biomarkers/analysis , Female , Humans , RatsABSTRACT
GRID directs alternating regions of high- and low-dose radiation at tumors. A large animal model mimicking the geometries of human treatments is needed to complement existing rodent systems (eg, microbeam) and clarify the physical and biological attributes of GRID. A pilot study was undertaken in pet dogs with spontaneous soft tissue sarcomas to characterize responses to GRID. Subjects were treated with either 20 Gy (3 dogs) or 25 Gy (3 dogs), delivered using 6 MV X-rays and a commercial GRID collimator. Acute toxicity and tumor responses were assessed 2, 4, and 6 weeks later. Acute Radiation Therapy Oncology Group grade I skin toxicity was observed in 3 of the 6 dogs; none experienced a measurable response, per Response Evaluation Criteria in Solid Tumors. Serum vascular endothelial growth factor, tumor necrosis factor α, and secretory sphingomyelinase were assayed at baseline, 1, 4, 24, and 48 hours after treatment. There was a trend toward platelet-corrected serum vascular endothelial growth factor concentration being lower 1 and 48 hours after GRID than at baseline. There was a significant decrease in secretory sphingomyelinase activity 48 hours after 25 Gy GRID ( P = .03). Serum tumor necrosis factor α was quantified measurable at baseline in 4 of the 6 dogs and decreased in each of those subjects at all post-GRID time points. The new information generated by this study includes the observation that high-dose, single fraction application of GRID does not induce measurable reduction in volume of canine soft tissue sarcomas. In contrast to previously published data, these data suggest that GRID may be associated with at least short-term reduction in serum concentration of vascular endothelial growth factor and serum activity of secretory sphingomyelinase. Because GRID can be applied safely, and these tumors can be subsequently surgically resected as part of routine veterinary care, pet dogs with sarcomas are an appealing model for studying the radiobiologic responses to spatially fractionated radiotherapy.
Subject(s)
Dose Fractionation, Radiation , Radiotherapy/methods , Sarcoma/radiotherapy , Animals , Combined Modality Therapy , Disease Models, Animal , Dogs , Female , Humans , Male , Pilot Projects , Radiotherapy/standards , Sarcoma/pathology , Sarcoma/surgeryABSTRACT
Craniofacial asymmetry is a very common finding. Possible etiologies include genetic and environmental factors or a combination of both. There is no age or gender preference for the development ofcraniofacial asymmetries in general, except for the postural plagiocephaly, which has been more frequently found in male babies. Craniofacial asymmetries have been identified before birth in presumably normalfetuses. Congenital and non-congenital craniofacial asymmetries have been related to certain types ofpathology. One or more of the different structures of the cranial, dentoalveolar, and/or mandibular areas may be involved in the existing asymmetry. Assuming there is good function, soft tissue may camouflage an existing skeletal craniofacial asymmetry. No correlation has been established between craniofacial asymmetries and malocclusion. However, a correlation between soft tissue dysfunction and postural changes has been established and may account for a chain ofcompensatory effects that may include the development or the amplification ofan existing craniofacial asymmetry.
