RESUMEN
PURPOSE: This multi-institutional study investigates whether computational verification of fluence-modulated treatment plans using independent software with its own Strahlerkopfmodel is an appropriate method for patient-related quality assurance (PRQA) in the context of various combinations of linear accelerators (linacs), treatment techniques and treatment planning systems (TPS). MATERIALS AND METHODS: The PRQA-software's (Mobius3D) recalculations of 9 institutions' treatment plans were analyzed for a horseshoe-shaped planning target volume (PTV) inside a phantom. The recomputed dose distributions were compared to a) the dose distributions as calculated by all TPS's and b) the measured dose distributions, which were acquired using the same independent measuring system for all institutions. Furthermore, dose volume histograms were examined. The penumbra deviations and mean gamma values were quantified using Verisoft (PTW). Additionally, workflow requirements for computational verification were discussed. RESULTS: Mobius3D is compatible with all examined TPSs, treatment techniques and linacs. The mean PTV dose differences (Mobius3D-TPS, <3.0%) and 3D gamma passing rates (>95.0%) led to a positive plan acceptance result in all cases. These results are similar to the outcome of the dosimetric measurements with one exception. The mean gamma values (<0.5) show a good agreement between Mobius3D and the TPS dose distributions. CONCLUSION: Using Mobius3D was proven to be an appropriate computational PRQA method for the tested combinations of linacs, treatment techniques and TPS's. The clinical use of Mobius3D has to be complemented with regular dosimetric measurements and thorough linac and TPS QA. Mobius3D's computational verification reduced measurement effort and personnel needs in comparison to dosimetric verifications.
Asunto(s)
Garantía de la Calidad de Atención de Salud/métodos , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/métodos , Humanos , Imagenología Tridimensional/métodos , Fantasmas de Imagen , Dosificación RadioterapéuticaRESUMEN
BACKGROUND: Acute HIV infection (AHI) is the phase of HIV infection immediately after acquisition, during which many patients develop symptoms and often seek healthcare. However, clinicians in sub-Saharan Africa are not currently taught about AHI. METHODS: This study pilot-tested a self-directed AHI training module among clinical officers (COs) in coastal Kenya and assessed knowledge gained and challenges to instituting screening. The training module included four domains: AHI definition and importance of AHI recognition; symptoms and screening algorithms; diagnostic strategies; and management. AHI knowledge was assessed before and immediately after training. Participants' ability to utilize an AHI screening algorithm was evaluated with a case-based exercise. RESULTS: Self-directed training was completed by 45 COs. Pre-test scores were low (median score 35% IQR 30-45%), but improved significantly after training (median post-test score 75%, IQR 70-85%, Wilcoxon signed-rank test p<0.0001). Participants had challenges in understanding the utility and application of a screening algorithm to identify patients for whom AHI testing would be indicated. Knowledge of AHI was poor at baseline, but improved with self-directed learning. Based on these findings, we revised and improved the AHI training module and pre- and post-assessments, which are now freely available online at www.marps-africa.org. CONCLUSIONS: Guidelines on AHI screening and diagnosis are urgently needed in high HIV transmission areas.
Asunto(s)
Educación a Distancia , Infecciones por VIH/diagnóstico , Tamizaje Masivo , Médicos de Atención Primaria/educación , Enfermedad Aguda , Adolescente , Adulto , Algoritmos , Atención Ambulatoria/estadística & datos numéricos , Competencia Clínica/estadística & datos numéricos , Femenino , Humanos , Kenia , Masculino , Aceptación de la Atención de Salud , Médicos de Atención Primaria/estadística & datos numéricos , Proyectos Piloto , Adulto JovenRESUMEN
PURPOSE: This project compares the different patient-related quality assurance systems for intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) techniques currently used in the central Germany area with an independent measuring system. MATERIALS AND METHODS: The participating institutions generated 21 treatment plans with different combinations of treatment planning systems (TPS) and linear accelerators (LINAC) for the QUASIMODO (Quality ASsurance of Intensity MODulated radiation Oncology) patient model. The plans were exposed to the ArcCHECK measuring system (Sun Nuclear Corporation, Melbourne, FL, USA). The dose distributions were analyzed using the corresponding software and a point dose measured at the isocenter with an ionization chamber. RESULTS: According to the generally used criteria of a 10 % threshold, 3 % difference, and 3 mm distance, the majority of plans investigated showed a gamma index exceeding 95 %. Only one plan did not fulfill the criteria and three of the plans did not comply with the commonly accepted tolerance level of ±3 % in point dose measurement. CONCLUSION: Using only one of the two examined methods for patient-related quality assurance is not sufficiently significant in all cases.
Asunto(s)
Neoplasias/radioterapia , Garantía de la Calidad de Atención de Salud/normas , Oncología por Radiación , Planificación de la Radioterapia Asistida por Computador/normas , Radioterapia Conformacional/instrumentación , Radioterapia Conformacional/normas , Análisis de Falla de Equipo , Alemania , Adhesión a Directriz/normas , Humanos , Atención Dirigida al Paciente/normas , Dosificación Radioterapéutica , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
4-Phenol diazonium salts undergo Pd-catalyzed Heck reactions with various styrenes to 4'-hydroxy stilbenes. In almost all cases higher yields and fewer side products were observed, compared to the analogous 4-methoxy benzene diazonium salts. In contrast, the reaction fails completely with 2- and 3-phenol diazonium salts. For these substitution patterns the methoxy-substituted derivatives are superior.
Asunto(s)
Compuestos de Diazonio/química , Fenoles/síntesis química , Sales (Química)/química , Estilbenos/síntesis química , Estirenos/química , Catálisis , Paladio/química , Fenoles/química , Estilbenos/químicaRESUMEN
Alkynes and phenol diazonium salts undergo a Pd-catalyzed [2+2+1] cyclization reaction to spiro[4,5]decatetraene-7-ones. This structure was confirmed for one example by X-ray single-crystal structure analysis. The reaction is believed to proceed through oxidative addition of the phenol diazonium cation to Pd(0), subsequent insertion of two alkynes, followed by irreversible spirocyclization.
RESUMEN
Arene diazonium tetrafluoroborates can be synthesized from aromatic acetamides via a sequence of deacetylation, diazotation and precipitation, induced by anion exchange. The reaction is conducted as a convenient one-flask transformation with consecutive addition of the appropriate reagents. Exchange of solvents or removal of byproducts prior to isolation of the product is not required. The arene diazonium salts are isolated from the reaction mixture by simple filtration. Two complementary protocols are presented, and the utility of the reaction is exemplified for a synthesis of the diarylheptanoid natural product de-O-methyl centrolobine.