Niveles de referencia para diagnóstico: una herramienta efectiva para la protección radiológica de pacientes / Diagnostic reference levels: an effective tool to radiological protection of patient

Se sabe que las exposiciones médicas con radiaciones ionizantes son actualmente la principal fuente de exposición a la radiación artificial a nivel global. Para prevenir dosis innecesariamente altas durante estas exposiciones a los pacientes, la Comisión Internacional de Protección Radiológica (ICRP) recomienda la utilización de los Niveles de Referencia para Diagnóstico (DRLs), como una herramienta efectiva de ayuda a la optimización de la protección radiológica en la exposición médica de pacientes para diagnóstico y procedimientos de intervención. Dado que la legislación chilena no tiene incorporado aún su uso, el presente trabajo de revisión tiene como objetivo, elaborar un documento guía para los profesionales de la salud y áreas afines, que contenga de manera sucinta y con recomendaciones prácticas, los principales aspectos a tener en cuenta para establecer los DRLs en procedimientos de radiodiagnóstico, intervencionismo y medicina nuclear, basados esencialmente en la publicación N° 135 de la ICRP sobre DRLs.

It is known that medical exposition with ionizing radiation is currently the main exposition source to artificial radiation at global level. To prevent unnecessarily high doses during these patient expositions, the International Commission on Radiological Protection (ICRP) recommends the use of Diagnostic Reference Levels (DRLs), as an effective tool to support the optimization of radiological protection for patient medical exposure for diagnosis and interventional procedures. Since that the Chilean legislation does not have its use incorporated yet, the present revision work aims to elaborate a guiding document for health professionals and related fields, that succinctly and with practical recommendations, the main aspects to consider for establishing DRLs in procedures for radiodiagnostic, intervention, and nuclear medicine, mainly based in N° 135 ICRP publication about DRLs.

Automated production of [68 Ga]Ga-DOTANOC and [68 Ga]Ga-PSMA-11 using a TRACERlab FXFN synthesis module.

The interest in gallium-68 labelled positron-emission tomography probes continues to increase around the world. However, one of the barriers for routine clinical use is the cost of the automated synthesis units for relatively simple labelling procedures. Herein, we describe the adaptation of a TRACERlab FXFN synthesis module for the automated production of gallium-68 radiopharmaceuticals using a cation-exchange cartridge for postprocessing of the 68 Ge/68 Ga generator eluate. The recovery of activity from the cartridge was 95.6% to 98.9% using solutions of acidified sodium chloride (5 M with pH = 1-3). The radiosyntheses of [68 Ga]Ga-DOTANOC and [68 Ga]Ga-PSMA-11 were performed using acetate sodium buffer or 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid, with a total duration of 21 and 23 minutes, respectively, including generator elution and radiopharmaceutical dispensing. Activity yields were 77% ± 2% for [68 Ga]Ga-PSMA-11 and 68% ± 3% for [68 Ga]Ga-DOTANOC (n > 100). The labelled peptides had a radiochemical purity exceeding 97%, and all quality control parameters were in conformity with the limits prescribed by the European Pharmacopoeia.

Satisfacción del alumnado en actividades de grupo reducido en Medicina mediante el uso de mandos de respuesta interactiva basados en radiofrecuencias / Student satisfaction in small group activities in Medicine using interactive response controls based on radio frequencies

INTRODUCCIÓN: El proceso docente actual necesita cambios mediante la introducción de las nuevas tecnologías de la información y la comunicación (TIC) por medio de nuevos sistemas de hardware y software. Tras unos primeros años de introducción y adaptación, hoy en día, el uso de equipos informáticos fijos, portátiles, móviles y tabletas se ha convertido en un aspecto cotidiano para todos los individuos, permitiendo que nuevas tecnologías se puedan implantar de una manera más natural. En este sentido, la Facultad de Medicina de Málaga se ha planteado el uso de mandos de respuesta interactivos mediante radiofrecuencias en actividades de grupo reducido ya que se postulan como una herramienta de gran utilidad que podrían mejorar la calidad de la docencia, permitiendo una evaluación de la misma en tiempo real, superando la realizada por los métodos más clásicos como el examen escrito u oral. MATERIAL Y MÉTODOS: Tras realizar cursos de formación al personal implicado y dotar las aulas con el hardware preciso, se procedió a entregar a todos los alumnos un mando de respuesta interactiva por radiofrecuencia de forma gratuita para realizar diversas actividades en grupos reducidos un total de 12 asignaturas (6 básicas y 6 clínicas) mediante preguntas tipo test unirrespuesta y posteriormente una encuesta de satisfacción. Se analizó la estadística descriptiva y comparativa de los datos obtenidos. RESULTADOS Y DISCUSIÓN: Los objetivos de nuestro estudio han ido enfocados a comprobar la eficacia de la implantación de los mandos de respuesta interactiva en las actividades de grupo reducido en el grado en Medicina. Todos los resultados mostraron una distribución normal. El número de alumnos que participaron en la experiencia fue de 1.645, divididos en 6 asignaturas básicas y 6 clínicas. En el análisis conjunto el promedio de aciertos en las actividades de evaluación de la docencia en grupos reducidos mediante test unirrespuesta fue de 73,3±2,7% con un grado de satisfacción de 4,3±0,2 sobre 5. En el análisis comparativo entre asignaturas básicas y clínicas mediante t de Student, se observó un mayor promedio de aciertos en las asignaturas básicas (79,3±2,9 vs. 67,3±3,1) con un grado de satisfacción similar (4,3±0,3 vs. 4,2±0,2). El uso de mandos de radiofrecuencia se ha mostrado como una herramienta útil como apoyo a la docencia en grupos reducidos, facilitando una buena adquisición de competencias específicas y un elevado grado de satisfacción por parte del alumnado

INTRODUCTION: The current teaching process needs changes with the introduction of new information and communications technology (ICT) using new hardware and software systems. After a few years of introduction and adaptation, the use of computers, laptops, mobile phones, and tablets is now normal for everyone, allowing new technologies to be implemented more naturally. The Faculty of Medicine of Malaga has proposed the use of interactive response controls through radio frequencies in small group activities, because they can be a very useful tool to improve the quality of teaching, allowing an evaluation in real time, and exceeding the classical methods, such as a written or oral examination. MATERIAL AND METHODS: After giving training courses for the staff involved and setting-up of classrooms with the necessary hardware, all students were given a remote interactive response radiofrequency control for free to be used in small groups for 12 teaching subjects (6 basic and 6 clinical) to answer single-response test questions. They then completed a satisfaction questionnaire. A descriptive and comparative statistical analysis was performed on the data obtained. RESULTS AND DISCUSSION: The objectives of our study were to test the effectiveness of the implementation of interactive response control in small group activities in the Faculty of Medicine. All the results showed a normal distribution. The number of students who participated were 1645, divided into 6 basic and 6 clinical subjects. The mean of correct responses in small activities in both groups using a single answer test was 73.32% ±2.7%, with a satisfaction level of 4.3±0.2 out of 5. In the comparative analysis between basic subjects and clinical subject, using Student's t test, a higher mean was observed in the basic subjects (79.3±2.9 vs 67.3±3.1), with a similar level of satisfaction (4.3±0.3 vs 4.2±0.2). These results show that the use of radiofrequency controls are a useful tool to support teaching in small groups, helping to acquire specific skills and a high level of satisfaction by the students

Mild Developmental Foreign Accent Syndrome and Psychiatric Comorbidity: Altered White Matter Integrity in Speech and Emotion Regulation Networks.

Foreign accent syndrome (FAS) is a speech disorder that is defined by the emergence of a peculiar manner of articulation and intonation which is perceived as foreign. In most cases of acquired FAS (AFAS) the new accent is secondary to small focal lesions involving components of the bilaterally distributed neural network for speech production. In the past few years FAS has also been described in different psychiatric conditions (conversion disorder, bipolar disorder, and schizophrenia) as well as in developmental disorders (specific language impairment, apraxia of speech). In the present study, two adult males, one with atypical phonetic production and the other one with cluttering, reported having developmental FAS (DFAS) since their adolescence. Perceptual analysis by naïve judges could not confirm the presence of foreign accent, possibly due to the mildness of the speech disorder. However, detailed linguistic analysis provided evidence of prosodic and segmental errors previously reported in AFAS cases. Cognitive testing showed reduced communication in activities of daily living and mild deficits related to psychiatric disorders. Psychiatric evaluation revealed long-lasting internalizing disorders (neuroticism, anxiety, obsessive-compulsive disorder, social phobia, depression, alexithymia, hopelessness, and apathy) in both subjects. Diffusion tensor imaging (DTI) data from each subject with DFAS were compared with data from a group of 21 age- and gender-matched healthy control subjects. Diffusion parameters (MD, AD, and RD) in predefined regions of interest showed changes of white matter microstructure in regions previously related with AFAS and psychiatric disorders. In conclusion, the present findings militate against the possibility that these two subjects have FAS of psychogenic origin. Rather, our findings provide evidence that mild DFAS occurring in the context of subtle, yet persistent, developmental speech disorders may be associated with structural brain anomalies. We suggest that the simultaneous involvement of speech and emotion regulation networks might result from disrupted neural organization during development, or compensatory or maladaptive plasticity. Future studies are required to examine whether the interplay between biological trait-like diathesis (shyness, neuroticism) and the stressful experience of living with mild DFAS lead to the development of internalizing psychiatric disorders.

Loss of regional accent after damage to the speech production network.

Lesion-symptom mapping studies reveal that selective damage to one or more components of the speech production network can be associated with foreign accent syndrome, changes in regional accent (e.g., from Parisian accent to Alsatian accent), stronger regional accent, or re-emergence of a previously learned and dormant regional accent. Here, we report loss of regional accent after rapidly regressive Broca's aphasia in three Argentinean patients who had suffered unilateral or bilateral focal lesions in components of the speech production network. All patients were monolingual speakers with three different native Spanish accents (Cordobés or central, Guaranítico or northeast, and Bonaerense). Samples of speech production from the patient with native Córdoba accent were compared with previous recordings of his voice, whereas data from the patient with native Guaranítico accent were compared with speech samples from one healthy control matched for age, gender, and native accent. Speech samples from the patient with native Buenos Aires's accent were compared with data obtained from four healthy control subjects with the same accent. Analysis of speech production revealed discrete slowing in speech rate, inappropriate long pauses, and monotonous intonation. Phonemic production remained similar to those of healthy Spanish speakers, but phonetic variants peculiar to each accent (e.g., intervocalic aspiration of /s/ in Córdoba accent) were absent. While basic normal prosodic features of Spanish prosody were preserved, features intrinsic to melody of certain geographical areas (e.g., rising end F0 excursion in declarative sentences intoned with Córdoba accent) were absent. All patients were also unable to produce sentences with different emotional prosody. Brain imaging disclosed focal left hemisphere lesions involving the middle part of the motor cortex, the post-central cortex, the posterior inferior and/or middle frontal cortices, insula, anterior putamen and supplementary motor area. Our findings suggest that lesions affecting the middle part of the left motor cortex and other components of the speech production network disrupt neural processes involved in the production of regional accent features.

Bilateral brain reorganization with memantine and constraint-induced aphasia therapy in chronic post-stroke aphasia: An ERP study.

Changes in ERP (P100 and N400) and root mean square (RMS) were obtained during a silent reading task in 28 patients with chronic post-stroke aphasia in a randomized, double-blind, placebo-controlled trial of both memantine and constraint-induced aphasia therapy (CIAT). Participants received memantine/placebo alone (weeks 0-16), followed by drug treatment combined with CIAT (weeks 16-18), and then memantine/placebo alone (weeks 18-20). ERP/RMS values (week 16) decreased more in the memantine group than in the placebo group. During CIAT application (weeks 16-18), improvements in aphasia severity and ERP/RMS values were amplified by memantine and changes remained stable thereafter (weeks 18-20). Changes in ERP/RMS occurred in left and right hemispheres and correlated with gains in language performance. No changes in ERP/RMS were found in a healthy group in two separated evaluations. Our results show that aphasia recovery induced by both memantine alone and in combination with CIAT is indexed by bilateral cortical potentials.

Valor de la resonancia magnética en la medición del espesor tumoral en el cáncer de lengua: correlación del espesor radiológico con el espesor anatomopatológico en una muestra de 15 pacientes / Magnetic resonance imaging for measuring tumour thickness in cancer of the tongue: Correlation with the histopathological thickness in a sample of 15 patients

Objetivo: El propósito de este estudio ha sido estudiar la correlación de la medida del espesor radiológico en el cáncer de lengua en el estudio prequirúrgico por resonancia magnética respecto al espesor anatomopatológico tras la resección tumoral. El espesor tumoral es un factor predictivo para la presencia de metástasis cervicales, además de ser un factor pronóstico independiente para la supervivencia global y libre de enfermedad. La medida del espesor en estadios precoces es crucial para determinar la actitud terapéutica en estos pacientes. Material y método: Análisis retrospectivo de 15 pacientes intervenidos en el Servicio de Cirugía Maxilofacial del Hospital Regional Universitario Carlos Haya en el periodo 2008-2010. Se realizaron mediciones del espesor radiológico por resonancia magnética en secuencias T1 con contraste y se estudió la correlación respecto al espesor anatomopatológico de la pieza quirúrgica. Resultados: Al realizar el test de correlación lineal de Pearson con ambas medidas hallamos un índice de correlación del 0,897, lo cual apunta hacia una correlación positiva y fuerte. Conclusiones: La resonancia magnética es útil en la evaluación prequirúrgica en el cáncer de lengua y ha demostrado ser una prueba diagnóstica fiable en la medición del espesor tumoral (AU)

Objective: The aim of this study was to analyse the correlation between the radiological thickness of cancer of the tongue in the pre-surgical study using magnetic resonance imaging and the histopathological thickness after the tumour resection. The tumour thickness is a predictive factor for the presence of neck metastases, as well as an independent prognostic factor of overall and disease free survival. The measuring of the thickness in the early stages is essential to determine the therapeutic response in these patients. Material and method: A retrospective analysis was performed on 15 patients subjected to surgery in the Maxillofacial Surgery Department HRU Carlos Haya in the period 2008-2010. Measurements of the radiological thickness were made using magnetic resonance in T1sequences with contrast, and the correlation with histopathological thickness of the surgical piece was analysed. Results: Using the Pearson linear correlation test with both measurements, there was a correlation of 0.897, which indicated a positive and strong agreement. Conclusions: Magnetic resonance is useful in the pre-surgical evaluation in cancer of the tongue and has shown to be a reliable diagnostic test for measuring tumour thickness (AU)

Repeating with the right hemisphere: reduced interactions between phonological and lexical-semantic systems in crossed aphasia?

Knowledge on the patterns of repetition amongst individuals who develop language deficits in association with right hemisphere lesions (crossed aphasia) is very limited. Available data indicate that repetition in some crossed aphasics experiencing phonological processing deficits is not heavily influenced by lexical-semantic variables (lexicality, imageability, and frequency) as is regularly reported in phonologically-impaired cases with left hemisphere damage. Moreover, in view of the fact that crossed aphasia is rare, information on the role of right cortical areas and white matter tracts underpinning language repetition deficits is scarce. In this study, repetition performance was assessed in two patients with crossed conduction aphasia and striatal/capsular vascular lesions encompassing the right arcuate fasciculus (AF) and inferior frontal-occipital fasciculus (IFOF), the temporal stem and the white matter underneath the supramarginal gyrus. Both patients showed lexicality effects repeating better words than non-words, but manipulation of other lexical-semantic variables exerted less influence on repetition performance. Imageability and frequency effects, production of meaning-based paraphrases during sentence repetition, or better performance on repeating novel sentences than overlearned clichés were hardly ever observed in these two patients. In one patient, diffusion tensor imaging disclosed damage to the right long direct segment of the AF and IFOF with relative sparing of the anterior indirect and posterior segments of the AF, together with fully developed left perisylvian white matter pathways. These findings suggest that striatal/capsular lesions extending into the right AF and IFOF in some individuals with right hemisphere language dominance are associated with atypical repetition patterns which might reflect reduced interactions between phonological and lexical-semantic processes.

Dissociated repetition deficits in aphasia can reflect flexible interactions between left dorsal and ventral streams and gender-dimorphic architecture of the right dorsal stream.

Assessment of brain-damaged subjects presenting with dissociated repetition deficits after selective injury to either the left dorsal or ventral auditory pathways can provide further insight on their respective roles in verbal repetition. We evaluated repetition performance and its neural correlates using multimodal imaging (anatomical MRI, DTI, fMRI, and(18)FDG-PET) in a female patient with transcortical motor aphasia (TCMA) and in a male patient with conduction aphasia (CA) who had small contiguous but non-overlapping left perisylvian infarctions. Repetition in the TCMA patient was fully preserved except for a mild impairment in nonwords and digits, whereas the CA patient had impaired repetition of nonwords, digits and word triplet lists. Sentence repetition was impaired, but he repeated novel sentences significantly better than clichés. The TCMA patient had tissue damage and reduced metabolism in the left sensorimotor cortex and insula. DTI showed damage to the left temporo-frontal and parieto-frontal segments of the arcuate fasciculus (AF) and part of the left ventral stream together with well-developed right dorsal and ventral streams, as has been reported in more than one-third of females. The CA patient had tissue damage and reduced metabolic activity in the left temporoparietal cortex with additional metabolic decrements in the left frontal lobe. DTI showed damage to the left temporo-parietal and temporo-frontal segments of the AF, but the ventral stream was spared. The direct segment of the AF in the right hemisphere was also absent with only vestigial remains of the other dorsal subcomponents present, as is often found in males. fMRI during word and nonword repetition revealed bilateral perisylvian activation in the TCMA patient suggesting recruitment of spared segments of the left dorsal stream and right dorsal stream with propagation of signals to temporal lobe structures suggesting a compensatory reallocation of resources via the ventral streams. The CA patient showed a greater activation of these cortical areas than the TCMA patient, but these changes did not result in normal performance. Repetition of word triplet lists activated bilateral perisylvian cortices in both patients, but activation in the CA patient with very poor performance was restricted to small frontal and posterior temporal foci bilaterally. These findings suggest that dissociated repetition deficits in our cases are probably reliant on flexible interactions between left dorsal stream (spared segments, short tracts remains) and left ventral stream and on gender-dimorphic architecture of the right dorsal stream.

Atypical conduction aphasia and the right hemisphere: Cross-hemispheric plasticity of phonology in a developmentally dyslexic and dysgraphic patient with early left frontal damage.

We report the rare case of a patient, JNR, with history of mixed handedness, developmental dyslexia, dysgraphia, and attentional deficits associated with a Klippel-Trenaunay syndrome and a small subcortical frontal lesion involving the left arcuate fasciculus. In adulthood, he suffered a large right perisylvian stroke and developed atypical conduction aphasia with deficits in input and output phonological processing and poor auditory-verbal short-term memory. Lexical-semantic processing for single words was intact, but he was unable to access meaning in sentence comprehension and repetition. Reading and writing deficits worsened after the stroke and he presented a combination of developmental and acquired dysgraphia and dyslexia with mixed lexical and phonological processing deficits. This case suggest that a small lesion sustained prenatally or early in life could induce a selective rightward shift of phonology sparing the standard left hemisphere lateralisation of lexical-semantic functions.