Dosimetric accuracy of tomotherapy dose calculation in thorax lesions

<p>Abstract</p> <p>Background</p> <p>To analyse limits and capabilities in dose calculation of collapsed-cone-convolution (CCC) algorithm implemented in helical tomotherapy (HT) treatment planning system for thorax lesions.</p> <p>Methods</p> <p>The agreement between measured and calculated dose was verified both in homogeneous (Cheese Phantom) and in a custom-made inhomogeneous phantom. The inhomogeneous phantom was employed to mimic a patient's thorax region with lung density encountered in extreme cases and acrylic inserts of various dimensions and positions inside the lung cavity. For both phantoms, different lung treatment plans (single or multiple metastases and targets in the mediastinum) using HT technique were simulated and verified. Point and planar dose measurements, both with radiographic extended-dose-range (EDR2) and radiochromic external-beam-therapy (EBT2) films, were performed. Absolute point dose measurements, dose profile comparisons and quantitative analysis of gamma function distributions were analyzed.</p> <p>Results</p> <p>An excellent agreement between measured and calculated dose distributions was found in homogeneous media, both for point and planar dose measurements. Absolute dose deviations <3% were found for all considered measurement points, both inside the PTV and in critical structures. Very good results were also found for planar dose distribution comparisons, where at least 96% of all points satisfied the gamma acceptance criteria (3%-3 mm), both for EDR2 and for EBT2 films. Acceptable results were also reported for the inhomogeneous phantom. Similar point dose deviations were found with slightly worse agreement for the planar dose distribution comparison: 96% of all points passed the gamma analysis test with acceptable levels of 4%-4 mm and 5%-4 mm, for EDR2 and EBT2 films respectively. Lower accuracy was observed in high dose/low density regions, where CCC seems to overestimate the measured dose around 4-5%.</p> <p>Conclusions</p> <p>Very acceptable accuracy was found for complex lung treatment plans calculated with CCC algorithm implemented in the tomotherapy TPS even in the heterogeneous phantom with very low lung-density.</p

Surgical outcome and indicators of postoperative worsening in intra-axial thalamic and posterior fossa pediatric tumors: Preliminary results from a single tertiary referral center cohort

Background: Shared indications about the best management of intra-axial thalamic (IAT) and posterior fossa (PF) pediatric tumors are still lacking. The aim of this study was to analyze neurosurgical outcome in these tumors and to investigate factors associated with postoperative worsening. Methods: A retrospective single-center study on IAT and PF pediatric tumor patients treated surgically over a 7-year period was conducted. The Lansky Scale (LS) was used to assess patients' functional status. Surgical complexity was graded with the Milan Complexity Scale (MCS). The following analyses were performed: a longitudinal analysis of the preoperative, discharge, and 3 months' follow-up (FU) LS, a comparison between improved/unchanged and worsened patients, and an analysis of the predictive value of single MCS items. Results: 37 cases were collected: 20 PF and 17 thalamic. Mean MCS score was 6 ± 1.7. Mean preoperative, discharge and FU LS were 80.8, 74.6 and 80.3 respectively. Surgical mortality was 0%.The longitudinal analysis showed a neurological worsening at discharge compared to preoperative status (p = 0.011) and an improvement at FU compared to discharge (p < 0.004), both statistically significant. None of the variables analyzed showed a significant predictive value of early postoperative change; however, higher MCS scores were associated with a greater risk of worsening. Conclusions: The surgical management of IAT and PF pediatric brain tumors remains challenging; early postoperative worsening is possible, but most deficits tend to improve at FU. The MCS seems to be a valuable tool to estimate the risk of early postoperative worsening and to facilitate parents' informed consent

Genetic alterations and in vivo tumorigenicity of neurospheres derived from an adult glioblastoma

Pediatric brain tumors may originate from cells endowed with neural stem/precursor cell properties, growing in vitro as neurospheres. We have found that these cells can also be present in adult brain tumors and form highly infiltrating gliomas in the brain of immunodeficient mice. Neurospheres were grown from three adult brain tumors and two pediatric gliomas. Differentiation of the neurospheres from one adult glioblastoma decreased nestin expression and increased that of glial and neuronal markers. Loss of heterozygosity of 10q and 9p was present in the original glioblastoma, in the neurospheres and in tumors grown into mice, suggesting that PTEN and CDKN2A alterations are key genetic events in tumor initiating cells with neural precursor properties

Eleven-year experience with the avidin-biotin pretargeting system in glioblastoma: Toxicity, efficacy and survival

Background: The 3-step avidin-biotin pretargeting approach is applied in patients with recurrent glioblastoma (GBM), using biotinylated anti-tenascin monoclonal antibody as the first step of pretargeting followed by avidin and 90Ybiotin. Methods: The present study reviews objective response and overall survival rates in 502 glioblastoma patients treated with 3-step radioimmunotherapy in our institute from December 1994 to December 2005. Patients underwent standard treatment before receiving Pretargeted Antibody-Guided Radionuclide Therapy with 90Y-biotin (PAGRIT ®). Results: Of the 502 patients, 272 (54%) were evaluable for response and 375 (75%) for overall survival. 174 patients (64%) continued to progress after PAGRIT ®, 77 (28%) obtained disease stabilization, and 21 (8%) showed objective tumor regression. Survival of the 375 evaluable patients was 98.4% at 6 months, 79.2% at 12 months, 51.7% at 18 months, and 30.7% at 24 months after the first cycle of PAGRIT ®. All 375 received 3-step PAGRIT ® at recurrence of GBM. The median survival time from diagnosis was 19 months. Conclusion: The results from this retrospective analysis suggest that 90Y-biotin PAGRIT ® interferes with the progression of glioblastoma, prolonging survival in a larger number of patients. Our analysis forms the basis for further prospective trials, where radioimmunotherapy, which is known to be more effective in minimal residual disease, could be offered immediately after surgery. © Grana et al.; Licensee Bentham Open

Deepbrain stimulation of the nucleus accumbens in obsessive compulsive disorder: clinical, surgical and electrophysiological considerations in two consecutive patients

Abstract Obsessive compulsive disorder is a highly disabling pathological condition which in the most severe and drug-resistant form can severely impair social, cognitive and interpersonal functioning. Deep-brain stimulation has been demonstrated to be an effective and safe interventional procedure in such refractory forms in selected cases. We here report the first Italian experience in the treatment of this pathology by means of nucleus accumbens stimulation, pointing out to some technical data which could be of help in localization of the target

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more patients, 1 with focal motor epilepsy once again (resulting in status epilepticus) and the other with behavioural comorbidity and multifocal epilepsy. Results: A significant reduction in seizure frequency was observed, and the 2 patients with behavioural comorbidity also showed a dramatic improvement in their disruptive behaviour. The patient with motor focal seizures showed a 70% reduction in seizure frequency, and in the last patient remission from status epilepticus was obtained. Conclusion: Our data confirm DBS of deep brain structures modulates the functional activity of the cerebral cortex as suggested by Adrian Upton in 1985. In the reported series, deep-brain stimulation of 2 unconventional targets belonging to the reticulo-cortical system (the brainstem-diencephalon functional system including structures that act as remote controls in modulating cortical excitability) was found to be effective in controlling otherwise refractory multifocal (pHyp) and focal sensorimotor (CZi) epilepsy when resective surgery was not feasible

Caracterización y manejo del nódulo tiroideo en niños, en el Servicio de Cirugía de Cabeza, Cuello y Máxilo Facial del Instituto Nacional de Salud del Niño - Breña, 2000 - 2020

Introduction. The thyroid nodule in children is usually asymptomatic, multiple and isolated presentation, with difficulty in establishing the risk of malignancy, especially if it is not palpable. Objective. To determine the epidemiological, clinical and ultrasound characteristics and surgical management of thyroid nodules in patients of the Head, Neck and Maxillofacial Surgery Service of the Instituto Nacional de Salud del Niño (INSN) – Breña, 2000-2020. Methods. Observational, descriptive and retrospective study. The Bethesda classification was used for cytological studies. Qualitative variables were expressed in absolute and relative frequencies; and quantitative variables in measures of central tendency and dispersion. Results. There were 66 cases, the average age was 10.94 ± 0.88 years, 48.5% between 11 and 15 years, 78.8% were female, 89.4% had no family history of cancer. The asymptomatic form predominated (74.2%). Ultrasonographically, 43.9% of nodules were located in the right lobe, single presentation (68.2%) and smaller than two centimeters (43.9%). 82.6% of the 23 Bethesda II cases were hemithyroidectomized and 86.4% of 22 Bethesda VI cases were thyroidectomized. Conclusions. In pediatric patients, thyroid nodules occurred mostly in women aged 11 to 15 years, with no family history of cancer, asymptomatic, located in the right lobe, single and less than two centimeters. Grade II of the Bethesda classification was the most frequent. Hemithyroidectomy was the most used surgical intervention.Introducción. El nódulo tiroideo en niños generalmente es asintomático, de presentación múltiple y aislada, con dificultad para instaurar el riesgo de malignidad, sobre todo si no es palpable. Objetivo. Determinar las características epidemiológicas, clínicas, ecográficas y manejo quirúrgico del nódulo tiroideo en pacientes del Servicio de Cirugía de Cabeza, Cuello y Máxilo Facial del Instituto Nacional de Salud del Niño (INSN) – Breña, 2000 -2020. Métodos. Estudio observacional, descriptivo y retrospectivo. Se usó la clasificación Bethesda para los estudios citológicos. Los datos fueron analizados en el programa SPSS versión 22. Las variables cualitativas fueron expresadas en frecuencias absolutas y relativas; y las cuantitativas en medidas de tendencia central y dispersión. Resultados. Fueron 66 casos, el promedio de edad fue 10,94 ± 0,88 años, el 48,5% entre 11 a 15 años, el 78,8% fueron del sexo femenino, un 89,4% no referían antecedente familiar de cáncer. Predominó la forma asintomática (74,2%). Ecográficamente el 43,9% de nódulos se localizaron en lóbulo derecho, presentación única (68,2%) y menor a dos centímetros (43,9%). El 82,6% de los 23 casos Bethesda II fueron hemitiroidectomizados y el 86,4% de 22 casos Bethesda VI fueron tiroidectomizados. Conclusiones. En pacientes pediátricos, los nódulos tiroideos se presentaron mayormente en mujeres de 11 a 15 años, sin antecedente familiar de cáncer, asintomáticos, localizados en lóbulo derecho, únicos y menor a dos centímetros. El grado II de la clasificación Bethesda fue la más frecuente. La hemitiroidectomía fue la intervención quirúrgica más utilizada

BriXs ultra high fluxinverse compton source based on modified push-pull energy recovery linacs

We present a conceptual design for a compact X-ray Source BriXS (Bright and compact X-ray Source). BriXS, the first stage of the Marix project, is an Inverse Compton Source (ICS) of X-ray based on superconducting cavities technology for the electron beam with energy recirculation and on a laser system in Fabry-Pérot cavity at a repetition rate of 100 MHz, producing 20–180 keV monochromatic X-Rays devoted mainly to medical applications. An energy recovery scheme based on a modified folded push-pull CW-SC twin Energy Recovery Linac (ERL) ensemble allows us to sustain an MW-class beam power with almost one hundred kW active power dissipation/consumption