Development of a leakage monitoring system in isolated limb perfusion with portable gamma camera. / Desarrollo de un protocolo de monitorización de fuga en perfusión de miembro aislado con gammacámara portátil.

Isolated limb perfusion (ILP) is a method for treating unresectable lesions of limbs in patients with melanoma or sarcoma by using high doses of tumor necrosis factor alpha and melphalan. These high doses can result in high systemic toxicity if there is a drug leak from the isolated circulation of the limb to the systemic. This makes it imperative to monitor the leakage rate (F[%]) during the infusion, currently performed with radiotracers. The objective of this work was to develop a leakage monitoring protocol as accurate as possible to ensure safe ILP. MATERIAL AND METHOD: We built a phantom with 3compartments (body, limb and precordial area) and a high sensitivity collimator fitted to a portable gammacamera. We simulate ILP with scheduled leaks every 10minutes from 1% to 9% (theorical F[%]). We mesured F(%) using 2equation: one is the proposed in the literature and another corrected by decay of the radioisotope. We test the optimal radiopharmaceutical doses to minimize the detector dead time error and compare F(%) mesured by both equations regarding the theoretical F(%). The leakage monitoring protocol was used in 17 ILP of 16 patients and an analysis of the recorded data was performed. RESULTS: We found significant differences between F(%) mesured using the first equation and theoretical F(%), obtaining results very adjusted to the theorical after applying the decay correction. CONCLUSIONS: The decay correction of the radioisotope is a simple manner to carry out the procedure more safely, reducing the error in the calculation of F(%).

Retinoblastoma: The importance of early diagnosis. / Retinoblastoma: la importancia de su diagnóstico precoz.

INTRODUCTION: Retinoblastoma is the most frequent malignant intraocular tumour in childhood, and both its cure and the sequelae arising from it, mainly depend on an early diagnosis. There is currently no consensus on its diagnostic and therapeutic management. PATIENTS AND METHODS: A descriptive, retrospective, and non-randomised study was conducted on a series of cases (39 patients -58 eyes), treated during the period 2006-2013, in the Regional Reference Centre for Tumours of the National Health Service Quality Agency. RESULTS: The most frequent presentation sign is leukocoria (71.8%), followed by strabismus (17.9%). All cases of bilateral tumour had a germline mutation of the RB1 gene, and 20% had a family history. Stage E was observed in 55% of the patients, and 90% required chemotherapy treatment. The eye was maintained in 57% of those who had mild stages, compared to 43% who maintained it in advanced stages. CONCLUSIONS: This analysis included 58 eyes. There are no previous studies in our community and there are few series so numerous throughout the country. Based on non-standardised treatment, the most appropriate is chosen according to the characteristics of the tumour. The multidisciplinary management, formed by ophthalmology, paediatric oncology, radiotherapy, and radiophysical oncology, is fundamental for the selection of the most appropriate treatment. Chemo-reduction, along with consolidation treatments, offers encouraging results in the control of these tumours, especially in those of less severity. Enucleation continues to be the method of choice in the most advanced staging with vitreous involvement, with the importance of early diagnosis being highlighted.

Algoritmos de planificación en radiocirugía / Planning algorithms in radiosurgery

La Radiocirugía como técnica de Radioterapia tiene unas particularidades bien definidas. Estas mismas son las que determinan las consideraciones en los algoritmos de cálculo de los sistemas de planificación. El objeto del trabajo es presentar, no cómo se realiza el cálculo de dosis sino conocer y clasificar los algoritmos utilizados en este tipo de sistemas con relación a la generalidad de los sistemas así como las particularidades de los mismos.Se presenta una clasificación general de los métodos de cálculo en función de los datos empleados y aproximaciones realizadas (cálculo de inhomogeneidades, dispersión, ...) y se analizan las características especiales de los sistemas empleados en Radiocirugía, con el objeto de clasificar estos últimos. Se estudian los algoritmos utilizados en los dos sistemas de Radiocirugía actuales (Gamma Knife y Acelerador lineal) y se presenta la aplicación en uno de ellos (AU)