First Ex-Vivo Validation of a Radioguided Surgery Technique with beta- Radiation

Purpose: A radio-guided surgery technique with beta- -emitting radio-tracers was suggested to overcome the effect of the large penetration of gamma radiation. The feasibility studies in the case of brain tumors and abdominal neuro-endocrine tumors were based on simulations starting from PET images with several underlying assumptions. This paper reports, as proof-of-principle of this technique, an ex-vivo test on a meningioma patient. This test allowed to validate the whole chain, from the evaluation of the SUV of the tumor, to the assumptions on the bio-distribution and the signal detection. Methods: A patient affected by meningioma was administered 300 MBq of 90Y-DOTATOC. Several samples extracted from the meningioma and the nearby Dura Mater were analyzed with a beta- probe designed specifically for this radio-guided surgery technique. The observed signals were compared both with the evaluation from the histology and with the Monte Carlo simulation. Results: we obtained a large signal on the bulk tumor (105 cps) and a significant signal on residuals of $\sim$0.2 ml (28 cps). We also show that simulations predict correctly the observed yields and this allows us to estimate that the healthy tissues would return negligible signals (~1 cps). This test also demonstrated that the exposure of the medical staff is negligible and that among the biological wastes only urine has a significant activity. Conclusions: This proof-of-principle test on a patient assessed that the technique is feasible with negligible background to medical personnel and confirmed that the expectations obtained with Monte Carlo simulations starting from diagnostic PET images are correct.Comment: 17 pages, 4 Figs, Accepted by Physica Medic

Overview of the TCV tokamak experimental programme

The tokamak a configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019-20 campaign its configurational flexibility has been enhanced with the installation of removable divertor gas baffles, its diagnostic capabilities with an extensive set of upgrades and its heating systems with new dual frequency gyrotrons. The gas baffles reduce coupling between the divertor and the main chamber and allow for detailed investigations on the role of fuelling in general and, together with upgraded boundary diagnostics, test divertor and edge models in particular. The increased heating capabilities broaden the operational regime to include T (e)/T (i) similar to 1 and have stimulated refocussing studies from L-mode to H-mode across a range of research topics. ITER baseline parameters were reached in type-I ELMy H-modes and alternative regimes with \u27small\u27 (or no) ELMs explored. Most prominently, negative triangularity was investigated in detail and confirmed as an attractive scenario with H-mode level core confinement but an L-mode edge. Emphasis was also placed on control, where an increased number of observers, actuators and control solutions became available and are now integrated into a generic control framework as will be needed in future devices. The quantity and quality of results of the 2019-20 TCV campaign are a testament to its successful integration within the European research effort alongside a vibrant domestic programme and international collaborations

International law and the conduct of military operations

TABLE OF CONTENTS: 1. The nature and temporal extent of the armed conflict between Eritrea and Ethiopia. \u2013 2. The applicable international law of armed conflict. \u2013 3. Attribution to the State of violations of the law of armed conflict. \u2013 4. The content of State responsibility for violations of international humanitarian law. \u2013 5. Means of warfare. \u2013 6. Methods of warfare. 6.1. Land warfare. \u2013 6.2. Air warfare. \u2013 7. Concluding remarks

Tumor-non-tumor discrimination by a β- detector for Radio Guided Surgery on ex-vivo neuroendocrine tumors samples

This paper provides a first insight of the potential of the β− Radio Guided Surgery (β−-RGS) in a complex surgical environment like the abdomen, where multiple sources of background concur to the signal at the tumor site. This case is well reproduced by ex-vivo samples of 90Y-marked Gastro-Entero-Pancreatic Neuroendocrine Tumors (GEP NET) in the bowel. These specimens indeed include at least three wide independent sources of background associated to three anatomical districts (mesentery, intestine, mucose). The study is based on the analysis of 37 lesions found on 5 samples belonging to 5 different patients. We show that the use of electrons, a short range particle, instead of γ particles, allows to limit counts read on a lesion to the sum of the tumor signal plus the background generated by the sole hosting district. The background on adjacent districts in the same specimen/patient is found to differ up to a factor 4, showing how the specificity and sensitivity of the β−-RGS technique can be fully exploited only upon a correct measurement of the con- tributing background. This locality has been used to set a site-specific cut-off algorithm to discriminate tumor and healthy tissue with a specificity of 100% and a sensitivity, on this test data sample, close to 100%. Factors influencing the sensitivity are also discussed. One of the specimens set allowed us evaluate the volume of the lesions, thus concluding that the probe was able to detect lesions as small as 0.04 mL in that particular case

Radio-guided surgery with β− radiation: tests on ex-vivo specimens

Radio-Guided Surgery (RGS) is a surgical technique aimed at assisting the surgeon to reach as complete a resection of the tumoural lesion as possible. Established methods to date make use of γ -emitting tracers to radio-mark the neoplastic tissue. However, in case of uptake from healthy organs around the lesion the large penetration of photons yields a non-negligible background that can limit the RGS application. The adoption of β− radiation has been proposed to overcome this limit. To validate the entire RGS procedure, from the evaluation of the tracer uptake of the tumor, to the assumptions on the bio-distribution and the signal detection, tests on ex vivo specimens of meningioma brain tumour were performed. Meningioma was selected due to the well known high receptivity to a β− emitting radio-tracer already in use in the clinical practice: 90Y-labelled DOTATOC. Patients were enrolled according to the tumour Standard Uptake Value (SUV > 2) and the expected Tumour to Non-tumour Ratio (TNR > 10) estimated from 68Ga-DOTATOC PET images. After injecting the patients with 93–167, MBq of 90Y - DOTATOC, 26 samples excised during surgery were examined with a dedicated β− detecting probe to assess the sensitivity of millimetre-sized tumour remnants in case of administration of low activity value compatible with those injected for diagnostic exams. Even injecting as low as 1.4, MBq/kg of radio-tracer, tumour remnants greater than 0.06, ml would be discriminated by the healthy tissue in few seconds