The first probe of a FLASH proton beam by PET.

The recently observed FLASH effect related to high doses delivered with high rates has the potential to revolutionize radiation cancer therapy if promising results are confirmed and an underlying mechanism understood. Comprehensive measurements are essential to elucidate the phenomenon. We report the first-ever demonstration of measurements of successive in-spill and post-spill emissions of gammas arising from irradiations by a FLASH proton beam. A small positron emission tomography (PET) system was exposed in an ocular beam of the Proton Therapy Center at MD Anderson Cancer Center to view phantoms irradiated by 3.5 × 1010protons with a kinetic energy of 75.8 MeV delivered in 101.5 ms-long spills yielding a dose rate of 164 Gy s-1. Most in-spill events were due to prompt gammas. Reconstructed post-spill tomographic events, recorded for up to 20 min, yielded quantitative imaging and dosimetric information. These findings open a new and novel modality for imaging and monitoring of FLASH proton therapy exploiting in-spill prompt gamma imaging followed by post-spill PET imaging.

The first PET glimpse of a proton FLASH beam.

We demonstrate the first ever recorded positron-emission tomography (PET) imaging and dosimetry of a FLASH proton beam at the Proton Center of the MD Anderson Cancer Center. Two scintillating LYSO crystal arrays, read out by silicon photomultipliers, were configured with a partial field of view of a cylindrical poly-methyl methacrylate (PMMA) phantom irradiated by a FLASH proton beam. The proton beam had a kinetic energy of 75.8 MeV and an intensity of about 3.5 × 1010protons that were extracted over 101.5 ms-long spills. The radiation environment was characterized by cadmium-zinc-telluride and plastic scintillator counters. Preliminary results indicate that the PET technology used in our tests can efficiently record FLASH beam events. The instrument yielded informative and quantitative imaging and dosimetry of beam-activated isotopes in a PMMA phantom, as supported by Monte Carlo simulations. These studies open a new PET modality that can lead to improved imaging and monitoring of FLASH proton therapy.

Search for Neutrinoless Quadruple-ß Decay of

We report the results of a first experimental search for lepton number violation by four units in the neutrinoless quadruple-ß decay of ^{150}Nd using a total exposure of 0.19 kg yr recorded with the NEMO-3 detector at the Modane Underground Laboratory. We find no evidence of this decay and set lower limits on the half-life in the range T_{1/2}>(1.1-3.2)×10^{21} yr at the 90% C.L., depending on the model used for the kinematic distributions of the emitted electrons.

Attrition of advanced trauma life support (ATLS) skills among ATLS instructors and providers in Mexico.

BACKGROUND: Mexico has had the Advanced Trauma Life Support (ATLS) program since 1986. We assessed the attrition of ATLS skills among ATLS providers and instructors in this country. STUDY DESIGN: Three groups (S, 16 students [new medical graduates enrolled for an ATLS course]; P, 33 providers; and I, 26 instructors [who had completed courses previously]) were evaluated. Group S read the manual before pretesting. Groups P and I were subdivided based on the length of time since the course had been completed: P1, less than 2 years (n = 22); P2, more than 2 years (n = 11); I1, less than 2 years (n = 16); and I2, more than 2 years (n = 10). Multiple-choice and psychomotor testing using ATLS scoring criteria were used. Affect was assessed post-ATLS for motivational factors, interactivity, and attitude toward trauma care. RESULTS: Multiple-choice test scores (means +/- SD) out of a maximum of 40 were as follows: S, 24.3 +/- 2.6; P1, 24.0 +/- 5.7; P2, 21.3 +/- 8.0; I1, 23.2 +/- 8.2; and I2, 24.0 +/- 7.2. Group S all passed the post-ATLS multiple-choice test (with correct answer percentages of 60.3% +/- 6.6% pre-ATLS versus 88.8% +/- 5.6% post-ATLS). An ATLS passing score of 80% correct answers was achieved in 2 of 33 for group P and 8 of 26 for group I (p < 0.05), with no statistically significant differences between groups P1 and P2 or between groups I1 and I2. For the psychomotor skills testing component, 5 of 16 in the S group passed, 15 of 22 in P1 passed, 9 of 11 in P2 passed, 14 of 16 in I1 passed, and 6 of 10 in I2 passed. The pass rate was significantly lower in the S pre-ATLS group than in the P and I groups (p < 0.05, Fisher's exact test). More than 60% preferred interactive components and enrolled for professional improvement, and more than 90% reported improved post-ATLS attitude to trauma care. CONCLUSIONS: Reading the manual alone yields similar cognitive but inferior psychomotor performance compared with subjects who completed the course previously. The majority of previous providers and instructors did not obtain a passing score (80%) in the multiple-choice test, but all the new providers passed the post-ATLS multiple-choice test, suggesting major attrition of cognitive skills but maintenance of psychomotor skills. Instructors had superior cognitive performance versus providers with worsening performance over time, but clinical skills performance was maintained at an equally high level by all groups. A very positive attitude toward ATLS prevailed among all participants.