In Brazil, there is a higher prevalence of Li-Fraumeni Syndrome (LFS) compared to worldwide, due to the founder mutation in the TP53 gene p.R337H. However, a large portion of the population, that ...depends on National Health Care System, does not have access to effective screening through the Toronto Protocol guidelines that enables early diagnosis and improves overall survival. Population strategies for early cancer detection recommended in Brazil are limited and additional screening is not offered to patients at a high risk, leading to late diagnoses and higher cancer mortality. This study aims to assess the cost-effectiveness of introducing annual screening that follows the Toronto Protocol for patients diagnosed with LFS in Brazil.
A Markov decision analytic model was developed to estimate cost-effectiveness of 1,000 LFS carriers under surveillance and non-surveillance strategies over a patient's lifetime. The main outcome was the incremental cost-effectiveness ratio (ICER), expressed as cost per additional life year gained, comparing surveillance and non-surveillance strategies in p.R337H TP53 carriers.
For females, the model showed a mean cost of $2,222 and $14,640 and yielded 22 and 26·2 life years for non-surveillance and surveillance strategies, respectively. The ICER for early cancer surveillance versus no surveillance was $2,982 per additional life year gained. For males, the model predicts mean lifetime costs of $1,165 and $12,883 and average life years of 23·5 and 26·3 for non-surveillance and surveillance strategies, respectively. This amounts to an ICER of $ 4,185 per additional life year. Surveillance had 64% and 45% probabilities of being the most cost-effective strategy for early cancer detection in female and male carriers, respectively.
The adoption of surveillance for patients diagnosed with LFS by the Brazilian National Health Care System is cost-beneficial for both males and females.
This research received no specific grant from any funding agency.
No Brasil, há uma maior prevalência da Síndrome de Li-Fraumeni (LFS) em comparação ao mundo, devido à mutação fundadora no gene TP53 p.R337H. No entanto, uma grande parte da população brasileira, que depende do Sistema Único de Saúde (SUS), não tem acesso a um rastreamento eficaz através das diretrizes do Protocolo de Toronto, que possibilitam o diagnóstico precoce e ganho em sobrevida dos portadores da síndrome. As estratégias populacionais para detecção precoce do câncer recomendadas no Brasil são limitadas e o rastreamento adicional não é oferecido a pacientes de alto risco, levando a diagnósticos tardios e maior mortalidade por câncer. Este estudo tem como objetivo avaliar a relação custo-efetividade do rastreamento anual, conforme o Protocolo de Toronto, para pacientes diagnosticados com LFS no Brasil.
Foi desenvolvido o modelo analítico de decisão Markov para estimar a relação de custo-efetividade de 1.000 portadores da LFS sob estratégias de vigilância e de não-vigilância durante a vida útil do portador. O principal desfecho é a razão de custo-efetividade incremental (ICER), que expressa qual o custo adicional por ano de vida ganho, comparando as estratégias de vigilância e não-vigilância em portadores da mutação p.R337H TP53.
Para as mulheres, o modelo demonstrou o custo médio de $2.222 e $14.640 e resultou em 22 e 26·2 anos de vida útil para as estratégias de vigilância e não-vigilância, respectivamente. O ICER para rastreamento precoce do câncer versus nenhum rastreamento foi de $2.982 por ano de vida adicional ganho. Para os homens, o modelo prevê custos médios de vida de US$ 1.165 e US$ 12.883 e anos de vida médios de 23·5 e 26·3 anos para estratégias de vigilância e não-vigilância, respectivamente. Isto equivale a um ICER de US$ 4.185 por ano de vida adicional ganho. A realização do rastreamento conforme o Protocolo de Toronto tem probabilidades de 64% e 45% de ser a estratégia mais custo-efetiva para a detecção precoce do câncer em portadores do sexo feminino e masculino, respectivamente.
A adoção do rastreamento para pacientes diagnosticados com LFS pelo Sistema Único de Saúde Brasileiro é custo-efetiva tanto para portadores do sexo masculino quanto feminino.
Esta pesquisa não recebeu nenhum subsídio específico de nenhuma agência de financiamento.
Abstract
During 2022 data taking (Run III) PADME searched for a resonant production and a visible decay of the X17 particle into e
+
e
-
. A precise knowledge within 1% uncertainty of the number of ...positrons was required for the observation. To that purpose, an array of 2 × 6 Timepix3 (total of 512 × 1536 pixels) hybrid pixel detectors operated in data-streaming mode with ToA resolution of 1.56 ns for every pixel was employed. Two methods for data acquisition were developed. A frame-based method, integrating the number of hits for each individual pixel for a predefined period of time served for monitoring the beam conditions and to provide a rough estimation of the beam distribution and number of positrons. A data streaming mode exploiting the nanosecond time resolution of Timepix3 detector was used for precise characterization of the transverse beam profile and the distribution of the incident positrons within each bunch of ∼ 200 ns duration.
Abstract
The PADME experiment at LNF-INFN employs positron-on-target-annihilation
to search for new light particles. Crucial parts of the experiment are the charged
particle detectors, composed of ...plastic scintillator bars with light transmitted
by wavelength shifting fibers to silicon photomultipliers (SiPMs). The location of
the detector — close to a turbomolecular pump, inside a vacuum tank, and exposed
to 0.5 T magnetic field — has driven the design of custom modular SiPM front-end
and power supply electronics. The design of the system and its performance, confirming
the desired sub-ns resolution on the reconstructed particle flying times, is shown
and discussed.
Abstract
PADME (Positron Annihilation into Dark Matter Experiment) is a fixed target experiment located at the Beam Test Facility (BTF) at the Laboratori Nazionali di Frascati (LNF) designed to ...search for a massive dark photon
A
′
in the process
e
+
e
−
→
γ
A
′
, using a positron beam of energy up to 550 MeV. The experiment exploits the missing mass technique which allows for a search of
A
′
in a model independent way. A sensitivity on the mixing constant
ϵ
> 10
−3
for a dark photon mass in the range
1
≤
m
A
′
≤
23.7
MeV
/c
2
can be achieved by collecting 4 × 10
13
positrons on target. Run 2 data taking finished in December 2020 and allowed to reach an integrated luminosity of 5 × 10
12
positrons on target.
The PADME experiment, at the Laboratori Nazionali di Frascati (LNF), in Italy, will search for invisible decays of the hypothetical dark photon via the process e+e−→γA′, where the A′ escapes ...detection. The dark photon mass range sensitivity in a first phase will be 1 to 24 MeV. We report here on performance measurements and simulation studies of a prototype of the Small-Angle Calorimeter, a component of PADME’s detector dedicated to rejecting 2- and 3-gamma backgrounds. The crucial requirement is a timing resolution of less than 200 ps, which is satisfied by the choice of PbF2 crystals and the newly released Hamamatsu R13478UV photomultiplier tubes (PMTs). We find a timing resolution of 81 ps (with double-peak separation resolution of 1.8 ns) and a single-crystal energy resolution of 10% at 550 MeV with light yield of 2.05 photo-electrons per MeV, using 100 to 400 MeV electrons at the Beam Test Facility of LNF. We also propose the investigation of a two-PMT solution coupled to a single PbF2 crystal for higher-energy applications, which has potentially attractive features.
The electromagnetic calorimeter for the new muon (g−2) experiment at Fermilab will consist of arrays of PbF2 Cherenkov crystals read out by large-area silicon photo-multiplier (SiPM) sensors. We ...report here on measurements and simulations using 2.0–4.5GeV electrons with a 28-element prototype array. All data were obtained using fast waveform digitizers to accurately capture signal pulse shapes vs. energy, impact position, angle, and crystal wrapping. The SiPMs were gain matched using a laser-based calibration system, which also provided a stabilization procedure that allowed gain correction to a level of 10−4 per hour. After accounting for longitudinal fluctuation losses, those crystals wrapped in a white, diffusive wrapping exhibited an energy resolution σ/E of (3.4±0.1)%/E/GeV, while those wrapped in a black, absorptive wrapping had (4.6±0.3)%/E/GeV. The white-wrapped crystals—having nearly twice the total light collection—display a generally wider and impact-position-dependent pulse shape owing to the dynamics of the light propagation, in comparison to the black-wrapped crystals, which have a narrower pulse shape that is insensitive to impact position.
The PADME beam line Monte Carlo simulation Bossi, F.; Branchini, P.; Buonomo, B. ...
The journal of high energy physics,
09/2022, Letnik:
2022, Številka:
9
Journal Article
Recenzirano
Odprti dostop
A
bstract
The PADME experiment at the DAΦNE Beam-Test Facility (BTF) of the INFN Laboratory of Frascati is designed to search for invisible decays of dark sector particles produced in ...electron-positron annihilation events with a positron beam and a thin fixed target, by measuring the missing mass of single-photon final states. The presence of backgrounds originating from beam halo particles can significantly reduce the sensitivity of the experiment. To thoroughly understand the origin of the beam background contribution, a detailed G
eant
4-based Monte Carlo simulation has been developed, containing a full description of the detector together with the beam line and its optical elements. This simulation allows the full interactions of each particle to be described, both during beam line transport and during detection, a possibility which represents an innovative way to obtain reliable background predictions.
Abstract
In dark matter studies, the absence of experimental evidences other than the astrophysical observations, has triggered new approaches. Nowadays, many particle physics experiments at ...accelerators are trying to contribute by looking for signals of hidden particles postulated by different theoretical extensions of the Standard Model. This results in a vaste hunting for new particles with a wide range of properties with the intention to also give reason to other unexplained particle physics phenomena. Within this scenario is inserted the Positron Annihilation into Dark Matter Experiment (PADME) ongoing at the Laboratori Nazionali di Frascati of INFN that is looking for signals of hidden particles by studying the annihilations of a positron beam with the electrons of a fixed target. PADME had, up to now, two data taking periods devoted to the search of a dark photon signal, but its setup turned out to be also suited to explore the existence of a protophobic new boson of mass 17 MeV/
c
2
postulated to explain an anomalous effect observed by a Hungarian group while studying nuclear excited states. In this paper it is reported an overview of the PADME experiment and of the modifications implemented to allow a dedicated data taking at 282 MeV beam energy, meant to produce the new particle at resonance.
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