🔬 physics

The SPES_MED project

This paper outlines the goals of the SPES_MED project (2025–2027) at INFN-LNL, which aims to produce medical radionuclides using both direct activation and ISOL techniques, while presenting initial results from its first year on nuclear cross-section measurements, production, and modeling.

Original authors: Gaia Pupillo, Alberto Andrighetto, Alberto Arzenton, Michele Ballan, Francesca Barbaro, Nicola Belcari, Francesco Broggi, Fiorella Maria Cagnetta, Luciano Canton, Sara Cisternino, Michele Colucci, Gia

Published 2026-07-08

📖 5 min read🧠 Deep dive

CC BY 4.0

Original authors: Gaia Pupillo, Alberto Andrighetto, Alberto Arzenton, Michele Ballan, Francesca Barbaro, Nicola Belcari, Francesco Broggi, Fiorella Maria Cagnetta, Luciano Canton, Sara Cisternino, Michele Colucci, Giancarlo D'Agostino, Pasquale Delogu, Lucia De Dominicis, Laura De Nardo, Marco Di Luzio, Antonietta Donzella, Juan Esposito, Lorenzo Gaddi, Andrea Gandini, Flavia Maria Groppi Garlandini, Alisa Kotliarenko, Yuliia Lashko, Aurora Leso, Marcello Lunardon, Simone Manenti, Sandra Moretto, Liliana Mou, Elisa Persico, Daniele Scarpa, Davide Serafini, Omorjit Singh Khwairakpam, Giancarlo Sportelli, Giulia Saveria Valli, Giacomo Voltan, Lisa Zangrando, Emilio Mariotti

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine a massive, high-tech kitchen in Italy called SPES (Selective Production of Exotic Species). Its main job is usually to cook up rare, exotic ingredients for scientists studying the very building blocks of the universe. However, a new team called SPES_MED has moved into this kitchen with a specific mission: to cook up special "ingredients" (radioactive atoms) that doctors can use to diagnose and treat diseases.

This paper is like a progress report from the first year of their new project. Here is what they are doing, explained simply:

The Two Cooking Methods

The team is using two different ways to make these medical ingredients:

The "Direct Hit" Method (LARAMED): Imagine firing a cannonball (a beam of protons) directly at a target made of specific metals. The impact shatters the metal atoms and creates new, useful radioactive ones. This is like smashing a watermelon to get the seeds out.
The "Oven" Method (ISOL): Imagine putting a block of material (like a special ceramic) into a super-hot oven (2000°C). The heat makes the atoms inside "sweat" and escape as gas. These gas atoms are then caught, sorted, and collected. This is like heating a block of cheese until the flavor oils melt out and can be collected.

What They Did This Year (The Three Work Packages)

The project is split into three main tasks, or "Work Packages" (WP):

1. Testing the Recipes (WP1: Cross-Section Measurements)
Before you can cook a meal for thousands of people, you need to know exactly how much heat and how long to cook it to get the perfect result without burning it.

The Experiment: The team fired different types of particle beams (like deuteron and alpha particles) at specific metal targets (like Titanium and Europium).
The Goal: They wanted to measure exactly how many "medical atoms" were created and how many "junk atoms" (impurities) were made as a side effect.
The Discovery: They found a new, efficient way to make a specific atom called Scandium-47 (great for theranostics, which means using one atom for both imaging and treatment). They also studied Terbium isotopes.
The Surprise: They found that some existing "cookbooks" (scientific data) had the wrong numbers for how certain atoms decay. They measured a specific "branching ratio" (a path an atom takes when it changes) for Terbium-154 and found it was much lower than everyone thought. This means previous calculations might have been wrong, and they need to rewrite the recipe.

2. Setting Up the Collection Station (WP2: ISOL Production)
Now that they know the recipes, they need to build the assembly line to catch the atoms.

The New Station: They installed a special collection station called IRIS. Think of it as a high-tech vacuum cleaner that sucks up the radioactive gas coming out of the hot oven and deposits it onto small, edible-looking tablets (made of sugar-like materials) so doctors can easily pick them up later.
The Laser Tuner: They tested a Laser Ion Source. Imagine using a very specific color of laser light to "tag" only the atoms you want, ignoring the ones you don't. They successfully tested this with Silver beams, proving they can now catch specific atoms with high purity.
The Stopwatch: They also re-measured the "half-life" (how long an atom lasts before it disappears) of Silver-111. They found it lasts slightly less time than the standard number says. This is crucial because if you think a medicine lasts longer than it actually does, the dosage could be wrong.

3. The Simulation Kitchen (WP3: Nuclear Modeling)
Before they burn expensive materials, they use computers to simulate the cooking process.

The Genetic Algorithm: They used a computer program that acts like evolution. It tries thousands of different "recipes" (parameters) to see which one produces the best results. They used this to perfect the simulation for making Scandium-47, finding that their new computer model is much more accurate than the old standard models.
The Virtual Oven: They used advanced 3D simulations (like a video game physics engine) to design the best shape for the ceramic targets. They are testing different shapes to see how heat and atoms move inside them, aiming to make targets that can handle more power without melting.

The Bottom Line

The SPES_MED project is in its first year and has successfully:

Built new equipment to catch and sort radioactive atoms.
Tested new ways to make specific medical atoms (Scandium and Terbium) and found they work better than expected.
Discovered that some old scientific data was wrong and needs updating.
Proved that using smart computer simulations helps them cook up these atoms more efficiently.

They are essentially building a state-of-the-art factory to produce the raw materials for future medical treatments, ensuring that the "ingredients" are pure, plentiful, and produced exactly the way doctors need them.

Technical Summary: The SPES_MED Project

Problem Statement
The production of medical radionuclides is critical for the expanding field of nuclear medicine, which increasingly relies on novel isotopes for theranostics, bimodal imaging, and targeted radiotherapy. However, the availability of high-purity research-grade radionuclides remains a challenge, necessitating advanced research infrastructures. While the SPES (Selective Production of Exotic Species) facility at the INFN-Laboratori Nazionali di Legnaro (INFN-LNL) is primarily designed to produce re-accelerated exotic ion beams for fundamental physics, its dual-beam extraction system offers a unique opportunity for applied research. The SPES_MED project addresses the need to optimize the production of specific medical radionuclides by leveraging both direct activation methods and the Isotope Separation On-Line (ISOL) technique. A key challenge identified is the lack of precise nuclear cross-section data and reliable decay parameters for emerging isotopes, which hinders the optimization of production routes and the assessment of radionuclidic purity.

Methodology
The SPES_MED project (funded for 2025–2027) is structured around three Work Packages (WPs) involving a collaboration between INFN-LNL and various Italian universities and research institutes.

WP1 (Nuclear Cross-Section Measurements): The team conducts experimental measurements of nuclear reactions using charged particle beams. Specific campaigns include:
- Deuteron-induced reactions on enriched $^{49}$ Ti targets ( $^{49}$ Ti(d,x) $^{47}$ Sc) performed at the GIP ARRONAX facility using the stacked-foils method.
- Alpha-particle induced reactions on natural Europium targets ( $^{nat}$ Eu( $\alpha$ ,x)) and proton-induced reactions on Gadolinium, covering energies up to 65–68 MeV.
- Post-irradiation analysis is conducted via high-resolution $\gamma$ -spectrometry using HPGe detectors, with decay curves followed for several days to resolve interferences.
WP2 (ISOL Production and Installations): This work package focuses on the ISOLPHARM Radionuclide Implantation Station (IRIS).
- The IRIS system, located in the SPES low-energy experimental hall, collects Radio Ion Beams (RIBs) onto organic substrates (hypromellose/sorbitol tablets) for subsequent analysis.
- Commissioning activities include the SPES Laser Ion Source (SPES-LIS), utilizing resonant stepwise photoionization (validated with stable Samarium beams) to enhance elemental purity and reduce isobaric contamination.
- Ionization efficiency tests are performed using stable beams (e.g., Silver) at the offline front-end to optimize conditions for future radioactive beam production.
WP3 (Nuclear Modeling and Simulations): This package employs computational tools to interpret experimental data and optimize production parameters.
- Genetic Algorithms (GA): A GA is used to optimize TALYS nuclear reaction model parameters (specifically level-density parameters) to better fit experimental cross-section data for the $^{49}$ Ti(p,x) $^{47}$ Sc reaction.
- Monte Carlo Simulations: Geant4 is used to simulate diffusive processes in SiC target boxes to calculate mean escape times for nuclides. FLUKA and PHITS codes are utilized to model production rates in SiC, TiC, and UCx targets and to benchmark theoretical predictions against experimental data.
- Photoionization Studies: The intrinsic efficiency of laser ionization schemes for Mg, Sc, Ga, and Ag is evaluated to predict ion yields within the SPES-LIS.

Key Contributions and Results

Cross-Section Data: The project has generated new experimental cross-section data for the $^{49}$ Ti(d,x) $^{47}$ Sc reaction and the $^{nat}$ Eu( $\alpha$ ,x) reactions producing Terbium isotopes ( $^{149-156}$ Tb). These results provide essential input for nuclear databases and help identify optimal irradiation parameters.
Decay Data Revision: A significant finding involves the branching ratio for the internal transition $^{154m1}$ Tb $\rightarrow$ $^{154g}$ Tb. Experimental fitting of decay curves yielded a preliminary value of ~8%, which is substantially lower than the literature value of 21.8 ± 0.7%. This discrepancy suggests a need for revised decay data to accurately assess radionuclidic purity.
Half-Life Determination: A new, high-precision measurement of the $^{111}$ Ag half-life was conducted, resulting in a value of 7.4236(11) days. This value conflicts with the currently recommended value of 7.45(1) days, confirming a known discrepancy in the literature.
Infrastructure Commissioning: The IRIS system was successfully installed and tested offline, including venting and evacuating procedures. The SPES-LIS was commissioned with stable beams, demonstrating the capability to produce elements like $^{111}$ Ag with high efficiency and low isobaric contamination.
Model Optimization: The GA-based optimization of TALYS parameters for the $^{49}$ Ti(p,x) $^{47}$ Sc reaction demonstrated a consistently lower Root Mean Square Error (RMSE) compared to the default model, validating the approach for improving nuclear reaction simulations.
Target Design: Preliminary Geant4 simulations of SiC target geometries and ongoing FLUKA/PHITS studies of TiC targets are establishing benchmarks for production rates and optimizing target designs for high-power irradiation.

Significance
The paper positions the SPES_MED project as a critical step in bridging the gap between fundamental nuclear physics infrastructure and the practical needs of nuclear medicine. By generating precise cross-section data and refining nuclear models, the project aims to optimize production yields and radionuclidic purity for isotopes such as $^{47}$ Sc, $^{111}$ Ag, and Terbium isotopes. The project claims that the integration of experimental data with advanced numerical techniques (such as genetic algorithms and Monte Carlo simulations) is essential for overcoming limitations in existing theoretical predictions. Furthermore, the successful commissioning of the IRIS station and SPES-LIS expands the range of isotopes that can be produced with high efficiency, directly supporting the goals of the European PRISMAP+ consortium to provide high-purity radionuclides for research. The work underscores the importance of dedicated experimental studies in resolving discrepancies in nuclear decay data, which have direct consequences for the safety and efficacy of radiopharmaceuticals.

The Two Cooking Methods

What They Did This Year (The Three Work Packages)

The Bottom Line

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