I received some interesting feedback from Mastodon.
Electrons—long used to treat surface tumors and to generate X-rays—are light, nimble particles, far easier to control than protons or carbon ions. At low energies, they stop quickly in tissue, but new high-energy systems can drive electrons deeper. Now researchers are working on machines that combine multiple high-energy beams at different angles to let doctors sculpt radiation doses that match the tumor’s shape.
，这一点在新收录的资料中也有详细论述
https://www.wired.com/story/openai-president-greg-brockman-political-donations-trump-humanity/
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