Radium-226, $^{226}_{88}\text{Ra}$, is an $\alpha$-emitter. It is placed directly into cancerous tumours. This is safe to use because it destroys the cancerous cells without harming the healthy cells around the tumour. Which properties of $\alpha$-particles, when compared with other emissions, allow radium-226 to be used in this way?
- Aionising effect of $\alpha$-particles: high; penetration of $\alpha$-particles: high
- Bionising effect of $\alpha$-particles: high; penetration of $\alpha$-particles: low
- Cionising effect of $\alpha$-particles: low; penetration of $\alpha$-particles: high
- Dionising effect of $\alpha$-particles: low; penetration of $\alpha$-particles: low