Case: Read the passage and answer the following questions

The f-block consists of the two series, lanthanoids (the fourteen elements following lanthanum) and actinoids (the fourteen elements following actinium). . Because actinium closely resembles the actinoids, it is usually included in any discussion of the actinoids for which the general symbol An is often used. The chemistry of actinoids is complex. The complication arises partly owing to the occurrence of a wide range of oxidation states in these elements and partly because their radioactivity creates special problems in their study.

Which of the actinoids is used in the treatment of cancer because of its radioactivity?

Thorium

The uranium-230 \((^{230}_{92}U)\)/thorium-226\((^{226}_{90}Th)\) pair does indeed have the unique advantage of emitting multiple alpha particles as they decay. This characteristic allows them to deliver more destructive energy to cancer cells during radiotherapy. This type of treatment, known as alpha-particle radiotherapy, shows promise in targeting and effectively destroying cancer cells while minimizing damage to healthy surrounding tissues.

The high linear energy transfer (LET) of alpha particles allows them to deposit a large amount of energy over a short distance, making them more effective in damaging cancer cells compared to other types of radiation like beta particles or gamma rays. This property makes uranium-230 \((^{230}_{92}U)\) / thorium-226 \((^{226}_{90}Th)\) a potential candidate for targeted alpha-particle radiotherapy in certain cancer treatments. However, it's important to note that such treatments are still in the experimental and research stages, and rigorous clinical trials and safety assessments are necessary before they can be widely used in medical practice.