You don’t need a Geiger counter. These are the instructions Mayo gives to their patients, A lot less rigorous than you are thinking.

Someone posted these instructions they received at Mayo Rochester from the team that gave my husband Pluvicto. Here they are:
For three days: drink at least eight glasses or water or other non-alcoholic liquid each day.

For one day: use separate bathrooms when possible.

Males should sit while using the toilet to prevent splashing of urine.

Clean up spilled urine yourself. Wipe with damp toilet tissue and flush down the toilet.
Flush twice, and close lid if applicable.

Contact with children under 10: For one day,
Do not be closer than arms' length for an extended period of time.

Contact with pregnant women:
For two days, sleep in separate bed from your partner if they are pregnant.

It is safe to share a bed with a person who is not pregnant or under 10 years old

You may travel home by car or plane immediately after treatment.

You may stay in a hotel the night of treatment.