Final answer:
Pregnant women, children under 18, and individuals unable to follow safety precautions should not visit a client with a radioactive implant due to the risks associated with radiation exposure.
Step-by-step explanation:
Individuals who should not be allowed to visit a client with a radioactive implant include pregnant women, children under the age of 18, and anyone who may not be able to maintain the recommended safety precautions. The reason behind this restriction is due to the risk of radiation exposure, which can be particularly harmful to developing fetuses and young children whose bodies are still growing. Safety protocols must be strictly followed by visitors and healthcare professionals to minimize radiation exposure. Additionally, visitors should limit their time in the vicinity of the patient and maintain a safe distance as recommended by healthcare providers to reduce radiation risks.