Worried about radiation exposure? Get questions answered in this live chat.

The radiation threat from Japan’s nuclear reactors in the aftermath of the powerful quake and tsunami last Friday has raised concerns around the world. People wonder how radiation exposure might affect them and their loved ones. Here’s an expert who can explain some basic facts and answer questions.

Keisuke Iwamoto of the division of molecular and cellular oncology at UCLA will be featured in a live Web chat Thursday (4 p.m. EDT, 2 p.m. CDT, 1 p.m. PDT). Iwamoto studied how the body responds to radiation exposure and how it can lead to cancer. He also explores ways to improve the use of radiation for medical therapies.

First review the basics in this L.A. Times story and graphic about the effects of radiation exposure. Then join the Web chat with your concerns and questions.