Radiation treatment and decreasing brain fluid levels appeared to have eased Mayor Bob O'Connor's headache and lethargy yesterday.

Mr. O'Connor, who was diagnosed with primary central nervous system T-cell lymphoma last month, had his second treatment of whole-brain radiation yesterday afternoon.

He is not expected to have any treatments over the weekend. Doctors plan to begin administering intensity-modulated radiation therapy on Monday. The technique will deliver high doses of radiation specifically to four lymphoma masses in his brain.

Doctors started Mr. O'Connor on radiation therapy Thursday, earlier than planned, because his headache and lethargy had worsened. A UPMC spokeswoman said yesterday that the treatments appeared to be contributing to an improvement in his symptoms.

"The overall improvement we're seeing is probably due to a combination of factors: decreasing fluid buildup and the effect of radiation," said spokeswoman Clare Collins.

A member of his medical team indicated that "lymphomas are particularly sensitive to radiation, so that you may see an effect sooner than you might with other cancers," she said.

She said Mr. O'Connor was more alert Friday and was talking to family members.

The mayor was not showing signs of side effects from the radiation, and doctors said side effects were unlikely to occur so soon after beginning radiation therapy, she noted.

Also yesterday, the Fraternal Association of Professional Paramedics and the Western Pennsylvania and West Virginia chapter of the Leukemia and Lymphoma Society announced that 5,000 wristbands saying "Everybody's Mayor, Bob O'Connor" had been sold Thursday and yesterday.

Five thousand more have been ordered and are expected soon. Proceeds benefit the society's local patients.