Thanks, Craig. For the 3 months ended March 31, 2012, revenue increased 0.8% to $4,403,000 compared to $4,367,000 for the first quarter of 2011. In addition to the impact on our revenue growth of the weak economy that Craig mentioned, this year's first quarter revenue also was affected by the shutdown of one of our Gamma Knife units for a month for a cobalt reload. The closure in last year's third quarter of our Gamma Knife center at Lehigh Valley Hospital in Allentown, Pennsylvania, that we have discussed on prior calls also affected the revenue comparison. As you know, we have added new Gamma Knife centers since then, but they are still ramping up and haven't yet reached their maturity. This affects both our revenue line and our gross margin percentage.
Net income for the first quarter of 2012 was $9,000 or $0.00 per diluted share. This compares to net income of $21,000, $0.00 per diluted share for the first quarter of 2011. The number of procedures performed on Gamma Knife Perfexion systems supplied by AMS increased 2.8% for the first quarter of 2012 compared to the first quarter of 2011.
The total number of procedures performed in AMS Gamma Knife business increased 5.1% for this year's first quarter compared to first quarter of 2011. Revenue increased more slowly than procedure volume primarily because of quarter-to-quarter variations in the procedure mix between sites. Gross margin for this year's first quarter decreased to 41.7% compared to 41 -- excuse me, 44.1% for the first quarter of 2011 but increased sequentially compared to gross margin of 39.5% for the first -- fourth quarter of 2011, also reflecting quarter-to-quarter variations in the mix of procedures between sites.
Selling and administrative expenses for the first quarter of 2012 decreased 8.7% to $1,024,000 compared to $1,122,000 for the first quarter of 2011, primarily the result of reduced payroll costs. Operating income increased to $239,000 for the first quarter of 2012 compared to $226,000 for the first quarter of 2011. Cash flow as measured by earnings before interest, taxes, depreciation and amortization or EBITDA increased to $2,139,000 for the first quarter of 2012 compared to $2,047,000 for the first quarter of 2011.
On the balance sheet at March 31, 2012, cash, cash equivalents and certificates of deposit were $10,788,000 compared to $11,580,000 at December 31, 2011. Borrowing on our line of credit was reduced by $350,000 to $7,500,000 at March 31, 2012. Shareholders' equity at March 31, 2012 was $25,115,000 or $5.45 per outstanding share. This compares to shareholders' equity at December 31, 2011, of $25,171,000 or $5.46 per outstanding share. Craig?