On a trading day that saw the S&P 500 gain 0.1%, the Health Care sector (XLV) showed little change.

Although down today, the ETF, as a as a proxy for sector performance, tracked closer to the overall market than over the past week. Going into trading today, XLV was down 1.6% over the last seven trading days while the S&P 500 was down 0.4%.

Fonar Corporation (FONR) was a significant gainer in the sector, rising 13.5%. The stock closed at $4.30 with 414,493 shares moving. The stock traded in a range of $3.67 to $4.39.

STAAR Surgical Company (STAA) was a major loser in the sector, falling 6.6% (-63 cents) to close at $8.94 with 452,779 shares moving. The stock traded between $8.60 and $9.53. The stock has been dropping in the last two months, down $2.42 (-21.3%) from a price of $11.36 on March 26, 2012.

Threshold Pharmaceuticals (THLD) rose 6.3% to close at $6.93, cross its 50-day moving average of $6.68 and 200-day moving average of $4.37.

HMS Holdings (HMSY) rose 3.6% to close at $25.76, approaching its 50-day moving average of $25.90. It has also moved closer to its 200-day moving average of $29.18. Alexion Pharmaceuticals (FRX) fell 2.1% to close at $90.57, moving closer to its 50-day moving average of $89.06. Also, the stock moved closer to its 200-day moving average of $32.48.

AstraZeneca (AZN) hit a new 52-week low today, hitting $40.76 to fall below the previous low of $40.89.