Shares of Hologic ( HOLX) were among the best-performing health-related stocks Wednesday, rising 20% after the provider of digital imaging systems posted third-quarter results that topped Wall Street forecasts.

The company earned $8.2 million, or 36 cents a share, on sales of $74.1 million. Analysts polled by Thomson First Call were expecting earnings of 28 cents a share on sales of $70.8 million. A year ago the company earned $3.3 million, or 15 cents a share, on sales of $59.2 million. During the most recent quarter, the company sold 64 Selenia digital mammography systems, up from 37 a year ago. Shares were trading up $7.39 to $44.52.

Aspect Medical ( ASPM) rose 10% after the company reported second-quarter results that were better than expected. The maker of brain monitoring systems earned $1.6 million, or 7 cents a share, on sales of $18.7 million. Analysts were expecting earnings of 5 cents a share on sales of $17.5 million. A year ago the company reported a loss of $376,000, or 2 cents a share, on sales of $13.4 million. Looking ahead, Aspect Medical forecast third-quarter earnings of 7 cents to 8 cents a share on sales of $18.9 million to $19.4 million. Analysts had been expecting earnings of 5 cents a share on sales of $18.1 million. Shares were trading up $3.11 to $33.66.

Shares of Intuitive Surgical ( ISRG) rose 25% after the company posted second-quarter results that were well above expectations. The company, which makes the da Vinci surgical system, earned $14.8 million, or 40 cents a share, on sales of $52.8 million. Analysts were expecting earnings of 21 cents a share on sales of $44.5 million. A year ago the company earned $4.8 million, or 14 cents a share, on sales of $31.1 million. During the most recent period the company sold 26 da Vinci systems, up from 19 a year ago. System sales, which include da Vinci systems, fourth arms, and Aesop systems, totaled $28.5 million during the second quarter, up from $18.1 million a year ago. On the company's conference call, Intuitive said that it now expects 2005 sales growth of between 40% and 45%, up from previous guidance of 20% to 30%. System sales are now expected to grow by 30% or more over 2004, up from previous guidance of 10% to 15%. Shares were trading up $12.71 to $64.01.

Repligen ( RGEN) rose 36% after the company swung to a first-quarter profit. The biopharmaceutical company earned $2.2 million, or 7 cents a share, on sales of $4.2 million. A single-analyst estimate called for a loss of 3 cents a share on sales of $2.8 million. A year ago the company reported a loss of $645,000, or 2 cents a share, on sales of $1.4 million. During the most recent quarter Repligen recorded $1.2 million in other income that was related to a previously expensed but disputed royalty obligation that was reversed as a result of a settlement in May 2005. Shares were trading up 86 cents to $3.19.

Shares of Applied Biosystems ( ABI) rose 9% after the company posted fourth-quarter earnings and sales that topped forecasts. The company posted earnings from continuing operations of $71.6 million, or 35 cents a share, on sales of $478.5 million. Excluding items, the company would have earned $61.7 million, or 31 cents a share. Analysts were expecting earnings of 27 cents a share on sales of $472.5 million. A year ago the company reported pro forma earnings of $54.3 million, or 27 cents a share, on sales of $460.5 million. Shares were trading up $1.83 to $21.60.

Other health-care volume movers included Pfizer ( PFE), up 34 cents to $26.58; Ivax ( IVX), down 5 cents to $25.45; Millennium Pharmaceuticals ( MLNM), up 32 cents to $11.01; Teva Pharmaceutical ( TEVA), down 3 cents $31.92; Amgen ( AMGN), down $1.15 to $80.99; Elan ( ELN), up 11 cents to $8.05; Johnson & Johnson ( JNJ), up $1.66 to $64.33; Manor Care ( HCR), up 73 cents to $38.02; UnitedHealth Group ( UNH), down 45 cents to $51.55; IMS Health ( RX), up 21 cents to $27.37; Merck ( MRK), up 41 cents to $31.10; and Schering-Plough ( SGP), up 18 cents to $20.93.