It’s well known that Senate Minority Leader Mitch McConnell, R-Ky., faces a tough race this year — a fact not lost on radiologists lobbying furiously to get a fix to the Medicare payment system before their fees are cut by 24 percent on March 31.

The American College of Radiology, which is unusual among its physician group peers in that it has jumped into the outside spending fray, has already spent $108,000 in support of McConnell in his race against Democrat Allison Lundergan Grimes. Nearly $30,000 of that amount went to mailers since late February as the Medicare issue has heated up, according to Sunlight’s Real-Time FEC tracker.

Last week, Bibb Allen, vice chair of the group’s Board of Chancellors, met with McConnell’s staff; the organization’s newsletter helpfully noted that meeting and another with the staff for Sen. Kay Hagan, D-N.C., “were particularly important. [They] face serious challenges in upcoming re-election bids.”

While the American Medical Association is by far the most powerful political powerhouse pushing for the Medicare — can you say more than $18 million reported on federal lobbying in 2013 alone? — groups representing a long list of physician specialities are also thick in the fray, backed by political action committees with healthy balances. With the House passing its version of the bill last week, which pays the $138 billion price tag with the veto-meat of delay of the individual mandate, the action is now in the Senate, where the elusive pay-for is still undecided. As the Senate’s Republican leader, McConnell has been one of the primary targets: See this February letter to congressional leadership from the American Medical Association and a long list of specialty physician groups.

There is rare bipartisan support in Congress for repealing the 1997 formula — known as SGR, or Sustainable Growth Rate — for determining physician fees under the federal Medicare program. The formula has required a reduction in physician fees every year since 2001. But every year, Congress has jumped in to rescue doctors with a temporary fix. Doctors want a permanent repeal of the system; legislation under consideration would replace the current clunky fee-per-service schedule with a different system meant to reward physicians for quality of care over volume of procedures. However, as set out in the legislation, it’s the specialty physicians groups that are given the power to help determine what these new quality measure are, a system obviously favored by these groups.

McConnell’s PAC donor list alone has long looked like who’s who of these groups, including: $15,000 from the American Society of Anesthesiologists; $15,000 from the American Academy of Family Physicians; $22,000 from the American Optometric Association; and $24,000 from the American Academy of Orthopaedic Surgeons, among others. Overall, McConnell has raised more from health professionals over his years in the Senate — nearly $2 million — than any other industry save Wall Street, according to Influence Explorer. That is more than the also hefty $1.4 million that Senate Majority Leader Harry Reid, D-Nev., has gotten from the health professions.

McConnell is second only to Cornyn in collecting campaign money from health professionals so far this cycle. The American College of Radiology has sunk even more cash into the Texas race, spending more than $230,000 to support Cornyn, by far the largest amount spent by an outside group in that race.

Overall, the American College of Radiology PAC has divided $600,500 direct contributions to 138 members of the House and 14 members of the Senate this election cycle so far, 73 percent to Republicans, and is sitting on more than $890,000 in cash on hand, according to Sunlight’s Real-Time FEC tracker. The group’s newsletter notes that Allen also attended three fundraisers while he was in town, including one for House Majority Leader Eric Cantor, R-Va., and Rep. Phil Roe, R-Tenn., a physician himself.

The American Association of Anesthesiologists, which has more than $2.1 million cash on hand, has already distributed more than $338,000, 60 percent of that to Republicans. That includes $40,000 for Senate members. The organization’s webpage says the group has decided not to take a formal position on pending legislation “at this time” but fully supports repeal of the formula by which Medicare payments are now calculated.

Favoring members on the other side of the aisle, the American Academy of Family Physicians PAC has more than $445,000 cash on hand and has given $5,000 apiece to vulnerable Senate Democrats Mark Begich of Alaska and Mark Udall of Colorado, as well as $2,500 to McConnell among the $275,000 it has distributed so far this election cycle. The group is urging members to contact members of Congress to urge for the repeal, has sent at least seven formal letters to members of Congress since the start of the year and has sent representatives to testify at various hearings dating back to at least 2005, among other advocacy activities.

Overall, it is hard to find a senator who hasn’t gotten at least some financial support from health professionals. When the 2012 election was all done, 92 senators had gotten campaign money from health professionals, according to the Center for Responsive Politics. The American Medical Association counts three members of the Senate who are also doctors themselves: Sen. John Barrasso, R-Wyo., Tom Coburn, R-Okla., and Rand Paul, R-Ky. Every senator has plenty of doctors in his or her district who are backed by the well-organized specialty groups.

The power of the physician groups is so high that Baucus’ replacement at the helm of the powerful Senate Finance Committee, Wyden last week turned the tables and urged physician specialty groups to get five senators on board to support his version of the Medicare payment reform bill — S. 2110, according to a report in the trade publication Inside Health Policy. Wyden himself has collected more than $1 million from health professionals.