Mayo Clinic's Investment - NYTimes.com Re "It Costs More, but Is It Worth More?," by Ezekiel J. Emanuel and Steven D. Pearson (Op-Ed, Jan. 3): We take issue with the assessment of Mayo Clinic's motivation in investing in proton therapy, a kind of radiation used to treat cancers. Mayo Clinic is resolute in its commitment to advance new, superior treatments that best serve patients based on clinical evidence. Our intent is not profit, nor is it to contribute to the medical arms race. In fact, we chose not to build a proton beam center on our Florida campus. That area was served by another center. Instead, Mayo Clinic invested money - not American taxpayer dollars - to develop proton therapy centers that will provide more effective treatment and much-needed access for patients in the upper Midwest and Southwest. Mayo Clinic continues to pioneer new treatments that benefit patients and advance science. Our proton therapy program will build on that tradition. We will always do what's best for our patients. We will carefully study proton therapy and other new therapies, compare clinical outcomes and offer high-quality, cost-effective, proven and safer treatments for patients. JOHN NOSEWORTHY President and Chief Exec., Mayo Clinic Rochester, Minn., Jan. 3, 2012