As an artificial radioactive isotope, Technetium Pentetic Acid (Tc-PCA) has no natural antonyms. However, various alloys and minerals that naturally contain no technetium can be considered antonyms in terms of the substance's characteristics. Some of these minerals include gold, silver, copper, lead, and zinc. Tc-PCA is commonly used in medical imaging for diagnosing a range of conditions, including brain tumors, heart disease, and bone infections. But despite its importance in the medical field, Tc-PCA also poses significant environmental risks due to its radioactive properties. Therefore, antonyms for Tc-PCA can refer to elements or substances that are safer and more eco-friendly for medical and industrial purposes.