Nodules of 0.9 cm are small, and although they are not big, they need to be followed up and observed. A 0.9 cm nodule can occur in the breast, thyroid, lungs, and other organs and areas. Nodules in the lungs are defined as those that are less than three centimeters in diameter. When the diameter is less than one centimeter, it is called a small nodule, and when the diameter is less than 0.5 cm, it is called a micronodule, so a nodule of 0.9 cm is considered a small nodule. Whether it is a lung nodule or a 0.9cm nodule in the breast, thyroid or other parts of the body, it is necessary to carry out follow-up observation to determine the growth rate and size of the nodule according to the results of the imaging tests, as well as other morphological features. If it is found that the nodule grows faster in a short period of time, the border is not clear, and the internal echogenicity is not irregular, then it is necessary to carry out surgical treatment in a timely manner. If a nodule of 0.9cm is found, it is recommended to consult the relevant departments of regular hospitals.