Diagnostic imaging is a highly specialized medical process that uses various methods to take images of the inside of the body, such as X-rays, CT scans, MRIs, and ultrasounds. These procedures can provide valuable information that can be critical to diagnosing and treating a wide range of diseases and conditions. However, they're not without potential risks, both physical (like radiation exposure) and diagnostic (like over-interpretation or under-interpretation of the images).

Therefore, to ensure the safe and appropriate use of diagnostic imaging, it's usually necessary to have an order from a licensed medical professional, such as a doctor, nurse practitioner, or physician assistant, for the following reasons:

1. Appropriateness: These professionals can evaluate a patient's symptoms, medical history, and condition to determine if an imaging test is appropriate. Unnecessary tests can lead to unnecessary risk, anxiety, and cost.

2. Risk management: Certain imaging tests, like X-rays and CT scans, involve radiation exposure. It's critical to balance the potential benefits of these tests with the risks of radiation exposure. Medical professionals are trained to make these risk-benefit assessments.

3. Interpretation and follow-up: Once imaging has been completed, the results need to be interpreted in the context of the patient's overall health and medical history. This requires medical expertise. Moreover, based on the results, further steps may need to be taken, including additional tests, referrals to specialists, or initiation of treatment.

4. Regulatory and legal reasons: In many jurisdictions, the law requires a medical order for diagnostic imaging tests to ensure that they are conducted appropriately, for the right reasons, and that the results are properly managed.

Laws related to the need for a doctor's order for diagnostic imaging can vary by state, the state of Florida, like many other states, requires a licensed healthcare provider's order for diagnostic imaging studies.

These laws help ensure patient safety, appropriateness of the imaging, and the accurate interpretation and application of the results. They also aim to prevent unnecessary testing and the associated costs. The order typically needs to come from a physician, nurse practitioner, or physician assistant, as they are trained to understand when imaging is necessary and to interpret the results. Under Florida law, a patient does not need a referral from another physician to go directly to a radiologist for diagnostic imaging service, however, the radiologist will still need to order the imaging tests. This means that the patient cannot simply walk into a diagnostic imaging center and request an exam. They will need to see first the radiologist and discuss their medical history. The radiologist will then order the appropriate imaging tests. (2009, Florida Third District Court of Appeal ruled in Fernandez vs State).  To summarize, you need by law a referral from a healthcare provider to any diagnostic imaging exam. It is illegal in the State of Florida a diagnostic ultrasound without a referral, no matter if the case of payment is a self-pay option.

In the state of Florida, performing a diagnostic ultrasound without a referral generally goes against standard medical practice and could lead to legal and professional issues. Here are some key points to consider:

1. Standard Medical Practice: Typically, diagnostic ultrasounds are ordered by licensed healthcare providers to ensure they are medically necessary and appropriately interpreted. Performing an ultrasound without a referral might raise questions about the necessity and accuracy of the procedure.

2. Professional Guidelines: Professional organizations, such as the American College of Radiology (ACR) and the American Institute of Ultrasound in Medicine (AIUM), have guidelines that emphasize the importance of performing diagnostic ultrasounds based on a referral from a qualified healthcare provider.

3. Legal and Liability Concerns: Performing a diagnostic ultrasound without a referral might expose the provider to legal and liability risks, especially if the procedure results in misdiagnosis or harm to the patient. It could be viewed as practicing medicine without proper oversight, leading to potential malpractice claims.

4. State Regulations: While specific regulations regarding diagnostic ultrasounds may vary, it’s essential to comply with broader state regulations governing medical practice. In Florida, the Department of Health oversees medical practices and licensing, and any deviation from accepted standards could result in disciplinary action.

The specific regulations for diagnostic imaging can be found in Florida's state laws, medical board guidelines, and administrative codes. You can usually access these online, but they can be quite complex and are often subject to changes and updates.

For the most accurate, up-to-date information on this topic, consider consulting a legal professional or contacting Florida's Department of Health or Medical Board.