Diagnostic ultrasound imaging has no known risks or long-term side effects. Discomfort to the patient is very rare if the sonogram is accurately performed by using appropriate frequencies and intensity ranges. However, the application of the ALARA principle is always recommended.
There are reports of low birth weight of babies after applying more than the recommended ultrasound examinations during pregnancy. Women who think they might be pregnant should raise this issue with the doctor before undergoing an abdominal ultrasound, to avoid any harm to the fetus in the early stages of development.
Since ultrasound is energy, sensitive tissues like the reproductive organs could possibly sustain damage if vibrated to a high degree by too intense ultrasound waves. In diagnostic ultrasonic procedures, such damage would only result from improper use of the equipment.

Possible ultrasound bioeffects:
The thermal effect is controlled by the displayed thermal index and the mechanical index indicates the risk of cavitation.
An ultrasound gel is applied to obtain better contact between the transducer and the skin. This has the consistency of thick mineral oil and is not associated with skin irritation or allergy.
Specific conditions for which ultrasound may be selected as a treatment may be attached with higher risks.

See also Ultrasound Imaging Procedures, Fetal Ultrasound and Obstetric and Gynecologic Ultrasound.

Any abnormal reaction of a patient to an examination or procedure, like for example side effects of contrast agents or claustrophobia. Claustrophobic attacks as can happen with MRI are unknown with ultrasound examinations. Adverse reactions with ultrasonic contrast agents are very infrequent. In general, adverse reactions increase with the quantity of contrast media and also with the osmolarity of the compound.
Most frequently encountered adverse reactions are: Heat sensation, dizziness, nausea, hypotension due to vasodilatation, which can progress to hypotensive shock and anaphylactic reactions.

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From POINT Biomedical Corp
BiSphere™ is a technology for drug delivery applications by ultrasound. BiSpheres™ consists of microparticles comprising a shell of an outer layer of a biologically compatible material and an inner layer of biodegradable polymer. The core of the microbubbles contains a filling gas, liquid, or solid for use in drug delivery or as a contrast agent for ultrasonic contrast imaging. The contrast agent particles are capable of passing through the capillary systems of a subject. The drug-loaded biSpheres™ would be administered intravenously and freely circulate throughout the body, while the drug encapsulated within would remain biologically unavailable. The drug would only be released when the biSpheres become flooded when passing through an externally directed ultrasound field.
The use of biSpheres™ to transport agents to specific sites within the body is expected to substantially increase local efficacy while decreasing systemic side effects or adverse reactions. The biSpheres™ may also serve to protect labile agents from metabolism or degradation. The noninvasive release of a protected, encapsulated agent can be controlled by ultrasound imaging to a depth of 20-30 cm from the skin surface.
The flexibility in size control in the biSphere™ technology has enabled the construction of submicron ultrasound contrast agents suitable for lymphatic imaging, with a diameter in the submicron range. This agent, while much smaller in size than CardioSphere®, is based on the BiSphere configuration: a shell within a shell enclosing a gas. The inner layer, made from a biodegradable polymer, provides the physical structure and controls the acoustic response. The outer layer functions as the biological interface. Each of these layers has been independently tailored to fulfill the specific requirements for lymphatic imaging.

Breast ultrasound (sonography or ultrasonography) it is an important tool in the characterization of breast lesions, detected with mammography or clinical breast examination. However, a breast sonogram is not approved by the U.S. Food and Drug Administration (FDA) as a screening tool for breast cancer and is used additional to a mammogram.
Ultrasound is useful in guiding needles for fine needle aspiration and core biopsies. Breast ultrasound has optimal contrast resolution, but it lacks the spatial resolution of conventional mammography and cannot provide as much detail as a mammogram image. In addition, ultrasound is unable to show tiny calcium deposits (microcalcifications) that are often early indications of breast cancer.

See also Biopsy, Interventional Ultrasound, Ultrasound Safety, Side Effect and Ultrasound Regulations.

Different stages of the drug development and approval process in the USA, lead from preclinical trials (testing in animals), first application in humans through limited and broad clinical tests, to postmarketing studies.


By Dale E. Wierenga, Ph.D. and C. Robert Eaton
Office of Research and Development
Pharmaceutical Manufacturers Association

'In reviewing this report, it is important to keep in mind the realities of the drug discovery and development process. The U.S. system of new drug approvals is perhaps the most rigorous in the world. On average, it costs a company $359 million to get one new medicine from the laboratory to the pharmacist's shelf, according to a February 1993 report by the Congressional Office of Technology Assessment.'

See also Phase 1 2 3 4 Drug Trials, Food and Drug Administration, and European Medicines Agency.