Yes — ultrasound can detect and monitor temperature changes in tissue, especially during thermal therapies like focused ultrasound. Techniques such as ultrasound thermometry and thermal strain imaging exploit temperature-dependent changes in sound speed, backscatter, and tissue displacement to estimate heating. However, ultrasound is better for real-time relative temperature mapping; MR thermometry is generally more accurate for absolute temperature measurements.

Ultrasound is usually delayed until about 8 weeks because before then the embryo and fetal heartbeat may be too small to visualize reliably. Scanning earlier often yields inconclusive results, can give false reassurance or unnecessary anxiety, and makes accurate dating and viability assessment difficult. Waiting reduces false positives/negatives and unnecessary repeat scans; transvaginal ultrasound is used sooner only for pain, bleeding, or high‑risk concerns.

Depends on the scan: for abdominal ultrasounds (liver, gallbladder, pancreas) fast 6–8 hours to reduce bowel gas and keep the gallbladder full. For transabdominal pelvic scans, drink about 1 litre (≈4 cups) of water and avoid voiding about 1 hour before. For transvaginal scans, empty your bladder. Follow any specific clinic instructions.

Ultrasound at 3.3 MHz is a superficial-frequency setting. Higher frequencies (around 3 MHz) penetrate less—typically about 1–2 cm—and are used for skin, tendons and superficial muscles, providing better resolution. For deeper structures (several centimetres), lower frequencies (around 1 MHz) are chosen because they penetrate farther but with lower resolution.

Diagnostic ultrasound is not inherently hot; it uses high-frequency sound waves and usually causes no noticeable heating. Very high-intensity or prolonged exposure can produce slight tissue warming. Therapeutic ultrasound intentionally produces heat to relax tissues and aid healing. Safety depends on intensity, frequency and duration, so diagnostic scans are designed to minimize thermal effects and are considered safe when used correctly.

Doctors measure body temperature using digital thermometers placed orally, rectally, or in the axilla, infrared tympanic (ear) or temporal artery (forehead) scanners, and invasive probes (esophageal, bladder, or pulmonary artery) in critically ill patients. Rectal and core probes are most accurate; oral and axillary are convenient but can be affected by drinking or sweat. Readings guide fever diagnosis and treatment decisions.