How is an X-ray performed on a rat? - briefly
The animal is anesthetized, positioned on a radiographic cassette (typically prone or lateral), and exposed to a calibrated X‑ray beam while protective shielding minimizes scatter; the resulting image is captured digitally for immediate analysis. Proper dose settings and brief exposure times reduce radiation risk and ensure clear anatomical detail.
How is an X-ray performed on a rat? - in detail
Radiographic examination of a laboratory rat begins with verification of protocol approval and preparation of a sterile work area. Required items include a calibrated small‑animal X‑ray unit, a radiolucent table, anesthesia delivery system, heating pad, and personal protective equipment for the operator.
The animal is weighed, identified, and placed in an induction chamber. Inhalation anesthesia (e.g., isoflurane at 2–3 % in oxygen) or injectable agents (e.g., ketamine‑xylazine) is administered to achieve a surgical plane of anesthesia. Vital signs—respiratory rate, heart rate, and body temperature—are monitored throughout the procedure.
Positioning follows a standardized sequence:
- Place the rat in dorsal recumbency for thoracic imaging or lateral recumbency for skeletal studies.
- Align the region of interest with the central axis of the X‑ray beam using radiopaque markers.
- Apply a gentle restraining device or adhesive tape to minimize movement while preserving respiratory function.
- Maintain core temperature with a warmed platform to prevent hypothermia.
Exposure parameters are adjusted according to the target tissue and animal size. Typical settings for a 250 g rat include:
- Tube voltage: 40–50 kVp for soft‑tissue contrast, 60–70 kVp for bone.
- Tube current: 0.5–1 mA, exposure time 10–30 ms.
- Filtration: 0.5–1 mm aluminum to reduce low‑energy photons.
- Source‑to‑image distance: 15–20 cm to achieve adequate magnification and sharpness.
The radiographic cassette or digital detector is positioned behind the animal, and a single exposure is taken. Immediately after exposure, the image is reviewed for proper contrast, penetration, and absence of motion artefact. If necessary, repeat exposures are performed with adjusted settings, keeping cumulative dose within ethical limits.
Following image acquisition, the anesthetic plane is reversed, and the rat is transferred to a recovery cage with continuous temperature support. Analgesics are administered as required, and the animal is observed until normal locomotion resumes. All data, including exposure parameters and animal identification, are recorded in the study log for traceability.