Cause of Device-Related Incident
Device factors; User errors

Clinical Specialty or Hospital Department
Radiology / Ultrasound / Nuclear Med.

Device Factors
Device failure

Document Type
Hazard Reports

External Factors
*Not stated

Mechanism of Injury or Death
Mechanical (puncture, perforate, lacerate, break, cut, tear, nick, crush); Monitoring failure

Support System Failures
*Not stated

Tampering and/or Sabotage
*Not stated

User Errors
Inappropriate reliance on an automated feature

Cameras, Gamma [15-944]; Cameras, Gamma, Mobile [16-891]; Cameras, Gamma, Stationary [16-892]

Leaving SPECT Patients Unattended

Hazard [Health Devices Jun 1986;15(6):177-8]


During a scanning procedure involving a single photon emission computed tomographic (SPECT) gantry system, the patient's arm became trapped between the rotating detector and the table assembly while the technologist was temporarily out of the room. When the patient cried out, the technologist returned and immediately operated the emergency (abort) safety switch. The gantry stopped before the patient sustained any injury. ECRI believes that the incident was probably avoidable and that users of all SPECT systems should be aware of the possibility of injuries resulting from patient entrapment.


A SPECT system comprises three major components: an operator console, a computer, and a rotational gantry. The operator console controls the data acquisition process, while the computer stores the collected data and reconstructs images of selected planes for display. The gantry supports the scintillation camera detector, which rotates around the body and advances either continuously or in discrete increments (step-and-shoot).

In a typical scanning procedure, the patient is injected with a radiopharmaceutical. After the organ to be scanned has had sufficient time to absorb the radiopharmaceutical, the acquisition (imaging) process begins. The detector, supported by the gantry, rotates axially about the patient, acquiring data in the form of photons emitted from the organ. During this process, the patient's position is critical. In order to achieve maximum resolution of the emitted radiation, the detector must be close to the patient. Entrapment may occur during acquisition if the patient's arm extends outward over the table assembly and rests within the path of the rotating detector. The procedure can last as long as 45 minutes, and technologists may become distracted or involved in other cases. As a result, they may leave the patient unattended.

Although emergency stop (abort) switches are part of all gantries and/or operator consoles, a technologist must be present to activate the switch. Some manufacturers provide other types of emergency stops to halt the gantry if it meets an opposing force. However, technologists should not rely solely on the existence of an emergency system or systems to avoid accidents. Therefore, ECRI recommends that all hospitals have procedures to ensure that patients are not left unattended while the scanning procedure is in progress.


  1. Write and implement procedures that ensure that a technologist or another authorized person is present during the entire procedure. This person must observe both the patient and the unit and should be prepared to promptly terminate gantry motion at any time. Explain the procedures and the rationale behind them to all appropriate personnel within the Nuclear Medicine Department.
  2. If an emergency requires that a patient be left momentarily unattended, the technologist should stop the gantry before leaving the room. The study can then be continued or repeated when the patient's safety can be ensured.
  3. Follow all manufacturer's recommendations in the operations manual concerning proper patient positioning and use of the patient positioning straps and supports. Some manufacturers also recommend a carefully observed, manually controlled test run of the SPECT procedure to ensure proper clearance between the detector and patient. Closely monitor the patient during the actual procedure to make sure that the patient remains in the correct position.


  • Cameras, Gamma [15-944]
  • Cameras, Gamma, Mobile [16-891]
  • Cameras, Gamma, Stationary [16-892]

Cause of Device-Related Incident

Device factor: Design/labeling error

User error: Inappropriate reliance on an automated feature

Mechanism of Injury or Death

Mechanical (crush); Monitoring failure

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