1. Prepared by Mrs. Rana AL-Dahlawi RAD 453 Radiation Protection Course

2. Safety in Various Imaging Modalities N.M MRI US

3. Nuclear Medicine Imaging

5.  Gamma Rays are used to form images in nuclear medicine. They are emitted by radioactive atoms called Radioisotopes. There are two principal hazards in nuclear medicine There are two principal hazards in nuclear medicineimaging:1.Contamination. 2. Radiation Exposure.  Contamination is the uncontrolled spread of radioactive material. It is hazardous because radioactive material can be inhaled or ingested. Some radioactive sources used in nuclear medicine pose Some radioactive sources used in nuclear medicine pose an external radiation hazard.

6. Hot Lab

8.  Contamination control requires protective shielding such as disposable gloves, gowns, & shoe covers.  Contamination control requires periodic surveys with a Geiger Counter or a portable scintillation counter.  A chemical fume hood without a charcoal filter is required for storage & use of radioactive gases such as ׀-131 & Xe-133.  Ingestion is minimized by frequent hand washing with soap & warm water. No eating, drinking or smoking should be allowed in No eating, drinking or smoking should be allowed in radioactive materials areas.

10. The syringe used for administrate Radiopharmaceutical to the patient must be shielded.

11.  Patient misadministration can be avoided by implementing strict procedures: 1. Physician orders must be verified. 2. Mode of administration must be verified. 3.Quantity of radioactive material must be verified.  Quantity of radioactive material should be assayed in a dose calibrator. Type of radioactive material must be verified.  Patient misadministration includes using: 1.Wrong radioisotopes. 2.Wrong quantity. 3.Wrong mode of administration.

12.  Nursing mothers should cease breast feeding for at least 24 hours following Tc-99m diagnostic study.  Radionuclide therapy with I-131presents special radiation protection problems.  I-131 in capsule form is preferred to that in liquid form. Iodine- 131 is secreted in urine, saliva & perspiration.

14. Guide points to Nuclear Medicine Technologist:  Generally, nuclear medicine technologist receive lower occupational exposures than radiographer.  N.M technologist should prepare millicurie quantities of radioactive behind protective barrier.  N.M technologist should always employ syringe & vial shields.  N.M technologist should be provided with ring badge for hand monitoring in addition to a body badge.  Radioactive waste should be segregated into short-lived & long lived material.  Short-lived radioactive waste includes that containing Tc-99mm & I-123.

15.  long-lived radioactive waste includes that containing Ga-67, I-131,& I-111.  Radioactive waste should be stored for decay before disposable in the normal solid waste system.  Before depositing radioactive waste in a storage decay receptacle, remove or obliterate all radiation symbols. Radioactive waste must be stored for decay to the level Radioactive waste must be stored for decay to the level of natural background before disposable in a sanitary system.

16. Ring T.L.D is required to monitoring the accumulated dose resulting from dealing with radioactive materials

18. Dose Calibrator used to assay amount of radioactivity in a syringe. System is based on a calibrated ionization chamber chamber.

19. Survey instrument used to detect location & relative amount of radioactivity. System is based on a Geiger- Muller counter.

20. Proper technique for administration of radiopharmaceutical

21. Magnetic Resonance Imaging

22.  M.R.I is an imaging modality that doesn’t used ionizing Radiation. It used low Radiofrequency therefore there is no risk associated with exposing the patients to this frequency.  M.R.I is based on excited protons in the body, this modality has great contrast over the other modality.  The primary hazard associated with the static magnetic field is that of ferromagnetic attraction.  When a ferromagnetic object, e.g. one containing iron or steel is close to the magnet if sufficiently close, this can turn this object into a dangerous projectile.

23. Practical Guidelines: Practical Guidelines:  Everyone entering the magnet room should be carefully screened, using checklist &/or details questioning, to ensure that they don’t have any contraindications to M.R.I either internally or about their person.  This includes the patient’s relatives, friend or nurse. The key to M.R.I safety in this respect is to be acutely vigilant at all time. Metallic object taken into the bore of a magnet may at worse cause serious injury or death & at best may produce unwanted artifacts on the image.

24. M.R.I Contraindications: M.R.I Contraindications:  Patients with implanted surgical clips or other ferromagnetic material.

25. Patients who have engaged in occupations or activities that may have caused the accidental lodging of ferromagnetic materials. e.g. metal-workers or who may have embedded metal fragments from military duties.

26. Neonates & infants, for whom data establishing safety are lacking. Patients with tattoos, including permanent eye-liner.

27.  Patients with compromised thermoregulatory systems, e.g. neonate, low-birth-weight infants, certain cancer patients.  Patients with metallic implants which may cause artifacts in the images due to distortion of the static magnetic field.

28.  Patients with prosthetic heart valves. Pregnant patients (the safety of M.R.I has not been completely established for embryo & fetus).

29. Diagnostic Ultrasound Imaging

30.  There are tow types of responses to ultrasound exposure- thermal responses and non thermal responses.  Both thermal and non thermal responses have been observed only at intensities much higher than that employed in diagnostic ultrasound.  Thermal responses are heating of soft tissue and bone.  Non thermal responses are mechanical in nature cavitation, tiny bubble formation, & membrane shearing.

33. TTTThere has never been a report of patient injury from diagnostic ultrasound examination. TTTThere are no concerns of operator safety in applications of diagnostic ultrasound. TTTThere are concerns of patient safety in diagnostic ultrasound because of expanding application & increasing beam intensity. FFFFor more ultrasound beam, highest tissue heating occurs near the skin.

34.  High intensity ultrasound waves can permanently alter the structure of the tissue through which they pass.  These effects range from slight warming of the tissues to total necrosis & destruction.  The power level that produce these changes are many orders of magnitude greater than the power level that are used in diagnostic scanning.  However, as far as our present knowledge goes no immediate manifest injury or late effect has over occurred in human exposed to diagnostic level of medical ultrasound.