Practical measures for the reduction of patient radiation dose

Radiation Sign. Please Take care.

   (A) Some dose-saving equipment:

1.  Fast screen-film combinations (e.g. rare earth)

2. Low attenuation (e.g. carbon fiber) materials for cassette fronts, antiscatter grid interspacing.

3. Constant potential generators with appropriate kilovoltage.

4. Appropriate beam filtration (minimum 2.5 mm Al for general radiography).

5.  Specialized equipment for mammography and pediatrics

6. Pulsed and frame-hold (image storage) fluoroscopy equipment.

7.  Digital radiography equipment.

8. Dose-area product meter to monitor patient exposure.

   (B) Some dose-saving techniques:

1. Use smallest possible field size and good collimation.

2. Collimate to exclude radiosensitive organs (gonads, breasts and eyes).

3. When gonads lie outside the primary beam, make distance between the edge of the field and the gonads as large as possible.

4. Shield breasts, eyes, and gonads unless the area of interest would be masked. Dose to ovary can be halved and that to testes reduced by a factor of 20.

5. Use largest practicable focus to skin distance: never less than 30 cm, especially in mobile radiography.

6. Position the patient carefully. Reduce the dose to the female breast and, in skull radiography, to the eye by postero-anterior projection. Minimize the gap between patient and film-screen.

7. Use compression of patient where possible.

8. Use non-grid techniques when examining children and small adults.

9. Keep film reject rate due to all causes down to 5%. Check the factors before exposure. Quality assurance, particularly of automatic processors, is important.

10. In fluoroscopy use the minimal field size and minimal screening time essential for good diagnosis.

11. Use zoom or small field techniques, which require a higher dose rate, with discretion.

(C) High-risk examinations:

1. Keep pediatric radiation doses to an absolute minimum consistent with adequate diagnosis as children up to the age of 10 years are believed to be 3-4 times more radiosensitive than adults.

2. In pelvimetry: use MRI or CT scanography where possible; otherwise use fast rare earth screens and carbon fiber components.

3. Mammography is not generally performed on women younger than 50 years unless there is a family history of breast cancer or the patient has related symptoms.

4. In CT scanning, take the minimum number of slices, position the patient to avoid the eyes and other critical organs; reduce milliamperage if appropriate, e.g. for the chest.

5.  Patients who are or might be pregnant.

6. Interventional radiology needs  care  to avoid  skin  reactions;  use  pulsed and frame-hold systems: minimize screening times.