The Forgotten ,yet most important Radiology-Lead Aprons

Teaching points by Dr MGK Murthy, Ms Shwetha Namani, Dr Sumer Sethi

1.    Lead(Pb)with Atomic No 82 is used , primarily because of high atomic mass (means more electrons to maintain neutral charge, thus permitting absorption) and relatively small size of its bond lengths and Atomic Radius(means atoms can be packed in to structure)

2.    If Pb does not exist in the path, scatter radiation energy will   damage cell DNA   of the region

3.    Is good enough for low energy Radiation like X-rays/Gamma Rays

4.    Not good enough for high energy Radiation like Beta Rays(produces Bremsstrahlung Radiation which is  more dangerous) and Neutron Rays

5.     Has disadvantage of  weight for 0.5mm/0.25 mm equivalent thickness (generally preferred for Radiology )

6.    Lead free Aprons (for lightweight) in the market today consists of materials Zinc(50), Tin(Sn),Antimony(Sb51),Tungsten(W74).

7.    However  some reports caution  against usage of these , being less efficacious  in absorption of scatter Radiation

8.    Typical Wraparound full-length,Lead apron is 100-150cms wide and 100-120cms length

LEAD  APRON WITH CRACKS

CHECKING OF APRONS

1. Lay them out on Flat surface and visually check the seams and the covers

2. Use hands, feel the surface for lumps/cracks/evidence of separation from seams/sagging

3.If suspect, can be inspected radiographically or fluoroscopically (preferred technique, but avoided in view of operators unwanted radiation)

4. Radiogrpahy of the Apron is adequate  with High Kv Technique

5. Either Suspect area (on inspection/palpation) (preferred) or the whole of the Apron can be Radiographed  in components

6.If the Crack is likely to come in critical area of Exposure like Gonads , it should be rejected, if the sum of areas of the defects  exceed 15 sq mm(Eq to4.3 mm  diameter circular hole)

7. For Thyroid shield the limit is projected as 11Sq mm( Eq to3.8 mm diameter circular hole)

8. In other general areas including the back straps  a limit of 670 Sq mm(Eq to 29 mmdiameter circular hole)  OR  a single  defect larger than 15 Sqmm is  recommended. Usual life of well maintained aprons is 10 years

9. Always keep unused aprons on heavy duty hangers and avoid leaving on the floor as heap or folding them

10. Percent of Transmission of radiation accepted through aprons is  0.02%(at 50Kvp),0.82%(at 70Kvp),3.9%(at 100Kvp) etc

11. If an apron needs to be retired, it should preferably be  returned  to the  manufacturer to  avoid environmental contamination and under no situation discard them as routine trash.