Upload
others
View
3
Download
0
Embed Size (px)
Citation preview
X-RAY PROTECTIVE CLOTHING :
ANALYSIS METHODOLOGY
Bastiaens L. – 21/09/2017
Introduction
Protective aprons :
▪ Play a key role in radiation protection
▪ Used in a variety of diagnostic imaging
procedures
▪ Shields 75% of the red bone marrow
▪ Attenuates more than 90% of the radiation
Introduction
Protective aprons are useful but :
▪ Often made with lead
• Dangerous waste for the environment
▪ Are heavy and uncomfortable
• Backpain for the wearer
▪ Are costly and subject to normal wear and
abuse
Introduction
Protective aprons requires :
▪ To be adapted to the situation
▪ Examination & Control
• Initial check
• Periodic testing for their efficiency
▪ Rational basis for criteria acceptance
▪ ALARA
Introduction
Introduction
Introduction
Introduction
Methodology – visual inspection :
Visual Inspection
▪ General state
• Wear ? Tears ? Attaches broken ?
• One should not be able to touch lead parts ?
▪ Quality of the storage (!)
▪ CE marking
▪ Lead equivalence in accordance with hazard
▪ Marking in compliance with [IEC-61331-3:1998]
Department 100 kVp
(0.35mm Lead Eq.)
< 100 kVp
(0.25mm Lead Eq.)
Casualty X
Consulting X
Gastrointestinal X
Angiography X
Endoscopy X
Mastology X
Dentistry X
Neonatal care X
Bones X
CT-SCAN X
Nuclear Medicine X
Operating block X
Visual inspection – Lead equivalence
best practices
Visual inspection - Marking in
compliance with [IEC-61331-3:1998]
• Name of the manufacturer
• Type of protection
• Lead Equivalence (mm Lead eq.)
• For a given potential (kV)
• Size of the protection
• Reference to the norm
Methodology – QA :
Quality Assurance (1/2)
▪ Inventory is needed !
▪ Internal ID number
▪ Date of the previous control
▪ Results of previous control
• Print and localisation of defects
▪ Age
▪ Track of the repairs
▪ Note the ID, brand, model & composition
Quality Assurance (2/2)
▪ Size of the protection
• From the throat to the knees
▪ Type of protection (apron, gloves, thyroïd,…)
▪ Stated Lead Equivalence
• Front and back might differ !
• Composition
• Beam quality (kV, filtration if stated,…)
▪ Department
Methodology – QA :
Methodology – X-Ray examination :
X-ray examination
▪ Radio-inspection of the inner shielding
▪ Best done with radioscopy devices
• ALARA
• Ergonomy
▪ First, perform a blank check for imagingartifacts
▪ Check for potential inhomogeneities
Methodology – X-Ray examination :
Location Maximum size of defect
(mm²)
Whole body Total : max. 670 mm²
Single defect : max. 15 mm²
Gonads Max 1 defect of max. 15 mm²
Thyroïd Total : max. 11 mm²
Lambert, Kent & McKeon, Tara. (2001). Inspection of Lead Aprons. Health Physics. 80. S67-9
Methodology – X-Ray examination :
Criteria based on assumtions :
▪ Cost of protection (1000$/mSv averted)
▪ Average residual life time of apron (5 years)
▪ Cost of apron (400$)
▪ Unattenuated whole body yearly dose (50mSv/y)
▪ Transmission factor (0.05 %)
ALARA principle
Lead-equivalence verification
▪ Should be verified once
▪ More challenging :
• Needs radiography device
• Sensitive and costly detector (Barracuda, RaySafe
XI,…)
• More time…
Methodology – Lead Eq. Verification :
Methodology – Lead Eq. Verification :
Methodology – Lead Eq. Verification :
Formula based on NCRP147 (A.3)
▪ (α,β,γ) are function of beam quality and kV
▪ Be consistent when choosing the kV
• kV stated on Apron marking
• kV chosen on X-ray device
Methodology - Conclusions
Decide if :• The protection is ok
• The protection needs temporary removal for repair
• The protection needs closer follow-up
o Identify the location of the defects
o Take pictures to follow evolution
• The protection shall be used for another use (otherdepartment)
• The protection is out of order
o Explain the reasons (Lessons Learned)
Methodology - Conclusions
Evaluate the followings :
▪ The quality of storage
• Has a direct impact on wear and cracks apparition !
▪ The amount of available protections
▪ Their variety in types
• Aprons, thyroïd protection, skirt, jackets,…
▪ Their variety in sizes
• Must be adapted to the workers
Methodology – Lessons Learned
Size of aprons not always adapted
Lead equivalence thickness not alwaysadapted.
▪ Easy to solve !
Need to better inform the workers about right storage and importance of self-check (palpation)
Use the thyroïd protections
Methodology – Recommendations
Visual inspection : yearly
X-Ray examination : yearly
Lead thickness verification : once per
protection
… Thank you for your attention !
References
NCRP Report 147. Structural Shielding Design for Medical X-Ray Imaging Facilities. 2004.
IEC 61331-13:1998. Protective Devices again Radiodiagnostic medical X-Radiation – Part 3 : Protective Clothing and Protective Devices for Gonads
Finnerty M., Brennan P. C. Protective aprons in imaging departments: manufacturer stated lead equivalence values require validation. Eur. Radiol., 15, 2005, p. 1477–1484.
Lambert, Kent & McKeon, Tara. (2001). Inspection of Lead Aprons. HealthPhysics. 80. S67-9
ASTM-F2547, Standard Test Method for Determining the AttenuationProperties in a Primary X-Ray Beam of Materials Used to Protect Against Radiation Generated During the Use of X-Ray Equipment.
Masayuki Zuguchi, et Al. Usefulness of Non-Lead Aprons in Radiation Protection for Physicians Performing Interventional Procedures. Rad. Prot. Dosim. (2008). Vol. 131. No.4.p. 531-534.
Questions ?