X-RAY PROTECTIVE CLOTHING : ANALYSIS …...2017/09/22  · Radiation –Part 3 : Protective Clothing and Protective Devices for Gonads Finnerty M., Brennan P. C. Protective aprons

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 ?