Radiological protection in paediatric diagnostic and interventional radiology

Draft document: Radiological protection in paediatric diagnostic and interventional radiology
Submitted by Cari Borras, Radiological Physics and Health Services Consultant
Commenting as an individual

General Comments

The draft compiles a series of recommendations but does not offer any new material that could really make it useful. Furthermore, there are several omissions in the draft that should be addressed in the final document. For example:

1. There should be a paragraph addressing equipment designed specifically for pediatric work, with x-ray tubes with smaller focal spots for improved resolution, generators capable of shorter exposure times, etc; and the need for Radiology Departments that do a lot of pediatric radiology to acquire them.
2. The document uses entrance skin dose (ESD) as the parameter for “radiation dose” in the section of readiography/fluoroscopy. This term has been considered inadequate by ICRU. It would be good to help readers who may not be familiar with ICRU’s nomenclature to have data expressed in both ESD and air-kerma. Otherwise we will never get the medical community to accept the new terms. The same issue occurs in CT.
3. The section on radiography is very poor. It only refers screen-film detectors. It should be expanded to include CR/DR.
4. Overall, the draft uses equipment-related parameters as an indication of radiation risk. Organ doses should be introduced and their determination, suggested.
5. It is strange that successful campaigns such as Image Gently is never mentioned; yet their impact world-wide is significant.

Specific Comments

Lines 413-424
To adjust parameters using equipment designed for adult work may not yield the desired effect. As stated in the General Comments, facilities doing a lot of pediatric work should install equipment specifically designed for pediatric use.

Lines 430-452
DRLs should be specified in measurable quantities such as air-kerma, as recommended by ICRU. Where appropriate, the equivalence should be calculated and both numerical values given.

Lines 460-461
DRLs for CR/DR should be included

Lines 471-472
Either convert to air-kerma or give both ESD and air-kerma values.

Line 502
The ACR Appropriateness criteria are available on line. The URL reference should be given here.

Lines 547-550
The current draft uses as “model” the European Guidelines for pediatric radiology which were published 15 years ago before CR and DR were commonly employed in radiology. It should use more recent references from the scientific literature.

Lines 685-691
Adequate added filtration for neonates needs to be stated, as tube potentials will be relatively low.

Lines 729-731
This statement seems to be in contradiction with the one on 716-718. A clarification of both should be given.

Lines 783-785
Many fluoroscopic systems do not allow switching off automatic brightness control (ABC). Should fluoro systems exclusively dedicated for pediatric work have the ABC feature disabled by the service engineer?

Lines 789-810
These are very good observations that should go to a special section on pediatric imaging equipment.

Lines 898-899
The statement “At 15, 7.5 and 3.75 frames per second the dose reduction is about the same” requires some clarification. Is it true for all the fluoro systems that use grid-controlled x-ray tubes?

Lines 924-926
The statement “The image intensifier should be positioned over the area of interest before fluoroscopy is commenced rather than positioning during fluoroscopy” is odd since there is an interlock that prevents to energize the x-ray beam unless the image intensifier is centered on the radiation field. Perhaps it addresses table positioning?

Lines 932-935
Here kerma is used, which is OK. But it was never defined. The whole document should use kerma rather than entrance surface dose. Air kerma and the terms used in this section such as Kar and PKA need to be defined.

Lines 1008-1010
This recommendation should go to a justification section; it is not an optimization issue.

Line 1011
How does archiving fluoroscopy runs help to reduce dose?

Lines 1045-1047
The fact that leaded gloves will increase the dose if they enter the beam by raising kV, ma and/or ms should be mentioned here.

Line 1172
MRI is also very costly and may not be appropriate for developing countries. Reference could be made to the publication: World Health Organization. Rational use of diagnostic imaging in paediatrics: report of a WHO study group. Geneva: WHO; 1987. (Technical report series 757).

Lines 1177-1179
At least the order of magnitude of that “added risk” should be included. Or a reference on how to calculate it, given.

Footnote after line 1265
As stated above, the decision of using absorbed dose to air rather than air kerma is wrong. It is especially disturbing that one section uses one term; another one, the other. The ICRU 75 terms should be used instead. In any case, the footnote should appear earlier in the document.

Line 1381
Some of the recommendations given in paragraph 121 have not been discussed before; so the word “summary” is misleading. Section 6.6 could be titled: “List of principles….”

Line 1569
Replace “radiation dose exposure” by “radiation exposure”

Line 1671
Spell CXR and AXR