Radiological protection in paediatric diagnostic and interventional radiology


Draft document: Radiological protection in paediatric diagnostic and interventional radiology
Submitted by MARIA LUISA ESPAÑA LÓPEZ, SOCIEDAD ESPAÑOLA DE PROTECCIÓN RADIOLÓGICA/ SOCIEDAD ESPAÑOLA DE RADIOLOGÍA PEDIÁTRICA
Commenting on behalf of the organisation

(Line 54) Replace “and an estimated 6% to 11 % of CT examinations”, with “and up to 11% of CT examinations”, since it is an estimation.

 

(Line 309) Since “referring clinician” is almost every doctor in a hospital, it is almost impossible to establish cooperation between them and the practitioners.

 

(Line 328) Maybe include pregnancy tests in protocols just for girls above 15-16, perform pregnancy tests to every girl specially to short age ones seems exaggerated.

 

(Line 363) Not ‘medically’ justified, but yet ‘justified’ in most of the cases.

 

(Line 369) What does ‘protection measures’ mean: protection devices or protection standards? It doesn’t sound clear.

 

(Line 374) The words ‘adjustment of parameters’ should be substituted with ‘adequacy of radiation parameters’ or ‘adequacy of technical protocols to children’, since adjustment could be understood asit was ‘broken’ and it has to be repaired.

 

(Line 383) The sense of the phrase is perfectly clear with just ‘international, national or regional’, it is not necessary to include local, state….

 

(Line 390) ‘Facilities’ is the word  usually utilized to mention the x-ray unit plus the room, so perhaps it would be better to use ‘units with pulsed fluoroscopy’, or just ‘pulsed x-ray units’

 

(Line 392) Which is the ‘full’ range of settings? More precisely would be a ‘broadest range of settings’

 

(Line 393) What does the phrase ‘Programs should be…’ mean here? Protocols for each type of acquisition and children size? It is not clear.

 

(Paragraph 36) This paragraph mentions, on one hand, the necessity of adequating technical parameters to children, and on the other hand the quality control of the units and their limiting values. It seems to be all a little mixed up, and both aspects have significance enough so as to generate two separated paragraphs. It would be much clear.

 

(Line 400) With the phrase ‘quick and constancy checks’, the work of technicians and medical physicists seems to be despised, it should be substituted by ‘can be assured by routine constancy checks’, which means more or less the same but without downplaying that work.

 

(Line 401) Use ‘medical facility’ instead of ‘hospital’, since it can be another kind of facility.

 

(Line 413) Use ‘Adequacy of hardware and technical parameters’ or ‘Adequacy of equipment and technical parameters’ instead of ‘Adjustment in parameters’, since some modifications such as adding filtration really mean a hardware change.

 

(Line 415) As a consequence of the proposed title, the phrase ‘modifications of the above mentioned parameters may be necessary’ could be substituted with ‘modifications of the above mentioned parameters and also of the hardware may be necessary’.

 

(Line 418) Nowadays, interventional equipment incorporates up to 0.9 mm Cu, so maybe it should be suggested to add at least 0.3 mm Cu. European Guidelines (1996) proposed to add 0.3 mm Cu, but 15 years later units incorporate much more options.

 

(Line 453) Since this document is about paediatric diagnostic and interventional radiology, maybe some DRL’s regarding interventionism should also be included, and not just the projection radiography DRLs, based on European Guidelines and other sources up to year 1996. It should be taken into account that digital radiography has been widely installed since 1996 and maybe these DRL values should be actualized.

Data from table 32 included in  Doses to Patients from Radiographic and Fluoroscopic X-ray Imaging procedures in the UK’ could also be included here, or other data in documents also mentioned in the references like ‘A review of current local dose–area product levels for paediatric fluoroscopy in a tertiary referral centre compared with national standards. Why are they so different?’.

 

(Table 2) Since DRLs included in the table are for 5 year old patients, 4th line should be eliminated, because it is for new-borns. Besides, the item Pelvis (AP infants), in the 8th line, doesn’t appear in the same table of European Guidelines.

 

(General comment to chapter 3) Calibration and quality assurance of dosimeters and other equipment used for QA of X-ray units could perhaps be included anywhere in this chapter.

 

(Line 566) Children at certain age should also receive some information and instructions, as European Guidelines suggested.

 

(Line 578) Add ‘but also to the child’, as previously commented children at certain age can perfectly understand explanations regarding x-ray examinations.

 

(Line 588) One of the major problems encountered when working in paediatric radiology is the lack of collimation, especially since the introduction of digital technology, now widely used. Digital units incorporate tools in order to cut the images once acquired; then, they can be stored as if they had been properly acquired. So, giving ‘some degree of flexibility’ in collimation for children could even mean for example that teeth of a newborn could appear (or have been cut but yet irradiated) in a chest examination….if units are properly adjusted, no degree of flexibility should be allowed. Also some recommendations should be given to manufacturers in order to restrict the use of those ‘cutting’ tools in paediatric-dedicated equipment.

 

(Lines 617-618) ‘cannot be shielded’ instead of ‘effectively shielded’.

 

(Line 643) Some authors like Geleijns (Paediatr Radiol, 40, 1744-1747) have published some papers against the use of bismuth shielding in children, for they cause artefacts and propose reduction of mAs instead of their use. Does ICRP recommend the use of this shielding? If so, some mention to the artefacts should be done, since other artefacts are already mentioned.

(Lines 655-657)  For clarity, instead of ‘PA examinations’ and ‘AP projection’, use always ‘projection’. The last sentence is not clearly understood, the last part could be omitted ‘where PA-examinations should replace AP projections’, since it is understood without it.

 

(Line 668) Eliminate the word ‘nominal’, since the technician doesn’t know this nominal size, but just chooses between small-large.

 

(Line 671) Substitute the word ‘apparatus’ with units, or equipment.

 

(Lines 686-687) It can be specified that dose is absorbed ‘in the patient’s skin’. Besides, the soft part of the spectrum ‘does not contribute to image generation’, instead of “does not contribute to radiological examinations”, which is not clear. The phrase ‘unnecesarily adding to the examination dose’  would be more clear with something like ‘unnecessarily increasing the patient dose’ or ‘unnecesarily adding dose to the patient’.

 

(Line 688) The sentence ‘In general, radiation dose can be reduced by using higher kVp and an additional filtration’ could be removed, since it is mentioned in lines 696-697, and also better explained.

 

(Lines 693-694) End the sentence with ‘that are required for the higher kVp techniques recommended for paediatric patients’ instead of ‘these higher kVp..’.

 

(Line 713) Add ‘radiation dose..to the patient’.

 

(Lines 728-729) Change first sentence for clarity: ‘Depending on manufacturer recommendations, fluoroscopic equipment with the capability for quick and easy removal of the grid should be used in children’. The next sentence is easier with something like ‘Removable grids are desirable not only for fluoroscopic units, but ideally for all equipment used in paediatrics’

 

(Line 736) This paragraph is partially taken form European Guidelines, but is incomplete, since Focus-image distance should always be taken into account, and not only when grid is used. The following could be added: ‘The correct adjustment of the focus to image plane distance should be always observed. For over-couch tubes with grid tables, the focus to image plane is usually approximately 115 cm, and for vertical stands is approximately 150 cm’.

 

(Line 750) What does ‘Those investigating’ mean? Those manufacturers designing paediatric devices?

 

(Line 750) 100 kg seems a little exaggerated, 70 kg like proposed in European Guidelines may be more reasonable.

 

(Line 751) Use ‘AEC devices’, because the verb is plural.

 

(Paragraph 67) This paragraph regarding AEC totally discourages the use of these devices, and nowadays some digital units allow using it without grid. Besides, central chamber can be usually used in children apart from newborns. It is true that it would be better to have trained technicians specialised in paediatrics and therefore perform manual acquisitions, but this is not always possible, so AEC devices can help. The fact that it would be helpful to have specialised radiographers should be mentioned anywhere in the document.

 

(Line 770) In 2011, it seems to be strange to talk about ‘modern screens’.

 

(Line 777) The sentence ‘Small and simple computer programs may use the multiple parameters to calculate optimal exposure data’ sounds a little strange, it should be eliminated and also add something about specific protocols or proceedings for paediatrics included in the units: ‘Specific proceedings for paediatric patients can be implemented on the X-ray unit consoles. These proceedings may contain the paediatric exposure charts for age and weight above mentioned’.

 

(Line 792) ‘Reproducibilty’ instead of ‘constancy’, or besides.

 

(Line 795) This sentence regarding generators is obsolete, practically every unit manufactured today has a HF genetaror, and 12-pulse or multipulse are not ‘mare recent’ anymore.

 

(Line 807) This sentence could easily be understood as follows: ‘For most of the radiographic units it is difficult to obtain optimized short exposure times. That equipment which cannot achieve this range of exposure times should be disregarded for paediatric exposures’. Specific equipment for paediatrics with trained workers could be recommended.

 

(Line 820) The word ‘sufficient’ is ambiguous, perhaps from 2 meters or so could be proposed.

 

(Line 853) This team proposal is too ambitious, since some countries like ours don’t even have biomedical engineers…It would be enough to include a physician, a medical physicist, a radiographer and the manufacturer applications engineer, but also very difficult to establish and coordinate.

 

(Line 882) ‘with the speed class’, better than plural.

 

(Line 907) ‘the’ excluded from “on the one hand”.

 

 

(Line 987) Use ‘complexity’ instead of ‘sophistication’. For clarity, change “the potential for high patient overall radiation dose is greater” with “the overall radiation dose to the patient can be potentially greater.”

 

(Line 990) ‘Radiological’ instead of ‘Radioprotective’.

 

(Line 995) In some countries, especially in EU, the second level of training is not ‘desirable’, it is ‘mandatory’, and the additional training ‘must’ be planned instead of ‘should’.

 

(Line 1002) Use ‘interventionism’ instead of ‘intervention’. Besides, the phrase ‘a unique feature’ sound more like it is something positive, maybe modify with something simpler like: ‘In paediatric interventionism, the image intensifier size can be large relative to the infant size’.

 

(Line 1008) ‘and when it is performed’ instead of ‘when a procedure is performed’, to avoid repeating ‘procedure’.

 

(Paragraph 94) This paragraph seems to mix effects in organs, in patient’s skin and also, in the last sentence, aspects of quality assurance. Perhaps separate concepts in two or three paragraphs.

 

(General comments to chapter 5.1) Some other aspects of operational radiation protection should be included to reduce dose to patients: minimize use of magnification modes, avoid great obliquities, use additional filtration.

 

(Line 1022) Duration of procedure in children may be longer, but that doesn’t actually mean greater fluoroscopy times, so staff’s dose won’t be necessarily greater than with adults. Besides, children are usually sedated so the movement is reduced.

 

(Line 1028) 100 kg is a little exaggerated, better propose 3-70 kg as a reasonable interval.

 

(Line 1030) ‘ocassions’ in plural.

 

(Line 1036) Protection should always be used inside the operating room, not only close to the X-ray tube, because it is very difficult for staff to a priori recognize those procedures which mean ‘significant scattering dose’.

 

(Line 1039) Use ‘by about 90%’ instead of ‘by 90%’, because not all available lead glasses attenuate necessarily the same, and it also depends on the filtration and kVp used.

 

(Line 1041) Already mentioned in first point, remove.

 

(Line 1045) The same as for lead glasses, ‘by about 40-50%’.

 

(Line 1046) ‘However’ instead of ‘on the other hand’, to avoid repeating ‘hand’.

 

(Line 1052) ‘badge dosimeter’ instead of just ‘badge’.

 

(Line 1058) Since it is not always possible to stay where doses are lower, include ‘and, whenever possible, team members…’.

 

(Line 1061) ‘In an adult study’ could be removed, for it can be inferred that applied to infants would also reduce doses to staff.

 

(Line 1084-1085) Since C-arms are manufactured taking into account IEC 60601-1-3 (2008), minimum distance between focus and skin is greater than 20 cm, and so it is expected that it will never be ‘closer than permitted’, neither in PA nor in oblique projections.

 

(Line 1088) Use ‘projections’ instead of ‘runs’.

 

(Line 1151) Justification is mandatory always, and especially in CT, and not only for ‘brain CT’.

 

(Line 1160-1161) The sense of the sentence is not clear, if it is beneficial to perform CT or not.

 

(Line 1196) The image noise is not really a ‘contribution’ to image quality, in fact it contributes to deteriorate image quality, so it could be better considered as an ‘objective attribute’.

 

(Line 1198) Bismuth shielding also generates artefacts, as found in the literature. Multislice CTs could be here mentioned, since they really are faster and motion artefacts may be reduced.

 

(Line 1211) ‘Indication of the study’ instead of ‘Indication for the study’

 

(Line 1219) Ambient illumination would actually affect the study quality perception, but not the quality itself.

 

(Paragraph 109) This part about CTDI is perhaps too detailed when comparing it to the rest of the text, and there is no need to include so much information about the measurement of this parameter or the volume of the pencil chamber in this kind of document about paediatrics. Besides, there are no more explanations about dose measurements in the document. However, it could be mentioned that there are some solid state detectors available now.

 

(Line 1252) It seems that ‘or’ is actually ‘of’.

 

(Line 1266) ‘numbers’ should be singular, ‘number’.

 

(Line 1267) Apart from geometrical efficiency in MSCT, ‘overranging’ phenomenon could also be mentioned, for it is extremely important especially in kids, since the excess of rotations performed can result in irradiating organs outside the imaged volume such as thyroids or male gonads.

 

(Line 1268) Manufacturers try to improve image quality not only through filters, but also by applying new iterative reconstruction algorithms.

 

(Line 1283) Solid state detectors can be used to overcome this problem, as already proposed.

 

(Paragraph 113) The AAPM Report 204 “Size specific dose estimates in paediatric and adult body CT examinations” proposes some conversion tables to report CTDIvol as a function of the ‘real’ size of the patient from measurements made in standard CT phantoms. Additional paragraph(s) would have to be included in order to introduce DLP, which takes into account the total volume or length irradiated. Notice that table 5 includes DLP values and this parameter has not been explained.

 

(Line 1298) ‘Alternatively, automatic exposure control techniques, a form of automatic exposure control available in...’ could be replaced by ‘Alternatively, automatic exposure control techniques/systems available in newer multidetector scanners can be used to reduce the CT radiation dose to children’.

 

(Line 1305) If CT unit meets requirements of use, then dose is ‘always’ linear with mAs, not ‘in general’.

 

(Paragraph 119) Some recommendations about optimal thickness for children could be included.

 

(Line 1352) ‘Resolution’ or ‘Spatial resolution’ instead of ‘geometrical’.

 

(Line 1354) Too complicated sentence, it could be replaced by ‘Keeping the noise level constant requires an increase in mAs, and consequently in radiation exposure, that is inversely proportional to the square of the slice thickness. A reduction of the thickness to one half requires an increase of mAs by a factor 4.’

 

(Line 1368) Use ‘scout view’, widely used, better than ‘scanogram’, used only by some manufacturers. Since the scout view is not only used for AEC but also to localize the part being imaged, exclude the text in parenthesis for it is not a pre-AEC system, it is also used as a pre-AEC system.

 

(Line 1371) Replace ‘for the scanner’ by ‘for each scanner’.

 

(Line 1392) Sentence better included in previous point.

 

(Line 1397) Include ‘Provide aprons and instructions to stay outside the primary beam to the parents.’

 

(Line 1417) Use ‘the adequate considering the size’, instead of ‘adjusted for the size’.

 

(Line 1418) Children are usually less elliptical than adults so xy-collimation is not always suitable. Therefore, last sentence could finish with ‘if available and suitable’.

 

(Line 1432) ‘a smaller volume’ should be replaced by ‘the smallest volume possible’.

 

(Line 1452) Last point missing.

 

(Line 1555) Use ‘especially in young patients’ instead of ‘the young’.

 

(Line 1579) Use ‘may be’ instead of ‘maybe’.

 

(Line 1594) Replace ‘operators’ with ‘staff’.

 

 

Appendix A:

 

1. Central nervous system

 

(1614-1615) Depending on the clinical of the child, CT can be indicated in case of TBI, using available protocols, agreed between the departments involved.

 

(1617-1618) In cases of abnormal head appearance with open fontanel, e.g. hydrocephalus, suspected bleeding, suspected pathology of the midline, ultrasound is indicated...

 

(1624) ...possible cerebral palsy or alterations of the pituitary stalk.

 

(1624-1625) Headache, mastoiditis or suspected sinusitis...

 

(1626) CT will be used when suspected neurological complications, encephalitis, subdural epyema or cerebral sinus thrombosis. CT is also necessary for 3D reconstruction, prior to cranial surgery for deformities of the skull bone requiring remodelling or surgical complications in hydrocephalus treated surgically. MRI is preferably indicated to confirm or discard specialised pathological suspicions, such as tumours, congenital disorders of the head or spine, encephalitis, cerebillitis, postoperative follow-up, treatment responses, disease progression, etc.

 

2. Neck and spine

 

(1634) Ultrasound is indicated in a child with torticollis without trauma, lymphadenopathy, thyroid disease, soft tissue tumors, such as congenital cysts of the gill arches, suspected vascular malformations such as lymphangioma, etc. Radiography or TC are indicated only in specific circumstances when clinical findings are atypical or long-term, or in case of foreign bodies in the upper airway. Spina bifida occulta is not an indication for any imaging as it is a common variation. Ultrasound or MRI are indicated if neurological symptoms or signs are present, such as sacral pit, abnormal skinfold or soft tissues, always starting with ultrasound.

 

3. Musculoskeletal system

 

(1644) X-ray of the left wrist/hand (over 2 years of age) or the left ankle (below 2 years of age) for bone age determination...

 

(1645) In children with irritable hip or limping ultrasound is indicated to discard effusion and to guide diagnosis assessment and also treatment. X-rays or nuclear medicine examinations are only indicated in case of ultrasound negative finding. MRI is a specialized investigation in cases of unusual pathology suspicion such as osteomyelitis, avascular necrosis or tumors.

 

(1648) ... ultrasound can be helpful in case of suspected osteomyelitis and there is...

 

(1649) Clicking hip should be assessed with ultrasound, by expert personnel in ages between 2 and 5 months. Radiography is useful when no expert available or child older than 5 months.

 

4. Cardiothoracic system

 

(1655) ...persist despite treatment, or in cases of fever of unknown origin, or in severe ill children such as patients with distress admitted on ICU, oncologic neutropenia or lung sepsis suspicion.

 

(1657-1658) In the latter case there is wide variation in local policy about expiratory films, inspiration/expiration or directly performing bronchoscopy. A normal finding on radiography cannot discard aspirate. Fluoroscopy or TC should not be used unless there exists post extraction lung complications, but in this case a chest x-ray should be performed.

 

(1661) ...abscess is suspected. Ultrasound can help to achieve a better definition of lesion, also MRI if available, and even TC as the last resort. Ultrasound, MRI and TC are powerful techniques on lesion definition.

 

 

5. Gastrointestinal system

 

Ultrasound:

It has a high sensitivity and specificity for the diagnosis of suspected intussusception, being also a very effective method for ultrasound-guided therapy with serum enemas. It is also predictive jointly with the clinical reducibility degree. Radiography should not be used because, even in case of normal findings, does not exclude intussusceptions.

 

It is the test of choice to discard internal lesions (eco-fast) in the polytrauma. In case of doubt and depending on the degree of polytrauma, a thoracoabdominal CT will be performed.

 

It is also the technique of choice to rule out suspected hypertrophic pyloric stenosis in case of projectile vomiting.

 

When there is a palpable abdominal mass, ultrasound is the first technique to perform. Once confirmed the mass, further imaging, either MRI or CT, should be in a specialist centre performed by expert radiologists.

 

Plain radiography:

 

Including the neck, it is indicated to confirm the suspected ingestion of sharp foreign bodies, toxic or poisonous (batteries). It can be repeated on the 6th day to confirm their evacuation in doubtful cases.

 

Abdominal radiography in constipation is not routinely indicated and if Hirschsprung’s disease is suspected, specialist referral (gastroenterologist or paediatric surgery specialist) plus biopsy is preferred.

 

Minor trauma to the abdomen is not routinely an indication for abdominal radiography, unless there are positive physical signs suggestive of intra-abdominal pathology (pneumoperitoneum) or injury to the spine or bony pelvis.

 

CT remains the primary imaging investigation of choice for blunt abdominal trauma when ultrasound shows free fluid and is unable to determine its origin. Once confirmed the origin and type of injury, ultrasound may be useful in follow-up of known organ injuries.

 

Upper gastrointestinal contrast examinations are not normally indicated for recurrent vomiting or simple gastro-oesophageal reflux, but it can be indicated in those cases that have specific diseases such as oesophageal fistulae, postoperative, caustic post-ingesta oesophagitis, stenosis, suspected malrotation, volvulus found by ultrasound, etc.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


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