ASN Report 2015

Essentially two methods of interchange are used:

•

telediagnosis, which enables a doctor on the scene (ex: an

emergency doctor), who is not a radiologist, to perform

the radiological examination and then send the results

to a radiologist in order to obtain an interpretation

of the images. If necessary the radiologist can guide

the radiological operator during the examination and

imaging process. In this case, the doctor on the scene is

considered to be the doctor performing the procedure

and assumes responsibility for it;

•

tele-expertise, which is an exchange of opinions between

two radiologists, where one asks the other – the “expert

radiologist” (teleradiologist) – for a remote confirmation

or contradictionof a diagnosis, todetermine a therapeutic

orientation or to guide a remote examination.

The data transmissions are protected and preservemedical

secrecy and image quality.

Teleradiology involves many responsibilities whichmust

be specified in the agreement binding the practitioner

performing the procedure to the teleradiologist. The

teleradiology procedure is amedical procedure in its own

right, like all other imaging procedures, and cannot be

reduced to a simple interpretation of images. Teleradiology

therefore fits into the general healthcare organisation

governed by the Public Health Code and obeys the rules

of professional ethics in effect (see the good practices

recommendations issued by the professionals).

1.1.2 Interventional practices using

ionising radiation

Interventional practices using ionising radiation comprise

“all invasive diagnostic and/or therapeutic medical procedures,

as well as surgical procedures that use ionising radiation

for guidance, including monitoring

”

The machines used are either fixed machines installed

in rooms dedicated to this activity, chiefly vascular

(neurology, cardiology, gastroenterology, etc.), in

which case one talks of interventional radiology, or

mobile radiology machines used in operating theatres

in several medical specialities, notably digestive surgery,

orthopaedics and urology. They involve techniques that

use fluoroscopy with an image intensifier or digital images

(flat panel detector) which require special equipment.

Interventional techniques using computed tomography

are on the increase, mainly thanks to recent technical

developments (acquisition speed, miniaturisation, mobile

CT scanners, etc.). These techniques are used during

diagnostic interventions (coronarography or examinationof

coronary arteries, etc.) or for therapeutic purposes (dilation

1. Definition from the GPMED Advisory Committee for Radiation

Protection for the Medical and Forensic Applications of Ionising

Radiation (reporting to ASN).

of coronary arteries, angioplasty, vascular embolization,

etc.) as well as during surgical procedures using ionising

radiation to guide or monitor the surgeon’s actions. They

can require long-duration exposure of the patients who

then receive high doses which can, in some cases, lead

to deterministic effects on tissues due to the ionising

radiation (cutaneous lesions, etc.).

The staff usually work in the immediate vicinity of the

patient and are also exposed to higher dose levels than

during other radiological practices. In these conditions,

given the exposure risks for both the operator and the

patient, practices must be optimised to reduce doses

and ensure the radiation protection of operators and

patients alike.

ASN does not know exactly how many facilities are

used for interventional procedures, mainly due to a

rapid increase in interventional practices in medical

specialities as a whole in recent years. Only the

numbers of rhythmology, interventional cardiology

and interventional neuroradiology units are known

with precision since these healthcare activities require

an authorisation from the Regional Health Agency

(ARS). The regional divisions of ASN make increasing

use of the data on hospital activities to have better

insight into the activities and the risks associated

with medical imaging. More than 1,000 centres

(lower bracket) practising interventional radiology

and fluoroscopy-guided procedures have thus been

inventoried in France.

1.1.3 Dental radiodiagnosis

Intra-oral radiography

Intra-oral radiography generators, which are usually

mounted on an articulated arm, are used to take localised

planar images of the teeth (the radiological detector is

placed in the patient’s mouth). They operate with low

voltage and current and a very short exposure time, of

about a few hundredths of a second. This technique is

most often associatedwith digital systems for processing

and filing the radiographic images.

Panoramic dental radiography

Panoramic radiography (orthopantomography) gives a

single picture showing both jaws in full, by rotating the

radiation generating tube around the patient’s head for a

few seconds.

Cone-beam computed tomography

Cone-beam computed tomography (3D) is developing

very rapidly in all areas of dental radiology, due to the

exceptional quality of the images produced (spatial

resolution of about 100microns). The price of this better

performance is that these devices deliver significantly

higher doses than in conventional dental radiology.

298

CHAPTER 09:

MEDICAL USES OF IONISING RADIATION

ASN report on the state of nuclear safety and radiation protection in France in 2015