ASN Report 2015

1.2 Technical rules for fitting

out radiology and tomography

installations

Radiology installations

A conventional radiological facility usually comprises

a generator (high-voltage unit, X-ray tube), associated

with a support (the stand) for moving the tube, a control

unit and an examination table or chair.

The mobile facilities that are commonly used in the same

room, such as the X-ray generators used in operating

theatres, are to be considered as fixed facilities.

As of 2013, radiological facilities must be installed

in accordance with the provisions of the new ASN

technical resolution 2013-DC-0349 of 4th June 2013

(see chapter 3). This resolution requires that the layout

and access to the facilities comply with the radiation

protection rules set by French Standard NFC 15-160

in its March 2011 version.

The new standard NFC 15-160 common to all medical

radiology facilities, including computed tomography

and dental radiology, introduces a method of calculating

the required thickness of the protection screens in all

facilities that use X-ray generators.

This resolution came into effect on 1st January 2014

and is being applied progressively according to the

schedule appended to it. It is to be noted that it does not

concern radiology devices used at the patient’s bedside.

2. NUCLEAR MEDICINE

2.1 Presentation of nuclear

medicine activities

Nuclearmedicine includes all uses of unsealed radioactive

sources for diagnostic or therapeutic purposes. Diagnostic

uses can be divided into

in vivo

techniques, based on

administrationof radionuclides to apatient, andexclusively

invitro

applications(medicalbiology).Functionalexploration

examinations can combine

in vitro

and

in vivo

techniques.

This sector of activity comprises 225 nuclear medicine

units with associated

in vivo

and

in vitro

facilities and

62 biology laboratories, of which 40 are independent

of the nuclear medicine units.

At the end of 2014 the inventory stood at 131 Positron

EmissionTomography(PET)camerasand477Single-Photon

Emission Tomography (SPECT) devices (including

215 hybrids, that is to say combining a CT scanner

with the SPECT. Forty-four nuclear medicine units

accommodate a total of 161Targeted Internal Radiotherapy

(RIV – brachytherapy) rooms.

Nuclear medicine involves about 700 specialist

practitioners in this field

, to whichmust be added some

1,000 physicians from other specialities working with

the nuclear medicine units (internal medicine specialists,

cardiologists, endocrinologists, etc.).

2.1.1

In vivo

diagnosis

This technique consists in examining an organ or a function

of the organism with a specific radioactive substance

– called a radiopharmaceutical – administered to a patient.

The nature of the radiopharmaceutical depends on the

studied organ or function. The radionuclide can be used

directly or fixed to a carrier (molecule, hormone, antibody,

etc.). For example, table 1 presents some of the main

radionuclides used in various investigations.

The administered radioactive substance – often

technetium-99m – is localised in the organism using

a specific detector and scintigraphy techniques. This

detector, called a scintillation camera or gamma camera,

consists of a crystal of sodium iodide (in the majority

of cameras) coupled to a computerised acquisition and

analysis system. This equipment produces images of

the functioning of the explored tissues or organs. The

physiological or physiopathological processes can be

quantified.

The majority of gamma cameras allow tomographic

acquisitions, cross-sectional imaging and a three-

dimensional reconstruction of the organs (Single-Photon

Emission Tomography – SPECT).

Fluorine-18, a positron-emitting radionuclide, is commonly

used today, frequently in the form of a marked sugar,

fluorodeoxyglucose, particularly in oncology. Its utilisation

necessitates the use of a special camera. The principle

of operation of PET (Positron-Emission Tomography)

cameras is the detection of the coincidence of the photons

emitted when the positron is annihilated in the matter

near its point of emission. Other radiopharmaceuticals

markedwith other positron emitters, notably gallium-68,

are starting to be used.

Nuclearmedicine enables functional images tobeproduced.

It is therefore complementary to the purelymorphological

images obtainedusing the other imaging techniques, such

as conventional radiology, X-ray computed tomography,

ultrasonographyorMagneticResonance Imaging (MRI). In

2. Source: Review of nuclear medicine department inspections

(2012-2014).

3. Source: dashboard (SFMN website) 2014.

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CHAPTER 09:

MEDICAL USES OF IONISING RADIATION

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