RADIATION
FOR HEALTHCARE
5.1

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RADIATION
FOR HEALTHCARERADIOACTIVITYIN HOSPITALS

Ionising radiation and radioactive
substances are used to identify or treat
disease. Precautions must be taken to
ensure that the benefits outweigh the risks.
Hospitals are home to diagnostic,
production, treatment and management
units for the radioactive waste used to treat
patients.

DIAGNOSE
X-rays and gamma rays allow the inside of the human body to be viewed without the need for surgery.
This is called medical imaging.

IMAGING BY TRANSMISSION...

...OR BY EMISSION

The patient is placed between a radiation source and a
detector. This is the case with conventional X-rays and scans,which use X-rays.

The patient is injected with a radioactive substance.

The rays are attenuated to a greater or lesser extent
depending on the parts of the body they pass through.
Tumours, fractures and infections interact differently with therays, producing different images that doctors are able torecognise.

Outside, the rays are captured by a camera. This is the casewith scintigraphy.

The substance travels to a specific area and emits gamma raysfrom inside the body.

TREAT
Radiation can be used directly fortreatment.
The aim of irradiation is to destroy acancerous tumour, for example, whilesparing healthy tissue.
This process is known as radiotherapy.

Radiology is a bit like antibiotics: it should not be usedsystematically.
Healthcare professionals must ensure that they do not
automatically resort to ionising radiation when there arealternative solutions, such as magnetic resonance imaging(MRI) or ultrasound, which do not present any risks.

DEBATERADIATION,

NO MORE
THAN NECESSARY

France has fewer than 14 MRI machines per million inhabitants,
while the average in Western Europe is close to 20.

Every year, tens of millions of X-rays and scans are carried out
in France and more than 200,000 people are treated withradiotherapy.
The use of ionising radiation in the medical field is genuinely
effective. Over the period 1989-2010, there was an
improvement in standardised 5-year net survival rates for mostcancers.

5.2

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RADIATION
FOR HEALTHCAREDIAGNOSE
To reveal the inside of a body, we can introduce
radioactivity or temporarily expose it to radiation.
However, doses must be carefully controlled.

IMAGINGBY EMISSION
The patient is injected with a radioactive product called a tracer 1 . The tracer is chosen so that it binds tothe organ to be studied.
Like a lamp in the dark, the radiation emitted by the tracer provides an image of the organ inside the body.
This procedure uses products that quickly lose their radioactivity: only the minimum amount of radioactivity
needed is injected into the patient, minimizing their exposure.

EXAMPLES OF TECHNIQUES
Conventional scintigraphy
or single-photon emission
computed tomography(SPECT)

Gamma camera

Example of diagnosis: thyroid.
The radioactive
tracer naturally
emits gamma
photons whichare "captured"by the camera.

Tracer: iodine-123 or technetium-99m.
Radiation emitted: gamma.
Average dose: 4 mSv.

1

Slow rotationof the camera
Injection of aradioactive
tracerTechnetium (99mTc)

Detectors

Collimator

Positron emission
tomography (PET)The detector consists of a sodium
iodide (Nal) crystal with thallium (Tl)
impurities. It transforms gamma
photons into light photons.
They are then converted into anelectric current using
photomultipliers.

Example of diagnosis: brain diagnosis,
Alzheimer's disease.
Tracer: a glucose analogue labelledwith fluorine-18.
Average dose: 7 mSv.

IMAGING
BY TRANSMISSION
The patient is irradiated directly with X-rays. By placing a detector behind the patient,
we can draw up a map of the inside of the body. The denser the tissue, the more it
attenuates the rays. Bones and tumours are clearly visible.

EXAMPLES OF TECHNIQUESThe scanner
Example of diagnosis: thoracic
scanner
Specificity: mobile X-ray source.
Allows for cross-sectional X-rays(by slice) and 3D reconstruction.

Conventional
radiography
Example of diagnosis: in dental
panoramic X-ray, the X-ray source
rotates around the headapproximately 120°.

Average dose (chest scan):5 to 10 mSv

X-ray tube

Electron ejectedfrom the electron layer

High-voltage
sleeveLead shielding

Specificity: fixed X-ray source.
Average dose: 0.02 mSv.

Electronreplacingthe missing
electron

Anode

CathodeX-raysFilament

1

X-rays are produced byan X-ray generator or
X-ray tube.
A cathode is heated andemits electrons which
are accelerated by a highelectrical voltage.

TungstentargetElectrons

FilterDiaphragm

X-rays2 By bombarding the tungsten

plate, the electrons transiently
excite the atoms in the plate.
When these atoms return to astable state, X-rays are emitted.

Bone densitometry
Example of diagnosis: hipSpecificity: two X-ray sources.
Measures bone mineral content
and density.

Photosensitive film
or digital plate

Average dose: 0.001 mSv

X-ray viewer

3

5.3

The images are produced by irradiating the organ with X-rays.
Photons passing through the organ are stopped by a detector
on the other side.
The quantity of photons absorbed depends on the chemicalcomposition of the tissues passed through.
The denser the tissue, the more it blocks photons.

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RADIATION
FOR HEALTHCARETREAT
The destructive power of radiation is used to treat
tumours. Working like a kind of laser, they are capableof reaching and destroying tumours inside the body.
There are several treatment methods.

EXTERNAL RADIOTHERAPYIN BRACHYTHERAPY,

is a treatment used in more than half of allcancer patients.

a radioactive source is temporarily or permanently placed
inside the patient. The source then delivers radiation locallyto the tumour to be treated.

It involves focusing radiation from a particle
accelerator or X-ray generator on cancer cells,in order to destroy them or stop them frommultiplying.

Brachytherapy is commonly used to treat cervical, prostateand skin cancer. Only in the case of prostate cancer does
the source remain permanently in place.

RADIOSURGERYAND STEREOTACTIC RADIOTHERAPYMETABOLICRADIOTHERAPY

are external radiotherapy techniques that use high-dose, ultraprecise radiation, like an intangible scalpel, to destroy a tumour.
Precision is greater than with conventional radiotherapy.

The patient is given a radioactive product thatwill bind to the target organ. The technique issimilar to scintigraphy.

These include the Gamma Knife®, CyberKnife® and multileaf
collimators. In 2019, there were 19 CyberKnife® and 5 Gamma Knife®
systems in France.

Substances are used to irradiate the diseased
cells as locally as possible, preventing theradiation from reaching healthy cells as much as
possible.

Radiotherapy is truly effective. More than
200,000 people are treated each year.

DEBATEBENEFITS AND DANGERS

OF RADIOTHERAPY

Very precise protocols enable the radiation
to be concentrated on the diseased tissue to
avoid affecting other organs and prevent theappearance of secondary cancers. The doseis divided into several sessions andirradiation is performed at different angles.
Considerable progress has been made in thisarea in recent years.

Radiotherapy uses high doses of radiation.
There is a risk of causing lesions, or evensecondary cancer, if healthy tissue andorgans surrounding the tumour, which
may be organs at risk, are irradiated.

5.4

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RADIATION
FOR HEALTHCAREMEDICALIMAGING:

LIMITING DOSES
Beware of the proliferationof unjustified examinations.

CAUTION
WITH X-RAYS AND SCANSA FEW TIPSFOR PATIENTS

Although used for medical purposes, radiation
presents risks and must be used with caution.

X-RAYS ARE NOT SYSTEMATIC
Don't ask your doctor for an X-ray or scan just to getreassurance. Only your doctor can decide whether such an
examination is worthwhile.
In addition, ask your doctor why, in your case, an X-ray or
CT scan is preferable to imaging that does not use X-rays,
such as an ultrasound or MRI.

BE VIGILANT
Cranialscan
2 mSv

Keep your X-rays and examination reports and bring them toyour appointments. If they are recent, you may not need to
redo them. In addition, make sure that the radiation dose
received during the examination is included in your report,
for better monitoring.
DentalPanoramic
0.02 mSv

Chest X-ray
0.05 mSv

TAKE PARTICULAR CARE OF YOUNG PEOPLE
Because their organs are still growing, children are moresensitive to X-rays than adults. Particular attention should
therefore be paid to young children and pregnant women.

Mammogram
0.2 mSv

X-ray of theabdomen
2 mSv

Abdominopelvic
scan
15 mSv

A FEW TIPSFOR HEALTHCARE WORKERSMINIMISE EXPOSURE TIME
Do not stay in the room when an X-ray is being taken.

PROTECT YOURSELF
Use personal protective equipment that absorbs radiation: wear leadaprons, leaded goggles and thyroid shields, and use movable leaded
screens.

X-ray of a
limb
0.005 mSv

INCREASE DISTANCE
Multiplying the distance by 2 divides the dose received by 4. Practicalexample: using tongs to handle radioactive sources.

Increased doses
Medical imaging (scanners, etc.)
is used more and more often
around the world.
While the use of increasingly
high-performance imaging
technology is making it possible
to reduce the dose received, we
still need to remain vigilant!

ANALYSESIN FRANCE
Scan the following QR codes to find out more:• analysis of diagnostic exposureof French population

5.5• analysis of doses received
by patients in France

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RADIATION
FOR HEALTHCARERADIOTHERAPY:CONTROLLINGRISKSSkills, protocols and highly supervised
equipment.

Lung radiotherapy
between 40 and 60
grays on the tumour

THE GRAYFIGURESFOR CANCERS DETECTED

is used to measure theenergy due to theamount of radiation
received.

The number of cancers has increased overthe last thirty years. This increase is due inparticular to the ageing of the populationand to advances in diagnostic techniques.
Change in cancer occurrence from 1990 to 2018 by sex(source: Santé publique France)
400

402.1

Change in cancer occurrence from 1990 to2018 by sex
370.5
352.0
(source: Santé publique France)
344.3

RADIOTHERAPY:
PROPER CONDUCT

300
400

320.7

336.1

• t he chance of permanently destroying
diseased tissue or a cancerous tumour ismaximised. This is the notion of a control
dose;• t he risk of causing secondary complications
or cancers is minimised. This is the notion ofa tolerance dose.
If the prescribed dose is kept to a minimum,
healthy tissue is protected, but there
is a risk that the patient will not beRadiotherapy oftreated (under-irradiation).
the prostate
Conversely, prescribing too high a
between 50 anddose increases the effectiveness of
80 grays on thethe treatment, but runs the risk oftumourgenerating undesirable side-effects.
The aim is therefore to find a compromise
between treatment efficacy and side effects.

SPACING OUT DOSESThe doctor must spread the dose over
several sessions to allow the healthy tissue
to regenerate.

MASTERING TECHNOLOGY
Equipment must be carefully adjusted andmaintained.

REGULAR CHECKS

Rate per 100,000
Rate people/year
per 100,000 people/year

In radiotherapy, the doctor must optimise thedose to ensure that:

100
200

0
100

336.1
320.7 215.1
200.6

200.6

1990

215.1

1995

258.7
248.9 370.5

233.6

2000

248.9

2005

258.7

2010

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MEN

330.2
274.0

2018

Year

250

Trends in cancer mortality from 1990 to 2018 by sex(source: Santé publique France)
200

250

205.9

194.6
178.7

150
200

162.4
205.9

100
150

145.8

131.5

194.6
178.7

90.1

86.9

83.2

162.4
79.9

83.2

79.9

50

76.6
145.8

73.8
131.5

100
0
50

0

90.1
1990

86.9
1995

2000

2005

MEN

123.8
WOMEN
MEN
72.2
123.8
WOMEN

76.6 201573.8 2018
72.2

2010

Year

1990

1995

2000

2005

2010

2015

2018

Year

The 5-year survival expectancy following
cancer remains very uneven today. Somecancers are very well treated, such as prostatecancer, but others, such as lung cancer,
are fatal for more than 8 out of 10 patients.
More than 200,000 patients are treatedwith radiotherapy every year in France.

In external radiotherapy, once thesession in the treatment room isover, the patient does not take any
radioactivity with him or her. Thereis no risk to those around them.

5.6

268.1

2015

IRRADIATED BUT NOTCONTAMINATED!

Scan this QR code to access it.

344.3

274.0

WOMEN

ASN regularly inspects all radiotherapy
centres, paying particular attention to humanand organisational factors. ASN raises
awareness among professionals throughpublications and training courses.

Visit the e-cancer.fr website to
download the patient guide (under theheading "Expertises et publications") andfind out more about treatment methods
and side effects (under the heading"Patients et proches/Se faire soigner").

268.1

Trends0in cancer
mortality from1990 cancer
to 2018 by has
sex decreased
However,mortalityfrom(source: SantéFrance)2005
1990 publique
1995
2000
2010
2015
2018
as a result of advancesin medical techniques.
Year

Rate per 100,000
Rate people/year
per 100,000 people/year

CONTROLLING THE
RISK/BENEFIT RATIO

200
300

330.2
WOMEN

402.1
352.0
233.6

MEN

RADIATION
FOR HEALTHCAREACCIDENTS

IN RADIOTHERAPY
Errors in positioning and dosage have already been
made in radiotherapy in France and around the world.
Checks must be carried out regularly and feedback
taken into account.

A GRADING SCALE

4
3

2

1
0

DEATH

Dose or irradiated volume much higher thannormal, leading to complications orafter-effects that are not compatible with life.

CONSEQUENCES
Death

ACCIDENT

6

CAUSES

DEATH

CAUSESSERIOUS EVENT

life-threatening,disabling complications
or after-effects.

Dose or irradiated volume well in excess
of tolerable doses or volumes.

CONSEQUENCES

Serious, unexpectedor unpredictable acuteor late effect, grade 4.

CAUSESEVENT CAUSING

severe deterioration of one
or more organs or functions.

CONSEQUENCES

Dose or irradiated volume higher
than tolerable dose or volume.

Severe, unexpectedor unpredictable acuteor late effect, grade 3.

CONSEQUENCES

CAUSESEVENT CAUSING OR LIKELY TO CAUSE

moderate deterioration of an organ or function.

Dose greater than the recommended
doses, or irradiation of a volume that
may lead to unexpected but moderatecomplications.

Moderate, unexpected or
unpredictable acute or late effect,
grade 2, with minimal or zerodeterioration in quality of life.

CAUSESEVENT WITH DOSIMETRIC CONSEQUENCES
but no expected clinical consequences.

Error in dose or volume, for example :• dose error or target error in one treatment
session that cannot be compensated forover the entire duration of treatment;• misidentification of patients treated for thesame condition (can be compensated for).

INCIDENTEV
If t ENTh• a e num(ex "+" sig ber oam
ple n is a f patie:3d
bec ded nts is
om to the great
es
e
lev
3+)
el s r tha.
ele n 1:
cte
d

EV

E

5

7

CONSEQUENCES

No symptoms expected.

EVENT

In t NTS• m he eve
if th inimu nt ofmd• m e num leve eath
if th inimu ber o l 5 is r of sev
e n m le f pa aise eralumvd to patt
ber el 5 is ients
ien
6
i
ts:
s
of p
rais
b
e
twe
atie ed
t
en
nts
o
2a
exc 7
nd
eed
10;
s 10
.

The ASN-SFRO scale provides information on the seriousness of radiotherapy events:
patient positioning error, dose error, etc.

EVENT OF NO CONSEQUENCE
for the patient.

ÉPINAL ACCIDENT
2004/2005

TOULOUSE ACCIDENT
2006/2007

Between May 2004 and August 2005
at the Jean-Monnet hospital in Épinal(Vosges), 24 patients treated forprostate cancer received too high adose because of incorrect use of thetreatment scheduling software.

Between April 2006 and April
2007, calibration errors on theradiosurgery equipment at
Toulouse University Hospital
led to the overexposure of
145 patients.

Some of them died as a result of thisoverexposure. The investigation
revealed that other malfunctions had
caused the overexposure of 5,000
patients.

Some suffered severe
neurological complications
as a result of the accident.

Aujourd'hui en France , 13/10/2006

Aujourd'hui en France, 23/05/2007

LESSONS FROM
THE PAST
Following the serious accidents in Épinal and Toulouse, the publicauthorities took drastic measures:• examination of the practices of 178 private and public radiotherapy
centres, resulting in the merger or closure of those that did notcomply with the requirements;

ASN INSPECTORSAND IRSN EXPERTS• recruitment of additional medical physicists, specialised in the
management of radiation and associated equipment;

The use of radioactive
substances and radiation in
hospitals creates a risk thatneeds to be managed.

• large-scale renewal of equipment and increase in the number oftreatment units;• specialisation of the accelerators available with the appearance anddistribution of dedicated machines;• obligation to monitor patients for 5 years after the end oftreatment;

ASN and IRSN therefore
carry out inspections andexpert assessments in theinterests of both patientsand healthcare staff.

• obligation to report any incident or accident to ASN;• obligation for centres to formalise practices (quality assurance);• obligation for centres to analyse all malfunctions, including minor
ones.

5.7

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RADIATION
FOR HEALTHCARE

THE PRODUCTS

USED

Many radioactive substances are used in hospitals.
They each have specific characteristics that makethem effective for particular organs.

WHICH PRODUCTS
FOR WHICH USES?
TECHNETIUM-99M(INJECTION)

FLUORINE-18(INJECTION)GALLIUM-68(INJECTION)

Half-life: 6.02 hours

Half-life: 110 minutes

Half-life: 68 minutes

Technetium-99m is the product mostcommonly used in medical imaging.
Combined with different molecules, it canbe used to explore a large number oforgans (thyroid, bones, heart, kidneys,
lungs, etc.).

It is used in medical imaging. Its rays travel
only a short distance through the body,
giving a precise image. Its half-life is very
short, less than 2 hours, which limits
contamination and patient exposure.
It is mainly used in oncology.

This isotope is similar to fluorine-18 in its
physical characteristics and is used in thesame way as fluorine-18 for medical
imaging in oncology. Its current main
application is the diagnosis of digestive
neuroendocrine tumours. It should soon beapproved in France for the diagnosis of
prostate cancer.

Its half-life is long enough to monitor
physiological processes, but short enoughto limit patient irradiation.

THALLIUM-201(INJECTION)

The energy of its radiation is ideal:
sufficient to penetrate living tissue and tobe easily detected, but low enough to limit
patient exposure.

Half-life: 3 days
Thallium-201 is a radioactive isotope usedin cardiac scintigraphy. Used for a longtime, it is starting to be abandoned infavour of more recent markers.

IODINE-123(INJECTION)YTTRIUM-90(INJECTION/RADIOTHERAPY)

Half-life: 13 hours
Iodine-123 is an isotope of iodine used to
study the thyroid because it binds naturally
to it. Its low-energy gamma photon
radiation and short half-life make it well
suited to imaging.

Half-life: 2.7 days
Yttrium-90 is used in radiotherapy.
It is injected into patients in the form of
microspheres, mainly to treat liver cancer.
The resin microspheres will attach
themselves to the capillaries of the liver
and those supplying the tumour to be
destroyed.

IODINE-131(CAPSULE / RADIOTHERAPY)
Half-life: 8.2 days
Iodine-131 is another isotope of iodine.
Its radiation rich in beta particles and its
relatively long half-life make it ideal fortreating thyroid disorders.

INDIUM-111(INJECTION)
Half-life: 2.8 days
An indium-labelled tracer can be injected
to image cerebrospinal fluid production,
migration and reabsorption.
The indium tracer attached to the patient's
white blood cells can also be used to detect
infection.

LUTETIUM-177(INJECTION/RADIOTHERAPY)
Half-life: 6.7 days
Like iodine-131, this isotope emits beta
particles and has a relatively long half-life,
making it ideal for therapy. It is currently
used in the treatment of digestive
neuroendocrine tumours. It is due to beapproved shortly in France for thetreatment of prostate cancer.

It is used to remove overactive thyroid
nodules, to treat certain forms ofhyperthyroidism, and to find and remove
thyroid tumours.

SAMARIUM-153(INJECTION / RADIOTHERAPY)
Half-life: 46.8 hours
Samarium-153 is used in symptomaticradiotherapy, mainly to relieve pain causedby bone metastases from cancer.

HALF-LIFE
The half-life ofradioactive material is
the time after which halfof the original atoms
have decayed.

AND BEFORE THE PRODUCTS
ARE ADMINISTERED?
The relatively short lifespan of the isotopes used in the medical
sector means that frequent deliveries have to be made to hospitals.
Around 30% of packages containing radioactive substances aretransported for medical purposes.

MAKING TECHNETIUM-99m
UtargetLiquid 99Mo in
bulk

235

Mo factory
Purification ofmolybdenum-99

ReactorTargetirradiation99

Tc
generators
99m

Generator factory
Generator fabrication

HospitalTechnetium-99m has a very short lifespan.
It must be prepared a few hours before use, hence the importanceof having a production centre within hospitals.

5.8

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Injection into
the patient