5. 5
X - actly So!
The Roentgen Rays, the Roentgen Rays,
What is this craze?
The town's ablaze
With the new phase
Of X-ray's ways.
I'm full of daze,
Shock and amaze;
For nowadays
I hear they'll gaze
Thro' cloak and gown and even stays,
Those naughty, naughty Roentgen Rays.
(Wilhelma, Electrical Review, April 1896)
6. First Reports of Injury
Late 1896
Elihu Thomson - burn from deliberate
exposure of finger
6
Edison’s assistant - hair fell out & scalp
became inflamed & ulcerated
9. Sister Blandina
(1871 - 1916)
• 1898, started work as radiographer in
Cologne
• held nervous patients & children with
unprotected hands
• controlled the degree of hardness of
the X-ray tube by placing her hand
behind of the screen.
09/06/2008 9
10. Sister Blandina
• After 6 months strong flushing & swellings of hands
• diagnosed with an X-ray cancer,
• some fingers amputated
• then whole hand amputated
• whole arm amputated.
09/06/2008 10
11. Sister Blandina
• 1915 severed difficulties of breathing
• extensive shadow on the left side of her thorax
• large wound on her whole front- and back-side
• Died on 22nd October 1916 .
09/06/2008 11
12. William Rollins
Rollins W. X-light kills. Boston Med Surg J
1901;144:173.
Codman EA. No practical danger from the
x-ray. Boston Med Surg J 1901;144:197
09/06/2008
12
13. Mechanisms of Radiation Injury
13
„ LD(50/30) = 4 Gy
≅ 280 J to 70 kg man
≅ 1 milli-Celsius rise in body temp.
≅ drinking 6 ml of warm tea
i.e. not caused by heating, but ionisation.
15. 15
Methods of Potential Damage from
Ionizing Radiation
• Indirect Action
assumes cellular damage occurs as a
result of the action of radiation on water
(roughly 85% of a cell’s composition);
damage results from the indirect action
of toxic compounds on cellular DNA
17. Los efectos sobre las células
17
„ Muerte celular después de mitosis anormales.
„ Muerte celular antes de la mitosis.
„ Mitosis anormales a pesar de acciones de reparación
celular.
„ Mitosis anormales, sin muerte celular, con replicación del
daño en las generaciones futuras.
„ Síntesis tardía de ADN o mitosis muy lentas.
„ Cambios en el protoplasma celular durante la mitosis que
alteran el proceso de la citocinesis.
18. Ley de Bergonié y Tribondeau (1906)
18
„ En términos generales las células tienden a ser
radiosensibles si tienen tres propiedades:
1. Una alta tasa de división mitótica
2. Una vida futura larga en permanente división
3. Son células no especializadas.
Hay tres importantes excepciones: Linfocitos pequeños, oocitos primarios y
neuroblastos.
19. 19
Radiosensibilidad relativa de las
células comunes
Baja: Células sanguíneas maduras, células
musculares, células ganglionares, tejidos
conectivos maduros
Alta: mucosa gástrica, membranas mucosas,
epitelio esofágico, epitelio de la vejiga urinaria
Muy alta: células sanguíneas primordiales, epitelio
intestinal, espermatogonias, células foliculares
ováricas, linfocitos.
20. Dos tipos de efecto
•Efectos determinísticos (“efectos con umbral”)
• Llamados también “tempranos” o “ agudos”
•Efectos estocásticos (“efectos al probabilísticos”)
• Conocidos también como efectos “tardíos” o “a largo plazo”
09/06/2008
20
22. 09/06/2008
22
Categories of Radiation Bioeffects :
Deterministic (Nonstochastic) Effects
Those effects whose severity increases with
increases in dose; a threshold dose is
assumed (e.g., erythema, cataract
formation, blood effects)
23. Stochastic Effects
09/06/2008
23
„Caused by cell mutation leading to cancer
or hereditary disease
„Current theory says, no threshold
„The bigger the dose, the more likely
effect.
24. 09/06/2008
24
Categories of Radiation Bioeffects :
Stochastic Effects
Those effects that appear to be random in
nature; effects that tend to increase with
increasing dose to the population (e.g.,
cancer and genetic effects)
25. ICRP risk factors
(International Commission on Radiological
Protection, ICRP Publication 60)
25
Detriment per mSv
Exposed Population Fatal cancer Non-fatal cancer Severed hereditary
effects
Total
Adult workers 4.0 x 10-5
0.8 x 10-5
0.8 x 10-5
5.6 x 10-5
Whole population 5.0 x 10-5
1.0 x 10-5
1.3 x 10-5
7.3 x 10-5
(fetus 3.0 x 10-5
3.0 x 10-5
6.0 x 10-5
)
5.0 x 10-5 per mSv ≡ 1 in 20,000 chance .
26. 09/06/2008
26
Explosiones Atómicas: 6 Aug 1945 Hiroshima - 9 Aug 1945 Nagasaki
70 000 murieron inmediatamente y 200 000 en los 4 meses siguientes
100 000 personas que recibieron más de 200 mSv, sobrevivieron. Las víctimas de
las bombas fueron estudiados y tienen un seguimiento de por vida.
28. Evidencias de los efectos estocásticos:
Estudio de la expectativa de vida de un grupo
de sobrevivientes de las bombas atómicas
09/06/2008
28
„ Se estudió a 94 000 personas
„ Más del 50% todavía vivían en 1995
„ Para 1991 cerca de 8 000 habían muerto por cáncer
„ Unos 430 de esos cánceres podían ser atribuibles a la
radiación.
„ 21 de 800 personas expuestas in utero con dosis mayores a
10 mSv resultaron severamente afectados con retardo
mental.
„ No se demostró incremento de las frecuencias
poblacionales de las enfermedades de origen genético.
„ http://www.rerf.or.jp/eigo/glossary/lsspopul.htm
29. Dose range Number of
cancer deaths
Estimated
excess death
Attributable
fraction
5 - 200 mSv 3391 63 2 %
00 - 500 mSv 646 76 12 %
0.5 - 1 Sv 342 79 23 %
> 1 Sv 308 121 39 %
All 4687 339 7 %
09/06/2008
29
Cancer deaths between 1950 and 1990 among Life Span Study
survivors with significant exposure
(i.e. > 5 mSv or within 2.5 km of the hypercentre)
30. Data Sources for Risk Estimates
09/06/2008
30
„North American patients - breast, thyroid, skin
„German patients with Ra-224 - bone
„Euro. Patients with Thorotrast - liver
„Oxford study - in utero induced cancer
„Atomic bomb survivors - leukaemia, lung, colon,
stomach, remainder .
31. 09/06/2008
31
Linear Dose Response Curve:
Probability of
Observing the
Response
Dose
Assumes some level of hazard is associated with
all doses regardless of how small.
32. 09/06/2008
32
Linear Dose Response Implications and
Assumptions:
• Certain effects (e.g., leukemia, genetic effects) are
observed even at zero radiation dose since it occurs
naturally in populations (stochastic effects)
• Assumes the probability of observing the response
is proportional to the dose
• This theory is the basis of radiation protection
programs
33. 09/06/2008
33
Nonlinear Threshold Dose Response:
Threshold
Response
Dose
Assumes there exists some minimal (threshold) dose
below which no observable effects occur.
34. 09/06/2008
34
Nonlinear Threshold Dose Response Implications
and Assumptions:
• This type of response curve more accurately
describes bioeffects associated with high doses (e.g.,
blood changes, GI effects, epilation, organ damage,
etc.) - Deterministic or certainty effects
• Assumes recovery from bioeffects at low doses
(i.e., in the dose range below the threshold)
35. Doses in Interventional Radiology
Taken from “Real-time quantification and display of skin radiation during coronary angiography and intervention”,
den Boer A, et al., Oct 2001
35
09/06/2008
•332 patients
•25 - 99 Gy.cm2 dose-area product
•4 - 18 mGy effective dose
•1:5000 - 1:1100 risk of inducing fatal cancer
.
36. Hereditary Effects
09/06/2008
36
„ Observed in animal experiments
„ Not observed in A-bomb victims
„ ICRP Detriment for severe hereditary disease = 1.3 x 10-5 per
mSv (i.e. approx 1/4 fatal cancer risk)
37. 09/06/2008
37
Total risk of cancer up to age 15 years following in utero exposure (per mGy)
Cancer type Fatal Non-fatal Total
Leukaemia 1.25 × 10
-5
1.25 × 10
-5
2.5 × 10
-5
Other 1.75 × 10
-5
1.75 × 10
-5
3.5 × 10
-5
Total 3.0 × 10
-5
3.0 × 10
-5
6.0 × 10
-5
• at 8-15 weeks it is estimated that 30 IQ points are lost per 1000 mGy.
• Risk of heritable effects estimated at 2.4 × 10
-5
per mGy
"Natural Risks"
Heritable disease 1 × 10
-2
to 6 × 10
-2
Fatal cancer to age 15 years 7.7 × 10
-4
Lifetime cancer risk 20 × 10
-2
to 25 × 10
-2
