LOW DOSE RADIATIONIN RADIOLOGY:
Consultancy Meeting on Science and Technology and Society Perspectives onNuclear Science, Radiation and Human Health: The International Perspective
Hiroshima University, Japan; May 23-24, 2017

Miriam Joy C. Calaguas, MD, FPCR, FPROS
Department of Radiotherapy

Jose R. Reyes Memorial Medical Center, Philippines

0How is Radiation Delivered?

1

NAKAMURA Family Story

A-Bomb Survivors

nosmohTarumakaN
Hirokon,osmoh
TarumakaNoMother of Akikremimw
SicpmlyOoinFilip2A-Bomb Survivor

3

LECTURE OUTLINE
Definition of Radiation

Low Dose Radiation

Natural and Background Exposure

Low Dose Radiation in Medicine

Radiation Protection
4

Definition of Radiation

5

HISTORICAL PERSPECTIVE:
1899: 1stpatient
CURED withradiotherapy
(RT)

1895:
Roentgendescribed
X-rays1898: theCuries
discovered
radiumInnovationsinTechnologies
in the use ofradiation

up to 1920’s,
GROWTH
period ofclinicalradiology
6

Definition of Radiation•“Radiation is an energy in the form of• Electro-magnetic waves or particulate matter• Traveling in the air

The EM SpectrumIONIZINGNON-IONIZINGUVINFRARED

Radiowave

X-raysGamma rays

VisibleLightMicrowave

8Ionizing Radiation: Particulate VS E.M.

Particulate –Particles movingat very highspeeds

Neutrons

Subatomicparticles

Ions

Electrons

Protons

EM – Highfrequency EM
wave

Atoms

X-RaysGamma Rays

9RADIATIONRADIOBIOLOGYUSE of high-energy
x-raysTo KILL cancer cells

MOST
RADIOSENSITIVE

Grow
DESTROY their ability
toMultiplySpread
Normal cells: Better
RECOVERY
Affect ALL cells
Cancer cells: Moresensitive to DAMAGE
MOST
RADIORESISTANT

10Radiation induced DNA damage
Primary Target of Radiation: DNADNA Damage- Strand Breaks- Abasic Sites- Base modification

CellularSenescence
OrApoptosis

Inhibition ofCell GrowthOrCell Death11

Direct and Indirect Action of Ionizing Radiation

PHOTONDIRECTACTION

INDIRECTACTIONe-e-p+p+PHOTON

Quality of radiation

Radiation
Exposure

Potential Biologic
Effects andDamages

Quantity ofradiation

Received Dose ofRadiation
Exposure
Conditions (SpatialDistribution)

The different kinds of radiation have different energy loss effects LET.

Low Dose Radiation

14

Low Dose Radiation Exposure
⦿Dose up to 100 mSv● United Nations Scientific Committee on the Effects of AtomicRadiation (UNSCEAR) 2012 report

Low-dose Radiation Exposure and Carcinogenesis. 2012
Keiji Suzuki1 and Shunichi Yamashita1,2

Natural and Background Exposure

17Hall and A.J. Giaccia, Radiobiology for the Radiologist, Seventh Ed., Lippincott, Williams and Wilkins, 2012

RADON20

Backgrou
2.4 mS ndv/yr

CT Scan
7 mSv

Chest
X-rays0.05 mSv

Low Dose Radiation in Medicine

22United Nations Scientific Committee on the Effects ofAtomic Radiation (UNSCEAR) 2008 report

E.J. Hall and A.J. Giaccia, Radiobiology for the Radiologiist, Seventh Ed.
Lippincott, Williams and Wilkins, 2012

Ionizing Radiation
Dose in mGy or mSv
Conventional X-rays

0.02-10

Conventional Complex X-rays

3-10

CT

5-15

Spiral CT

10-20

Angiography

10-200Interventional

10-300

Nuclear imaging

3-14

Annual background radiation

2.4mSv

Health Risks From Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2 2006.

27

Cancer risks attributable to low doses of ionizing radiation: Assessing what we really know by Brenner et al (2003)28

29

https://cna.ca/issues-policy/radiation/quantifying-radiation/

Low dose radiation risks by Dendy et. al. The British Journal of Radiology, 76 (2003), 674–677

31

Radiation Protection and Safety32

Low Dose Radiation: LONG TERM Effects
Carcinogenesis

5%/Sv

MentalRetardation

40%/Sv
Hereditaryeffects

0.2%/Sv
Health Risks From Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2 2006.

33

INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION, 2007 Recommendations of the ICRP,Publication 103, Pergamon Press, Oxford (2007).
34

InternationalPhilippines
Jose R. Reyes Memorial Medical Center
Department Of Radiotherapy

Authorized staff
Individual

Categories of Exposures• International Basic Safety Standards– Medical– Occupational– PublicCONCLUSION
Risks

Benefits
Diagnostic

Toxicities
Radiation
Carcinogenesis

Therapeutic

Quality of Life42

Mt. Pinatubo

MARAMING SALAMAT PO!

Underground River, Palawan

Manila Bay Sunset

Boracay beach