Radiobiology of Particle Therapy

CERN Summer School Student Lectures, 2014

Manjit Dosanjh, CERN [email protected] Cancer – a growing challenge

More than 3 million new cancer cases in Europe each year and 1.75 million associated deaths

Increase by 2030: 75% in developed countries and 90% in developing countries

Manjit Dosanjh, 2014 Cancer – a growing societal challenge

Over 3 million cancer cases in Europe each year

Surgery Radiotherapy Chemotherapy & others

X-ray, IMRT, Brachytherapy, Hormones; Immunotherapy; Cell therapy; Genetic treatments; Hadrontherapy Novel specific targets (genetics..) Local control Local control Limited Local control

Survival Quality of life Radiotherapy in the 21st century 3 "Cs" of Radiation

Cure (~ 50% cancer cases are cured) Conservative (non-invasive, few side effects) Cheap ( 5-10% of total cost of cancer on RT)

• There is no substitute for RT in the near future • The rate of patients treated with RT is increasing • More than 50% patients treated with RT

(J.P.Gérard) Manjit Dosanjh, 2014

The ideal treatment eliminate all tumour cells without affecting normal cells

ª Physics : ² 100% of the dose on target ² 0% dose in surrounding healthy tissues or critical organs ª Biology : ² differential effect ² kill 100% of cancer cells ² "protect" normal cells

Manjit Dosanjh, 2014 Single photon beam

80 50 30

Manjit Dosanjh, 2014 Two opposite photon beams

110 100 110

Manjit Dosanjh, 2014 Alternative – Particle Therapy

• 1946: Robert Wilson Protons can be used clinically

Robert Wilson

Manjit Dosanjh, 2014 Why hadron/particle therapy


Carbon Protons Depth in the body (mm) Tumours near critical organs Tumours in children Radio-resistant tumours

Manjit Dosanjh, 2014 Depth-Dose Curves of Photon vs. Ion Beams

Advantages of ion beams • Physical selectivity • High-LET effect • Reduced integral dose

Manjit Dosanjh, 2014 No treatment without detection!

Particle Detection Imaging

PET Scanner

Breast imaging (ClearPEM)

Manjit Dosanjh, 2014 Multimodality imaging: CT with PET

morphology metabolism

Manjit Dosanjh, 2014 Two sides of Radiation

Manjit Dosanjh, 2014 Radiation Sickness

System effected/ Syndrome Symptoms Dose

Nervous system Shock, severe 100 Gy CNS or Cerebrovascular nausea, Syndrome disorientation, seizures, coma G.I. system Nausea, vomiting, 10 Gy Gastrointestinal Syndrome diarrhea, dehydration Blood cells / bone marrow Chills, fatigue, 3-8 Gy Hematopoietic Syndrome hemorrhage, ulceration, infections, anemia Skin Burning/ infection, 10 Gy Erethema sloughing of skin, hair loss Ovaries/ Sterilit y 0.6-0.8 Gy Testes 2-6 Gy Manjit Dosanjh, 2014

Variation in Radiation Sensitivity Among Adult Human Organs

Approximate Tolerance Dose (TD) beyond which there is a high probability of delayed injury, e.g. 5% clinical injury within 5 years after exposure.

Manjit Dosanjh, 2014 2 1.8 1.6 1.4 1.2 Typical doses in mSv 1 0.8 0.6 0.4 0.2 0 Dental X-ray Chest X-ray Breast X-ray Spine X-ray Natural CT Scan - Head radiaon per year

100 90 80 70 60 50 40 30 20 10 0 Airline Dose in PET CT Scan - CT Scan - PET+CT Curave RT 5 year Lowest crew flying full-body abdomen heart maximum annual polar route CT scan and pelvis limit . dose (annual) Workers increase Manjit Dosanjh, 2014 cancer Questions

• What is ? • Why do we need biology for radiotherapy? • What kinds of biology are important for radiotherapy? • How do you invesgate biological effects of parcle beams? • What do the data tell you? • Do we know everything we need to know?

Manjit Dosanjh, 2014 The Beginning …………….

Radio waves Microwave Infrared Visible Ultraviolet X-Ray

Energy, E 10 neV 10 μeV 1 meV 10 meV 1 eV 10 eV 100 eV 100 keV 1 MeV 1 GeV 1 TeV Source: ESA

X-rays – November 1895: – 1901: first physics Nobel prize

Wilhelm Röntgen Manjit Dosanjh, 2014 ………..of radiation biology

Henri Becquerel (1852-1908)

1896: Discovery of natural radioactivity

Thesis of Mme. – 1904 1898: Discovery of α, β, γ in magnetic field radium

used immediately for “Brachytherapy”

Marie Curie Pierre Curie19 Manjit Dosanjh, 2014 (1867 – 1934) (1859 – 1906) First radiobiology experiment:

The first radiobiology experiment. Pierre Curie using a radium tube to produce radiaon ulcer on his arm. Hall fig. 1-2

Manjit Dosanjh, 2014 Early results…..

1896 -The first radiaon therapy of a cancer paent (Victor DESPEIGNES, Lyon) 1896: First diagnosc use Kaiser, Vienna 1899 - The first successful radiaon treatment of tumour -Thor Stenbeck, Stockholm 1900 – Palliaon of tumour 1902- radium used to treat pharyngeal carcinoma in Vienna 1904 - Paents in New York undergoing implantaon of radium tubes in the tumours 1904 - Chromosomal damage caused by radiaon in embryos 1907-The first described fatal cases (11) of cancer 1910 - Hypothesis - Cancer arises from damage on the chromosomes (Muller) 1911 - The first specificaon of skin cancer (94 cases) - Herman Hesse 1911 - Report on radiaon causes mutaon in fruit fly Drosophila - Herman Muller

1917 – Observaons of sterility among radiologists 1921 – The 100 th death among radiologists 1926 - Muller showed radiaons role in mutaon and chromosomes are target 1928 – The Internaonal Commission on Radiological Protecon (ICRP) formed

Manjit Dosanjh, 2014

Direct and indirect action of radiation

Critical target for the biological effects of radiation: DNA Direct action: secondary e- resulting from absorption of e.g. an X-ray photon interacts with the DNA dominant process for radiations with high LET: neutrons, α-particles, heavy ions Indirect action: - secondary e interacts with another molecule, e.g. H2O, to generate OH• which produces the damage to the DNA dominant process for radiations with low LET: X-, γ-rays. 2 nm

H O e- H OH• p+ indirect

e- direct p+ Manjit Dosanjh, 2014 DNA damage

Manjit Dosanjh, 2014 Cell culture techniques and cell survival curves

Puck and Marcus promoted the study of radiation on individual cells…cell culture

S/S0 = colonies produced / cells plated * PE PE = plating efficiency (correction factor derived from control samples)

Manjit Dosanjh, 2014 Clonogenic cell survival 100



D10 dose Surviving fraction Surviving



0 2 4 6 8 10 12 14 16 18 Dose (Gy)

Manjit Dosanjh, 2014 Cell survival curves

• describe the relationship between the radiation dose and the proportion of cells that survive

• presented with the dose plotted on a linear scale and the surviving fraction on a logarithmic scale



Surviving fraction

0.01 0 100dose (cGy)200 300

Manjit Dosanjh, 2014 Cellular Survival Curves and Relative Biological Efectiveness

Dx ____ = RBE Di

Manjit Dosanjh, 2014 RBE and how does it vary

• Varies with type of radiation • Varies with type of cell/tissue • Varies with the biological effect under investigation • Varies with dose rate and fractionation • An increase in RBE in itself does not offer therapeutic advantage unless there is differential effect between normal and tumour tissues • OER (oxygen enrichment ratio) effects RBE • Effected by presence of other chemicals present

Manjit Dosanjh, 2014 Cell killing by diferent radiation types

Manjit Dosanjh, 2014 Ions vs x-rays, radiobiological advantages RBE = Dx/Dion (at same effect level)


RBE=1.62 x-rays RBE=3.97 C-266MeV/u



Survival RBE=3.63 RBE=1.57

0.01 0 1 2 3 4 5 6 7 8 9 10 11 Dose (Gy)

Manjit Dosanjh, 2014 Chromatin Rejoining From Heavier Ion Damage is Slower

Manjit Dosanjh, 2014Goodwin et al. Tissue Dependence of RBE on Repair

Manjit Dosanjh, 2014 Radiobiological Damage

• Molecular • Subcellular • Cellular: Cell cycle effect, cell types • Tissue/organ • Whole multicellular organism • Population of multicellular organisms

Manjit Dosanjh, 2014 Major Events Which Follow Energy Absorption Major Events Which Follow Energy Absorption FromFrom Ionizing Ionizing RadiationRadiation

Genetic Heredity Damage Defects (germ cells)

Energy Biochemical Cellular Deposition Changes Damage

Cancer Induction Somatic Damage Developmental (other cells) Defects (Fetal)

Other Medical Effects Manjit Dosanjh, 2014 Efects on DNA Macromolecules

• Point mutation – that ruptures the chemical bond of a macromolecule severing one of the sugar-phosphate chain siderails of the DNA ladder (Single-strand break) – Gene mutations may result – These can occur with low-LET radiation – Repair enzymes can reverse this damage

Manjit Dosanjh, 2014 Manjit Dosanjh, 2014 Double Strand Breaks

• One or more breaks in each of the two sugar-phosphate chains • Not repaired as easily as single strand breaks • More common with high LET radiation

Manjit Dosanjh, 2014 Efects of Ionizing Radiation Upon Chromosomes

• If chromosomes are broken, two or more fragments are produced • Each fragment has a fractured extremity • These can join to another fractured extremity • These new formations are known as an aberration

Manjit Dosanjh, 2014 Track Structures of Proton vs. Carbon Ions

Linear Energy Transfer (LET) stands for the radiation energy deposited per unit length in tissue. • X-rays and proton beams are low-LET radiations • Heavy ion beams are high-LET radiation in Bragg peaks

Biological advantages: • High LET to provide significant differences in DNA damages • Suppression of radiation repair • Yet avoids some complications with higher-Z ions

Manjit Dosanjh, 2014 DNA X-rays Protons Carbon ions

Marx, Nature, 2014

Manjit Dosanjh, 2014 DNA damage and its consequences

repair misrepair cancer

DNA single strand break mutation

DNA double strand break chromosome aberration

repair no repair cell death

Manjit Dosanjh, 2014 Timing of damage efect

• Immediate/early effects: cell death, animal death • Short term: , , weeks….. • Delayed effects: cancer induction, genetic effects • Long term/late effects: years , centuries • Bystander effect

Manjit Dosanjh, 2014 OER for high and low LET radiaons X-rays

OER varies with LET: X-rays=2.5 Neutrons=1.6 Alpha parcles=1.0 neutrons Alpha parcles

Manjit Dosanjh, 2014 Re-oxygenation in Radiotherapy

•Hypoxia confers resistance to X-rays/ gamma rays – also to chemotherapeuc drugs •Human tumours that do not respond to radiotherapy may not re-oxygenate •Opmal fraconaon regimen depends on reoxygenaon

Manjit Dosanjh, 2014 Fractionation

• Increased survival when a dose is split into two or more fracons separated by a me interval • There is a point at which an increase in the number of fracons will no longer increase survival—plateau in the response

Manjit Dosanjh, 2014 Manjit Dosanjh, 2014 Cells spend most me in G0 phase—out of the cell cycle

Go= growth arrest G1= Gap 1 G2 + Gap 2 S = synthesis M = mitosis

Fate of different Chromosomes in each Phase of the cell cycle Experiments of Warren Sinclair: Survival curves during cell cycle

----- calculated for -hypoxic condions of -Mitoc cells

Late S—least sens.

M>G2>G1>early S>late S for sensivity Difference caused by cell cycle are similar to difference caused by Oxygen effect Manjit Dosanjh, 2014 Figure 8.4 The Biology of Cancer (© Garland Science 2007) Manjit Dosanjh, 2014 Regulation of the cell cycle

IR block

IR block

Cell cycle arrest can occur in response to DNA damage (e.g. IR) in order to allow for DNA repair.

Manjit Dosanjh, 2014 P53-guardian of the genome…..Lane,92

Contributions to Pre-Clinical Theoretical Modeling • Software for Cell Inactivation Modeling & Statistics (Albright) • Neyman Distributions and their importance to particle effects (Albright, Tobias) • Lethal-Potentially-Lethal Model of Cell Inactivation (Curtis) • Design for Study of Radioactive Beams (Chatterjee, Tobias) • Design for Particle Radiography (Tobias, Fabrikant) • Spiral Filter Design for Spread-Out Bragg Peaks (Tobias) • Design for Particle Beam Wobbling (Tobias) • Repair-Misrepair Model of Cell Inactivation (Tobias) • Design for Particle Beam Raster Scanning (Tobias)

Manjit Dosanjh, 2014 Simplified view of some of the cellular pathways involved in response IR

Connell, P. P. et al. Cancer Res 2009;69:383-392

Copyright ©2009 American Association for Cancer Research Manjit Dosanjh, 2014

Basic radiobiology of high-LET damage & repair--which genes/proteins are important ?

• Bcl-2 is an anti-apoptotic protein that is frequently overexpressed in 30-50% of tumors, and overexpression is associated with radioresistance Brahme 2004 Manjit Dosanjh, 2014 Int J Radiat Oncol Biol Phys, V 58, pp 603-616 4Rs of Radiobiology Relevant to Clinical Dose Fractionation • Repair - spares late responding normal tissue preferentially • Reassortment/Redistribution of cells in the cell cycle – increases acute effects – no influence on late effects – increases damage to tumor • Repopulation/Regeneration – spares acute responding normal tissue preferentially – no influence on late effects, – danger of tumor repopulation • Reoxygenation – no influence on normal tissue responses – increases tumor damage

Manjit Dosanjh, 2014 Department of Radiation Oncology

Holthusen-Curve: Dose-Response-Relationship

10 Tumor Control 0 80

60 Adverse Effects

40 Therapeutic Window Probability [%] Probability 20 Cure w/o Side Effects

10 20 30 40 50 60 70 80 90 10 „Optimal Dose“ [Gy] After: Holthusen, H. und Braun, R. ( 1933 ) : 0 Grundlagen und Praxis der Röntgenstrahldosierung, Thieme Verlag, Leipzig Ultimate Goal: Heavy Ions & Therapeutic Gain

• Overcoming tumour radioresistance • Enhancing tumour cell killing • Protecting normal cells

Hadrontherapy vs x-radiotherapy

• Tumours close to critical organs • Tumours in children • Radio-resistant tumours

Photons and Electrons vs. Hadrons • Physical dose high near surface • Dose highest at Bragg Peak • DNA damage easily repaired • DNA damage not repaired • Biological effect lower • Biological effect high • Need presence of oxygen • Do not need oxygen • Effect not localised • Effect is localised Charged Particle Therapy – 2014

• Goal now is to evaluate “best” clinical implementation for each of two charged particle modalities (proton or carbon) for maximizing dose to the tumor, while sparing surrounding normal tissue. Other intermediate ions (helium, lithium, boron) are also under consideration. • Criteria for comparison • New physical dose gold standard: IMRT/IGRT • New understanding of biological models • New understanding of treatment planning models • New molecular tools to probe mechanisms of action

Manjit Dosanjh, 2014 https://cds.cern.ch/record/1611721 References

• cern.ch/crystalclear • cern.ch/enlight • cern.ch/medipix • cern.ch/twiki/bin/view/AXIALPET • cern.ch/medaustron • cern.ch/fluka/heart/rh.html • www.fluka.org/fluka.php • cern.ch/wwwasd/geant • cern.ch/wwwasd/geant/tutorial/tutstart.html Acknowledgements

• ENLIGHT community (cern.ch/enlight) • ULICE (cern.ch/ulice) • ENVISION (cern.ch/envision) • PARTNER (cern.ch/partner) • ENTERVISION (cern.ch/partner)

• CERN KNOWLEDGE TRANSFER (cern.ch/knowledgetransfer)