Detector technologies: from particle physics to radiotherapy

B. Camanzi

STFC – RAL & University of Oxford

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 2/22

Outline

Why cancer The detector challenges: dosimetry and

imaging Positron Emission Tomography (PET) Time-Of-Flight PET Future activities Conclusions

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 3/22

The challenge of cancer in UK

Cancer is the leading cause of mortality in people under the age of 75. 1 in 4 people die of cancer overall.

293k people/year diagnosed with cancer, 155k people/year die from cancer.

Incidence of cancer is rising due to:1. Population ageing2. Rise in obesity levels3. Change in lifestyle

Cancer 3rd largest NHS disease programme.

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 4/22

Radiotherapy and cancer in UK

Radiotherapy given to 1/3 of cancer patients (10-15% of all population).

Overall cure rate = 40%. In some instances 90-95% (for ex. breast and stage 1 larynx cancers).

Radiotherapy often combined with other cancer treatments: 1. Surgery2. Chemotherapy3. Hormone treatments

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 5/22

Radiotherapy treatments

External beam radiotherapy:1. X-ray beam2. Electron beam3. Proton/light ion beam

Internal radiotherapy:1. Sealed sources (brachytherapy)2. Radiopharmaceuticals

Binary radiotherapy: 1. Boron Neutron Capture Therapy (BNCT)2. Photon Capture Therapy (PCT)

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 6/22

The technological challenges

The challenge of radiotherapy from the patient end Make sure that the right dose is delivered at the right place = improved dosimetry + improved imaging

The challenge of early diagnosis “See” smaller tumours = improved imaging

New advanced technologies desperately needed for dosimetry and imaging

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 7/22

How particle physics can help

"The significant advances achieved during the last decades in material properties, detector characteristics and high-quality electronic system played an ever-expanding role in different areas of science, such as high energy, nuclear physics and astrophysics. And had a reflective impact on the development and rapid progress of radiation detector technologies used in medical imaging."

“The requirements imposed by basic research in particle physics are pushing the limits of detector performance in many regards, the new challenging concepts born out in detector physics are outstanding and the technological advances driven by microelectronics and Moore's law promise an even more complex and sophisticated future.”

D. G. Darambara "State-of-the-art radiation detectors for medical imaging: demands and trends" Nucl. Inst. And Meth. A 569 (2006) 153-158

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 8/22

In-vivo dosimetry

Radiation sensitive MOSFET transistors (RadFETs) used in particle physics experiments (BaBar, LHC, etc.) for real-time, online radiation monitoring.

Development of RadFET based miniaturised wireless dosimetry systems to be implanted in patient body at tumour site for real-time, online, in-vivo dosimetry.

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 9/22

Imaging

Most medical imaging systems, CT, gamma cameras, SPECT, PET, use particle physics technologies: scintillating materials, photon detectors, CCDs, etc.

Courtesy Mike Partridge (RMH/ICR)

Collimator

Scintillator

Diode

CT scanner Gamma camera (SPECT)

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 10/22

Positron Emission Tomography 18F labelled glucose given to patients:

e+ annihilates in two back-to-back 511 keV .

A ring of scintillating crystals and PMTs detects the

511 keV

511 keV

Courtesy Mike Partridge (RMH/ICR)

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 11/22

Conventional PET

Conventional PET scanner: 1. Coincidences formed within a very

short time window

2. Straight line-of-response reconstructed

3. Position of annihilation calculated probabilistically

Courtesy Mike Partridge (RMH/ICR)

PET CT PET + CT

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 12/22

Time-Of-Flight PET (TOF-PET) TOF-PET scanner:

1. Time difference between signals from two crystals measured

2. Annihilation point along line-of-response directly calculated

Goal: 100 ps timing resolution (ideally 30 ps and below) = 3 cm spatial resolution (ideally sub-cm)

Advantages: higher sensitivity and specificity, improved S/N Technology needed: fast scintillating materials and fast photon

detectors

D2

line of response

time-of-flight envelope

D1

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 13/22

Fast scintillating materials

Decay time (ns)

Light yield (/keV)

Density (g/cm3)

Latt at 511keV (cm)

LaBr3(Ce) BrilLanCeTM380

16 63 5.3 2.23

LYSO PreLudeTM420

41 32 7.1 1.20

LSO 40 27 7.4 1.14

BGO 300 9 7.1 1.04

GSO 60 8 6.7 1.43

BaF2 0.8 1.8 4.9 2.20

NaI(Tl) 250 38 3.7 2.91

BrilLanCeTM380 and PreLudeTM420 produced by Saint-Gobain Cristaux et Detecteurs

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 14/22

Photon detectors: SiPMs Array of Silicon Photodiodes

on common substrate each operating in Geiger mode

SiPMs have speed (sub ns) and high gain (106), small size and work in high magnetic fields (7T)

Hamamatsu Inc.

1x1 mm2

3x3 mm2

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 15/22

Tests on TOF-PET prototypes

0

500

1000

1500

2000

2500

-80

-70

-60

-50

-40

-30

-20

-10 0 10 20 30 40 50 60 70 80 90 10

011

0

Time Difference (ps)

Co

un

ts

LaBr3(Ce) and LYSO scintillating crystals from Saint-Gobain

SiPMs from Hamamatsu, SensL and Photonique

Various two-channel demonstrator systems tested at RAL and RMH

Timing resolution analysis still ongoing

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 16/22

Preliminary results

SiPM timing resolution with blue LED

0.00

100.00

200.00

300.00

400.00

500.00

600.00

Ham11-100

Ham11-50

Ham11-25

Ham33-100

Ham33-50

Ham33-25

SensL11

SensL33

Phot11

Phot33

Tim

ing

res

olu

tio

n (

ps)

SiPM single

SiPM pair

Prototypes with Hamamatsu 3x3 mm2 best of all. SensL blind to LaBr3.

Best timing resolutions measured:1. 430 ps with 3x3x10 mm3 LYSO

2. 790 ps with 3x3x30 mm3 LaBr3

Performance of prototypes with LaBr3 highly dependent from SiPM-crystal coupling.

Best SiPMs: Hamamatsu (electrical problem with 11-25) and SensL.

Best timing resolutions measured:1. 20 ps for single SiPM

2. 40 ps for pairs of SiPMs Hamamatsu performance as function

of pitch still under investigation.

2-channel prototype timing resolution with sources

0

0.5

1

1.5

2

2.5

3

3.5

4

Ham11-100

Ham11-50

Ham11-25

Ham33-100

Ham33-50

Ham33-25

SensL11

SensL33

Phot11

Phot33

Tim

ing

res

olu

tio

n (

ns)

LYSO 5mm Na22

LYSO 10mm Na22

LaBr3 Na22

LYSO 5mm F18

LaBr3 F18

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 17/22

Where next

Preliminary results very encouraging. Need to investigate technology further: build a dual-head demonstrator system. Two planar heads with identical number of channels.

Use of fast scintillators can be expanded to other imaging systems (CT, SPECT, etc.).

Use of SiPMs opens up the possibility of designing a compact PET/MRI scanner.

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 18/22

Future activities

Participation through Oxford to FP7 project ENVISION (European NoVel Imaging Systems for ION therapy).

Development of a technology roadmap for cancer care, to move toward a multi-modality approach to radiotherapy.

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 19/22

ENVISION

Participation in WP2: development of TOF in-beam PET systems.

Oxford/STFC contributions:1. Characterisation of scintillating materials

(LYSO and LaBr3)2. Characterisation of SiPMs3. Construction and test of a TOF-PET dual-

head demonstrator system4. Simulations of component (crystals and

SiPMs) and system performance

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 20/22

My vision: toward multi-modality

Multi-modality = bringing together the different forms of radiotherapy treatments:1. Select best treatment depending on tumour type

2. Combine different treatments when appropriate

New advanced imaging and dosimetry systems of paramount importance → Technology roadmap

Roadmap to be developed in consultation with end-user groups, universities, etc.

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 21/22

Conclusions

Cancer is a leading cause of mortality in UK. Its incidence is rising.

Radiotherapy is and will be given to a large number of patients.

Patients will benefit from a multi-modality approach to radiotherapy. This requires the development of new, advanced technologies.

Particle physics holds the key to the development of these technologies.

B. CamanziRAL & Oxford University

SEPnet RDI Kick-off Meeting 19/04/10 22/22

Acknowledgements

Prof Ken Peach (John Adams Institute) Dr Phil Evans and Dr Mike Partridge (Royal

Marsden Hospital / Institute of Cancer Research)

Gareth Derbyshire (STFC Healthcare Futures Programme)

Dr John Matheson and Matt Wilson (STFC-RAL)