Use of compact segmented Photodetectors : APD, MAPMT, MCPPMT ? Front-end Electronic

October 16th Picosecond Lyon 1

INNOTEP Project

Using HEP technologies to improve TEP imaging: Development of innovative schemes for front-end electronic, readout and DAQ

architecture

Check of HEP R&D (LHC, ILC, ..) for medical imaging instrumentation

To go beyond the state of art independently of the industry

To federate French labs effort in the domain of intrumentation applied to TEP imaging


INNOTEP project covers following R&D domains where techniques could be transfered to medical imaging

• Use of compact segmented Photodetectors: APD, MAPMT, MCPPMT ?

• Front-end Electronic – Fast, low noise,low power preamp– Fast Sampling ADCs

• Signal Filtering– Optimum filtering for pulse’s time and amplitude estimation– Signal analysis

• Read-Out/DAQ– Pipeline and parallel read-out, – Use of high bandwith system (microTCA and ATCA) for trigger and on-

line treatment


How to improve performances of clinical TEP

One exemple = Use of Time of Flight (TOF) Philips, Gemini TF™, Siemens

Reduction of backgrounds Improvment of image quality Decrease time of acquisition

GEMINI TF™, PhilipsTruFlight™

∆t ~ 550 ps

PET scanner LYSO : 4 x 4 x 22 mm3

28,338 cristaux, 420 PMTs cristal gap: 0.75 µm 2 = 4 ns couronne 70-cm , 18-cm FOVCT scanner Brilliance™ 16 or 64 slice


J. Karp, University of Pennsylvania

Advantage of TOF

Contrast improvment for detection of small structures in

background


Advantage of TOF

J. Karp, University of Pennsylvania

Dose injected=9.8 mCi

Non-TOF

TOF

CT CT/TEP


Second Application Novel Imaging Systems for in vivo Monitoring

and Quality Control duringTumour Ion Beam Therapy (proton, carbon)

Advantages of hadrontherapy for localized treatment of tumors : More localized energy deposition in target due to the Bragg peak Better biological efficiency of hadrons compared to photons


Many hadrontherapy centers planned worldwide:Protons : Carbon : GSI, Heidelberg, CNAO, ETOILE, Medaustron….

Hadrontherapy Treatement Protocol : Decomposition of the volume to be treated in voxels Maximum Energy in each voxel using Bragg peak Adjustement of the beam in energy and position to locate the Bragg peak in the voxel


Peripheral nucleus-nucleus-collisions, nuclear reactions

12C: E = 212 AMeVTarget: PMMA

15O, 11C, 13N ...

11C,10C

Penetration depth / mm

Arb

itrar

y un

its

16O: E = 250 AMeVTarget: PMMA

15O, 11C, 13N ...

15O,14O,13N,11C…

Therapy beam 1H 3He 7Li 12C 16O Nuclear medicine

Activity density / Bq cm-3 Gy-1 6600 5300 3060 1600 1030 104 – 105 Bq cm-3

Z 6

Target fragmentsProjectile fragments Target fragments

Z < 6

1H: E = 110 MeVTarget: PMMA

15O, 11C, 13N ...

3He: E = 130 AMeVTarget: PMMA

15O, 11C, 13N ...

Arb

itrar

y un

itsPenetration depth / mm

7Li: E = 129 AMeVTarget: PMMA

Physics


What do we have? In-beam PETRationale

Proportional to dose

3D

Non invasive

Real time

Time efficient

In situ

Tomography

Highly penetrable signal

Separation of the signal from the therapeutic irradiation

X- or -rays

Signal with: • well defined energy• spatial correlation• time correlation• time delay

Annihilation -rays,Positron Emitters

PET

High detection efficiency

??11C 11B + e+ + eT1/2

180 deg

t = 0E = 511 keV


12C

Off-

bea

m P

ET

: 1H

-th

erap

y a

t MG

H B

ost

on

In-b

ea

m P

ET

: 12C

-th

erap

y a

t GS

I Da

rmst

adt

In-beam PET and Off beam PET


In-beam PET Clinical implementation at GSI

0

1

T Time

S(t

)

Accelerator:

Synchrotrond 60 m

Particle beam:pulsedT 5 s, ≤ 2 s

PET data,list mode:

{K1, K2, S}(t)

Irradiation-time course:

{E, I, d}(t)


Presence of a large background noise comming mainly from the beam but also :large rate of high energy prompt gammas from nuclear desexcitation, as well of neutronslarge rate of randoms

Pause : P

Out of mbunch: A2

In mbunch: B2

Main experimental Constraints

P

Extraction A2 B2

At GSI : acquisition out of beam delivery period in correlation with in beam detectorBut low « true coincidence» statistic to recover dose monitoring


Pause : P

Out of bunch: A2

In bunch: B2


Clinical implementationIon range verification

Treatment plan: dose distribution

+-activity:prediction

+-activity:measurement


PET allows for a - beam delivery independent,

- simultaneous or close to therapy (in-beam, offline, resp.),- non-invasive

control of tumour irradiations by means of ion beams

An in-vivo measurement of the ion range

The validation of the physical model of the treatment planning

In-beam PET Advantages


The evaluation of the whole physical process of the treatment from

planning to the dose application- new ion species - new components, algorithms- high precision irradiations

The detection and estimation of unpredictable deviations between

planned and actually applied dose distributions due to- mispositioning- anatomical changes- mistakes and incidents

In-beam PET Advantages(II)


The ENVISION Project (European Novel imaging systems for in vivo monitoring

and quality control during tumour ion beam)

Upcoming FP7 call HEALTH-2008-1.2-4

The focus should be to develop novel imaging instruments, methods and tools for monitoring, in vivo and preferably in real time, the 3-dimensional distribution of the radiation dose effectively delivered within the patient during ion beam therapy of cancer.

The ions should be protons or heavier ions.

The system should typically be able to quantify the radiation dose delivered, to determine the agreement between the planned target volume and the actually irradiated volume, and for decreasing localisation uncertainties between planned and effective positions (e.g. of tissues or organs), and between planned and effective dose distribution during irradiation.

It should aim at improving quality assurance, increasing target site (tumour) to normal tissue dose ratio and better sparing normal tissue.


What do we need?WP1: Time-of-flight in-beam PET

-Aim: Remove the influence of limited angle tomographic sampling to quantitative imaging

-Subtask 1.1.: Development of a demonstrator of an in-beam TOF positron camera:

▪ 2t < 200 ps the more the time resolution, the faster and

efficient dose reconstruction

▪ hsingles > 50 %

▪ Dx < 5 mm

detector technology

DAQ

- Subtask 1.2.: Tomographic reconstruction and prediction of

measured activity distributions from treatment planning

real-time TOF reconstruction

simulation TP TOF IBPET


Main Partners involved in ENVISION project

INFN , TERA Project , CERN, IN2P3 , GSI , Heidelberg, Louvain, Birmingham, Oxford, Valencia

IBA, OncoRay, Icx, Siemens

Use of compact segmented Photodetectors : APD, MAPMT, MCPPMT ? Front-end Electronic

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