Medical requirements for FFAG as proton beam sources

Jacques BALOSSO, MD, PhD

Radiation oncologiste

UJF / INSERM / ETOILE

FFAG 2007, April 12-17, 2007 Grenoble

Plan

• Why to use protons in radiotherapy ?

• What kind of tumors are presently treated by protons ?

• What kind of tumors would be treated by widely available proton beams?

• Requirement for a medical proton source

• Prospective for a radiotherapy of the future

• Why to use protons in radiotherapy ?

• What kind of tumors are presently treated by protons ?

• What kind of tumors would be treated by widely available proton beams?

• Requirement for a medical proton source

• Prospective for a radiotherapy of the future

The protons Bragg peak

The 200 MeV Bragg peak of the CPO (Orsay, France)

The protons Spread Out Bragg Peak (SOBP)

The inside structure of the proton SOBP

Comparison of the « efficient » dose according to the depth for photons, a proton SOPB and a carbon ion SOBP. (GSI, Darmstadt, Germany)

PSI Villigen

PSI Villigen

PSI Villigen

PSI Villigen

Comparison of the « efficient » dose according to the depth for photons, a proton SOPB and a carbon ion SOBP. (GSI, Darmstadt, Germany)

X-Rays Protons Carbone

Neutrons

RBE 1

RBE >> 1

Protons and Carbon ions are not offering the same advantages

• Protons are representing a crude and important ballistic improvement for any type of radiotherapy…

providing they are affordable !

• Carbones are an innovative kind of radiations with particular radiobiological properties suitable for certain indications only.

Indication for Indication for a fractionated a fractionated radiotherapy radiotherapy of RBE of RBE 1 1

Indication for Indication for particle particle therapy having therapy having an RBE >> 1an RBE >> 1S

urv

ival

Consequently …

• Protons indications are not limited

• Protons can, with the time, replace X-Rays

• Carbon ions should have a definitive and limited number of indications

• These indications are a number of therapeutic spots present in different groups of tumors.

• Why to use protons in radiotherapy ?

• What kind of tumors are presently treated by protons ?

• What kind of tumors would be treated by widely available proton beams?

• Requirement for a medical proton source

• Prospective for a radiotherapy of the future

Indications for protontherapy in Loma Linda (1)

• Brain and spinal cord– Isolated brain metastases– Pituitary adenomas– Arteriovenous malformations (AVMs)

• Base of skull– Meningiomas– Acoustic neuromas– Chordomas and chondrosarcomas

• Eye– Uveal melanomas

In red: indications treated in France

Indications for protontherapy in Loma Linda (2)

Head and neck– Nasopharynx– Oropharynx (locally advanced)

• Chest and abdomen– Medically inoperable non-small-cell lung cancer– Chordomas and chondrosarcomas

• Pelvis– Prostate– Chordomas and chondrosarcomas

• Tumors in children– Brain– Orbital and ocular tumors– Sarcomas of the base of skull and spine

Uvea melanoma treated by protons

Chondrosarcoma of the skull base

Chordoma

Meningioma

• Why to use protons in radiotherapy ?

• What kind of tumors are presently treated by protons ?

• What kind of tumors would be treated by widely available proton beams?

• Requirement for a medical proton source

• Prospective for a radiotherapy of the future

Indications for protontherapy in Loma Linda (1)

• Brain and spinal cord– Isolated brain metastases +++– Pituitary adenomas– Arteriovenous malformations (AVMs)

• Base of skull– Meningiomas– Acoustic neuromas– Chordomas and chondrosarcomas

• Eye– Uveal melanomas

In red: indications treated in France

Indications for protontherapy in Loma Linda (2)

Head and neck– Nasopharynx +++– Oropharynx (locally advanced)

• Chest and abdomen– Medically inoperable non-small-cell lung cancer +++– Chordomas and chondrosarcomas

• Pelvis– Prostate +++– Chordomas and chondrosarcomas

• Tumors in children– Brain– Orbital and ocular tumors– Sarcomas of the base of skull and spine

• Why to use protons in radiotherapy ?

• What kind of tumors are presently treated by protons ?

• What kind of tumors would be treated by widely available proton beams?

• Requirement for a medical proton source

• Prospective for a radiotherapy of the future

Technical requirements

• Depth: 2 to 30 cm in water• Size: at least 10 x 10 cm up to 20 x 20• Dose rate: at least one Gy / min / liter• Precision of size & position: 1 mm• Precision of the dose: +/- 2 to 3%• Operability: > 97%• Session time: < 30 min• Beam control: active +++ (rapid change of

energy ??) better than passive

Exemple of a single proton beam

Exemple of the set-up with a gantry

• Why to use protons in radiotherapy ?

• What kind of tumors are presently treated by protons ?

• What kind of tumors would be treated by widely available proton beams?

• Requirement for a medical proton source

• Prospective for a radiotherapy of the future

Toward the future of radiotherapy

• 100% hadrontherapy:– with 95% proton– and 5% light-ions (carbon…)

• High precision and small volume of early diagnozed tumors

• Few sessions of >> « 2 Gy »• Fast shot RT to reduce immobilization and to

favor precision of moving target treatment (lung, lever, prostate…)

• About 5000 treatments / 106 inhabitants per year in 20 years

Open questions

• What type of machine for the generalized availability of protons ?

• What are the radiobiological characteristic of very high dose rates ?

• What could be the organization and the economical conditions of very short but highly sophisticated treatments ?

• Could FFAG be an answer?