Short-lived positron emitters in beam-on PET imaging during proton therapy

The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, providing the largest number of counts, the least biological washout and the fastest feedback. In this implementation, all nuclides, independent of their half-life, will contribute. As a first step towards assessing the relevance of short-lived nuclides (half-life shorter than that of (10)C, T1/2  =  19 s) for in vivo dose delivery verification using beam-on PET, we measured their production in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: (12)N (T1/2  =  11 ms) on carbon (9% of (11)C), (29)P (T1/2  =  4.1 s) on phosphorus (20% of (30)P) and (38m)K (T1/2  =  0.92 s) on calcium (113% of (38g)K). No short-lived nuclides are produced on oxygen. The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, (12)N dominates up to 70 s. On bone tissue, (12)N dominates over (15)O during the first 8-15 s (depending on carbon-to-oxygen ratio). The short-lived nuclides created on phosphorus and calcium provide 2.5 times more beam-on PET counts than the long-lived ones produced on these elements during a 70 s irradiation. From the estimated number of (12)N PET counts, we conclude that, for any tissue, (12)N PET imaging potentially provides equal to superior proton range information compared to prompt gamma imaging with an optimized knife-edge slit camera. The practical implementation of (12)N PET imaging is discussed.

[1]  F. A. Beck,et al.  The Clover: a new generation of composite Ge detectors , 1999 .

[2]  K. P. Jackson,et al.  [Formula Presented]-delayed particle decay of [Formula Presented] and the [Formula Presented] nuclear system: Experiment, data, and phenomenological analysis , 2000 .

[3]  G Janssens,et al.  Prompt gamma imaging of proton pencil beams at clinical dose rate , 2014, Physics in medicine and biology.

[4]  Hirohiko Tsujii,et al.  Acoustic pulse generated in a patient during treatment by pulsed proton radiation beam , 1995 .

[5]  Wolfgang Enghardt,et al.  Test of Compton camera components for prompt gamma imaging at the ELBE bremsstrahlung beam , 2014 .

[6]  Stephen E. Derenzo,et al.  Mathematical Removal of Positron Range Blurring in High Resolution Tomography , 1986, IEEE Transactions on Nuclear Science.

[7]  G Sportelli,et al.  First full-beam PET acquisitions in proton therapy with a modular dual-head dedicated system , 2014, Physics in medicine and biology.

[8]  P. Busca,et al.  Prompt gamma imaging with a slit camera for real-time range control in proton therapy , 2012, 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC).

[9]  A. Kraan,et al.  Range Verification Methods in Particle Therapy: Underlying Physics and Monte Carlo Modeling , 2015, Front. Oncol..

[10]  W. Enghardt,et al.  Online Irradiation Control by Means of PET , 2012 .

[11]  Joao Seco,et al.  Energy- and time-resolved detection of prompt gamma-rays for proton range verification , 2013, Physics in medicine and biology.

[12]  Wolfgang Enghardt,et al.  Range assessment in particle therapy based on prompt γ-ray timing measurements , 2014, Physics in medicine and biology.

[13]  Katia Parodi,et al.  Charged hadron tumour therapy monitoring by means of PET , 2004 .

[14]  Antony Lomax,et al.  In vivo proton range verification: a review , 2013, Physics in medicine and biology.

[15]  Georges El Fakhri,et al.  Proton Therapy Verification with PET Imaging , 2013, Theranostics.

[16]  F. Ajzenberg-Selove,et al.  Energy Levels of Light Nuclei A = 9 , 1984 .

[17]  Ying Xiao,et al.  Proton therapy dosimetry using positron emission tomography. , 2010, World journal of radiology.

[18]  W. Kaye,et al.  Evaluation of a multistage CdZnTe Compton camera for prompt γ imaging for proton therapy , 2015 .

[19]  D. R. White,et al.  The composition of body tissues. , 1986, The British journal of radiology.

[20]  K Parodi,et al.  Ionoacoustic characterization of the proton Bragg peak with submillimeter accuracy. , 2015, Medical physics.

[21]  Katia Parodi,et al.  Comparison between in-beam and offline positron emission tomography imaging of proton and carbon ion therapeutic irradiation at synchrotron- and cyclotron-based facilities. , 2008, International journal of radiation oncology, biology, physics.

[22]  G Sportelli,et al.  Proton range monitoring with in-beam PET: Monte Carlo activity predictions and comparison with cyclotron data. , 2014, Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics.

[23]  Magdalena Rafecas,et al.  First Compton telescope prototype based on continuous LaBr3-SiPM detectors , 2013 .

[24]  Denis Dauvergne,et al.  Development of a Compton camera for medical applications based on silicon strip and scintillation detectors , 2015 .

[25]  Wolfgang Enghardt,et al.  On the detector arrangement for in-beam PET for hadron therapy monitoring , 2006, Physics in medicine and biology.

[26]  Joao Seco,et al.  Proton range verification through prompt gamma-ray spectroscopy , 2014, Physics in medicine and biology.

[27]  A. Krasznahorkay,et al.  Absolute full-energy peak efficiency calibration of a Clover–BGO detector system , 2003 .

[28]  Mitsuru Uesaka,et al.  Measurement and verification of positron emitter nuclei generated at each treatment site by target nuclear fragment reactions in proton therapy. , 2010, Medical physics.

[29]  Shunsuke Kurosawa,et al.  Prompt gamma detection for range verification in proton therapy , 2012 .

[30]  K. Parodi,et al.  Suppression of random coincidences during in-beam PET measurements at ion beam radiotherapy facilities , 2005, IEEE Transactions on Nuclear Science.

[31]  E. Hoffman,et al.  Calculation of positron range and its effect on the fundamental limit of positron emission tomography system spatial resolution. , 1999, Physics in medicine and biology.

[32]  S Stute,et al.  GATE V6: a major enhancement of the GATE simulation platform enabling modelling of CT and radiotherapy , 2011, Physics in medicine and biology.

[33]  Chan Hyeong Kim,et al.  Development of array-type prompt gamma measurement system for in vivo range verification in proton therapy. , 2012, Medical physics.

[34]  K. Parodi.  In Vivo Dose Verification , 2011 .

[35]  S Beddar,et al.  Measurement and calculation of characteristic prompt gamma ray spectra emitted during proton irradiation , 2009, Physics in medicine and biology.

[36]  Hee Seo,et al.  Gamma electron vertex imaging and application to beam range verification in proton therapy. , 2012, Medical physics.

[37]  Yiping Shao,et al.  In-beam PET imaging for on-line adaptive proton therapy: an initial phantom study , 2014, Physics in medicine and biology.

[38]  Katia Parodi,et al.  Time-of-flight neutron rejection to improve prompt gamma imaging for proton range verification: a simulation study , 2012, Physics in medicine and biology.

[39]  W. Enghardt,et al.  Direct time-of-flight for quantitative, real-time in-beam PET: a concept and feasibility study , 2007, Physics in medicine and biology.

[40]  G Ciangaru,et al.  Prompt gamma-ray emission from biological tissues during proton irradiation: a preliminary study , 2009, Physics in medicine and biology.

[41]  Katia Parodi,et al.  The modelling of positron emitter production and PET imaging during carbon ion therapy , 2004, Physics in medicine and biology.

[42]  K. Parodi,et al.  Experimental study on the feasibility of in-beam PET for accurate monitoring of proton therapy , 2005, IEEE Transactions on Nuclear Science.