A time-of-flight-based reconstruction for real-time prompt-gamma imaging in proton therapy.

We propose a novel prompt-gamma (PG) imaging modality for real-time monitoring in proton therapy: PG time imaging (PGTI). By measuring the time-of-flight (TOF) between a beam monitor and a PG detector, our goal is to reconstruct the PG vertex distribution in 3D. In this paper, a dedicated, non-iterative reconstruction strategy is proposed (PGTI reconstruction).

Influence of sub-nanosecond time of flight resolution for online range verification in proton therapy using the line-cone reconstruction in Compton imaging.

Online ion range monitoring in hadron therapy can be performed via detection of secondary radiation, such as prompt-rays, emitted during treatment. The promptemission profile is correlated with the ion depth-dose profile and can be reconstructed via Compton imaging. The line-cone reconstruction, using the intersection between the primary beam trajectory and the cone reconstructed via a Compton camera, requires negligible computation time compared to iterative algorithms.

A Study of the Radiation Tolerance of CVD Diamond to 70 MeV Protons, Fast Neutrons and 200 MeV Pions.

We measured the radiation tolerance of commercially available diamonds grown by the Chemical Vapor Deposition process by measuring the charge created by a 120 GeV hadron beam in a 50 μm pitch strip detector fabricated on each diamond sample before and after irradiation. We irradiated one group of samples with 70 MeV protons, a second group of samples with fast reactor neutrons (defined as energy greater than 0.1 MeV), and a third group of samples with 200 MeV pions, in steps, to (8.

Ultra-fast prompt gamma detection in single proton counting regime for range monitoring in particle therapy.

In order to fully exploit the ballistic potential of particle therapy, we propose an online range monitoring concept based on time-of-flight (TOF)-resolved prompt gamma (PG) detection in a single proton counting regime. In a proof of principle experiment, different types of monolithic scintillating gamma detectors are read in time coincidence with a diamond-based beam hodoscope, in order to build TOF spectra of PG generated in a target presenting an air cavity of variable thickness. Since the measurement was carried out at low beam currents (< 1 proton/bunch) it was possible to reach excellent coincidence time resolutions, of the order of 100 ps (σ).

The therapeutic effectiveness of Lu-lilotomab in B-cell non-Hodgkin lymphoma involves modulation of G2/M cell cycle arrest.

Some patients with B-cell non-Hodkin lymphoma Lymphoma (NHL) become refractory to rituximab (anti-CD20 antibody) therapy associated with chemotherapy. Here, the effect of the anti-CD37 antibody-radionuclide conjugate lutetium-177 (Lu)-lilotomab (Betalutin) was investigated in preclinical models of NHL. In SCID mice bearing DOHH2 (transformed follicular lymphoma, FL) cell xenografts, Lu-lilotomab significantly delayed tumor growth, even at low activity (100 MBq/kg).

Realistic multi-cellular dosimetry for Lu-labelled antibodies: model and application.

Current preclinical dosimetric models often fail to take account of the complex nature of absorbed dose distribution typical of in vitro clonogenic experiments in targeted radionuclide therapy. For this reason, clonogenic survival is often expressed as a function of added activity rather than the absorbed dose delivered to cells/cell nuclei. We designed a multi-cellular dosimetry model that takes into account the realistic distributions of cells in the Petri dish, for the establishment of survival curves as a function of the absorbed dose.

Model-based versus specific dosimetry in diagnostic context: comparison of three dosimetric approaches.

Purpose: The dosimetric assessment of novel radiotracers represents a legal requirement in most countries. While the techniques for the computation of internal absorbed dose in a therapeutic context have made huge progresses in recent years, in a diagnostic scenario the absorbed dose is usually extracted from model-based lookup tables, most often derived from International Commission on Radiological Protection (ICRP) or Medical Internal Radiation Dose (MIRD) Committee models. The level of approximation introduced by these models may impact the resulting dosimetry.

Multi-scale hybrid models for radiopharmaceutical dosimetry with Geant4.

The accuracy of radiopharmaceutical absorbed dose distributions computed through Monte Carlo (MC) simulations is mostly limited by the low spatial resolution of 3D imaging techniques used to define the simulation geometry. This issue also persists with the implementation of realistic hybrid models built using polygonal mesh and/or NURBS as they require to be simulated in their voxel form in order to reduce computation times. The existing trade-off between voxel size and simulation speed leads on one side, in an overestimation of the size of small radiosensitive structures such as the skin or hollow organs walls and, on the other, to unnecessarily detailed voxelization of large, homogeneous structures.

A review of the use and potential of the GATE Monte Carlo simulation code for radiation therapy and dosimetry applications.

In this paper, the authors' review the applicability of the open-source GATE Monte Carlo simulation platform based on the GEANT4 toolkit for radiation therapy and dosimetry applications. The many applications of GATE for state-of-the-art radiotherapy simulations are described including external beam radiotherapy, brachytherapy, intraoperative radiotherapy, hadrontherapy, molecular radiotherapy, and in vivo dose monitoring. Investigations that have been performed using GEANT4 only are also mentioned to illustrate the potential of GATE.

Dosimetry for nonuniform activity distributions: a method for the calculation of 3D absorbed-dose distribution without the use of voxel S-values, point kernels, or Monte Carlo simulations.

Purpose: Nonuniform activity within the target lesions and the critical organs constitutes an important limitation for dosimetric estimates in patients treated with tumor-seeking radiopharmaceuticals. The tumor control probability and the normal tissue complication probability are affected by the distribution of the radionuclide in the treated organ/tissue. In this paper, a straightforward method for calculating the absorbed dose at the voxel level is described.

Development and validation of RAYDOSE: a Geant4-based application for molecular radiotherapy.

We developed and validated a Monte-Carlo-based application (RAYDOSE) to generate patient-specific 3D dose maps on the basis of pre-treatment imaging studies. A CT DICOM image is used to model patient geometry, while repeated PET scans are employed to assess radionuclide kinetics and distribution at the voxel level. In this work, we describe the structure of this application and present the tests performed to validate it against reference data and experiments.

Usefulness of 124I PET/CT imaging to predict absorbed doses in patients affected by metastatic thyroid cancer and treated with 131I.

Aim: The aim of this work was the evaluation of the usefulness of 124I PET/CT sequential scans to predict absorbed doses to metastatic thyroid cancer in patients undergoing 131I therapy.

Methods: From July 2011 until April 2012 8 patients affected by metastatic thyroid cancer were enrolled. Each patient underwent 4 PET/CT scans at 4, 24, 48, 72 h after the administration of about 74 MBq of 124I.

Characterization of a PET detector head based on continuous LYSO crystals and monolithic, 64-pixel silicon photomultiplier matrices.

The characterization of a PET detector head based on continuous LYSO crystals and silicon photomultiplier (SiPM) arrays as photodetectors has been carried out for its use in the development of a small animal PET prototype. The detector heads are composed of a continuous crystal and a SiPM matrix with 64 pixels in a common substrate, fabricated specifically for this project. Three crystals of 12 mm × 12 mm × 5 mm size with different types of painting have been tested: white, black and black on the sides but white on the back of the crystal.

Advanced radiation measurement techniques in diagnostic radiology and molecular imaging.

This paper reports some technological advances recently achieved in the fields of micro-CT and small animal PET instrumentation. It highlights a balance between image-quality improvement and dose reduction. Most of the recent accomplishments in these fields are due to the use of novel imaging sensors such as CMOS-based X-ray detectors and silicon photomultipliers (SiPM).

Alterations of the endoalveolar surfactant after surgery with extracorporeal circulation.

In 10 patients who required extracorporeal circulation (ECC) during surgery, we studied the damage induced by surgery to the pulmonary surfactant and the effectiveness of ambroxol in preventing changes in the phospholipid pool. There were 5 control patients and 5 patients who were given 1 g/day of ambroxol on the 4 days prior to and the 4 days after surgery. To follow changes in phospholipid concentrations, bronchoalveolar lavage (BAL) was performed before surgery and 24 h and 8 days after ECC.

Ambroxol for the prevention of chronic bronchitis exacerbations: long-term multicenter trial. Protective effect of ambroxol against winter semester exacerbations: a double-blind study versus placebo.

In a 6-month, double-blind multicenter trial conducted over the winter, the effects of daily administration of ambroxol retard (75 mg) were compared with those of placebo in preventing exacerbations and improving symptoms and clinical signs in chronic bronchitis patients. The trial was completed by 110 patients in the ambroxol group and by 104 in the placebo group. Initially, there were no significant differences between the groups.