Laboratório de Instrumentação e Física Experimental de Partículas




Orthogonal Ray Imaging for Radiotherapy Improvement

// Instruments and methods for biomedical applications

Instrumentos e Métodos para Aplicações Biomédicas

This is LIP’s core project in instrumentation for radiation therapy, and is developed in partnership with one Portuguese Oncology Institute, the Hospital of the University of Coimbra, and several medical research centers. The aim is to improve radiotherapy by optimizing the treatment in near real time, so that the irradiation can better accommodate the tumor and spare surrounding healthy tissue. To do this, we use  X- or gamma-rays emitted orthogonally to the treatment beam.

The OR Imaging technique may be divided into two main branches: OrthoCT (orthogonal computer tomography) for monitoring radiotherapy (high-energy x-rays); and O-PGI (orthogonal prompt-gamma imaging) for monitoring proton therapy. The LIP team pursues the two lines of research.

As an example of recent progress, the results of the analysis of a cavity irradiated inside an acrylic, cylindrical phantom using a small-scale OrthoCT system recently proved for the first time that it is possible to obtain images of the interior of an object without rotating the X-ray source. As for O-PGI studies, a multi-leaf collimator has been fully optimized using Geant4 simulation and our own reconstruction routines. The optimization was based on the analysis of images obtained after the irradiation of the NCAT phantom (cardiac-torso anthropomorphic phantom) with realistic, therapeutic proton beams. The most difficult of the three scenarios considered was the irradiation of the pituitary gland. Here, edematous tissue may account for a Bragg peak shift as small as 2 mm, which the O-PGI system was able to discriminate clearly. Work is now ongoing in order to devise an optimum crystal granularity and positioning so that the 2-mm resolving power is maintained with a realistic O-PGI system. Organ motion (e.g. lung) and vertebra motion in pediatric total body irradiation will also be analyzed via Monte Carlo simulations.

// Research Area
Física Experimental de Partículas com aceleradores
Group Leader:  
Paulo Crespo



  • Distal edge determination precision for a multi-slat prompt-gamma camera: A comprehensive simulation and optimization of the detection system
  • Author(s):  A. Morozov, H. Simoes, P. Crespo
  • Submission:  2021-04-01, Acceptance:  2021-04-01, Publication:  2021-04-01
  • Reference:  Phys. Medica 84 (2021) 85-100  

  • Rotation-free scattered-radiation imaging with a radiotherapy X-ray linac
  • Author(s):  H. Simões, R. Ferreira Marques, P.J.B.M. Rachinhas, A. Wagner, P. Crespo
  • Publication:  2018-11-10
  • Reference:  2018 IEEE Nucl. Sci. Symp. & Med. Imag. Conf. (NSS/MIC), Nov. 10–17, 2018, Sydney, Australia  

  • Simulation of proton range monitoring in an anthropomorphic phantom using multi-slat collimators and time-of-flight detection of prompt-gamma quanta
  • Author(s):  Patricia Cambraia Lopes, Paulo Crespo, Hugo Simoes, Rui Ferreira Marques, Katia Parodi, Dennis R. Schaart
  • Submission:  2018-10-01, Acceptance:  2018-10-01, Publication:  2018-10-01
  • Reference:  Phys. Medica 54 (2018) 1-14  

  • Optimization of the Signal-to-Background Ratio in Prompt Gamma Imaging Using Energy and Shifting Time-of-Flight Discrimination: Experiments With a Scanning Parallel-Slit Collimator
  • Author(s):  Patricia Cambraia Lopes, Paulo Crespo, Jan Huizenga, Dennis R. Schaart
  • Submission:  2018-09-01, Acceptance:  2018-09-01, Publication:  2018-09-01
  • Reference:  IEEE Trans. Radiat. Plasma Med. Sci. 2 (2018) 510-519  

View all the group publications

  • ANTS
  •  Anger camera-type detector simulation and experimental data processing tools.
  •     website

View all the group publications

Andrey Morozov

Duarte Guerreiro

Hugo Simões

João Gentil

Jorge Sampaio

José Patuleia Venâncio

Márcia Quaresma
External Collaborator

Patrícia Gonçalves

Paulo Crespo

Pedro Assis

  • TPPT - Time of flight PET for Proton Therapy
  • Code:  LISBOA-01-0247-FEDER-045904
  • Dates :  2020-01-01 :  2022-12-31
  • Funding:  222,004.00 €  

  • Optimization, construction and first in-beam tests of range monitoring and quality assurance systems for the improvement of proton therapy
  • Code:  CERN/FIS-TEC/0017/2021
  • Dates :  2022-01-01 :  2023-12-31
  • Funding:  90,000.00 €  

View all the group publications




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Laboratório de Instrumentação e Física Experimental de Partículas   LIP.PT

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