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J M Caudrelier

Publications and source records attributed to J M Caudrelier.

5 recordsLinked to original sources
PubMed2005

Clinical use of a commercial Monte Carlo treatment planning system for electron beams.

In 2002 we fully implemented clinically a commercial Monte Carlo based treatment planning system for electron beams. The software, developed by MDS Nordion (presently Nucletron), is based on Kawrakow's VMC++ algorithm. The Monte Carlo module is integrated with our Theraplan Plustrade mark treatment planning system. An extensive commissioning process preceded clinical implementation of this software. Using a single virtual 'machine' for each electron beam energy, we can now calculate very accurately the dose distributions and the number of MU for any arbitrary field shape and SSD. This new treatment planning capability has significantly impacted our clinical practice. Since we are more confident of the actual dose delivered to a patient, we now calculate accurate three-dimensional (3D) dose distributions for a greater variety of techniques and anatomical sites than we have in the past. We use the Monte Carlo module to calculate dose for head and neck, breast, chest wall and abdominal treatments with electron beams applied either solo or in conjunction with photons. In some cases patient treatment decisions have been changed, as compared to how such patients would have been treated in the past. In this paper, we present the planning procedure and some clinical examples.

Algorithms↗
PubMed2002

[In vivo dosimetry and radiation therapy of breast cancer].

INTRODUCTION: Verification of absorbed dose in target volume is a key factor for quality assurance in radiotherapy. In vivo measurements allow evaluation of the variations in dose with time and variations between measured doses and calculated doses by TPS. The aim of this work were to evaluate reproducibility of patient positioning and to compare calculated doses by 2 different TPS. PATIENTS AND METHODS: Twenty patients were divided in 2 groups according to the thickness of their breast (mean SSD = 92.9 cm). In vivo measurement was performed within the first two sessions. RESULTS: Reproducibility of SSD evaluation was made on 12 beams between 2 fractions. With a tolerance margin of 0.5 cm, positioning errors were present in 33% (4/12). The 2 TPS were in agreement in 75% (30/40). CONCLUSION: In vivo dosimetry can be a very interesting tool to assess patients positioning variations and TPS dose calculation.

Breast↗
PubMed2001

[Comparison of conventional and conformational dosimetry in radiotherapy of cerebral neoplasms].

PURPOSE: We prospectively compared a conventional treatment planning (PT2D) and 3-dimensional conformal treatment planning (PT3D) for radiotherapy of cerebral tumours. PATIENTS AND METHODS: Patients treated between 1/10/98 and 1/4/99 by irradiation for cerebral tumours were analysed. For each case, we planned PT2D using conventional orthogonal x-ray films, and afterward, PT3D using CT scan. Gross tumor volume, planning target volume and normal tissue volumes were defined. Dose was prescribed according to report 50 of the International Commission on Radiation Units and Measurements (ICRU). We compared surfaces of sagittal view targets defined on PT2D and PT3D and called them S2D and S3D, respectively. Irradiated volumes by 90% isodoses (VE-90%) and normal tissue volumes irradiated by 20, 50, 90% isodoses were calculated and compared using Student's paired t-test. RESULTS: There was a concordance of 84% of target surfaces defined on PT2D and PT3D. Percentages of target surface under- or-over defined by PT2D were 16 and 13% respectively. VE-90% was decreased by 15% (p = 0.07) with PT3D. Normal brain volume irradiated by 90% isodose was decreased by 27% with PT3D (p = 0.04). CONCLUSION: For radiotherapy of cerebral tumors using only coplanar beams, PT3D leads to a reduction of normal brain tissue irradiated. We recommend PT3D for radiotherapy of cerebral tumors, particularly for low-grade or benign tumors (meningiomas, neuromas, etc.).

Brain Neoplasms↗
PubMedDate not supplied

[Progress in dosage optimization for stereotactic radiosurgery].

Stereotactic radiosurgery is a technique for treatment of intracranial lesions requiring high precision in all steps--from image acquisition to final irradiation. One of most difficult steps is the treatment planning phase, consisting of determination of irradiation parameters sufficient to cover the target volume by avoiding sensitive volumes. A manual and empirical definition can be very long and difficult, especially in the case of complex target volumes situated in sensitive zones. As in conventional radiotherapy, stereotactic radiosurgery has taken advantages from dosimetric optimization. The question is: "What is the configuration of irradiation parameters used in order to obtain the treatment plan by satisfying defined constraints?". The purpose of this article is to summarize optimization methods used in radiosurgery and to describe the technical alternatives proposed for this treatment as well as the possibilities of plan evaluation between different techniques. This purpose will be illustrated by the optimization methodology used in the Center Oscar Lambret of Lille, France for the radiosurgical treatment with linear accelerator.

Algorithms↗