Early clinical experience with a total body irradiation technique using field-in-field beams and on-line image guidance.
Phys Imaging Radiat Oncol
; 16: 12-17, 2020 Oct.
Article
em En
| MEDLINE
| ID: mdl-33458337
ABSTRACT
BACKGROUND AND PURPOSE:
Total body irradiation (TBI) is a treatment used in the conditioning of patients prior to hematopoietic stem cell transplantation. We developed an extended-distance TBI technique using a conventional linac with multi-leaf collimator to deliver a homogeneous dose, and spare critical organs. MATERIALS ANDMETHODS:
Patients were treated either in lateral recumbent or in supine position depending on the dose level. A conventional linac was used with the patient midline at 350 cm from the beam source. A series of beams was prepared manually using a 3D treatment planning system (TPS) aiming to improve dose homogeneity, spare the organs at risk and facilitate accurate patient positioning. An optimized dose calculation model for extended-distance treatments was developed using phantom measurements. During treatment, in-vivo dosimetry was performed using electronic dosimeters, and accurate positioning was verified using a mobile megavoltage imager. We analyzed dose volume histogram parameters for 19 patients, and in-vivo measurements for 46 delivered treatment fractions.RESULTS:
Optimization of the dose calculation model for TBI improved dose calculation by 2.1% at the beam axis, and 17% at the field edge. Treatment planning dose objectives and constraints were met for 16 of 19 patients. Results of in-vivo dosimetry were within the set limitations (±10%) with mean deviations of 3.7% posterior of the lungs and 0.6% for the abdomen.CONCLUSIONS:
We developed a TBI treatment technique using a conventional linac and TPS that can reliably be used in the conditioning regimen of patients prior to stem cell transplantation.
Texto completo:
1
Bases de dados:
MEDLINE
Tipo de estudo:
Guideline
Idioma:
En
Revista:
Phys Imaging Radiat Oncol
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Holanda