This study evaluates 3 different imaging modalities—ultrasound (US), stereoscopic X-ray imaging of implanted markers (Visicoils) (X-ray), and kV cone-beam computed tomography (CBCT)—to assess interfraction and intrafraction localization error during conformal radiation therapy of prostate cancer.
The study population consisted of 186 consecutive prostate cancer patients treated with an image-guided radiotherapy (IGRT) hypofractionated protocol using 3 techniques: 32 with X-ray, 30 with CBCT, and 124 with US. Treatment dose of 70.2 Gy was delivered in 26 fractions with a conformal dynamic arcs technique. Interfraction prostate localization errors were determined for the 3 techniques. Moreover, interfraction and intrafraction prostate motion in terms of translations and rotations, as well as residual errors, were determined with X-ray.
The systematic and random components of the prostate localization errors were as follows: (1) with X-ray 3.0 ± 3.4, 2.3 ± 2.7, 1.8 ± 2.3 mm in anterior-posterior (AP), superior-inferior (SI), and left-right (LR) directions and 1.8° ± 1.2°, 2.3° ± 1.5°, 2.7° ± 3.1°, for the yaw, roll, and pitch rotations; (2) with CBCT 3.5 ± 4.2, 3.3 ± 3.3, 2.5 ± 3.1 mm in AP, SI, and LR directions; (3) with US 3.7 ± 4.7, 3.4 ± 4.3, 2.3 ± 3.5 mm in AP, SI, and LR directions. Residual errors with X-ray were less than 1 mm in all directions. Intrafraction prostate motion of less than 0.5 mm in LR and of the order of 1 mm in AP and SI directions was found. This led to a significant reduction of the margins, potentially important for dose escalation studies.
Daily on-line IGRT with stereoscopic X-ray imaging allowed a consistent PTV margin reduction considering residual interfraction prostate localization error and intrafraction motion. X-ray offers the best compromise among accuracy, reliability, dose to the patient, and time investment for daily IGRT treatment of prostate.
Tumori 2015; 101(3): 273 - 280
Article Type: ORIGINAL RESEARCH ARTICLE
AuthorsCristina Garibaldi, Barbara Alicja Jereczek-Fossa, Dario Zerini, Raffaella Cambria, Annamaria Ferrari, Flavia Serafini, Federica Cattani, Barbara Tagaste, Cristiana Fodor, Rosa Luraschi, Roberto Orecchia
- • Accepted on 14/01/2015
- • Available online on 22/04/2015
- • Published in print on 25/06/2015
This article is available as full text PDF.
- Garibaldi, Cristina [PubMed] [Google Scholar] 1, * Corresponding Author (firstname.lastname@example.org)
- Jereczek-Fossa, Barbara Alicja [PubMed] [Google Scholar] 2, 3
- Zerini, Dario [PubMed] [Google Scholar] 2
- Cambria, Raffaella [PubMed] [Google Scholar] 1
- Ferrari, Annamaria [PubMed] [Google Scholar] 2
- Serafini, Flavia [PubMed] [Google Scholar] 4
- Cattani, Federica [PubMed] [Google Scholar] 1
- Tagaste, Barbara [PubMed] [Google Scholar] 5
- Fodor, Cristiana [PubMed] [Google Scholar] 2
- Luraschi, Rosa [PubMed] [Google Scholar] 1
- Orecchia, Roberto [PubMed] [Google Scholar] 2, 3
Medical Physics Unit, European Institute of Oncology, Milan - Italy
Department of Radiation Oncology, European Institute of Oncology, Milan - Italy
Department of Health Sciences, Università degli Studi di Milano, Milan - Italy
Department of Radiation Oncology, Sant’Anna Hospital, Como - Italy
Bioengineering Unit, Centro Nazionale di Adroterapia Oncologica, Pavia - Italy