Quantifying Interfraction and Intrafraction Tumor Motion in Lung Stereotactic Body Radiotherapy Using Respiration-Correlated Cone Beam Computed Tomography

Journal Article · Sun Nov 01 04:00:00 EST 2009 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2008.11.066· OSTI ID:21362202

Bissonnette, Jean-Pierre ^[1]; Franks, Kevin N ^[1]; Purdie, Thomas G; Moseley, Douglas J ^[1]; Sonke, Jan-Jakob ^[2]; Jaffray, David A; Dawson, Laura A; Bezjak, Andrea ^[1]

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1. Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, Ontario (Canada)
2. Department of Radiation Oncology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

Purpose: Stereotactic body radiation therapy (SBRT) is an effective treatment for medically inoperable Stage I non-small-cell lung cancer. However, changes in the patient's breathing patterns during the course of SBRT may result in a geographic miss or an overexposure of healthy tissues to radiation. However, the precise extent of these changes in breathing pattern is not well known. We evaluated the inter- and intrafractional changes in tumor motion amplitude (DELTAM) over an SBRT course. Methods and Materials: Eighteen patients received image-guided SBRT delivered in three fractions; this therapy was done with abdominal compression in four patients. For each fraction, cone beam computed tomography (CBCT) was performed for tumor localization (+- 3-mm tolerance) and then repeated to confirm geometric accuracy. Additional CBCT images were acquired at the midpoint and end of each SBRT fraction. Respiration-correlated CBCT (rcCBCT) reconstructions allowed retrospective assessment of inter- and intrafractional DELTAM by a comparison of tumor displacements in all four-dimensional CT and rcCBCT scans. The DELTAM was measured in mediolateral, superior-inferior, and anterior-posterior directions. Results: A total of 201 rcCBCT images were analyzed. The mean time from localization of the tumor to the end-fraction CBCT was 35 +- 7 min. Compared with the motion recorded on four-dimensional CT, the mean DELTAM was 0.4, 1.0, and 0.4 mm, respectively, in the mediolateral, superior-inferior, and anterior-posterior directions. On treatment, the observed DELTAM was, on average, <1 mm; no DELTAM was statistically different with respect to the initial rcCBCT. However, patients in whom abdominal compression was used showed a statistically significant difference (p < 0.05) in the variance of DELTAM with respect to the initial rcCBCT in the superior-inferior direction. Conclusions: The inter- and intrafractional DELTAM that occur during a course of lung SBRT are small. However, abdominal compression causes larger variations in the time spent on the treatment couch and in the inter- and intrafractional DELTAM values.

• OSTI ID: 21362202
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 75; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BODY
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
DISEASES
LUNGS
MEDICINE
NEOPLASMS
NUCLEAR MEDICINE
ORGANS
RADIOLOGY
RADIOTHERAPY
RESPIRATION
RESPIRATORY SYSTEM
THERAPY
TOMOGRAPHY