Daily Alignment Results of In-Room Computed Tomography-Guided Stereotactic Body Radiation Therapy for Lung Cancer

Journal Article · Tue Feb 01 04:00:00 EST 2011 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2009.11.009· OSTI ID:21491587

Ikushima, Hitoshi; Balter, Peter ^[1]; Komaki, Ritsuko ^[2]; Hunjun, Sandeep ^[1]; Bucci, M Kara; Zhongxing, Liao; McAleer, Mary F ^[2]; Yu, Zhiqian H; Zhang, Yongbin ^[1]; Chang, Joe Y ^[2]; Dong, Lei ^[1]

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1. Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)
2. Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

Purpose: To determine the extent of interfractional setup errors and day-to-day organ motion errors by assessing daily bone alignment results and changes in soft tissue tumor position during hypofractionated, in-room computed tomography (CT)-guided stereotactic body radiation therapy (SBRT) of lung cancer. Methods and Materials: Daily alignment results during SBRT were analyzed for 117 tumors in 112 patients. Patients received 40-50 Gy of SBRT in four to five fractions using an integrated CT-LINAC system. The free-breathing CT scans acquired during treatment setup were retrospectively realigned to match with each of the bony references and the gross tumor volume (GTV) defined on the reference CT by rigid-body registration, and the daily deviations were calculated. Results: The mean magnitude ({+-} SD) three-dimensional shift from the initial skin marks to the final bone-aligned positions was 9.4 {+-} 5.7 mm. The mean daily GTV deviation from the bone position was 0.1 {+-} 3.8 mm in the anterior-posterior direction, -0.01 {+-} 4.2 mm in the superior-inferior direction, and 0.2 {+-} 2.5 mm in the lateral direction. A clinically noteworthy trend (net change >5 mm in any direction) in GTV position relative to the bone was observed in 23 cases (20%). Conclusions: Soft tissue target position can change significantly beyond the motion envelope defined in the original internal target volume in four-dimensional CT-based treatment planning for SBRT of lung cancer. Additional margin should be considered for adequate coverage of interfractional changes.

• OSTI ID: 21491587
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 2 Vol. 79; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ALIGNMENT
BODY
CAT SCANNING
COMPUTERIZED TOMOGRAPHY
CT-GUIDED RADIOTHERAPY
DIAGNOSTIC TECHNIQUES
DISEASES
ERRORS
LUNGS
MEDICINE
MOTION
NEOPLASMS
NUCLEAR MEDICINE
ORGANS
RADIOLOGY
RADIOTHERAPY
RESPIRATION
RESPIRATORY SYSTEM
SKELETON
THERAPY
TOMOGRAPHY