Abstract：
:Patient motion is an important factor affecting the quality of external beam radiotherapy in breast patients. We analyse the motion of a dense set of surface points on breast patients throughout their treatment schedule to assess the magnitude and stability of motion, in particular, with respect to breast volume. We use an optical sensor to measure the surface motion of 13 breast cancer patients. Patients were divided into two cohorts dependent upon breast volume. Measurements were made during radiotherapy treatment beam delivery for an average of 12 fractions per patient (total 158 datasets). The motion of each surface point is parameterized in terms of its period, amplitude and relative phase. Inter-comparison of the motion parameters across treatment schedules and between patients is made through the creation of corresponding regions on the breast surfaces. The motion period is spatially uniform and is similar in both patient groups (mean 4 s), with the small volume cohort exhibiting greater inter-fraction period variability. The mean motion amplitude is also similar in both groups with a range between 2 mm and 4 mm and an inter-fraction variability generally less than 1 mm. There is a phase lag of up to 0.4 s across the breast, led by the sternum. Breast patient motion is reasonably stable between and during treatment fractions, with the large volume cohort exhibiting greater repeatability than the small volume one.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Price GJ,Sharrock PJ,Marchant TE,Parkhurst JM,Burton D,Jain P,Price P,Moore CJdoi
10.1088/0031-9155/54/21/005subject
Has Abstractpub_date
2009-11-07 00:00:00pages
6515-33issue
21eissn
0031-9155issn
1361-6560pii
S0031-9155(09)23970-4journal_volume
54pub_type
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