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Variation in "supraclavicular" lymph node depth is partly determined by treatment position
H T Klages1, F Szafinski, H B Makoski
1Klinikum Duisburg, Wedau Kliniken, Germany.
Summary
The supraclavicular lymph node region depth varies significantly by patient anatomy and arm position, necessitating individualized radiation therapy planning. Standard 3 cm depth prescriptions are inadequate for accurate targeting in lung, breast, and head and neck cancers.
Area of Science:
- Radiation Oncology
- Medical Imaging
- Anatomy
Background:
- The supraclavicular region is a common target in radiation therapy for lung, breast, and head and neck cancers.
- Current treatment protocols often use a standardized 3 cm tissue depth, which may not reflect individual patient anatomy.
Purpose of the Study:
- To determine the actual tissue depth of the supraclavicular lymph node region in patients undergoing radiation therapy planning.
- To assess the impact of patient positioning and body mass on this tissue depth.
Main Methods:
- Computed tomography (CT) scans of 119 patients were analyzed for planning purposes.
- The subclavian blood vessels were used as anatomical landmarks to estimate lymph node region depth.
- Tissue depth measurements were correlated with patient body mass and arm position.
Main Results:
- Mean and median tissue depth were 5 cm (range 2-9 cm), with only 20% of measurements at or less than 3 cm.
- Increased body mass correlated with deeper vessel location.
- Arm position significantly affected depth: arms raised resulted in 55% of measurements at 6 cm or deeper, versus 6% with arms at the sides.
Conclusions:
- Standardized radiation therapy prescriptions for the supraclavicular region are insufficient due to anatomical variability.
- Patient positioning, particularly arm elevation, critically influences target volume location.
- CT-based target volume delineation is recommended for accurate treatment delivery, emphasizing patient immobilization.