SU-E-T-455: Novel Planning Techniques for Lung SBRT.

Area of Science:

• Radiation Oncology
• Medical Physics

Background:

• Stereotactic Body Radiation Therapy (SBRT) for lung cancer requires precise planning.
• Patient positioning and dose distribution are critical factors in lung SBRT.
• CyberKnife™ (CK) technology presents unique challenges for prone positioning and tracking.

Purpose of the Study:

• To present two novel lung SBRT planning techniques.
• To evaluate a differential dosing strategy for patients with impaired pulmonary function.
• To compare supine versus prone patient setups for treating posterior lung lesions.

Main Methods:

• Utilized CyberKnife™ (G.3) with Multiplan™ (V3.5) and Synchrony™/XSight™ Lung Tracking Systems.
• Implemented a differential dosing technique (54 Gy to PTV, 60 Gy to CTV) when V15Gy exceeded 10% in standard 60 Gy plans.
• Generated and evaluated dosimetric plans for both supine and prone setups for posterior tumors.

Main Results:

• The differential dose technique demonstrated good tumor response, comparable to standard 60 Gy treatments.
• Supine positioning for posterior tumors yielded dosimetrically similar plans to prone setups, with only slightly increased low-dose spillage.
• The differential dose strategy effectively reduced V15Gy, improving plan conformity.

Conclusions:

• The 54 Gy/60 Gy differential dosing strategy achieves tumor response similar to standard 60 Gy lung SBRT.
• Dosimetrically comparable supine plans can be created, potentially eliminating the need for complex prone setups.
• These techniques enhance treatment planning flexibility and patient tolerance in lung SBRT.