Program Information

To Evaluate Planning Quality of SBRT with Multiple Lung Metastases Generated with Pinnacle and Tomotherapy

Y Chen

Y Chen¹*, Y Zhang² , Y Zhang³ , K Doxsee⁴ , C Yang⁵ , (1) Monmouth Medical Center, Tinton Falls, NJ, (2) Cancer Hospital Chinese Academy of Medical Sciences, Chaoyang District, Beijing, (3) Emory University, Atlanta, GA, (4) Monmouth Medical Center, Long Branch, NJ, (5) Monmouth Medical Center, Long Branch, NJ

Presentations

SU-E-T-331 Sunday 3:00PM - 6:00PM Room: Exhibit Hall

Purpose: To evaluate planning quality of SBRT with multiple lung metastases generated with Pinnacle and Tomotherapy

Methods: Nine randomly selected patients diagnosed with non small-cell lung cancer with multiple lesions were planned with Pinnacle (version 9.2) and Tomotherapy (version 4.2). Coplanar and non_coplanar plans were generated on Pinnacle. A total dose of 60 Gy was prescribed to 95% of PTV in 3 fractions. Single isocenter was used. Nine static beams were used for Pinnacle plans. Planning outcomes such as minimum and mean dose, V₉₅, D₉₅ (95% of target volume receives prescription dose), D₅, and D₁ to PTV, maximum dose to heart, esophagus, cord, trachea, brachial plexus, rib, chest wall, and liver, mean dose to liver, total lung, right and left lung, volume of chest wall receives 30 Gy, volume of lungs receives 5 Gy and 20Gy, conformity index (CI = PIV / PTV) and heterogeneity index (HI = D₅ / D₉₅) were reported for evaluation.

Results: The mean volume of PTV was 37.77 ± 23.4 cm3. D₉₅ of PTV with Tomo, coplanar, non_coplanar was 60.2 ± 0.3 Gy, 58.6 ± 1.2 Gy, and 59.1 ± 0.7 Gy, respectively. Mean dose to PTV was lower for Tomo (p < 0.0001), so were D₅ (p < 0.0001) and D₁ (p = 0.001). CI was better with Tomo (p < 0.0001), so was HI (p < 0.0001). Maximum dose to other critical organs were also lower exclusively with Tomo plans. Treatment time was recorded only for Tomo plans (73 .0 ± 20.6 min).

Conclusion: With 51 beam angles, Tomo plans could generally achieve better tumor coverage while sparing more critical structures for multiple lung lesions study. Non_coplanar also has better tumor coverage with lower dose to critical organs such as lungs, liver, chest wall and cord compare to coplanar plans.


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