Abstract
Treating an inoperable bulky tumor is a challenge for modern medicine. Radiation therapy or chemotherapy is usually used as an alternative to surgery against this type of tumor. However, conventional radiation therapy cannot balance tumor control and the protection of organs at risk (OARs). Recent studies show that spatially fractionated radiation therapy (SFRT) is recommended for patients with an inoperable bulky tumor or advance malignant disease. SFRT promises both tumor control and reduced radiation damage to OARs.
In recent years, the rise of particle therapy predicts an increasing implementation of SFRT. Compared to photon radiation therapy, particle therapy benefits from its inherent physical property, Bragg peak, bringing in increased treatment delivery precision and lowing dose to normal tissue. LATTICE therapy is the most advanced type of SFRT, leading SFRT from a 2D technique to a 3D application. LATTICE particle therapy (LPT) is a combination of modern SFRT technique, LATTICE, with particle therapy, and it is anticipated to be more robust than common GRID therapy. Using the most advanced proton treatment delivery method, pencil beam scanning, the efficacy of LPT can be boosted.
In this dissertation, an innovative automated LPT planning system for bulky tumors has been developed. Two major tasks have been completed. The first one is tumor modeling and 3D vertices lattice generation. The second one is the LPT treatment plan simulation and analysis. The results of those two tasks demonstrate that the developed planning system satisfy proposed objectives. The vertices lattice generated from this planning system is able to meet the requirement of LPT. The geometric distribution of vertices lattice satisfies all the initial conditions.
Both LPT and LATTICE photon radiation therapy (LRT) plans show a high PVDR of the tumor and its surrounding tissue. The DVH analysis of LRT and LPT presents a great radiation toxicity reduction to surrounding tissue. Comparing planning simulation results between LPT and LRT proved the advantages of LPT. LPT promises higher PVDR and lowers radiation toxicity.
Although some modules of the developed planning system are still in need of further optimization, it has the potential to be implemented to clinical particle therapy facilities. Future works include the integration of simulation module, development of manual beam tuning, and the vertices lattice optimization based on the simulated plan.