Concise Matrix Analysis of Point-Based Prostate Targeting for Intensity Modulated Radiation Therapy

Abstract

Intensity Modulated Radiation Therapy (IMRT) has recently emerged as an effective clinical treatment tool to treat various types of cancers by limiting the external beam dose to the surrounding normal tissue. However, the process of limiting external radiation dose to the tissue surrounding the tumor volume is not a trivial task. Several parameters including tumor volume and inhomogeneity, position and shape of the tumor volume, and the geometrical distribution of the radiation beams directly affect the determination of the external radiation dose. In addition, a major variable in effective delivery of the radiation dose is "set-up error" caused by the changes in patient position. Any changes in the position of the patient affect the geometrical location of the tumor volume and, therefore, need to be accommodated in the delivery of radiation beams during the treatment. This work presents a complete matrix representation required to calculate the three-dimensional rigid body homogeneous transformation matrices corresponding to external beam radiotherapy setup error and subsequent corrections in treatment beam parameters. A new concise orthogonal rotation solution is presented for use with clinical noisy data. Monte Carlo simulations prove the new matrix results are consistently better than the standard inverse solution. The required corrections in beam table, gantry, and collimator angles as function of the planned beam gantry angle are derived. For transformations that include a rotation on the sagittal plane, the required offsets to beam parameters are complex functions of the planned gantry angle but are clearly documented graphically for clinical use. A case study is presented with an error analysis that supports the use of the presented method in a clinical environment. Clinical implementation and evaluation of the presented method with patient data is also included in the paper.

3D and 4D Medical Image Registration Combined with Image Segmentation and Visualization

“…Rigid image registration provides the best current solution to these clinical applications. Ultimately, deformable image registration will improve the registration accuracy substantially (Lu et al, 2006b), permitting highly conformal 3D/4D radiotherapy (Barbiere, Hanley, Song et al, 2007;Mackie, Kapatoes, Ruchala et al, 2003).…”

Comparison of two treatment approaches for prostate cancer: intensity‐modulated radiation therapy combined with seed‐implant brachytherapy or seed‐implant brachytherapy alone

“…Currently, radical prostatectomy, androgen deprivation therapy, external-beam radiotherapy (EBRT), and transperineal interstitial permanent 125 I seed implantation are the major treatment options for localized prostate cancer. (2,3) Although prostate brachytherapy has had a history of a Corresponding author: Yulin Song, Department of Medical Physics, Memorial Sloan-Kettering Cancer Center at Phelps, Sleepy Hollow, NY, U.S.A.; phone: 914-333-8676; fax: 914-887-8506; email: songy@mskcc.org moderate success, new technology-particularly the introduction of ultrasound-guided realtime brachytherapy-has led to a revival of interest in this treatment modality and a popularity that continues to grow.…”

“…In particular, implanted gold seed-markers guided by an onboard kilovoltage X-ray device offer a reliable approach to tracking prostate motion. (2) The possibility for dose escalation, the optimized dose distribution, and a favorable treatment outcome have shifted the treatment of choice toward IMRT. (3,(5)(6)(7)(8) Prostate cancer is now the most common tumor site treated with IMRT.…”