Adaptive Radiation Therapy for Prostate Cancer

Abstract

Adaptive radiotherapy has been introduced to manage an individual's treatment by, including patient-specific treatment variation identified and quantified during the course of radiotherapy in the treatment planning and delivering optimization. Early studies have demonstrated that this technique could significantly improve the therapeutic ratio by safely reducing the large target margin that has to be used in conventional radiotherapy for prostate cancer treatment. Clinical application of off-line image-guided adaptive radiotherapy for prostate cancer has demonstrated encouraging clinical outcome. Long-term clinical follow-up has shown significant improvement in terms of tumor control and low toxicity profile, emphasizing the beneficial effect of image-guidance and adaptive treatment. Continuous development in adaptive radiotherapy has made possible additional increases in target dose by further reducing target margin when using online image-guided adaptive intensity-modulated radiation therapy. However, clinical implementation of new techniques should be explored cautiously and should include a comprehensive management strategy to address uncertainties in target definition and delineation in the preclinical implementation studies.

Investigation into image quality and dose for different patient geometries with multiple cone‐beam CT systems

“…However, there is considerable interest in the use of CBCT images for the purposes of adaptive radiation therapy (ART). Studies have looked at the process of ART for several disease sites: prostate, [9][10][11] head and neck, [12][13][14] lung, 15,16 and so on. For each site, the use of CBCT images involves some advantages and difficulties.…”

Evaluation of mechanical and geometric accuracy of two different image guidance systems in radiotherapy

“…A good imaging system needs to be safe, mechanically and geometrically accurate providing good image quality with reasonable imaging dose. With the image guidance system capable of performing CBCT, it can be used for adaptive radiotherapy 9,10 to make decisions to change the treatment plan in the course of treatment to account for changes in patient anatomy due to tumour shrinkage or weight loss. With suitable CT to material density conversion curve, the CBCT can also be used for dose calculation in treatment planning.…”

Evaluation of Online/Offline Image Guidance/Adaptation Approaches for Prostate Cancer Radiation Therapy

“…In the current standard of clinical practice, daily online IGRT is used to correct interfaction translational target displacement. However, to account for rotation, nonrigid anatomic variation of target (prostate or prostate þ seminal vesicles [SV]) and critical organs during the treatment course, specifically during treatment delivery, adaptive planning modification could be applied using treatment volumetric image feedback (1,2). Different imaging and modification techniques have been proposed for adaptive radiation therapy of prostate cancer.…”