Knowledge-based IMRT treatment planning for prostate cancer.

PURPOSE: To demonstrate the feasibility of using a knowledge base of prior treatment plans to generate new prostate intensity modulated radiation therapy (IMRT) plans. Each new case would be matched against others in the knowledge base. Once the best match is identified, that clinically approved plan is used to generate the new plan. METHODS: A database of 100 prostate IMRT treatment plans was assembled into an information-theoretic system. An algorithm based on mutual information was implemented to identify similar patient cases by matching 2D beam's eye view projections of contours. Ten randomly selected query cases were each matched with the most similar case from the database of prior clinically approved plans. Treatment parameters from the matched case were used to develop new treatment plans. A comparison of the differences in the dose-volume histograms between the new and the original treatment plans were analyzed. RESULTS: On average, the new knowledge-based plan is capable of achieving very comparable planning target volume coverage as the original plan, to within 2% as evaluated for D98, D95, and D1. Similarly, the dose to the rectum and dose to the bladder are also comparable to the original plan. For the rectum, the mean and standard deviation of the dose percentage differences for D20, D30, and D50 are 1.8% +/- 8.5%, -2.5% +/- 13.9%, and -13.9% +/- 23.6%, respectively. For the bladder, the mean and standard deviation of the dose percentage differences for D20, D30, and D50 are -5.9% +/- 10.8%, -12.2% +/- 14.6%, and -24.9% +/- 21.2%, respectively. A negative percentage difference indicates that the new plan has greater dose sparing as compared to the original plan. CONCLUSIONS: The authors demonstrate a knowledge-based approach of using prior clinically approved treatment plans to generate clinically acceptable treatment plans of high quality. This semiautomated approach has the potential to improve the efficiency of the treatment planning process while ensuring that high quality plans are developed.

Through the Lenses of Q’eqchi Maya: (Re)Framing the Story of Development in a Guatemalan Indigenous Community Through Participant-Created Photographs

The question of evaluations of development projects has been widely debated within the field of international development, with scholars and development practitioners calling for increased community-driven evaluations. However, there has been a paucity of research in community-led project evaluations, and a largely absent investigation utilizing visual anthropology/sociology methodologies. This paper seeks to shift this power by giving voice to the intended beneficiaries of an eco-tourism project in a rural indigenous Guatemala village. Through photographs taken by community members and corresponding interviews, this paper shows the way in which community members have and continue to reframe the idea of development in their village. Specifically, my analysis reveals how residents see changing forms of access, how they reframe ideas of beauty and modernization, and how they reframe their relationship to the land through Western conservation and private property ideals. This research thus provides an alternative narrative to the Western NGO’s evaluations and knowledge production, especially in respect to development and indigenous knowledge. By showing how community members are reframing the story of development, this paper demonstrates the usefulness of using participatory documentary photography in community-led evaluations, and helps balance the playing field by providing a much-needed alternative narrative of project evaluation.