Incremental learning with selective memory (ILSM): Towards fast prostate localization for image guided radiotherapy

Yaozong Gao, Yiqiang Zhan, Dinggang Shen

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Image-guided radiotherapy (IGRT) requires fast and accurate localization of the prostate in 3-D treatment-guided radiotherapy, which is challenging due to low tissue contrast and large anatomical variation across patients. On the other hand, the IGRT workflow involves collecting a series of computed tomography (CT) images from the same patient under treatment. These images contain valuable patient-specific information yet are often neglected by previous works. In this paper, we propose a novel learning framework, namely incremental learning with selective memory (ILSM), to effectively learn the patient-specific appearance characteristics from these patient-specific images. Specifically, starting with a population-based discriminative appearance model, ILSM aims to 'personalize' the model to fit patient-specific appearance characteristics. The model is personalized with two steps: backward pruning that discards obsolete population-based knowledge and forward learning that incorporates patient-specific characteristics. By effectively combining the patient-specific characteristics with the general population statistics, the incrementally learned appearance model can localize the prostate of a specific patient much more accurately. This work has three contributions: 1) the proposed incremental learning framework can capture patient-specific characteristics more effectively, compared to traditional learning schemes, such as pure patient-specific learning, population-based learning, and mixture learning with patient-specific and population data; 2) this learning framework does not have any parametric model assumption, hence, allowing the adoption of any discriminative classifier; and 3) using ILSM, we can localize the prostate in treatment CTs accurately (DSC ∼0.89 ) and fast (∼4 s), which satisfies the real-world clinical requirements of IGRT.

Original languageEnglish
Article number6668908
Pages (from-to)518-534
Number of pages17
JournalIEEE Transactions on Medical Imaging
Issue number2
Publication statusPublished - 2014 Feb


  • Anatomy detection
  • Image-guided radiotherapy (IGRT)
  • Incremental learning
  • Machine learning
  • Prostate segmentation

ASJC Scopus subject areas

  • Software
  • Radiological and Ultrasound Technology
  • Computer Science Applications
  • Electrical and Electronic Engineering


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