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Updated: May 2, 2026

Radiation Planning Assistant - A Streamlined, Fully Automated Radiotherapy Treatment Planning System
Published on: April 11, 2018
'Line' Constraints Optimization for Improved Dose Distribution in Locally Recurrent Nasopharyngeal Carcinoma Using
Xiaoli Yu1,2, Yixuan Wang1, Mingli Wang1
1State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center of Cancer Medicine, Department of Radiation Oncology, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China.
Abstract:
IntroductionTo investigate the efficacy of a knowledge-based planning (KBP) model in optimizing dose distribution, and identify the inter-institutional variation in radiotherapy of recurrent nasopharyngeal carcinoma (rNPC).MethodsA total of 70 rNPC patients treated with intensity-modulated radiotherapy (IMRT) were recruited to build a KBP model. Following model refinement, 36 patients were retrospectively enrolled for dosimetric comparison between manually optimized and KBP-generated plans. Ten experienced physicists from six different institutions were engaged to independently design manual plan for a representative case, to assess inter-institutional variations, and differences between KBP and manual plans.ResultsThe refined KBP model provided significant reduced dose in brainstem D1cc (the dose received by the "hottest"1 cm3 volume, 41.14 ± 8.51 Gy vs 38.48 ± 8.60 Gy, P < 0.001) and spinal cord D1cc (17.48 ± 9.38Gy vs 12.23 ± 6.56Gy, P < 0.001). In addition, The mean dose (Dmean) of brainstem, spinal cord, mandible, parotid, temporomandibular joint and inner ear were statistically decreased (P < 0.05). In validation cohort, KBP model eliminated the hotspot (0.57 ± 0.01% vs 0.00 ± 0.00%, P < 0.001), improved target homogeneity (HI: 0.06 ± 0.00 vs 0.08 ± 0.00, P < 0.001), and performed superior to the manual plans in sparing organs. While all institutions achieved comparable target coverage, manual plans exhibited substantial variability in sparing brainstem. KBP implementation reduced inter-institutional dose disparities for brainstem (46.30 ± 10.08 Gy vs 41.80 ± 5.80 Gy, P = 0.041) and spinal cord (26.08 ± 7.06 Gy vs 18.19 ± 1.98 Gy, P = 0.002). Additionally, planning efficiency increased by 48.7% (39 vs 76 min).ConclusionsThis KBP framework optimized rNPC reirradiation from three dimensions: 1) Enhanced OARs' protection; 2) Improved target homogeneity; 3) Improved the multi-institutional consistency and efficiency of planning. These advancements established a clinically actionable paradigm for precision reirradiation.
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