Rules of parotid gland dose variations and shift during intensity modulated radiation therapy for nasopharyngeal carcinoma

Wang, Wei; Yang, Haihua; Mi, Yucheng; Hu, Wei; Ding, Wei; Xie, Youyou; Cai, Yun; Chen, Xiaofeng

doi:10.1186/s13014-014-0307-2

Cited by 8 publications

(10 citation statements)

References 18 publications

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“…Radiation injury of the parotid gland can affect the secretory function of the parotid glands, cause symptoms such as dry mouth, and is the main reason that result in quality of life decreasing after radiotherapy for nasopharyngeal carcinoma. Therefore, it is particularly important to protect the parotid gland [13]. HT may further reduce the exposure dose of parotid glands.…”

Section: Discussionmentioning

confidence: 99%

Short-term efficacy comparison between helical tomotherapy and intensity-modulated radiotherapy in patients with locally advanced nasopharyngeal carcinoma

Cui

Liu

Sun³

et al. 2020

Preprint

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Background: To evaluate short-term safety and efficacy of helical tomotherapy (HT) versus intensity-modulated radiotherapy (IMRT) in patients with nasopharyngeal carcinoma (NPC).Methods: Retrospective analysis of locally advanced nasopharyngeal carcinoma treated with radiotherapy and concurrent platinum based neoadjuvant chemotherapy (cisplatin 80 mg/m2 every 3 weeks for 1 cycle) in our hospital from February 2017 to October 2019, including 70 patients in HT group and 70 in IMRT group. The target area of the tumor was delineated by magnetic resonance (MRI) imaging. The prescription doses delivered to the gross tumor volume (pGTVnx) and positive lymph nodes (pGTVnd), the high risk planning target volume (PTV1), and the low risk planning target volume (PTV2), were 69.96 Gy, 66-70 Gy, 60 Gy and 50-54 Gy, in 33 fractions, respectively. Acute reactions were evaluated according to the RTOG/EORTC criteria, whereas the therapeutic efficacy was assessed according to RECTST version 1.1 criteria in a 3-months period.Results: The CI of PGTVnx, PGTVnd, PTV1 and PTV2, and HI of PGTVnx, PTV1 and PTV2 in HT group was significantly better than those in IMRT group. The OAR Dmax and Dmean in HT group were better than those in IMRT group with a significant difference (all p <0.05). Patients in the HT group were significantly better than those in the IMRT group in the protection of acute parotid gland injury and hearing damage (p <0.05), but not other acute adverse reaction. No significant difference was found on the short-term efficacy illustrated by ORR between HT group and IMRT group (x2 = 0.119; p = 0.730).Conclusions: Compared with IMRT, HT has better radiophysical-related dosimetric advantages in radiotherapy for locally advanced nasopharyngeal carcinoma. Despite similar on short-term effects, HT has lower incidence of adverse reactions than IMRT.

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Section: Discussionmentioning

confidence: 99%

Short-term efficacy comparison between helical tomotherapy and intensity-modulated radiotherapy in patients with locally advanced nasopharyngeal carcinoma

Cui

Liu

Sun³

et al. 2020

Preprint

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“…around high-dose regions), knowledge about organ deformability or shrinkage (e.g. of parotid glands [ 12 ]) contribute to the IGRT correction of an experienced radiation therapist. In contrast, the rigid image registration does not ’know’ which of the structures should be aligned best.…”

Section: Discussionmentioning

confidence: 99%

Analyzing human decisions in IGRT of head-and-neck cancer patients to teach image registration algorithms what experts know

et al. 2017

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BackgroundIn IGRT of deformable head-and-neck anatomy, patient setup corrections are derived by rigid registration methods. In practice, experienced radiation therapists often correct the resulting vectors, thus indicating a different prioritization of alignment of local structures. Purpose of this study is to transfer the knowledge experts apply when correcting the automatically generated result (pre-match) to automated registration.MethodsDatasets of 25 head-and-neck-cancer patients with daily CBCTs and corresponding approved setup correction vectors were analyzed. Local similarity measures were evaluated to identify the criteria for human corrections with regard to alignment quality, analogous to the radiomics approach. Clustering of similarity improvement patterns is applied to reveal priorities in the alignment quality.ResultsThe radiation therapists prioritized to align the spinal cord closest to the high-dose area. Both target volumes followed with second and third highest priority. The bony pre-match influenced the human correction along the crania-caudal axis. Based on the extracted priorities, a new rigid registration procedure is constructed which is capable of reproducing the corrections of experts.ConclusionsThe proposed approach extracts knowledge of experts performing IGRT corrections to enable new rigid registration methods that are capable of mimicking human decisions. In the future, the deduction of knowledge-based corrections for different cohorts can be established automating such supervised learning approaches.

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“…In addition, the prediction model of clinical outcome and radiation injury based on modern technology will become more general and stable. At present, the accurate delineation of target volumes and OAR is the first step to evaluating radiation dose . However, currently, it is no longer difficult to determine the target volume for NPC radiation by multimodality imaging technology, and the contouring of OAR is continuously progressing .…”

Section: Discussionmentioning

confidence: 99%

Finding of dose evaluation for organs at risk in intensity‐modulated radiation therapy for nasopharyngeal carcinoma using magnetic resonance imaging

Gong

Kong

Wang

et al. 2017

Precision Radiation Oncology

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A critical step in predicting and avoiding radiation injury of organs at risk in radiation therapy of nasopharyngeal carcinoma is to carry out an accurate dose evaluation in planning design. In the present study, we investigated the dose evaluation feature of organs at risk on magnetic resonance imaging (MRI) images in intensity-modulated radiation therapy of nasopharyngeal carcinoma compared with computed tomography (CT) images. A total of 35 nasopharyngeal carcinoma patients were selected for this trial. CT simulation with non-contrast and contrast-enhanced scan, and MRI simulation with non-contrast and contrast-enhanced T1, T2, and diffusion weighted imaging were obtained sequentially. The organs at risk were contoured on the CT and MRI images after rigid registration, respectively. Nine-beam intensity-modulated radiation therapy plans with equal division angles were designed for every patient, and the prescription dose for the tumor target was set as 72 Gy (2.4Gy/fraction). The boundary display, volume, and dosimetric indices of each organ were compared between MRI and CT images. We found that MRI showed clearer boundary of the brainstem, spinal cord, deep lobe of the parotid gland, and the optical nerve in the canal compared with CT. MRI images increased the volume of the lens and optic nerve, while slightly reducing the volume of eye; the maximum dose of the lens, and the mean dose of the eyes and optic nerve increased to different extents, though no statistical differences were found. The left and right parotid gland volume on MRI increased by 7.07% and 8.13%, and the mean dose increased by 14.95% (4.01 Gy) and 18.76% (4.95 Gy), with a statistically significant difference (P < 0.05). The brainstem volume reduced by 9.33% (P < 0.05), and the dose of 0.1 cm 3 volume reduced by a mean 8.46% (4.32 Gy), whereas the dose of 0.1 cm 3 of the spinal cord increased by 1.5 Gy on MRI. The maximum dose region of the spinal cord was very close on CT and MRI images, and was similar to the brainstem. In conclusion, it is credible to evaluate the radiation dose of the lens, eye, brainstem, and the spinal cord by applying simulation CT; whereas MRI images are sometimes necessary to evaluate the dose of the parotid glands and the optical nerve.

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Rules of parotid gland dose variations and shift during intensity modulated radiation therapy for nasopharyngeal carcinoma

Cited by 8 publications

References 18 publications

Short-term efficacy comparison between helical tomotherapy and intensity-modulated radiotherapy in patients with locally advanced nasopharyngeal carcinoma

Short-term efficacy comparison between helical tomotherapy and intensity-modulated radiotherapy in patients with locally advanced nasopharyngeal carcinoma

Analyzing human decisions in IGRT of head-and-neck cancer patients to teach image registration algorithms what experts know

Finding of dose evaluation for organs at risk in intensity‐modulated radiation therapy for nasopharyngeal carcinoma using magnetic resonance imaging

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