Co-registration of cone beam CT and planning CT in head and neck IMRT dose estimation: a feasible adaptive radiotherapy strategy

Yip, Connie; Thomas, Christopher; Michaelidou, A.; James, Deborah St.; Lynn, R.; Lei, Mary; Urbano, Teresa Guerrero

doi:10.1259/bjr.20130532

Cited by 16 publications

(16 citation statements)

References 20 publications

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“…The difference between the mean planned doses and the mean delivered doses without ART ranged in the literature from -1 Gy to 6 Gy, with 85% of studies showing an increase in the parotid gland dose ( Supplementary Table S1) [2,12,14,[21][22][23][24][25][26][27][28][29][30]. Moreover, the increase in the parotid gland dose appeared to be strongly patient-dependent and was observed only in 30 to 65% of patients.…”

Section: Parotid Glandsmentioning

confidence: 99%

Adaptive radiotherapy for head and neck cancer

et al. 2018

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Introduction: Large anatomical variations can be observed during the treatment course intensitymodulated radiotherapy (IMRT) for head and neck cancer (HNC), leading to potential dose variations. Adaptive radiotherapy (ART) uses one or several replanning sessions to correct these variations and thus optimize the delivered dose distribution to the daily anatomy of the patient. This review, which is focused on ART in the HNC, aims to identify the various strategies of ART and to estimate the dosimetric and clinical benefits of these strategies. Material and methods: We performed an electronic search of articles published in PubMed/MEDLINE and Science Direct from January 2005 to December 2016. Among a total of 134 articles assessed for eligibility, 29 articles were ultimately retained for the review. Eighteen studies evaluated dosimetric variations without ART, and 11 studies reported the benefits of ART. Results: Eight in silico studies tested a number of replanning sessions, ranging from 1 to 6, aiming primarily to reduce the dose to the parotid glands. The optimal timing for replanning appears to be early during the first two weeks of treatment. Compared to standard IMRT, ART decreases the mean dose to the parotid gland from 0.6 to 6 Gy and the maximum dose to the spinal cord from 0.1 to 4 Gy while improving target coverage and homogeneity in most studies. Only five studies reported the clinical results of ART, and three of those studies included a non-randomized comparison with standard IMRT. These studies suggest a benefit of ART in regard to decreasing xerostomia, increasing quality of life, and increasing local control. Patients with the largest early anatomical and dose variations are the best candidates for ART. Conclusion: ART may decrease toxicity and improve local control for locally advanced HNC. However, randomized trials are necessary to demonstrate the benefit of ART before using the technique in routine practice.

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Section: Parotid Glandsmentioning

confidence: 99%

Adaptive radiotherapy for head and neck cancer

et al. 2018

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“…there was a 7% reduction in the weight of the patients during the first 3 weeks of the treatment, a 28% reduction in the target volume and an 11% reduction in the neck volume in HN RT (14). In Yip and colleagues' study, there was a decrease of 4.7% in PTV1 volume and 11.5% in (15).…”

Section: Discussionmentioning

confidence: 85%

Adaptive radiation therapy for cervical esophageal cancer: dosimetric and volumetric analysis

Karaca

Kırlı

2019

J. Gastrointest. Oncol

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Background: Cervical esophageal cancer (CEC) patients may suffer from significant anatomical changes due to tumor shrinkage or weight loss during radiotherapy. The aim of the study is to evaluate the volumetric and dosimetric changes in the target and critical volumes of CEC patients by using adaptive radiotherapy (ART) technique. Methods: Seven CEC patients treated in helical tomotherapy (HT) unit was analyzed. All patients had a replanning CT simulation at 3rd (CT2) and 5th (CT3) weeks in addition to the initial CT (CT1). Volumetric and dosimetric changes of target and organs at risk (OAR) were evaluated. Results: The average weight loss of the patients was 9.03%. The major changes of the planning target volume (PTV), PTV boost, right and left parotid volumes were 4.74%; 15.93%; 26.82% and 26.64%, respectively. Using ART software was evaluated with first planning values (CT1) and pre-CT2-CT3 verification values. The correlation was decrease of the D95 and increase of the Dmax was statistically significant. When evaluated the varying values of the new CTs, there was no significant change between the initial PTV and adapted PTV's. But a significant decrease was observed at the summation plan for left and right parotids (P<0.05). The mean dose reductions of left and right parotid were 2.48 and 2.49 Gy, respectively. Conclusions: Our results showed that using ART technique was beneficial to ensure adequate doses to the target volumes and safe doses to the OARs for the patients who need replanning during RT in uncommon CEC patients.

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“…[ 4 ] There are several imaging modalities used for IGRT, one of which is CT-on-rails. [ 5 6 7 ] CT-on-rails gives a complete three-dimensional representation of patient anatomy and enables accurate internal organ delineation and patient setup corrections. Variations in dose delivery stem from setup errors, internal organ motion, and deformation, which can contribute to underdosage of the tumor or overdosage of normal tissue.…”

Section: Introductionmentioning

confidence: 99%