Volumetric Change of Selected Organs at Risk During IMRT for Oropharyngeal Cancer

Ricchetti, F.; Wu, Binbin; McNutt, Todd; Wong, John W.; Forastiere, Arlene A.; Marur, Shanthi; Starmer, Heather M.; Sanguineti, Giuseppe

doi:10.1016/j.ijrobp.2010.01.071

Cited by 52 publications

(43 citation statements)

References 26 publications

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“…The variation in volume or geometry of the target and OARs could increase the risk of missing the target or applying higher doses to the OARs. Several studies have documented significant volumetric change in selected OARs during RT for head and neck cancer, but the PGs showed the largest modifications in volume [3,10]. In a recent evaluation of 26 consecutive patients with head and neck cancer, the authors concluded that it is necessary to monitor the PGs during RT because their volumetric modifications are associated with an increase in radiation dose [10].…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have documented significant volumetric change in selected OARs during RT for head and neck cancer, but the PGs showed the largest modifications in volume [3,10]. In a recent evaluation of 26 consecutive patients with head and neck cancer, the authors concluded that it is necessary to monitor the PGs during RT because their volumetric modifications are associated with an increase in radiation dose [10]. Another study on 10 oropharyngeal cancer patients reported a volume loss in the PGs with a medial shift of 3 mm and a change in the mean planned dose to both glands [12].…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have shown that the shrinkage of the PGs could alter the dose to the glands [2,[7][8][9]; therefore, in selected patients, replanning is recommended during the IMRT course. In a recent analysis, Ricchetti et al [10] concluded that some OARs underwent volumetric reduction, but the PGs showed the major change, with implications for daily dose distribution. Nishimura et al [11] reported that the volume of the PGs decreased from 43.1 to 32.0 ml in the third week of a 4-week course of IMRT (p,0.001), and another study [12] highlighted that the volume loss of the PGs correlated with the radiation dose (p,0.001).…”

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confidence: 99%

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Parotid gland volumetric changes during intensity-modulated radiotherapy in head and neck cancer

Fiorentino¹,

Caivano²,

Metallo³

et al. 2012

BJR

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Objective: To evaluate volumetric changes of parotid glands (PGs) during intensitymodulated radiotherapy (IMRT) in head and neck cancer patients. Methods: During IMRT all patients underwent kilovolt cone-beam CT (CBCT) scans to verify the set-up positioning in a protocol study. On each CBCT scan, the PGs were retrospectively contoured and evaluated with a dose-volume histogram. Results: From February to June 2011, 10 patients were enrolled. 140 CBCT scans were registered (280 PGs): for each patient, a median of 14 CBCT scans were performed (range 14-16). At the start of radiation, the average volume for ipsilateral PGs (iPGs) was 18.77 ml (range 12.9-31.2 ml), whereas for contralateral PGs (cPGs) it was 16.63 ml (range 8.3-28.7 ml). At the last CBCT scan, the average volume loss was 43.5% and 44.0% for the iPG and cPG, respectively. When we analysed the percentage of volume loss, we observed that the volume decreased by linear regression (r 2 50.92 for iPG; r 2 50.91 for cPG), with an average volume loss rate of 1.5% per day for both PGs. During the third week of treatment the volume of both PGs reduced by 24-30%. Conclusion: Our data show that, during IMRT, the shrinkage of PGs should be taken into account. A replan could be indicated in the third week of radiotherapy.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Parotid gland volumetric changes during intensity-modulated radiotherapy in head and neck cancer

Fiorentino¹,

Caivano²,

Metallo³

et al. 2012

BJR

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“…Several studies indicate that the anatomical changes in these patients over the course of treatment can be substantial [7][8][9]. Repeated imaging and replanning, even with a single mid-treatment computed tomography (CT), can significantly improve tumor coverage and normal tissue sparing [10][11][12].…”

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confidence: 99%

Accuracy of software-assisted contour propagation from planning CT to cone beam CT in head and neck radiotherapy

et al. 2016

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Background: Autocontouring improves workflow in computed tomography (CT)-based dose planning, but could also potentially play a role for optimal use of daily cone beam CT (CBCT) in adaptive radiotherapy. This study aims to determine the accuracy of a deformable image registration (DIR) algorithm for organs at risk (OAR) in the neck region, when applied to CBCT. Material and methods: For 30 head and neck cancer (HNC) patients 14 OARs including parotid glands, swallowing structures and spinal cord were delineated. Contours were propagated by DIR from CT to the CBCTs of the first and last treatment fraction. An indirect approach, propagating contours to the first CBCT and from there to the last CBCT was also tested. Propagated contours were compared to manually corrected contours by Dice similarity coefficient (DSC) and Hausdorff distance (HD). Dose was recalculated on CBCTs and dosimetric consequences of uncertainties in DIR were reviewed. Results: Mean DSC values of !0.8 were considered adequate and were achieved in tongue base (0.91), esophagus (0.85), glottic (0.81) and supraglottic larynx (0.83), inferior pharyngeal constrictor muscle (0.84), spinal cord (0.89) and all salivary glands in the first CBCT. For the last CBCT by direct propagation, adequate DSC values were achieved for tongue base (0.85), esophagus (0.84), spinal cord (0.87) and all salivary glands. Using indirect propagation only tongue base (0.80) and parotid glands (0.87) were !0.8. Mean relative dose difference between automated and corrected contours was within ±2.5% of planed dose except for esophagus inlet (-4.5%) and esophagus (5.0%) for the last CBCT using indirect propagation. Conclusion: Compared to manually corrected contours, the DIR algorithm was accurate for use in CBCT images of HNC patients and the minor inaccuracies had little consequence for mean dose in most clinically relevant OAR. The method can thus enable a more automated segmentation of CBCT for use in adaptive radiotherapy.

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“…Alternatively, the structural changes could be investigated by cross-sectional imaging studies, such as CT and MR imaging. So far, emphasis has been placed on volumetric changes during and after RT (18,19) and contrast enhancement on CT or volume had been shown during the first 40 Gy, which is in line with the results of Theshima et al who also found a significant correlation between the decrease in salivary gland volume and its function (18,21,22). The volume reduction in our study continued even three months after therapy, suggesting prolongation of destructive events and without any imaging signs of regeneration in irradiated glands even after completion of RT-ChT.…”

Section: Correlation Analysismentioning

confidence: 99%

Role of perfusion computed tomography in assessing submandibular gland radiochemotherapy-induced injury

Popović

Harej

Furlan

et al. 2014

Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology

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Volumetric Change of Selected Organs at Risk During IMRT for Oropharyngeal Cancer

Cited by 52 publications

References 26 publications

Parotid gland volumetric changes during intensity-modulated radiotherapy in head and neck cancer

Parotid gland volumetric changes during intensity-modulated radiotherapy in head and neck cancer

Accuracy of software-assisted contour propagation from planning CT to cone beam CT in head and neck radiotherapy

Role of perfusion computed tomography in assessing submandibular gland radiochemotherapy-induced injury

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