Parotid glands in whole-brain radiotherapy: 2D versus 3D technique for no sparing or sparing

Trignani, Marianna; Genovesi, Domenico; Vinciguerra, A.; Pilla, Angelo Di; Augurio, Antonietta; Tommaso, M. Di; Cèfaro, Giampiero Ausili; Nicola, Marta Di

doi:10.1007/s11547-014-0436-6

Cited by 9 publications

(11 citation statements)

References 18 publications

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“…In-depth clinical rational, feasibility studies for hippocampal-sparing WBRT including concurrent boost to brain metastatic diseases using modern radiotherapy systems, controversies, and future directions for hippocampal avoidance in cranial irradiation have also been discussed in a review article published by Kazda and colleagues. (29) Radiation-induced toxicity for WBRT patients has also been reported for other OARs such as parotid glands, (30,31) scalp, (32) and ear canals. (33) Radiation-induced toxicity to parotid glands is associated with xerostomia or dry mouth, impaired swallowing, and malnutrition, and unwanted scalp dose with hair loss.…”

Section: Discussionmentioning

confidence: 92%

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Potential for reduced radiation‐induced toxicity using intensity‐modulated arc therapy for whole‐brain radiotherapy with hippocampal sparing

Pokhrel

Sood

Lominska

et al. 2015

J Applied Clin Med Phys

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The purpose of this study was to retrospectively investigate the accuracy, plan quality, and efficiency of using intensity‐modulated arc therapy (IMAT) for whole brain radiotherapy (WBRT) patients with sparing not only the hippocampus (following RTOG 0933 compliance criteria) but also other organs at risk (OARs). A total of 10 patients previously treated with nonconformal opposed laterals whole‐brain radiotherapy (NC‐WBRT) were retrospectively replanned for hippocampal sparing using IMAT treatment planning. The hippocampus was volumetrically contoured on fused diagnostic T1‐weighted MRI with planning CT images and hippocampus avoidance zone (HAZ) was generated using a 5 mm uniform margin around the hippocampus. Both hippocampi were defined as one paired organ. Whole brain tissue minus HAZ was defined as the whole‐brain planning target volume (WB‐PTV). Highly conformal IMAT plans were generated in the Eclipse treatment planning system for Novalis TX linear accelerator consisting of high‐definition multileaf collimators (HD‐MLCs: 2.5 mm leaf width at isocenter) and 6 MV beam for a prescription dose of 30 Gy in 10 fractions following RTOG 0933 dosimetric criteria. Two full coplanar arcs with orbits avoidance sectors were used. In addition to RTOG criteria, doses to other organs at risk (OARs), such as parotid glands, cochlea, external/middle ear canals, skin, scalp, optic pathways, brainstem, and eyes/lens, were also evaluated. Subsequently, dose delivery efficiency and accuracy of each IMAT plan was assessed by delivering quality assurance (QA) plans with a MapCHECK device, recording actual beam‐on time and measuring planed vs. measured dose agreement using a gamma index. On IMAT plans, following RTOG 0933 dosimetric criteria, the maximum dose to WB‐PTV, mean WB‐PTV D2%, and mean WB‐PTV D98% were 34.9±0.3 Gy,33.2±0.4 Gy, and 26.0±0.4 Gy, respectively. Accordingly, WB‐PTV received the prescription dose of 30 Gy and mean V30 was 90.5%±0.5%. The D100%, and mean and maximum doses to hippocampus were 8.4±0.3 Gy,11.2±0.3 Gy, and 15.6±0.4 Gy, on average, respectively. The mean values of homogeneity index (HI) and conformity index (CI) were 0.23×0.02 and 0.96×0.02, respectively. The maximum point dose to WB‐PTV was 35.3 Gy, well below the optic pathway tolerance of 37.5 Gy. In addition, compared to NC‐WBRT, dose reduction of mean and maximum of parotid glands from IMAT were 65% and 50%, respectively. Ear canals mean and maximum doses were reduced by 26% and 12%, and mean and maximum scalp doses were reduced by 9 Gy (32%) and 2 Gy (6%), on average, respectively. The mean dose to skin was 9.7 Gy with IMAT plans compared to 16 Gy with conventional NC‐WBRT, demonstrating that absolute reduction of skin dose by a factor of 2. The mean values of the total number of monitor units (MUs) and actual beam on time were 719×44 and 2.34×0.14 min, respectively. The accuracy of IMAT QA plan delivery was (98.1±0.8) %, on average, with a 3%/3 mm gamma index passing rate criteria. All of these plans were considered clinically acceptable per ...

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Section: Discussionmentioning

confidence: 92%

“…Radiation‐induced toxicity for WBRT patients has also been reported for other OARs such as parotid glands, 30 , 31 scalp, (32) and ear canals (33) . Radiation‐induced toxicity to parotid glands is associated with xerostomia or dry mouth, impaired swallowing, and malnutrition, and unwanted scalp dose with hair loss.…”

Section: Discussionmentioning

confidence: 94%

Potential for reduced radiation‐induced toxicity using intensity‐modulated arc therapy for whole‐brain radiotherapy with hippocampal sparing

Pokhrel

Sood

Lominska

et al. 2015

J Applied Clin Med Phys

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“…It includes the brain tissue, skull, and spinal cord to the lower level of the atlas. However, Trignani et al [16] compared 2D-RT with 3D-CRT for WBRT and discovered that 28% of patients received a mean dose of >20 Gy in the parotid gland. Meanwhile, Noh et al [9] reported that mean parotid doses of ≥20 and ≥25…”

Section: Discussionmentioning

confidence: 99%

Whole brain radiotherapy using four-field box technique with tilting baseplate for parotid gland sparing

Park

Yea

2019

Radiat Oncol J

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The aim of this study is to evaluate the efficacy and feasibility of four-field box whole brain radiotherapy (FB-WBRT) with tilting baseplate by comparing bilateral WBRT (B-WBRT). Methods and Materials: Between March 2016 and September 2018, 20 patients with brain metastases underwent WBRT using the four-field box technique. WBRT is performed with a dose of 30 Gy in 10 fractions daily. Two computed tomography simulations per person were performed. One was in the traditional supine position for B-WBRT and the other by applying the tilting acrylic supine baseplate to elevate the head by 40° for FB-WBRT. The B-WBRT used the field-in-field technique, which is the most commonly used method in our institution. The FB-WBRT comprised anterior, posterior, and bilateral beams. A wedge was applied in anterior and posterior fields to compensate for skull convexity. Results: The average of Dmean of both parotid glands was 10.2 Gy (range, 3.8 to 17.8 Gy) in B-WBRT and 5.4 Gy (range, 2.0 to 11.7 Gy) in FB-WBRT (p < 0.05). Compared to B-WBRT, FB-WBRT reduced the mean dose of the right and left parotid glands from 10.1 Gy to 4.9 Gy and from 10.4 Gy to 5.8 Gy, respectively (p < 0.05). Further, V 5 , V 10 , V 15 , V 20 , and V 25 for the parotid gland decreased significantly in FB-WBRT (p < 0.05). The Dmax and Dmean of lens decreased according to the dose-volume histogram. Conclusion: Compared to B-WBRT, FB-WBRT with a tilting baseplate is a simple and effective method that takes feature of noncoplanar beam to protect the parotid gland.

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“…However, after the transition to the 3D era, by virtue of CT-simulation, it was possible to identify normal tissue dose distributions. Trignani et al compared the 2D technique with the 3D technique for WBRT, and discovered that 28% of patients received a mean dose in excess of 20 Gy to the parotid gland when using 2D-RT [12]. Noh et al also reported that the treatment fields encompassing the brain tissue, and the skull.…”

Section: Discussionmentioning

confidence: 99%

“…To avoid severe xerostomia, the Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) guidelines recommend that the mean dose to at least one parotid gland should be less than 20 Gy or that the mean dose to the combined volume of both glands should be less than 25 Gy [11]. However Trignani et al showed that 28% of patients treated with conventional treatment received parotid gland doses beyond the recommended limits [12]. Noh et al have recently showed through the normal tissue complication probability model that the parotid gland should be considered an organ-at-risk (OAR) during WBRT [13].…”

Section: Introductionmentioning

confidence: 99%

Non–coplanar whole brain radiotherapy is an effective modality for parotid sparing

Park¹,

Yea²

2019

Yeungnam Univ J Med

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Background: The purpose of this study was to evaluate the efficacy and feasibility of non-coplanar whole brain radiotherapy (NC-WBRT) for parotid sparing. Methods: Fifteen cases, previously treated with WBRT were selected. NC-WBRT plans were generated. The beam arrangement for the non-coplanar plans consisted of superior anterior, right, and left beams. After generation of the non-coplanar plans a field-in-field technique was applied to the bilateral parallel opposed beams in order to reduce maximum dose and increase dose homogeneity. The NC-WBRT plans were subsequently compared with the previously generated bilateral WBRT (B-WBRT) plans. A field-in-field technique was also used with the B-WBRT plans according to our departmental protocol. As per our institutional practice a total dose of 30 Gy in 10 fractions of WBRT was administered 5 days a week. Results: The mean dose to the parotid gland for the two different plans were 16.2 Gy with B-WBRT and 13.7 Gy with NC-WBRT (p<0.05). In the NC-WBRT plan, the V5Gy, V10Gy, V15Gy, V20Gy, and V25Gy of the parotid were significantly lower (p<0.05) than those of the B-WBRT plan. The D max of the lens was also lower by 10% with NC-WBRT. Conclusion: The use of NC-WBRT plans could be a simple and effective method to reduce irradiated volumes and improve the dose-volume parameters of the parotid gland.

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Parotid glands in whole-brain radiotherapy: 2D versus 3D technique for no sparing or sparing

Cited by 9 publications

References 18 publications

Potential for reduced radiation‐induced toxicity using intensity‐modulated arc therapy for whole‐brain radiotherapy with hippocampal sparing

Potential for reduced radiation‐induced toxicity using intensity‐modulated arc therapy for whole‐brain radiotherapy with hippocampal sparing

Whole brain radiotherapy using four-field box technique with tilting baseplate for parotid gland sparing

Non–coplanar whole brain radiotherapy is an effective modality for parotid sparing

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