Application of statistical and computational methodology to predict brainstem dosimetry for trigeminal neuralgia stereotactic radiosurgery

Du, Qian; Zhang, Chi; Zhu, Xiaofeng; Liang, Xiaoying; Verma, Vivek; Follet, Kenneth; Wang, Shuo; Fan, Qilin; Ma, Ruimei; Zhou, Sumin; Zheng, Dandan

doi:10.1002/mp.12852

Cited by 4 publications

(15 citation statements)

References 33 publications

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“…Increasing the dose to the brainstem seems to be related to a better pain control and a higher rate of trigeminal dysfunction [20]. Higher dose to the brainstem may result either from targeting a more proximal portion of the nerve, from a shorter nerve length, or both, which results in a higher exposure of the sensory bers [19,22,34]. The best nerve portion to target remains controversial: most authors suggest that more proximal targets induce more hypesthesia but better pain control [4,18,19,22], whereas some others did not nd any relation between position of the target and outcome [26].…”

Section: Discussionmentioning

confidence: 99%

Radiosurgery for classical trigeminal neuralgia: impact of shot size on clinical outcome

Ortholan

Colin

Serrano

et al. 2023

Preprint

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Background This study compares the outcome of radiosurgery using two different shot sizes (5-mm and 6-mm) in patients suffering from medically refractory classical trigeminal neuralgia (TN). Methods All patients included in this open, prospective, non-controlled study were treated in a single institution for TN (95 patients) by LINAC single-dose radiosurgery using 5-mm shot (43 patients) or 6-mm shot (52 patients). The target was positioned on the intracisternal part of the trigeminal nerve. Results Mean Dmax (D0.035) to the brainstem that was higher in the 6-mm group: 12.6 Gy vs 21.3 Gy (p < 0.001). Pain control was significantly better in the 6-mm group: rates of pain-free patients at 12 and 24 months were respectively 90.2% and 87.8% vs. 73.6% and 73.6% in the 5-mm group (p = 0.045). Post-radiosurgical hypesthesia was more frequent in the 6-mm group: 47.0% and 58% vs.11.3% and 30.8% at 12 and 24 months (p = 0.002). To investigate the respective effect of shot size and dose to the brainstem on outcome, patients were separated in 3 groups: group 1 = 5-mm shot, (all Dmax < 25 Gy, 43 patients), group 2 = 6-mm shot, Dmax < 25 Gy (32 patients), group 3 = 6-mm shot Dmax > 25 Gy (20 patients). Rate of 12 months hypesthesia was 11.3%, 33.5% and 76.0%, respectively, p < 0.001 in each group. Rate of 12 months pain recurrence was 26.4%, 16.5% and 5% respectively (p = 0.11). Conclusion LINAC treatment with 6-mm shot achieved excellent pain control, but increased the rate of trigeminal nerve dysfunction, especially when the maximum dose to the brainstem was higher than 25 Gy.

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Section: Discussionmentioning

confidence: 99%

Radiosurgery for classical trigeminal neuralgia: impact of shot size on clinical outcome

Ortholan

Colin

Serrano

et al. 2023

Preprint

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show abstract

“…This negative correlation between hypoesthesia and treatment success has previously been described [ 11 ] and may be explained by technical considerations. Indeed, it has been demonstrated that the outcome of TN radiosurgery was influenced by interdependent technical parameters such as total dose to the target, shot size, length of treated nerve, dose delivered to the brainstem, location of the target within the nerve and volume of the proximal nerve irradiated [ 6 , 13 , 21 – 26 , 30 , 33 – 35 ].…”

Section: Discussionmentioning

confidence: 99%

Radiosurgery for classical trigeminal neuralgia: impact of the shot size on clinical outcome

et al. 2023

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Background This study compares the outcome of patients suffering from medically refractory classical trigeminal neuralgia (TN) after treatment with radiosurgery using two different shot sizes (5- and 6-mm). Methods All patients included in this open, prospective, non-controlled study were treated in a single institution for TN (95 cases in 93 patients) with LINear ACcelerators (LINAC) single-dose radiosurgery using a 5-mm shot (43 cases) or 6-mm shot (52 cases). The target was positioned on the intracisternal part of the trigeminal nerve. Results The mean Dmax (D0.035) to the brainstem was higher in the 6-mm group: 12.6 vs 21.3 Gy (p < 0.001). Pain relief was significantly better in the 6-mm group: at 12 and 24 months in the 6-mm group the rate of pain-free patients was 90.2 and 87.8%, respectively vs. 73.6 and 73.6% in the 5-mm group (p = 0.045). At 12 and 24 months post-radiosurgical hypoesthesia was more frequent in the 6-mm group: 47.0 and 58% vs.11.3 and 30.8% in the 5-mm group (p = 0.002). To investigate the effect of cone diameter and the dose to the brainstem on outcomes, patients were stratified into three groups: group 1 = 5-mm shot, (all Dmax < 25 Gy, 43 cases), group 2 = 6-mm shot, Dmax < 25 Gy (32 cases), group 3 = 6-mm shot Dmax > 25 Gy (20 cases). At 12 months the rates of hypoesthesia were 11.3, 33.5 and 76.0%, respectively in groups 1, 2 and 3 (p < 0.001) and the rates of recurrence of pain were 26.4, 16.5 and 5%, respectively, (p = 0.11). Conclusion LINAC treatment with a 6-mm shot provided excellent control of pain, but increased the rate of trigeminal nerve dysfunction, especially when the maximum dose to the brainstem was higher than 25 Gy.

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“…When MRI cannot be performed on a patient, a CT cisternogram is needed, which requires the contrast agent injection into the cerebrospinal fluid (CSF) via a spinal tap. 238,244 The radiation oncologists contour the OARs, including the brainstem, cochlea, ipsilateral facial nerve (CN7), auditory vestibular nerve (CN8), ipsilateral temporal lobe, as well as the target. The length of CN5 selected as the target is somewhat arbitrary, so once delivery errors are taken into consideration, portions of the prescribed isodose volume could fall outside of the target but still overlap with CN5.…”

Section: Methodsmentioning

confidence: 99%

“…Using this technique, one can safely deliver 50 to 60 Gy in a single fraction to a 4 to 10 mm length of nerve typically about three millimetres wide. 238 Studies by Romanelli et al 239,240 and Villavicencio et al 241 have reported on the efficacy of CyberKnife SRS for the treatment of trigeminal neuralgia. Villavicencio et al 241 reported a preliminary multi-center study in which 67% of patients (N = 95) experienced initial pain relief, and 50% continued pain relief in a two-year follow-up.…”

Section: Introductionmentioning

confidence: 99%

“…Their study implied that dose and target volume could be very important in treatment outcomes. Du et al238 studied the impacts of anatomical variables on the dosimetry of the brainstem for forty patients treated on a conventional linac cone-based radiosurgery. They found that the features important to treatment outcomes were spatial nerve orientation relative to the brainstem, the distance between the isocenter and brainstem, and the utilized cone size.…”

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confidence: 99%

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Patient-Specific Planning Target Volume Margins for Liver Stereotactic Robotic Radiosurgery

Liu¹

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Purpose: To create analytical tools for a proposed clinical workflow, which implements patientspecific planning target volume (PTV) margins for liver radiation therapy treatments. Methods and Materials: Treatment log files are analyzed for liver treatments to assess tumour motion-tracking accuracy. A uniform PTV margin is estimated that considers motion-tracking errors and deformations, provided that the impact of uncorrected rotations is minimized. A supervised machine learning algorithm employing retrospective data, which emulates a dry-run session prior to treatment planning, is used to investigate if motion-tracking errors are less than 2 mm, and consequently, the standard PTV margins can be reduced by 2 mm. For a safer implementation in the clinic, we employ a warning system that quantifies the probability of a geographic miss if the PTV margin is reduced for every subsequent fraction. A dosimetric analytical tool is proposed to retrospectively assess the dose to a target against different types of delivery errors. The tool is validated by radiochromic film measurements for two very different types of treatments, liver and trigeminal neuralgia (a cranial nerve disorder). Case studies are conducted to access the suitability of a selected PTV margin based on the geometrical and dosimetric coverage of targets. The range of rotations that can be safely allowed for trigeminal neuralgia treatments is quantified since rotational corrections cannot be applied by the system for this specific disease site. Results: Isotropic 4 mm PTV margins are sufficient to account for tracking errors and deformations for 95% of patients. For patient-specific PTV margins, the accuracy of predicting if motion-tracking errors are less than 2 mm is 0.84 ± 0.06 using 5-fold cross-validation. Using the warning system, 11 out of 64 cases predicted to be treated with 2 mm reduced PTV margins might

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Application of statistical and computational methodology to predict brainstem dosimetry for trigeminal neuralgia stereotactic radiosurgery

Cited by 4 publications

References 33 publications

Radiosurgery for classical trigeminal neuralgia: impact of shot size on clinical outcome

Radiosurgery for classical trigeminal neuralgia: impact of shot size on clinical outcome

Radiosurgery for classical trigeminal neuralgia: impact of the shot size on clinical outcome

Patient-Specific Planning Target Volume Margins for Liver Stereotactic Robotic Radiosurgery

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