Risk analysis of linear accelerator radiosurgery

Voges, Jürgen; Treuer, Harald; Sturm, Volker; Büchner, C.I.R.; Lehrke, Ralph; Köcher, Martin; Staar, Susanne; Kuchta, Johannes; Müller, Rolf-Peter

doi:10.1016/s0360-3016(96)00422-1

Cited by 158 publications

(86 citation statements)

References 13 publications

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“…20,21 The incidence of RN is directly related to total radiation dose, volume, and fraction size. [22][23][24][25][26][27][28][29][30][31][32] RTOG 90-05 established that for patients who had previously received irradiation for primary brain tumors or brain metastases, maximum tolerated dose of single-fraction SRS was 24 Gy, 18 Gy, and 15 Gy for tumors 20 mm, 21 to 30 mm, and 31 to 40 mm in maximum diameter, respectively, with larger tumor diameter predictive of greater central nervous system (CNS) toxicity. 12 Incidence of RN in RTOG 90-05 was 5% at 6 months after SRS, and increased incrementally with time thereafter, up to 11% at 24 months.…”

Section: Discussionmentioning

confidence: 99%

Management Approach for Recurrent Brain Metastases Following Upfront Radiosurgery May Affect Risk of Subsequent Radiation Necrosis

Rae

Gorovets

Rava

et al. 2015

International Journal of Radiation Oncology*Biology*Physics

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Purpose: Many patients treated with stereotactic radiosurgery (SRS) alone as initial treatment require 1 or more subsequent salvage therapies. This study aimed to determine if commonly used salvage strategies are associated with differing risks of radiation necrosis (RN). Methods and materials: All patients treated with upfront SRS alone for brain metastases at our institution were retrospectively analyzed. Salvage treatment details were obtained for brain failures. Patients who underwent repeat SRS to the same lesion were excluded. RN was determined based on pathological confirmation or advanced brain imaging consistent with RN in a symptomatic patient. Patients were grouped according to salvage treatment and rates of RN were compared via Fisher's exact tests. Results: Of 284 patients treated with upfront SRS alone, 132 received salvage therapy and 44 received multiple salvage treatments. This included 31 repeat SRS alone, 58 whole brain radiation therapy (WBRT) alone, 28 SRS and WBRT, 7 surgery alone, and 8 surgery with adjuvant radiation. With a median follow-up of 10 months, the rate of RN among all patients was 3.17% (9/284), salvaged patients 4.55% (6/132), and never salvaged patients 1.97% (3/152). Receiving salvage therapy did not significantly increase RN risk (P Z .31). Of the patients requiring salvage treatments, the highest RN rate was among patients that had both salvage SRS and WBRT (delivered as separate salvage therapies) (6/28, 21.42%). RN rate in this group was significantly higher than in those treated with repeat SRS alone (0/31), WBRT alone (0/58), surgery alone (0/7), and surgery with adjuvant radiation (0/8). Comparing salvage WBRT doses <30 Gy versus 30 Gy revealed no effect of dose on RN rate. Additionally, among patients who received multiple SRS treatments, number of treated lesions was not predictive of RN incidence. Conclusion: Our results suggest that initial management approach for recurrent brain metastasis after upfront SRS does not affect the rate of RN. However, the risk of RN significantly increases when patients are treated with both repeat SRS and salvage WBRT. Methods to improve prediction of toxicity and optimize patient selection for salvage treatments are needed.

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Section: Discussionmentioning

confidence: 99%

Management Approach for Recurrent Brain Metastases Following Upfront Radiosurgery May Affect Risk of Subsequent Radiation Necrosis

Rae

Gorovets

Rava

et al. 2015

International Journal of Radiation Oncology*Biology*Physics

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“…However, such treatment schedules are consistently accompanied by a 3-7% risk of developing radiation necrosis [1,2,3,4,20,21].…”

Section: Discussionmentioning

confidence: 99%

“…The degree of neurological deficit is associated with the location and the size of the radiation necrosis [3,4]. Therefore, if functional areas are not involved in the high dose area, patients would be symptom-free even if they had radiation necrosis in a silent area.…”

Section: Discussionmentioning

confidence: 99%

“…However, once necrosis occurs in certain areas of the brain responsible for the motor function, visual function, or comprehension or production of speech, it results in permanent neurologic deficits [1][2][3][4]. The development of radiation necrosis is related to the dose of radiation received.…”

Section: Introductionmentioning

confidence: 99%

“…Considering that neuronal fibers are serial in structure, the severity of neurologic deficit is expected to be related to factors such as the maximum radiation dose administered to functional brain areas, as well as the volume of the area exposed to more than the threshold dose of radiation [5,6]. Although the threshold dose of radiation required to develop radiation necrosis has not been fully investigated, some clinical and experimental data have indicated that the threshold single dose lies within the range of 10-15 Gy [3,4,7].…”

Section: Introductionmentioning

confidence: 99%

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Integration of functional brain information into stereotactic irradiation treatment planning using magnetoencephalography and magnetic resonance axonography

Aoyama

Kamada

Shirato

et al. 2004

International Journal of Radiation Oncology*Biology*Physics

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Purpose: To minimize the risk of neurological deficit following stereotactic irradiation, functional brain information was integrated into treatment planning.Materials and Methods: Twenty-one magnetoencephalography and 6 magnetic resonance axonographic images were made in 20 patients in order to evaluate the sensorimotor cortex (n=15 patients, including the corticospinal tract in 6), the visual cortex (n=4) and the Wernicke's area (n=2). One radiation oncologist was asked to formulate a treatment plan without the functional images at first, and then to modify the plan after seeing them. The pre-and post-modification values were compared for the volume of the functional area receiving 15 Gy or more (V15), and the volume of the PTV receiving more than 80% of the prescribed dose (V80-PTV).Results: Fifteen out of 21 plans (71%) were modified after seeing the functional images.After modification, V15 was significantly reduced compared to the values of pre-modification in those 15 sets of plans (p=0.03), whereas there was no significant difference in V80-PTV (p=0.99). During follow-up, a radiation-induced necrosis at the corticospinal tract caused minor motor deficit in one patient for whom MR-axonography was not available in the treatment planning. No other radiation-induced functional deficit was observed in the other patients. AOYAMA H, et al.,3 Conclusions: Integration of MEG and MR-axonography in treatment planning has the potential to reduce the risk of radiation-induced functional dysfunction without deterioration of the dose distribution in the target volume.

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Optimization of multiple-isocenter treatment planning for linac-based stereotactic radiosurgery

Liao

Williams

Myers

et al. 2000

Comput. Aided Surg.

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Objective: Computer-assisted treatment planning for linac-based radiosurgery is still an open research problem, especially for multiple-isocenter procedures, primarily due to its high complexity and computational requirements. This paper focuses on the optimization of multipleisocenter treatment planning for linac systems, and addresses several important issues associated with multiple isocenters, such as dose conformality, homogeneity, and optimization of isocenter position and dose.Methods: The key idea behind our approach is that the desired dose distribution can be decomposed into a number of fundamental components. In the current paper, an analytical form, the so-called Ellipsoidal Dose Distribution Estimation (EDDE) model, represents each component. We establish ways (arc configurations) to achieve such ellipsoidal doses of arbitrary position, orientation, and size. Since the EDDE model is described by relatively few parameters, it allows very quick estimation of the dose distribution corresponding to a particular isocenter and thus makes the optimization of isocenter position very efficient. It is further used in a framework for optimal treatment planning, in which a number of ellipsoidal dose distributions, each corresponding to a different isocenter, are optimally placed to cover the target while sparing healthy tissue.Results: The general ellipsoidal dose distribution of linac-based radiosurgery is summarized as a mathematical model with the aid of supporting experiments. Comparisons between the EDDEoptimized and clinically implemented plans are made, revealing the superior performance of the former. In addition, a dramatic reduction in planning time is achieved using the EDDE model.Conclusion: The proposed EDDE model is a useful and effective dose model in multipleisocenter treatment planning for linac-based radiosurgery. Comp Aid Surg 5:220 -233 (

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Risk analysis of linear accelerator radiosurgery

Cited by 158 publications

References 13 publications

Management Approach for Recurrent Brain Metastases Following Upfront Radiosurgery May Affect Risk of Subsequent Radiation Necrosis

Management Approach for Recurrent Brain Metastases Following Upfront Radiosurgery May Affect Risk of Subsequent Radiation Necrosis

Integration of functional brain information into stereotactic irradiation treatment planning using magnetoencephalography and magnetic resonance axonography

Optimization of multiple-isocenter treatment planning for linac-based stereotactic radiosurgery

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