Stereotactic Radiosurgical Treatment Research Articles

Exploring feasibility criteria for stereotactic radiosurgical treatment of multiple brain metastases using five linac machines.

This study aimed to find descriptors that correlates with normal brain dose to determine the feasibility of performing fractionated stereotactic radiosurgery (SRS) for multiple brain metastases (BMs) using five linac machines. Thirty-two patients with 1-30 BMs were enrolled. Treatment plans were created using TrueBeam, Novalis Tx, TrueBeam Edge, Halcyon, and Tomotherapy linacs. The sum of all planning target volumes (PTVs) was defined as PTVall, and the brain region excluding PTVall was defined as normal brain. The total surface area (TSA) of the PTV was calculated from the sum of the surface areas of the equivalent spheres for each PTV. Volumes receiving more than 5, 12, and 18Gy (V5Gy, V12Gy, and V18Gy, respectively) were used for evaluation of normal brain dose. Correlations between normal brain dose and each tumor characteristic (number, PTVall, and TSA) were investigated using the Spearman rank correlation coefficient. Correlations between each characteristic and normal brain dose were statistically significant (p<0.05) across all machines. The correlation coefficients between each characteristic and V18Gy for the five machines were as follows: tumor number, 0.39-0.60; PTVall, 0.79-0.93; TSA, 0.93-0.99. The fit equations between TSA and V18Gy exhibited high coefficients of determination, ranging from 0.92 to 0.99 across five machines. This study devised fractionated SRS plans using for 1-30 BMs across five linac machines to find descriptors for determining SRS feasibility based on normal brain dose. TSA proved to be a promising descriptor of SRS feasibility for treating multiple BMs.

Deep-learning-driven dose prediction and verification for stereotactic radiosurgical treatment of isolated brain metastases

PurposeWhile deep learning has shown promise for automated radiotherapy planning, its application to the specific scenario of stereotactic radiosurgery (SRS) for brain metastases using fixed-field intensity modulated radiation therapy (IMRT) on a linear accelerator remains limited. This work aimed to develop and verify a deep learning-guided automated planning protocol tailored for this scenario.MethodsWe collected 70 SRS plans for solitary brain metastases, of which 36 cases were for training and 34 for testing. Test cases were derived from two distinct clinical institutions. The envisioned automated planning process comprised (1): clinical dose prediction facilitated by deep-learning algorithms (2); transformation of the forecasted dose into executable plans via voxel-centric dose emulation (3); validation of the envisaged plan employing a precise dosimeter in conjunction with a linear accelerator. Dose prediction paradigms were established by engineering and refining two three-dimensional UNet architectures (UNet and AttUNet). Input parameters encompassed computed tomography scans from clinical plans and demarcations of the focal point alongside organs at potential risk (OARs); the ensuing output manifested as a 3D dose matrix tailored for each case under scrutiny.ResultsDose estimations rendered by both models mirrored the manual plans and adhered to clinical stipulations. As projected by the dual models, the apex and average doses for OARs did not deviate appreciably from those delineated in the manual plan (P-value≥0.05). AttUNet showed promising results compared to the foundational UNet. Predicted doses showcased a pronounced dose gradient, with peak concentrations localized within the target vicinity. The executable plans conformed to clinical dosimetric benchmarks and aligned with their associated verification assessments (100% gamma approval rate at 3 mm/3%).ConclusionThis study demonstrates an automated planning technique for fixed-field IMRT-based SRS for brain metastases. The envisaged plans met clinical requirements, were reproducible across centers, and achievable in deliveries. This represents progress toward automated paradigms for this specific scenario.

Radiosurgical Treatment of a Patient With a Ruptured Arteriovenous Malformation Located in a Functionally Significant Area

Arteriovenous malformations (AVMs) of the brain are quite rare vascular pathologies, but they are life-threatening, due to the risk of intracerebral hemorrhage. Stereotactic radiosurgical treatment of patients with cerebral AVM is performed in cases where surgical removal is impossible or embolization with a stable occlusive effect cannot be performed. Currently, for the diagnosis of AVM, magnetic resonance imaging (MRI) is increasingly used because of its noninvasiveness and minimal risks. When a malformation is located in a functionally significant area, then a non-invasive technique is used to assess its interposition and mapping - functional magnetic resonance imaging.We have presented the experience of radiosurgical treatment of a 43-year-old male patient with a ruptured AVM located in the left temporal lobe, near Wernicke’s area. The patient underwent stereotactic radiosurgical treatment with Elekta Leksell Gamma Knife Perfection device, taking into account the location of the AVM in a functionally significant area, preoperative mapping was performed. After two years, according to MR angiography, the arterial component in the projection of the irradiated AVM was not visualized, which was confirmed by the data of cerebral angiography. Thus, a clinical example has demonstrated the high efficiency of MRI in the diagnosis and assessment of the results of the performed stereotactic radiosurgical treatment of AVMs.

Cavernous malformations of the brain and modern views on their treatment

Cavernous malformations of the brain have become an increasingly common pathology in recent years, thanks to the advancement of modern methods of neuroimaging. Despite the benign nature of the course in most cases, these formations can cause convulsions and serious neurological disorders. Typically, clinical manifestations are caused by hemorrhages in the structure of the cavernous and surrounding parenchyma of the brain. The management strategy chosen for patients with cerebral cavernous malformations is determined by the type of malformation, its size, localization, the presence of repeated hemorrhages, and the clinical picture. This literature review focuses on modern methods of treating cerebral cavernous malformations. The main methods of treatment for cavernous malformations of the brain, particularly surgical treatment, have been analyzed. If surgical intervention is not possible, alternative methods of treatment include radiation therapy, such as stereotaxic radiosurgery, and proton therapy, in cases of deep location of foci in functionally significant areas of the brain, which are characterized by the highest risk of complications. Thе possibilities, efficacy, and safety of stereotactic radiosurgical treatment are discussed, as well as the use of proton therapy in the treatment of cavernous malformations. Furthermore, radiation therapy has been shown to be beneficial for cavernous malformations.

Radiosurgical treatment of patients with intracranial pilocytic astrocytomas

The study objective is to assess the outcomes after stereotactic radiosurgical treatment (SRS) in patients with pilocytic astrocytomas after non-radical surgery and after continued tumor growth.Materials and methods. The report includes 56 patients (37 males and 19 females) who have undergone SRS in N. N. Burdenko National Medical Research Center of Neurosurgery from March 2005 to January 2018.Results. The majority of patients (75 %) were children. Almost 43 % of patients underwent SRS as part of the primary treatment after biopsy or incomplete removal, other patients – in the event of continued tumor growth after non-total surgery. Tumors involved the cerebellum (41 %), brainstem (23 %), thalamus (19.6 %) and cerebral hemispheres (16.1 %). The median tumor volume was 1.9 cm3 (0.14–19.00 cm3), 23 % of patients had cysts in the tumor. The prescribed dose was 12 to 22 Gy (median 18 Gy) over 50–80 % isodose line. The follow-up was available for 54 (96.4 %) patients. The median follow-up was 67 months (3–151 months). All patients were alive at the end of the follow-up examination. In 14 (25 %) patients, the development of pseudo-progression (PSP) was noted. The median detection of PSP is 11 months (3–65 months). Of these, in 7 (50 %) patients PSP was accompanied by clinical deterioration: in 5 – an increase in general cerebral symptoms and in 1 patient – an episode and an increase in cerebellar symptoms. Eight (57 %) patients with PSP were reoperated: 4 underwent removal of the tumor, 4 – emptying of the cyst and placement of the Ommaya reservoir, which led to regression of the existing symptoms. No other toxicity was observed in patients. At the time of the completion of the follow-up examination (with a given median follow-up), no relapses were detected. There was no clinical deterioration after SRS.Conclusion. Radiosurgical treatment is an effective and safe method of radiation treatment for patients with primary pilocytic astrocytomas and recurrent pilocytic astrocytomas, providing control over tumor growth in all patients with a low risk of complications.

Experience of Using Hyperbaric Oxygenation in the Treatment of Radionecrosis That Developed as a Complication of Stereotactic Radiosurgical Treatment of Meningioma on the Example of a Clinical Case

In contrast to conventional microsurgery, stereotactic radiosurgery has an advantage in the treatment of intracranial masses, avoiding severe complications associated with open surgery. In rare cases, the use of the method is associated with the development of radiation-induced injuries, one of which is radiation necrosis (RN). This is a late complication of radiosurgery, developing mainly 6 months after radiation exposure. The neurological manifestations of this complication depend on location, and the clinical picture is very diverse. The method of magnetic resonance imaging (MRI) with intravenous contrast enhancement is quite often the first link in neuroimaging, which helps to suggest the presence of this complication based on the X-ray picture and to clarify the location of changes.We presented the experience of radiation necrosis treatment in a 47-year-old patient who was referred to our department with a diagnosis of frontal meningioma. The patient underwent stereotactic radiosurgical treatment using the Elekta Leksell Gamma Knife Perfextion device, and 6 months later the gradual deterioration began, the patient complained of headache, nausea; central prosoparesis developed. Considering the clinical picture and control MRI data, the changes were interpreted as radionecrosis. In order to control the complication, the patient underwent standard glucocroticosteroid therapy, supplemented by hyperbaric oxygenation (HBO), which made it possible to achieve regression of the adverse clinical and radiological manifestations of the complication. Thus, on a clinical example, it was demonstrated that the combined use of glucocorticosteroids and HBOs is highly effective in the treatment of RN.

Spinal Cord Tolerance Guided by Stereotactic Radiosurgical Treatment of Intramedullary Arteriovenous Malformations

Spinal cord toxicity resulting in neurological deficits remains the most feared complication of spinal region stereotactic radiosurgery (SRS). In treating vertebral body disease, a radiation dose gradient can typically be established between tumor and spinal cord. This is difficult for intramedullary spinal cord arteriovenous malformations (iSCAVMs), which can be integrated throughout the cord. Here we report outcomes of cord tolerance in treatment of integrated iSCAVMs. A retrospective cohort of 17 consecutive patients with integrated iSCAVMs treated once with frameless robotic surgery, SRS between 2007 and 2018 was accrued. Clinical outcomes, dose prescriptions, and target dose-volume histogram (DVH) parameters were acquired. Volumes of interest (VOIs) comprising the proper AVM and cord were registered on treatment planning software. A cord minus AVM (CmA) structure representing independent spinal cord was generated by Boolean subtraction of the respective proper AVM from the cord. Various dose quantifiers were extracted from DVHs, statistical univariate analysis was performed, and Task Group 101 (TG101) constraints were interpolated to two-fraction regimens with α/β of 2-3 Gray (Gy) using Wolfram Mathematica (Wolfram Research, Champaign, IL). Among the 17 patients analyzed (eight male and nine female), all had CmA volumes smaller than cord, confirming the integrated nature of their iSCAVMs. Nine had a nidus in the C-spine; six in the T-spine; and two in the L-spine or lower. Median age at diagnosis was 23, ranging from 9 to 56 years. Nine patients had no prior intervention, while eight had prior embolization(s) and/or microsurgery. Median follow-up time was 40 months. Ten patients (59%) experienced Grade (G) 0 neurological toxicity post-treatment, seven (41%) experienced G1, and zero experienced G2+. Three patients were prescribed three fractions to 21 or 24 Gy. The rest received two fractions (20-22 Gy). Max dose (Dmax) to cord and CmA ranged from 2278-2874 cGy and 2000-2659 cGy, respectively. All patients had Dmax to cord and CmA greater than TG101 constraints. All patients received minimum dose to hottest 0.03 cc volume (D0.03) to cord greater than constraints; 15 patients (88%), to CmA. All patients received minimum dose to hottest 0.35 cc volume (D0.35) to cord greater than threshold; 13 patients (76%), to CmA. At significant level of 0.05, one-tailed binomial test suggests max monthly G2+ toxicity rate of 0.4% in exceeding tolerances. No neurologic toxicity beyond Grade 1 was experienced by any patient, all of whom received Dmax to spinal cord tissue (both independent and integrated with AVM) beyond recommended constraints. Further, all patients exceeded volumetric constraints to cord. Most exceeded volumetric constraints to CmA, as well. Novel tolerance data from rare iSCAVMs may influence current cord constraints to avoid limiting appropriate treatment of more common vertebral metastases.

STEREOTACTIC RADIOSURGICAL TREATMENT OF THE STALK CRANIOPHARYNGIOMA WITH APPARATUS LEKSELL GAMMA KNIFE PERFEXION

Craniopharyngioma is a benign tumor of the brain, developing from the epithelial cells of craniopharyngeal duct, from which are formed abiogenetically the stem and rear part of the pituitary gland. The peculiarity of stem craniopharyngiomas is dense accretion of the tumor with arterial and neural structures of supra-para-retrosellar area, which makes surgical treatment technically difficult, and sometimes — obviously impossible. In the world literature at this point does not contain messages about the isolated stem radiosurgical treatment of craniopharyngiomas with application installations, Gamma knife or CyberKnife. A clinical case of stereotactic radiosurgical treatment in the mode of hypofractionation on the Leksell Gamma Knife Perfexion apparatus with a positive result in the form of a significant regression of visual disturbances is presented. Index terms: stereotactic radiosurgery, hypofractionation, craniopharyngioma, sellar region.

PET/CT with 18F-Fluoroethyl-L-Tyrosine in Diagnosis of Radiation Necrosis of the Temporal Lobe after Radiotherapy for Nasopharyngeal Carcinoma (Clinical Case)

Clinical case of the patient with nasopharyngeal carcinomaafter stereotactic radiosurgical treatment for the persistent disease after chemoradiotherapyare presented. The diagnostic data of PET/CTwith 18F-Fluoroethyl-Ltyrosine (18F-FET)and MRI with intravenous contrastof head and neck were included in analysis. There was analyzeda clinical case of differential diagnosis of changes in thetemporal lobe of the brain after stereotactic radiation therapy of nasopharyngeal carcinoma using PET/CT with 18F-FET. Identified high diagnostic accuracy in the differential diagnosis of delayed changes in the brain (tumor or radiation necrosis) after radiation therapy ofnasopharyngeal carcinoma.

Stereotactic Radiosurgical Treatment of Glomus Jugulare Tumors.

Determine treatment outcomes of stereotactic radiosurgery (SRS) for glomus jugulare tumors (GJT), focusing on three-dimensional volume change and symptoms before and after SRS, as well as complications related to SRS. Retrospective case review. Tertiary referral center. Thirty-eight patients treated with SRS between 2000 and 2015. SRS treatment of GJT. The tumor volumes on pre- and posttreatment imaging were compared utilizing the Leskell GammaPlan treatment plan software to assess tumor progression. Pre- and posttreatment symptoms, Fisch classification, and complications were recorded. The mean radiographic follow-up was 39.1 months. The mean dose-to-tumor margin was 13.2 Gy. The mean tumor size at treatment was 5.8 and 5.2 cm at last follow-up. Thirty-three patients had follow-up imaging suitable for analysis. When defining both 10 and 15% tumor size increases as significant, 27 (82%) and 29 (88%) tumors decreased in size or remained stable, respectively. For the seven tumors with documented pre-SRS growth, treatment success was 86%. The mean marginal dose for treatment success and failure were 13.2 and 13.7 Gy, respectively. Patients receiving a higher margin dose had a greater risk of tumor progression (p = 0.0277). Fisch classification did not impact tumor progression rate. Initial tumor volume had no significance on tumor response to SRS. SRS is an effective treatment option for GJT. Both initial tumor volume and Fisch classification did not impact tumor progression. There were no significant patient or lesion characteristics that distinguished treatment success and/or failure.

Features stereotactic radiosurgical treatment large brain metastatic lesions of the brain with hypoxic radiosensitizers

Objective : Follow the dynamics of early reduction of tumor volume after stereotactic radiosurgery using hypoxic radiosensitizers and without radiosensitization, a comparison of these data with predictor of prolonged local control and median follow-up. Materials and methods: 107 patients (173 lesions) with large brain metastases (≥10cm 3 ) accounted for the main and control group of our research. Of these, the basic group (with radiosensitizers) 77 included, in the control group — 30 patients. Of the 77 patients, 40 patients (66 lesions) was used as a radiosensitizer metronidazole (M+), 37 (60 lesions) — nimorazol (H+). The average volume of metastases was 20.0cm 3 (range 10–60.0cm 3 ). SRS in one fraction to the average dose of 14 Gy (range 10–18 Gy), conducted an average of 4 fractions (range 3–5 fractions), with a mean dose of 26.5 Gy (range 21–40 Gy). Are taken into account only those patients who have at least passed the first compulsory MRI investigation a week after the SRS, with a further observation of 1.5 and 3 months. Results: During the term of supervision in metastases which considerably diminished in a volume already in a week after SRS, the signs of local control and median follow-up, unlike a control group, without of radiosensitizers at which it was not marked early and rapid reduction of tumour (r = .003, OR = 0.424; 95% confidence interval, 0.203-0.935), also in a group with radiosensitization the indexes of survivability were higher (19.0 months against 10.0, 95% [CI], 12.876-22.124 and 7.330-12.670, р=.0008 аnd р=.0001, respectively). Conclusions: Early reduction large brain metastases week after radiosurgery using hypoxic radiosensitizers may be a predictor of long-term local tumor control.

Evolving Trends in Stereotactic Radiosurgical Treatment of Meningioma

Evolving Trends in Stereotactic Radiosurgical Treatment of Meningioma

The stereotactic radiosurgical treatment of common benign brain tumors: pituitary adenomas, vestibular schwannoma and meningiomas

Introduction: Several treatment options exist following the diagnosis of common benign intra-cranial tumors including microsurgery, radiation and when appropriate medical management. This article will review the current stereotactic radiosurgical trends in the treatment of pituitary adenomas, vestibular schwannomas and meningiomas. Methods: The medical literature was used to review cutting edge current stereotactic radiosurgical practices in the treatment of benign intra-cranial tumors. Conclusions: Radiosurgery is a safe and effective alternative treatment option to microsurgery for the management of common benign intra-cranial tumors with excellent control rates and low morbidity.

Stereotactic Radiosurgery in Treatment of Cerebral Metastases: Histological Differences in Predictors of Survival

Brain metastases are the most common intracranial neoplasm. The incidence of metastatic disease has increased with improved survival of patients with common malignancies, such as lung, breast and melanoma [1]. Brain metastases generally represent an advanced stage of cancer with survival varying between two to three months [2-3] with only palliative treatment and eight to 13 months [4-6] with stereotactic radiosurgical treatment. Several reports have proposed that survival is adversely affected by increasing number and volume of lesions, old age (>65), low Karnofsky performance scores, presence of extracranial metastases, poor control of extracranial disease, and synchronicity of metastases. Several composite classifications, such as Recursive Partitioning Analysis (RPA) and Graded Prognostic Assessment (GPA), have been proposed based on some of the above variables. Though these classifications have been validated by numerous studies, they alone do not explain the risk of mortality [7-10]. For example, numerous reports have shown that the duration of survival and risk factors for mortality varies widely between histologies and that composite classification system, such as the RPA or GPA, cannot be generalized across all pathologies. We describe our multicenter experience treating 1,318 patients with intracranial disease and describe histological differences in predictors of survival and discuss the application of the composite prognostic criteria's across different histologies.

Stereotactic radiosurgical treatment of brain metastasis of primary tumors that rarely metastasize to the central nervous system

We evaluated the local control of gamma knife stereotactic radiosurgery (GKSRS) in the treatment of cerebral metastases from primary tumors that rarely metastasize to the central nervous system (CNS). There is little published data on this subject with very few series on specific primary tumors. We present our experience treating these lesions with GKSRS combined with a review of the salient literature. A retrospective study of 36 patients who collectively underwent 44 GKSRS procedures for CNS metastatic disease was undertaken. Our series includes four patients with sarcoma, two with prostate cancer, three with thyroid cancer, five with endometrial cancer, seven with ovarian cancer, two with cervical cancer, six with esophageal cancer, two with bladder cancer, one with liver cancer, one with pancreatic cancer, and three with testicular cancer. With 44 gamma knife sessions treating 74 tumors, 63 tumors showed no radiographic evidence of progression, and 13 tumors demonstrated radiographic progression between one and 12 months after gamma knife treatment. In six patients in the population, further treatment with GKSRS was necessary due to enlargement of untreated lesions or new metastatic disease. GKSRS for uncommon CNS metastases is appears to be efficacious in controlling the treated tumor. The majority of tumors treated in our study did not progress post gamma knife.

Cyberknife radiosurgery in treating trigeminal neuralgia

PurposeTo assess the short term efficacy of Cyberknife stereotactic radiosurgical treatment of trigeminal neuralgia (TN).Methods17 consecutive patients with medically or surgically refractory unilateral TN were treated with Cyberknife radiosurgery. Using...

A CASE REPORT OF COMBINATION TREATMENT FOR BRAIN MENINGIOMA: A DIFFERENT APPROACH

Meningiomas are among the most common primary tumors of the central nervous system. We describe the case of an 82-year-old woman with meningioma, the epicenter of which was above the sella, causing her terrible headaches and severely compromised visual acuity. Although the patient was eligible for stereotactic radiosurgical treatment (SRS), she was treated with conventional 3D conformal radiotherapy (3DCRT), at her will. We discuss alternative and innovative approaches regarding non-chemotherapy drugs, with concurrent radiation treatment.

Repeat Radiosurgery for Intracranial Arteriovenous Malformations

Despite a high success rate in the stereotactic radiosurgical treatment of intracranial arteriovenous malformations (AVMs) that cannot be safely resected with microsurgery, some patients must be managed after treatment failure. To provide an update on the use of repeat linear accelerator radiosurgery as a treatment for failed AVM radiosurgery at the University of Florida. We reviewed 103 patients who underwent repeat radiosurgical treatment for residual AVM at the University of Florida between December 1991 and December 2007. Each of these patients had at least 2 radiosurgical treatments for the same AVM. Patient information, including AVM nidus volume, prescription dose, age, and sex, was collected at the time of initial treatment and again at the time of retreatment. Patients were followed up after treatment with magnetic resonance, computed tomography, and angiographic imaging at standard intervals to determine the status of their AVM. The median follow-up after retreatment was 31 months. Between the first and second treatments, the median AVM nidus volume was decreased by 69% (from a median volume of 12.7 to 4.0 cm), allowing the median prescribed dose to be increased from 1500 cGy on initial treatment to 1750 cGy on retreatment. The final obliteration rate on retreatment was 65.3%. After salvage retreatment, 5 patients (4.9%) experienced radiation-induced complications, and 6 patients (5.8%) experienced posttreatment hemorrhage. Repeat radiosurgery is a safe and effective salvage treatment for AVMs.

Stereotactic Radiosurgical Treatment of Brain Metastases to the Choroid Plexus

Choroid plexus metastases (CPM) are uncommon lesions. Consequently, optimal management of CPM is uncertain. We summarize our experience with stereotactic radiosurgery (SRS) of CPM. Sixteen consecutive patients with presumed CPM treated with SRS between 1997 and 2007 were examined. Twelve were men with a median age at diagnosis of CPM of 61.9 ± 9.9 years; 14 had metastases from renal cell carcinoma (RCC). All patients had controlled primary disease at the time of treatment for CPM. Four patients with RCC and 1 with non-small-cell lung cancer had undergone whole-brain radiotherapy (WBRT) previously and 2 had received SRS to other brain metastases. The disease-free interval from the primary diagnosis to CPM diagnosis averaged 39.3 ± 46.2 months (range, 1.0-156.3). Five patients were asymptomatic; of the remaining 11, none had symptoms related to CPM. All presented with a single CPM. Average maximum diameter of the CPMs was 2.0 ± 1.0 cm (range, 0.9-4.1 cm); mean volume was 2.4 ± 2.6 cm(3) (range, 0.2-9.3). Median SRS dose was 24 Gy to the 53% isodose line (range, 14-24 Gy). Survival after SRS to the CPM was 25.3 ± 23.4 months (range, 3.2-101.6). Patients in Recursive Partitioning Analysis (RPA) class I (n = 10) had improved survival compared to those in class II (n = 6), as did those with better GPA scores. There were no local failures. After SRS, 1 patient underwent WBRT, 3 patients had one, and another had two subsequent SRS treatments to other brain lesions. Of the 14 patients who have died, 11 succumbed to systemic disease progression, 2 to progressive, multifocal central nervous system disease, and 1 to systemic disease with concurrent, stable central nervous system disease. There were no complications related to SRS. Most CPMs are associated with RCC. SRS represents a safe and viable treatment option as primary modality for these metastases, with excellent outcomes.

Dosimetric Effect of Extra-Parenchymal Dose Spill in the Stereotactic Radiosurgical Treatment of Metastatic Lesions

Dosimetric Effect of Extra-Parenchymal Dose Spill in the Stereotactic Radiosurgical Treatment of Metastatic Lesions