Gamma Knife Treatment Research Articles

Cranial Neuralgias.

This article describes the clinical features and diagnostic criteria, pathophysiology (when known), and treatment strategies of the major cranial neuralgias. Abnormal vascular loops compressing cranial nerves are the most common known pathogenesis associated with the primary neuralgias. The most frequently encountered primary neuralgias are trigeminal neuralgia, occipital neuralgia, and, rarely, glossopharyngeal neuralgia. Nervus intermedius neuralgia is even more rare. All neuralgias merit a careful workup for secondary causes. Drug treatment generally relies on antiepileptic drugs, antidepressants, and baclofen. OnabotulinumtoxinA can be useful in treating some cranial neuralgias. Surgical and invasive treatments include ablation, gamma knife treatment, and microvascular decompression.

Validation of frame-based positioning accuracy with cone-beam computed tomography in Gamma Knife Icon radiosurgery

BackgroundFrame based positioning accuracy in Gamma Knife (GK) stereotactic radiosurgery (SRS) is extremely high but removal of a post may be necessary to enable the treatment in selected patients. ObjectiveTo verify the positioning accuracy in clinical scenarios with 4 and 3 posts in patients and phantoms using cone-beam CT (CBCT) of Gamma Knife Icon™. MethodsWe analyzed positioning accuracy for 12 patients with standard 4 post setup using pretreatment CBCT (pre-CBCT) on GK Icon™ and report 4 patients with different clinical scenarios (removal of a post). We performed phantom measurements to verify the frame accuracy via CBCT in different clinical scenarios without the influence of the human patient. ResultsMean frame accuracy for 12 patients with 4 posts was 0.35 mm/0.34 degree. Mean motion during treatment was 0.11 mm/0.04 degree. For two of the clinical scenarios where a post was removed, we found acceptable deviations within 0.66 mm/0.61 degree. For 2 patients, a deviation of 2.94 mm/−3.47 degree and 1.85 mm/−0.74 degree was found and replanning was necessary. Phantom measurements showed good agreement when planning MR/CT was performed with 4 or 3 post. Larger deviations of 0.86 mm/0.88 degree were detected when a post was removed after planning MR/CT. ConclusionThe frame accuracy with 4 posts before and during GK treatments is as high as expected. For clinical situations, where a post is removed after planning-CT/MR, pre-treatment position verification is strongly suggested using stereotactic CBCT or the P-CT/MR should be repeated to avoid possible mistreatments.

Personalized repeat Gamma Knife Radiosurgery treatment in patients with recurrent refractory trigeminal neuralgia

Objective: To analyze the prognosis and untoward effect in recurrent refractory trigeminal neuralgia (RRTN) patients who underwent repeat Gamma Knife Radiosurgery treatment (GKRS) retrospectively, and to summarize the experience of repeat Gamma Knife Radiosurgery treatment of recurrent refractory trigeminal neuralgia. Methods: RRTN patients who treated with repeat GKRS during 1998.8.1 to 2014.10.1 in Gamma Knife treatment Center of the Fifth Affiliated Hospital of Zhengzhou University were involved. The factors influencing long-term prognosis and facial numbness adverse reactions were statistically analyzed. Results: Therapeutic dose was an independent factor that influence long-term prognosis of RRTN patients. Therapeutic dose was a dangerous factor that influence long-term facial numbness. Interval time between twice GKRS treatment was a favorable factor for facial numbness. Long-term prognosis of repeat GKRS treatment was positively correlated with therapeutic dose. Untoward effect of facial numbness after repeat GKRS treatment was positively correlated with therapeutic dose and negatively correlated with interval time between twice GKRS treatment. Conclusions: Repeat GKRS for RRTN patients is safe and effective, but personalized treatment plan should be given according to the patient's own condition.

Outcome of partially irradiated recurrent nonfunctioning pituitary macroadenoma by gamma knife radiosurgery.

Gamma knife treatment outcome of large pituitary tumors which are only partially irradiated secondary to immediate proximity to critical structures such as the optic apparatus have not been rigorously studied. From July 2003 to December 2013, there were 41 cases of recurrent or residual nonfunctioning pituitary macroadenoma partially treated with gamma knife radiosurgery (GKRS) because the adenoma obscured part of the optic apparatus on planning SRS MR imaging. The follow up period after GKRS was 92.3 ± 5.6months. The percentage of tumor coverage with the full dose was 88.5 ± 0.7%. Five of 43 (11.6%) patients experienced a transient visional decrease and one patient experienced a permanent visual field defect. During the follow up, two patients underwent transphenoidal surgery and one patient had a craniotomy due to tumor progression. Seven patients (16.2%) developed cortisol and thyroxine deficiencies. In multiple variant analyses, transient visual decline was correlated to the tumor volume (> 3.5cc), percentage of tumor coverage (< 90%), the distance from the optic apparatus to the pituitary stalk (> 15mm) and percentage of tumor above the orbital apex (65%). In the limited case of this cohort, we found that partially treated pituitary nonfunctioning macroadenoma yielded a high tumor control rate. However, visual decline as a result of tumor progression or radiation effect can occur in a minority of patients. The radiosurgical technique warrants further study to better define the long-term risk to benefit profile for its use in complex pituitary macroadenoma obscuring part of the optic apparatus.

The efficiency of the prescribed dose of the gamma knife for the treatment of trigeminal neuralgia

Abstract Background This study designed to evaluate the clinical response of the gamma knife (GK) treatment of primary trigeminal neuralgia (TN) with two modalities of radiation doses. We tried to determine the best of these modalities for the treatment. Patients and methods A randomized clinical prospective study conducted in the Gamma Knife Center, Neuroscience Hospital, Baghdad, Iraq. It extended from July 2016 to June 2017. Forty-five patients with essential TN included in this study. All the patients had either IV and V score of Barrow Neurological Institute Pain scale (BNI) before the Gamma Knife (GK) therapy. Twenty Patients treated with a dose of 80 Gy and twenty-five patients exposed to 89 Gy. The clinical response monitored at fixed time intervals. Imaging evaluation of the nerve thickness used with 3 Tesla MRI before and following the GK therapy. Results 32% of the patients treated with 89 Gy reached pain-free status after one year of GK treatment, while no one of the treated patients with the dose 80 Gy reached that scores. A significant increase in nerve thickness was obtained by the radiation dose 89 Gy as compared to the effect of 80 Gy six-month post GK. After twelve months 32% of those patients treated with 80 Gy had a recurrence, while 19.5% recurrence found in patients treated with 89 Gy. Conclusion The clinical outcome for a longer duration is better when applying the dose 89 Gy.

Early magnetic resonance image volumetric changes of vestibular schwannoma after Gamma Knife radiosurgery: a prospective study of 18 cases

BackgroundGamma Knife radiosurgery is the principal alternative to microsurgical resection for acoustic neuromas (vestibular schwannomas). However; its increasing use worldwide and evolution of Gamma Knife device precision and safety had led to its acceptance as primary management for small- and medium-sized vestibular schwannomas. We tried to evaluate the tumor volume changes that occur with these tumors following Gamma Knife radiosurgery.MethodsEighteen patients with stereotactic radiosurgery with Gamma Knife through the year 2016 completed 1-year MRI follow-up at the 3rd, 6th, and 12th month after the Gamma Knife treatment. All the patients had unilateral vestibular schwannomas; the mean dose of radiation to the tumors was 12 Gy (range 10–14 Gy). Post treatment imaging was done with a high-resolution 3 T MRI scanner. Tumor sizes are calculated by using Onis software.ResultsFour patterns of volumetric changes were noticed. Most of the tumors increased in size on the third month follow-up MRI (89%); 15 (83%) tumors on the sixth month returned to their initial pre-Gamma Knife radiosurgery (PGKR) sizes. On the last (12th month) follow-up MRI with tumor sizes compared to initial PGKR sizes, 8 (44%) tumors showed no change, 6 (33%) tumors became smaller, and 4 (22%) tumors increase in size. Tumor control rate was 78% for the first year after Gamma Knife radiosurgery.ConclusionsThe third month follow-up MR images are practically not informative and might lead to unnecessary intervention; sixth month follow-up MR images are a crucial point and they may predict tumor behavior. Age, gender, and Koos stage whether stage II or III are not affecting tumor control. Gamma Knife radiosurgery is an effective intervention for Koos II and Koos III vestibular schwannomas.

Unintended consequences of the potential phase-out of gamma irradiation

The radioisotope cobalt-60 (Co-60) is important for commercial, medical, and agricultural applications. Its widespread use has meant that Co-60 can be found in less secured facilities, leading to the fear that unauthorized persons could obtain and use it to produce a “dirty bomb”. This potential security concern has led to government calls for phasing-out Co-60 and other radiation sources, despite ongoing safety and security regulations for handling, transport and use of radioactive sealed sources. This paper explores potential implications of phasing out radioisotopic technologies, including unintended safety and cost consequences for healthcare and food in the US and globally. The use of Co-60 for healthcare and agricultural applications is well-documented. Co-60 is used to sterilize single-use medical devices, tissue allografts, and a range of consumer products. Co-60 is used in Gamma Knife treatment of brain tumors in over 70,000 patients annually. Co-60 is also used to preserve food and kill insects and pathogens that cause food-borne illness. Co-60 is effective, reliable, and predictable. Limitations of alternative sterilization technologies include complex equipment, toxicities, incompatibilities with plastic, and physical hazards. Alternative ionizing radiation sources for wide-reaching applications, including e-beam and x-ray radiation, have advantages and drawbacks related to commercial scale capacity, penetrability, complexity and reliability. Identifying acceptable alternatives would require time, costs and lengthy regulatory review. FDA testing requirements and other hurdles would delay replacement of existing technologies and slow medical innovation, even delaying access to life-saving therapies. A phase-out would raise manufacturing costs, and reduce supply-chain efficiencies, potentially increasing consumer prices, and reducing supply. These consequences are poorly understood and merit additional research. Given Co-60’s importance across medical and non-medical fields, restrictions on Co-60 warrant careful consideration and evaluation before adoption.

Unintended consequences of the potential phase-out of gamma irradiation.

The radioisotope cobalt-60 (Co-60) is important for commercial, medical, and agricultural applications. Its widespread use has meant that Co-60 can be found in less secured facilities, leading to the fear that unauthorized persons could obtain and use it to produce a "dirty bomb". This potential security concern has led to government calls for phasing-out Co-60 and other radiation sources, despite ongoing safety and security regulations for handling, transport and use of radioactive sealed sources. This paper explores potential implications of phasing out radioisotopic technologies, including unintended safety and cost consequences for healthcare and food in the US and globally. The use of Co-60 for healthcare and agricultural applications is well-documented. Co-60 is used to sterilize single-use medical devices, tissue allografts, and a range of consumer products. Co-60 is used in Gamma Knife treatment of brain tumors in over 70,000 patients annually. Co-60 is also used to preserve food and kill insects and pathogens that cause food-borne illness. Co-60 is effective, reliable, and predictable. Limitations of alternative sterilization technologies include complex equipment, toxicities, incompatibilities with plastic, and physical hazards. Alternative ionizing radiation sources for wide-reaching applications, including e-beam and x-ray radiation, have advantages and drawbacks related to commercial scale capacity, penetrability, complexity and reliability. Identifying acceptable alternatives would require time, costs and lengthy regulatory review. FDA testing requirements and other hurdles would delay replacement of existing technologies and slow medical innovation, even delaying access to life-saving therapies. A phase-out would raise manufacturing costs, and reduce supply-chain efficiencies, potentially increasing consumer prices, and reducing supply. These consequences are poorly understood and merit additional research. Given Co-60's importance across medical and non-medical fields, restrictions on Co-60 warrant careful consideration and evaluation before adoption.

Outcome of radiotherapy for unresectable renal cell carcinoma and renal pelvis and ureter cancer

Objective To retrospectively analyze the clinical outcome of radiotherapy for unresectable renal cell carcinoma and renal pelvis and ureter cancer. Methods A total of 29 patients with unresectable renal cell carcinoma or renal pelvis and ureter cancer received radiotherapy from 2006 to 2015. Those patients were 18 males and 11 females aged between 41 and 95 years (median age 76 years). In those patients, 17 had renal cell carcinoma and 12 renal pelvis and ureter cancer; 14 had hematuria and 7 low back pain. All patients received dose-escalation radiotherapy, with 17 treated by gamma knife treatment and 12 by helical tomotherapy(HT). For the gamma knife treatment, the 50% isodose line was set as the prescribed dose line; the radiation dose was 3 to 5 Gy per fraction, with a total dose of 40-50 Gy around the planning target volume and 60-70 Gy around the gross tumor volume. HT was performed with a dose of 50/60/70 Gy in 15-20 fractions. Results For the primary lesion, the complete response (CR) and partial response (PR) rates were 17%(5/29) and 69%(20/29), respectively, yielding an overall response rate (CR+ PR) of 86%. After treatment, 93% of patients recovered from hematuria and 100% of patients recovered from low back pain. The 3-and 5-year sample sizes were 15 and 11, respectively. The 3-, and 5-year survival rates were 81%, and 81%, respectively, for renal cell carcinoma, and, 69%, and 69%, respectively, for renal pelvis and ureter cancer. During treatment, 25 patients had grade 1-2 digestive system reaction and 20 patients had grade 1-2 bone marrow suppression. The radiation-induced toxicity was reduced by medication. Conclusions Radiotherapy is safe and effective for treating renal cell carcinoma and renal pelvis and ureter cancer. It can improve the local control and overall survival rates. Radiotherapy provides an effective way to treat unresectable renal cell carcinoma and renal pelvis and ureter carcinoma. Key words: Kidney neoplasms/radiotherapy; Renal pelvis ureteral neoplasms/radiotherapy; Prognosis

Multimodality Management of Vein of Galen Malformations-An InstitutionalExperience.

The vein of Galen aneurysmal malformation (VGM) is a rare intracranial arteriovenous fistula with a dramatic manifestation during infancy and 100% mortality without treatment. Therapeutic strategies for VGMs have changed over time as a result of advances in endovascular techniques. We present our experience and multimodality approach within the last 4 decades. A retrospective analysis and angiographic review were performed of patients with VGM between 1975 and 2016 at our institution. Eighteen consecutive patients were identified, including 10 with choroidal and 8 with mural VGMs. In 37 endovascular interventions, a transarterial approach was mostly performed (82.8%). One patient was initially treated surgically and received 2 Gamma Knife treatments after multiple embolizations. The preferred embolization agent was histoacryl for choroidal VGMs and a combination of coils and histoacryl for mural VGMs. Total occlusion was achieved in 87.5% of mural VGMs and 11.1% of choroidal VGMs. Cerebral hemorrhages and infarction occurred only in patients younger than 1 month. At a median follow-up interval of 4.6 years, good outcome was achieved in 53.8% and poor outcome in 46.2%, with an overall mortality of 16.7%. Poor outcome was significantly associated with choroidal-type VGMs, age <1 month at first embolization, and incomplete occlusion. Endovascular embolization using a transarterial approach is the therapy of choice. Gamma Knife radiosurgery can be considered as second-line therapy in a multimodal approach. Whereas treatment within the first month of life is associated with the highest mortality and complications, we did not detect any severe adverse events thereafter.

OUT-OF-FIELD DOSES IN CHILDREN TREATED FOR LARGE ARTERIOVENOUS MALFORMATIONS USING HYPOFRACTIONATED GAMMA KNIFE RADIOSURGERY AND INTENSITY-MODULATED RADIATION THERAPY.

The purpose of this study was to measure out-of-field organ doses in two anthropomorphic child phantoms for the treatment of large brain arteriovenous malformations (AVMs) using hypofractionated gamma knife (GK) radiosurgery and to compare these with an alternative treatment using intensity-modulated radiation therapy (IMRT). Target volume was identical in size and shape in all cases. Radiophotoluminescent (RPL), thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimeters were used for out-of-field dosimetry during GK treatment and a good agreement within 1-2% between results was shown. In addition, the use of multiple dosimetry systems strengthens the reliability of the findings. The number of GK isocentres was confirmed to be important for the magnitude of out-of-field doses. Measured GK doses for the same distance from the target, when expressed per target dose and isocentre, were comparable in both phantoms. GK out-of-field doses averaged for both phantoms were evaluated to be 120 mGy/Gy for eyes then sharply reduced to 20 mGy/Gy for mandible and slowly reduced up to 0.8 mGy/Gy for testes. Taking into account the fractionation regimen used to treat AVM patients, the total treatment organ doses to the out-of-field organs were calculated and compared with IMRT. The eyes were better spared with GK whilst for more distant organs doses were up to a factor of 2.8 and 4 times larger for GK compared to IMRT in 5-year and 10-year old phantoms, respectively. Presented out-of-field dose values are specific for the investigated AVM case, phantoms and treatment plans used for GK and IMRT, but provide useful information about out-of-field dose levels and emphasise their importance.

The evaluation of effect of gamma knife on cavernous sinus hemangioma through computed tomography

Objective: Using Computed Tomography (CT) to evaluate the treatment effect of gamma knife surgery in the treatment of Cavernous Sinus Hemangioma (CSHs). Method: This article retrospectively analysed 31 patients with CSHs who were confirmed clinically and pathologically from Oct 2013 to Apr 2015 in Imaging Center of Xian Central Hospital. Using CT scan images to observe the changes of patient’s clinical symptoms and tumour size before and after gamma knife treatment. The various data were statistically analysed. Further analysis of the influence of tumour lesion size, location and therapeutic dose on the therapeutic effect. Results: With CT scan, the location of tumour lesion and calcification for CHSs patients can be clearly be seen. After treatment with gamma knife, the diameter of tumour reduced from 3.57 ± 0.46 cm to 2.93 ± 0.56 cm, with significant reduction (P<0.05). From the change of Gross Tumour Volume (GTV) of these patients, 0 cases is complete remission, 22 cases are partial remission, 8 cases are stable and 1 case is progressive. The effective rate of gamma knife is 10.97%, and the stable rate is 96.77%. Furthermore, after treatment with gamma knife, 20 patient’s headache symptoms have been improved, 13 patient’s diplopia symptom have been improved, 5 patient’s tinnitus symptom have been alleviated, 18 patient’s eyelid ptosis symptom have been improved, 21 patient’s facial numbness symptom have been improved. Additionally, the location of tumour lesion is one factor that influences the treatment effect (P<0.05). Conclusions: Gamma knife treatment could improve nerve function and other symptoms in patients with CHSs, and has a good therapeutic effects and important value.

Proof of Concept in a Case Study of Glioblastoma Multiforme Successfully Treated with IV Quercetin in Combination with Leading Edge Gamma Knife and Standard Treatments

The Stupp protocol has become standard of care for the treatment of glioblastoma (GBM) (since its publication in 2005) and has led to some limited survival improvements. This protocol, consists of radiotherapy and concomitant chemotherapy with temozolomide, an alkylating agent. Temozolomide + radiation, compared to radiation alone had added in average 3 months additional life span, 16 percent improved survival at 2 years. That said since 2005, the standard of care has not changed in regards to the treatment of early diagnosed aggressive or multifocal GBM, and unfortunately the expected survival is still poor with 75 percent of patients dying in less than 2 years and average survival of 15 months. In patients with multifocal tumors (such as the case below) the average survival is even worse with less than 4 months at her age [1]. Here we present a case study of a patient with advanced multifocal, and rapidly progressing Glioblastoma Multiforme treated with STUPP protocol in combination with IV Quercetin. The patient experienced improved quality of life and response, compared to historical data. It is our recommendation to investigate such combinational approach in patients with Glioblastoma, as in our case it proved to be safe and effective with improved quality of life and performance as well as clinical response and survival.

Instant and Early Efficacy of Gamma Knife Treatment on Trigeminal Neuralgia

Instant and Early Efficacy of Gamma Knife Treatment on Trigeminal Neuralgia

γTools: A modular multifunction phantom for quality assurance in GammaKnife treatments

PurposeWe present the γTools, a new phantom designed to assess geometric and dosimetric accuracy in Gamma Knife treatments, together with first tests and results of applications. MethodsThe phantom is composed of two modules: the imaging module, a regular grid of 1660 control points to evaluate image distortions and image registration result and the dosimetry module for delivered dose distribution measurements. The phantom is accompanied by a MatLab routine for image distortions quantification. Dose measurement are performed with Gafchromic films fixed between two inserts and placed in various positions and orientations inside the dosimetry module thus covering a volume comparable to the full volume of a head. ResultsTests performed to assess the accuracy and precision of the imaging module demonstrated sub-millimetric values. As an example of possible applications, the phantom was employed to measure image distortions of two MRI scanners and to perform dosimetric studies of single shots delivered to homogeneous and heterogeneous materials. Due to the phantom material, the measured absolute dose do not correspond to the planned dose; doses comparisons are thus carried out between normalized dose distributions. Finally, an end-to-end test was carried out in the treatment of a neuroma-like target which resulted in a 100% gamma passing rate (2% local, 2 mm) and a distance between the real target perimeter and the prescription isodose centroids of about 1 mm. ConclusionsThe tests demonstrate that the proposed phantom is suitable to assess both the geometrical and relative dosimetric accuracy of Gamma Knife radiosurgery treatments.

Abstract ID: 157 Development of Geant4-based patient-specific QA system of gamma knife treatment plans using automated DICOM-RT interface

Gamma knife system which uses 192 small photon beams is widely considered as a very precise modality for intracranial radiosurgery. However, there are still limitations in current treatment planning system (TPS) for accurately estimating the absolute dose in the small volume, or the dose distribution in the inhomogeneous area such as the case of embolization of arteriovenous malformations and the located target volume behind an air cavity [1] . The purpose of this study is to develop quality assurance (QA) system of gamma knife treatment plans based on a patient-specific model constructed by an automated DICOM-RT interface in Geant4. The Leksell Gamma Knife Perfexion was designed in Geant4.10.00 based on the manufacturer’s detailed information. Dose distributions in the spherical water phantom with a diameter of 16 cm were compared between Geant4 and the film measurement for the validation system. For extracting the patient-dependent parameters, automated DICOM-RT interface was developed for constructing the patient-specific model. In-house developed system is able to manually define the physical property of a special volume using the region of interest (ROI) contour data stored in a DICOM file. The dose distributions in the water phantom were compared between Geant4, measurement data and manufacture’s values in terms of full width at half maximum (FWHM). FWHM of Geant4 and measurement were quite well matched with manufacture’s value within 0.3, 0.2 and 0.7 mm in both the x and y direction for 4, 8 and 16 mm, respectively. Furthermore, the dose distributions of Geant4 and commercial TPS were well matched for different beam size combinations for each of the eight sectors. The developed QA system shows the potential to precisely estimate the dose distribution in the patients. In the future, assessment of the absolute dose distribution calculated by Geant4 and commercial TPS for the clinical cases will be performed. Moreover, magnetic resonance (MR) images will be employed in our system for sophisticated modelling the heterogeneities in the patients.

Long-Term Outcome and Prognostic Factors After Repeated Surgeries for Intracranial Hemangiopericytomas.

The goals of the present study were to identify predictors of better survival and to propose appropriate management strategies for recurrent hemangiopericytomas (HPC) and anaplastic hemangiopericytomas (AHPC). Between 2008 and 2016, 191 patients underwent surgeries for HPC and/or AHPC at our institute, and during follow-up the tumors recurred in 57 patients, including 31 males (54.4%). At the first recurrence, 30 patients (52.6%) underwent surgery, 25 patients (43.9%) declined surgery, and 2 patients (3.5%) received Gamma Knife treatment. The 1-year, 3-year, and 5-year actuarial rates of second progression-free survival in the HPC group were 73.3%, 46.7%, and 24.9%, respectively; the rates in the AHPC group were 66.7%, 66.7%, and 0%, respectively. The actuarial 1-year, 3-year, and 5-year overall survival rates of HPC after the first recurrence were 87.4%, 69.2%, and 39.5%, respectively; in the AHPC group, the rates were 85.2%, 45.9%, and 24.5%, respectively. Each 1-month increase in the time interval from first surgery to first recurrence (first recurrence-free survival) (hazard ratio, 0.972; 95% confidence interval, 0.952-0.993; P= 0.010) was strongly associated with better overall survival. Patients who received surgery with or without radiation at their first recurrence survived longer than patients who did not (estimated median survival time, 53.0 months vs. 35.7 months; P= 0.028). Treatment is imperative for the first recurrence of HPC or AHPC. More attention should be paid to patients with shorter first recurrence-free survival. Surgery is the first choice for their first recurrence and radiotherapy should be administered if there is no history of radiotherapy.

Effect of tumor volume and radiation dose on the prognosis of hepatocellular carcinoma patients treated with whole body gamma knife

Objective To examine the effects of gross tumor volume (GTV) and radiation dose on the prognosis of hepatocellular carcinoma (HCC) patients treated with whole body gamma knife. Methods The clinical data of 69 HCC patients who underwent body gamma knife treatment from January 2012 to June 2015 in the Radiotherapy Center of the PLA General Hospital were retrospectively reviewed. Based on a 50% or 60% isodose coverage of the planning target volume (PTV), patients were treated with a radiation dose of 4-5 Gy per fraction, and a total marginal dose of 36-50 Gy (median dose 45 Gy). Short-term efficacy, overall survival (OS), and the adverse effect of the treatment were evaluated. The optimal cut-off tumor volume was identified using the receiver operating characteristic curve, and survival was determined by the Kaplan-Meier method. Univariate and multivariate analyses were performed using the log-rank test and Cox proportional hazards regression model, respectively. Results The overall short-term response rate of the 69 patients was 67%. The 1-and 2-year OS rates were 62% and 40%, respectively, with a median survival of 18.6 months. The multivariate analysis showed that gross tumor volume (GTV) 93 cm3(P=0.665). Conclusions GTV is an independent prognostic factor for overall survival of HCC patients. Although high-dose radiotherapy provides survival benefits to patients with small GTV, it is not necessarily suitable for patients with large GTV. Key words: Liver neoplasms/stereotactic radiotherapy; Gross tumor volume; Prognosis

Hypertrophic Olivary Degeneration and Palatal or Oculopalatal Tremor.

Hypertrophic degeneration of the inferior olive is mainly observed in patients developing palatal tremor (PT) or oculopalatal tremor (OPT). This syndrome manifests as a synchronous tremor of the palate (PT) and/or eyes (OPT) that may also involve other muscles from the branchial arches. It is associated with hypertrophic inferior olivary degeneration that is characterized by enlarged and vacuolated neurons, increased number and size of astrocytes, severe fibrillary gliosis, and demyelination. It appears on MRI as an increased T2/FLAIR signal intensity and enlargement of the inferior olive. There are two main conditions in which hypertrophic degeneration of the inferior olive occurs. The most frequent, studied, and reported condition is the development of PT/OPT and hypertrophic degeneration of the inferior olive in the weeks or months following a structural brainstem or cerebellar lesion. This “symptomatic” condition requires a destructive lesion in the Guillain–Mollaret pathway, which spans from the contralateral dentate nucleus via the brachium conjunctivum and the ipsilateral central tegmental tract innervating the inferior olive. The most frequent etiologies of destructive lesion are stroke (hemorrhagic more often than ischemic), brain trauma, brainstem tumors, and surgical or gamma knife treatment of brainstem cavernoma. The most accepted explanation for this symptomatic PT/OPT is that denervated olivary neurons released from inhibitory inputs enlarge and develop sustained synchronized oscillations. The cerebellum then modulates/accentuates this signal resulting in abnormal motor output in the branchial arches. In a second condition, PT/OPT and progressive cerebellar ataxia occurs in patients without structural brainstem or cerebellar lesion, other than cerebellar atrophy. This syndrome of progressive ataxia and palatal tremor may be sporadic or familial. In the familial form, where hypertrophic degeneration of the inferior olive may not occur (or not reported), the main reported etiologies are Alexander disease, polymerase gamma mutation, and spinocerebellar ataxia type 20. Whether or not these are associated with specific degeneration of the dentato–olivary pathway remain to be determined. The most symptomatic consequence of OPT is eye oscillations. Therapeutic trials suggest gabapentin or memantine as valuable drugs to treat eye oscillations in OPT.

Cerebellopontine angle meningioma diagnosed based on symptoms of trigeminal neuralgia in late pregnancy and showing spontaneous reduction in the early postpartum period: A case report

AbstractWe describe a case of cerebellopontine angle meningioma, diagnosed by the initial symptoms of trigeminal neuralgia in late pregnancy, that showed spontaneous tumor volume reduction in the puerperal period. A 28‐year‐old woman developed left facial pain at 30 weeks of pregnancy. Magnetic resonance imaging showed a left cerebellopontine angle tumor. She decided to undergo gamma knife treatment at her local hospital. Fifty‐five days postpartum, magnetic resonance imaging was repeated to plan for this treatment. Gadolinium‐enhanced T1‐weighted imaging showed that the tumor had decreased, with no mass effect. The tumor was considered a low‐grade meningioma present before pregnancy, which grew as a result of hypervascular changes or hormone‐induced cellular proliferation in late pregnancy, and subsequently decreased in volume because of blood flow normalization or hormone normalization. The differential diagnosis and treatment of cerebellopontine meningioma during puerperium require careful observation, as the tumor can spontaneously decrease in size despite being symptomatic.