Stereotactic Techniques Research Articles

Penumbra width determination of single beam and 201 beams of Gamma Knife machine model 4C using Monte Carlo simulation

AbstractBackgroundOne of the stereotactic radiosurgery techniques is Gamma Knife radiosurgery, in which intracranial lesions that are inaccessible or inappropriate for surgery are treated using 201 cobalt-60 sources in one treatment session. In this conformal technique, the penumbra width, which results in out-of-field dose in tumour-adjacent normal tissues should be determined accurately. The aim of this study is to calculate the penumbra widths of single and 201 beams for different collimator sizes of Gamma Knife machine model 4C using EGSnrc/BEAMnrc Monte Carlo simulation code and comparison the results with EBT3 film dosimetry data.Methods and materialsIn this study, simulation of Gamma Knife machine model 4C was performed based on the Monte Carlo codes of EGSnrc/BEAMnrc. To investigate the physical penumbra width (80−20%), the single beam and 201 beams profiles were obtained using EGSnrc/DOSXYZnrc code and EBT3 films located at isocentre point in a spherical Plexiglas head phantom.ResultsBased on the results, the single beam penumbra widths obtained from simulation data for 4, 8, 14 and 18 mm collimator sizes alongXaxis were 0·75, 0·77, 0·90 and 0·92 mm, respectively. The data for 201 beams obtained from simulation were 2·61, 4·80, 7·92 and 9·81 mm alongXaxis and 1·31, 1·60, 1·91 and 2·14 mm alongZaxis and from film dosimetry were 3·21, 4·90, 8·00 and 10·61 mm alongXaxis and 1·22, 1·69, 2·01 and 2·25 mm alongZaxis, respectively.ConclusionThe differences between measured and simulated penumbra widths are in an acceptable range. However, for more precise measurement in the penumbra region in which dose gradient is high, Monte Carlo simulation is recommended.

Concentric Stereotactic Technique of Percutaneous Endoscopic Transforaminal Discectomy and Radiation Exposure to Surgeons

In percutaneous endoscopic transforaminal discectomy (PETD), surgeons are exposed to intraoperative radiographic radiation over a long-term career, which may be correlated with high risk of iatrogenic radiation hazards. The purpose of this prospective cohort study was to assess the impact of concentric stereotactic technique on radiation exposure to surgeons in PETD. Patients who underwent conventional PETD were regarded as group A, whereas those undergoing PETD with concentric stereotactic technique were considered as group B. The primary outcomes were cumulative radiation dose to the surgeon's eye, thyroid gland, and breast. A total of 34 patients were treated in group A and 30 patients were treated in group B. The cumulative radiation dose of the eye per operation was 0.017 (0.58/34) mSv in group A and 0.010 (0.31/30) mSv in group B, which meant a reduction of 41.18%. The cumulative radiation dose of the thyroid gland per operation was 0.018 (0.60/34) mSv in group A and 0.011 (0.33/30) mSv in group B, which meant a reduction of 38.89%. The cumulative radiation dose of the chest per operation was 0.039 (1.33/34) mSv in group A and 0.023 (0.70/30) mSv in group B, which meant a reduction of 41.03%. There were no significant differences in hospital stay, visual analog scale score of waist and leg pain, Oswestry Disability Index score, MacNab satisfaction, and complications between the 2 groups (P > 0.05). The concentric stereotactic technique can effectively reduce radiation exposure to surgeons by about 40%.

P280] Comparison of two stereotactic body radiotherapy techniques for the treatment of prostate cancer

Purpose In this study, it has been compared the Planning Target Volume (PTV) and critical organs dose in Stereotactic Body Radiotherapy (SBRT) plans created by CyberKnife (CK) and volumetric arc radiotherapy (VMAT) techniques for patients with prostate cancer. Methods The computed tomography images of 8 patients with low or intermediate risk prostate cancer were acquired in 1 mm thickness and transferred to the MultiPlan v4.5.3 treatment planning system (TPS). The PTV and critical structures were contoured. The Clinical Target Volume (CTV) was generated by encompassing the prostate plus the 1 cm proximal part of seminal vesicles. To create the PTV, a margin of 3 mm was added in the posterior direction and 5 mm in the other directions to the CTV. The treatment plans were created with CK technique. To create the SBRT plans with the VMAT technique, the volumes were transferred to the Aria v15.1 system. The double arc VMAT plans were prepared. The prescribed dose for PTV was 33.50 Gy/5fr in both techniques. Conformity Index (CI), Homogeneity Index (HI) of PTV, critical organs doses, the integral dose (ID) to the patient body and monitor unit (MU) values were assessed using the Wilcoxon test. Results For plans created with CK and VMAT technique, CI was 1.11 ± 0.06 and 1.04 ± 0.01, HI was 1.20 ± 0.04 and 1.08 ± 0.01, respectively; there was a statistically significant difference between them. The differences between all critical organ doses except D1cc of the rectum were significant statistically in favor of VMAT. The mean of the difference of the mean right testicular dose was 137.1 cGy. It was 113.8 cGy for left testicular. MU value and the ID were found significantly to be higher in the CK technique. Conclusions The VMAT technique compared with the CK technique provides better sparing of the critical structures, and the irradiation time is shorter as the MU value is less. The less irradiation time is to be advantageous in minimizing uncertainties due to patient movement. In conclusion, the VMAT technique may be preferred, especially in young patients. This work was supported by Scientific Research Projects Coordination Unit of Istanbul University (Project Number: I.U. BAP-23057).

Geometric accuracy on verification of stereotactic radiotherapy with the use of a double mask versus the Leksell G frame

Patient immobilization is an important element for the geometric accuracy of stereotactic radiotherapy (SRT) techniques. However, differences in the immobilization and accuracy with the use of a G frame versus a double remain unknown. The aim of this retrospective comparative cross-sectional study was to compare the extents of geometrical shifting on verification of stereotactic techniques with the use of a G frame versus a double mask. The study cohort included patients who received RT between February and March 2016 at the Department of Radiotherapy of Cipto Mangunkusumo Hospital. The t-test was used to compare geometrical shifting values on verification with the use of a G frame versus a double mask. The mean value of geometrical shifting in patients with SRT with the use of a double mask on the laterolateral, craniocaudal, and anteroposterior axes were 0.4 ± 0.3, 0.5 ± 0.4, and 0.5 ± 0.4 mm, respectively, while values with the use of a G frame were 0.3 ± 0.2, 0.3 ± 0.4, and 0.4 ± 0.3 mm, respectively. There were no differences in the mean geometrical shifting values with the use of a double mask versus a G frame.

Anatomic Investigation of the Trajectory for Stereotactic Laser Amygdalohippocampectomy.

Magnetic resonance imaging-guided laser interstitial thermal therapy (LITT) has emerged as a promising treatment for mesial temporal lobe epilepsy. Surgeons must understand the relevant anatomy that is traversed by the catheter and affected by ablation. To study the anatomic structures crossed by the LITT catheter until it reaches the amygdala. Three human cadaveric heads were implanted with catheters using a frameless stereotactic technique. The Visualase® system (Medtronic, Dublin, Ireland) was utilized to ablate along the trajectory. Coronal and oblique axial slices were created. Fiber tract dissections were performed in a lateral-medial and inferior-superior scheme. Magnetic resonance tractography was acquired to illustrate the tracts dissected. Entry points occurred within 4 cm of the transverse and sagittal sinus, inferior to the lambdoid suture. The cortex of the inferior occipital gyrus was crossed in the region of the transverse occipital sulcus. The vertical occipital fasciculus was crossed en route to passing through the optic radiations. The catheter crossed through or inferior to the optic radiations before piercing the parahippocampal gyrus at about 4 cm from the skull. The catheter entered the hippocampus as it pierced the superior margin of the parahippocampus at 6 cm. The catheter entered the head of the hippocampus to lie inferolateral to the amygdala in the last centimeter of the trajectory. Understanding the anatomic principles of LITT catheter trajectories will improve the ability to perform this procedure. The current study is the first to examine the anatomy of this trajectory and will serve as the basis for future studies.

LINAC treating more patients having brain arteriovenous malformations with stereotactic radiosurgery technique

Background: Linear accelerator (LINAC) based radiosurgery for a brain arteriovenous malformation (bAVM) is replacing gamma knife radiosurgery. We present clinical outcome, obliteration rates and predictor factors of treatment success following LINAC radiosurgery for bAVM which is not much addressed subject in Middle East. Methods: 13 patients who underwent LINAC radiosurgery for brain arteriovenous malformations from November 2008 to November 2011 in our radiation oncology department were retrospectively analyzed. Recollection of demographic data, AVM and treatment characteristics along with clinical and radiographic follow up information was done by reviewing the electronic data base. Results: All thirteen patients underwent stereotactic radiosurgery by linear accelerator based treatment delivery system (BrainLab) over three years. These included 7 males and 6 females, with median age of 22 years. Intracranial hemorrhage was a presenting feature in 7 (54 %) of patients. Prior embolization was done in 10 (77%) patients with 7 patients having more than once undergone this procedure. The location of AVM was superficial in 9 (70%) and deep in brain in 4 (30%) patients. The mean AVM score was 0.97 with 3 patients having AVM score ≥ 1 with mean Spetzler-Martin grade of 2.7 and 8 (62%) patients having grade 3 or more. Median follow up was 30 months. Mean dose delivered was 21.7 Gy in single fraction. Complete obliteration of AVM nidus was achieved in 9 (70%) patients while 4 patients (30%) had partial obliteration. Six patients (67 %) achieved complete obliteration among 9 who had AVM score of less than 1. Post radiosurgery neurological deficit occurred in only one patient in form of right temporal field loss. Conclusions: Linear accelerator based radiosurgery is promising treatment option for brain AVMs in majority of cases with reasonable adverse effect profile.

Comparison of platelet-albumin-bilirubin (PALBI), albumin-bilirubin (ALBI), and child-pugh (CP) score for predicting of survival in advanced hcc patients receiving radiotherapy (RT).

PurposeThis work evaluated the prognostic performance of Child-Pugh (CP), albumin-bilirubin (ALBI) and platelet-albumin-bilirubin (PALBI) scores in hepatocellular carcinoma (HCC) patients undergoing radiotherapy (RT).ResultsThe study included 174 consecutive patients with 63% at CP A5 (n = 110) and 34% at CP A6 (n = 64). The median ALBI score was −2.39 (range: −3.61 to −1.41) with 34.5% at grade A1 (n = 60) and 65.5% at grade A2 (n = 114). The median PALBI score was −2.39 (range −3.39 to −1.24) with 33.3% at grade 1 (n = 58), 41.4% at grade 2 (n = 72) and 25.3% at grade 3 (n = 44). With a median follow-up of 21.7 months, the median OS of the entire cohort was 22.2 months. OS was significantly associated with the PALBI grade (p = 0.002) and for the ALBI grade (p = 0.00495), but not for the CP score (p = 0.46). The PALBI grade has a significantly higher AUC compared than the ALBI grade or CP scores in predicting OS. The PALBI grade was predictive of CP score decline ≥2 (20% grade 3 vs. 5.3% grade 1/2 p = 0.05) but the ALBI and CP scores were not.ConclusionAmong CP A HCC patients receiving radiotherapy, the PALBI and ALBI grade maybe a better prognostic tool than the CP score. The role of PALBI in predicting liver toxicity warranted further exploration.MethodsWe retrospectively reviewed HCC patients treated with individualized hypo-fractionated radiotherapy (IHRT) using stereotactic technique from 2006 to 2015. We collected CP, ALBI and PALBI scores prior to treatment and analyzed their correlation with overall survival (OS) and liver toxicity.

A simple method to account for skin dose enhancement during treatment planning of VMAT treatments of patients in contact with immobilization equipment.

PurposeThe ability to accurately predict skin doses and thereby design radiotherapy treatments that balance the likelihood of skin reactions against other treatment objectives is especially important when hypofractionated prescription regimes are used. However, calculations of skin dose provided by many commercial radiotherapy treatment planning systems are known to be inaccurate, especially if the presence of immobilization equipment is not accurately taken into account. This study proposes a simple method by which the accuracy of skin dose calculations can be substantially improved, to allow informed evaluation of volumetric modulated arc therapy (VMAT) treatment plans.MethodA simple method was developed whereby dose calculation is split into grid regions, each with a correction factor which determines MU scaling for skin dose calculation. Correction factors were derived from film measurements made using a geometrically simple phantom in partial contact with a vacuum immobilization device. This method was applied to two different test treatments, planned for delivery to a humanoid phantom with a hypofractionated stereotactic body radiotherapy technique, and results were verified using film measurements of surface dose.ResultsCompared to the measured values, calculations of skin dose volumes corresponding to different grade tissue reactions were greatly improved through use of the method employed in this study. In some cases, the accuracy of skin dose evaluation improved by 76% and brought values to within 3% of those measured.ConclusionThe method of skin dose calculation in this study is simple, can be made as accurate as the user requires and is applicable for various immobilization systems. This concept has been verified through use on SBRT lung treatment plans and will aid clinicians in predicting skin response in patients.

30 Gy single dose stereotactic body radiation therapy (SBRT): Report on outcome in a large series of patients with lung oligometastatic disease

ObjectivesTo evaluate the local control (LC) and long term adverse effects in a series of patients with lung metastases who received 30 Gy in single dose with stereotactic technique. Materials and MethodsBetween December 2008 and April 2016, a total of 166 lung metastases in 129 patients affected by oligometastatic disease were treated at our Institution with stereotactic body radiotherapy (SBRT). Mainly, the primary tumors were non small-cell lung cancer and colorectal cancer (45.2% and 28.8%, respectively). Prognostic factors were also assessed. ResultsThe median follow-up was 38 months. Local progression occurred in 24 (14.4%) lesions in 21 patients. Intra-thoracic progression (new lung lesions or thoracic lymph node metastases) occurred in 59 (45.7%) patients. Forty-five (34.8%) patients had distant progression after a median time of 14 months. The 3- and 5-years local relapse-free survival (LPFS) were 80.1% and 79.2% (median not reached), respectively. One-hundred forty-eight patients were evaluated for late toxicity (follow-up >6 months): 51 (34.4%) patients had grade ≤2 fibrosis, 11 (7.4%) patients experienced grade 3 fibrosis. Two (1.3%) cases of rib fracture occurred. One case of toxic death (grade 5) has been reported. Median OS was 39 months. At the univariate analysis, lesion diameter ≤18 mm correlated significantly with a longer LPFS (p = 0.001). At the multivariate analysis, lesion diameter <18 mm was predictive for longer LPFS (p = 0.006). Also, oligometastases from primary colorectal cancer was a significant predictive factor for worse LPFS (p = 0.041) and progression-free survival (p = 0.04). ConclusionsTo our knowledge, the current study represents the largest series on the use of SBRT 30 Gy single dose for lung metastases. Our results confirm the effectiveness and safety of this schedule administered in selected oligometastatic patients. Further prospective series could better validate these results.

Clinical outcomes of perioptic tumors treated with hypofractionated stereotactic radiotherapy using CyberKnife® stereotactic radiosurgery.

Stereotactic radiation technique is widely reported as an effective treatment for various types of benign intracranial tumors. However, single fraction radiosurgery (SRS) is not recommended for tumors located close to the optic apparatus due to the restricted radiation tolerance dose of the optic pathway. Recent advances in radiotherapy include advanced frameless radiosurgery using hypofractionated stereotactic radiotherapy (HSRT), and this has become an attractive treatment option for perioptic tumors within 2-3mm of the optic pathway. Accordingly, the aim of this study was to investigate the clinical outcomes of perioptic tumors treated with HSRT using CyberKnife® (CK) robotic radiosurgery system relative to tumor control, vision preservation and toxicity. This retrospective analysis of prospectively collected data included consecutive 100 patients that were diagnosed with and treated for perioptic tumor at the Radiosurgery center, Ramathibodi Hospital during the January 2009 to December 2012 study period. The median tumor volume was 6.81cm3 (range 0.37-51.6), and the median prescribed dose was 25Gy (range 20-35) in 5 fractions (range 3-5). After the median follow-up time of 37.5months (range 21-103), two patients developed tumor progression at 6 and 34months post-HSRT. The 5-year overall survival was 97%, and the 5-year local control was 97.5%. At the last follow-up, no vision deterioration or newly developed hypopituitarism was detected in our study. Although a longer follow-up is needed, HSRT yields a high level of local control and vision preservation, and should be considered a treatment of choice for perioptic tumor located close to the optic apparatus.

PROstate Multicentre External beam radioTHErapy Using a Stereotactic boost: the PROMETHEUS study protocol

BackgroundHigh Dose Rate Brachytherapy (HDRB) boost is a well-established treatment for prostate cancer (PC). We describe the PROstate Multicentre External beam radioTHErapy Using Stereotactic boost (PROMETHEUS) study. Non-surgical stereotactic techniques are used to deliver similar doses to HDRB boost regimens with a dose escalation sub-study.MethodsEligible patients have intermediate or high risk PC. PROMETHEUS explores the safety, efficacy and feasibility of multiple Australian centres cooperating in the delivery of Prostate Stereotactic Body Radiotherapy (SBRT) technology. A SBRT boost component Target Dose (TD) of 19Gy in two fractions is to be delivered, followed by a subsequent EBRT component of 46Gy in 23 fractions. Once accrual triggers have been met, SBRT doses can be escalated in 1 Gy increments to a maximum of 22Gy in two fractions. Patient safety will also be measured with the rate of both acute and late moderate to severe Gastro-Intestinal (GI) and Genito-Urinary (GU) Common Terminology Criteria for Adverse Events (CTCAE) toxicities as well as patient reported quality of life. Efficacy will be assessed via biochemical control after 3 years.DiscussionPROMETHEUS aims to generate evidence for a non-surgical possible future alternative to HDRB boost regimens, and introduce advanced radiotherapy techniques across multiple Australian cancer centres.Trial registrationThe study was retrospectively registered on the ANZCTR (Australian New Zealand Clinical Trials Registry) with trial ID: ACTRN12615000223538.

Brain and Behavior: Commentary on Two Cases Involving the Effect of Structural Brain Lesions on Psychiatric Disorders.

In this issue of the journal, 2 case reports are presented that illustrate explicit influences of structural brain lesions on psychiatric symptoms. In both cases, the patients had preexisting, classically diagnosed psychiatric disorders-schizophrenia in the first case and bipolar I disorder in the second case. In the first case, a 61-year-old woman with chronic paranoid schizophrenia experienced a marked reduction in psychotic symptoms after bilateral frontal strokes. In the second case, a 60-year-old man who had experienced manic and depressive episodes since his 20s developed partial complex seizures after having repeated head trauma in his 40s, with subsequent onset of chronic personality changes associated with temporal lobe epilepsy that made his psychiatric treatment a greater challenge. The presentations in these 2 cases raise intriguing neuropsychiatric questions concerning the effects on regional brain activity of a variety of nonpharmacological psychiatric interventions (eg, stereotactic neurosurgical techniques, deep brain stimulation, electroconvulsive therapy, certain types of psychotherapy), and concerning possible physiological pathways shared by seizure kindling in epilepsy and recurrent episodes of bipolar disorder.

Radiosurgical options in neuro-oncology: a review on current tenets and future opportunities. Part I: therapeutic strategies.

Stereotactic radiosurgery can nowadays be considered not only as a potential adjuvant to surgical treatment of several neuro-oncological pathologies, including primary tumors and metastatic lesions, but in some cases also as a valuable alternative tailored option. In Part I of the review, we propose a dissertation focused on the different irradiation stereotactic radiosurgery techniques to date available for clinical indications more relevant to oncologists and oncologic surgeons, such as high-grade and low-grade gliomas, metastases and meningiomas. It is noteworthy that the most recent body of literature correlated with this topic shows that the therapeutic results presently achievable are revolutionizing the way patients are diagnosed and managed worldwide. As we sought to shed light on the current potentialities of stereotactic radiosurgery, we must consider that to exploit all the benefits provided by this shift in clinical practice, a profound awareness by all practitioners involved in the care of neoplastic patients is certainly warranted.

Integrating interventional oncology in the treatment of liver tumors.

SummaryBackgroundPercutaneous ablation techniques offer a vast armamentarium for local, minimally invasive treatment of liver tumors, nowadays representing an established therapeutic option, which is integrated in treatment algorithms, especially for non-resectable liver tumors. The results of ablative treatment compare very well to surgical treatment in liver lesions, and confirm that these techniques are a valuable option for bridging for transplantation. Different techniques have been established to perform tumor ablation, and the feasibility varies according to the procedure and technical skills of the operator, depending on the size and location of the liver lesion. In recent years, stereotactic multi-needle techniques using 3D trajectory planning, general anesthesia, and tube disconnection during needle placement have had a strong impact on the application range of ablation for liver tumors.ConclusionIt is well known that creating a sufficient ablation margin and overlapping ablation zones is one key issue to enable ablation of large liver lesions with tumor-free margins (A0 ablation in analogy to R0 resection). Image fusion during treatment and follow-up assure highly accurate staging procedures and interventional planning.Novel aspectsReview on the standards in ablation techniques for the treatment of liver tumors. Update on different ablation techniques, indications, and contraindications for percutaneous liver tumor treatment. Summary of recently published reports on liver tumor ablation.

First-in-human evaluation of the Cleveland Multiport Catheter for convection-enhanced delivery of topotecan in recurrent high-grade glioma: results of pilot trial 1.

Progress in management of high-grade gliomas (HGGs) has been hampered by poor access of potential therapeutics to the CNS. The Cleveland Multiport Catheter (CMC), which deploys 4 independent delivery microcatheters, was developed to be a reliable, high-volume delivery device for delivery of therapeutic agents to the brain and other solid organs. The authors undertook this first-in-human clinical trial effort to evaluate the delivery characteristics of the CMC in patients with HGGs. A series of pilot studies were launched after approval of a sponsor-investigator IND (investigational new drug) application to evaluate the delivery of topotecan and gadolinium-DTPA (Gd-DTPA) via the CMC in patients with recurrent HGG. The first pilot trial evaluated delivery into enhancing tumor and nonenhancing, tumor-infiltrated brain. Two catheters were placed with the use of a conventional frameless stereotactic technique following a biopsy to confirm tumor recurrence, and drug infusion was performed both intraoperatively and postoperatively for a total of 96 hours with the same rate for all microcatheters. Delivery was assessed by intermittent MRI. Three patients were enrolled in the first pilot study. MRI demonstrated delivery from all 6 catheters (24 microcatheters). The volume of distribution (Vd) of Gd-DTPA was heavily dependent upon CMC location (enhancing vs nonenhancing) with an approximately 10-fold difference in Vd observed (p = 0.005). There were no hemorrhages related to catheter placement or removal, and all 3 patients completed the protocol-defined treatment. The CMC is capable of providing backflow-resistant drug delivery to the brain and brain tumors. The volume of distribution is heavily dependent upon the integrity of the blood-brain barrier. Assessment of delivery is essential for development of loco-regionally applied therapeutics in the CNS.Clinical trial registration no.: NCT02278510 (clinicaltrials.gov).

Fractionated stereotactic radiotherapy for the treatment of optic nerve sheath meningiomas

Radiosurgery has become an important treatment alternative to surgery for a variety of intracranial lesions. As currently practiced, it has in fact replaced surgery as a standard of care in some instances, compliments surgery as a post-operative adjunct in others, and most commonly represents an alternative to surgery or the only treatment option. Radiosurgery techniques have evolved quickly with the development of new technologies enabling more complex yet more efficient treatment plans. As a consequence, these technologies have broadened radiosurgery applications and improved radiosurgery outcomes. Among these newer techniques, treatments involving fractionated stereotactic radiation referred to as fractionated stereotactic radiotherapy, or FSR, have emerged as a consequence of linear accelerators designed for and dedicated to stereotactic techniques. Without the logistical constraints of retrofitted general purpose linear accelerators used in radiation oncology, often available only once or twice a week, dedicated units have enabled the design of treatment paradigms that strive for an ideal treatment based on the radiobiology of the target and dose-limiting contiguous tissues.This chapter will summarize our fifteen year experience with the Varian 600SR, initially with the Radionics software more recently modified to a Novalis shaped beam radiosurgery unit, and our practice of FSR for a variety of intracranial lesions. Special attention will be devoted to tumors involving or near the special sensory cranial nerves. Given the versatility of the Novalis treatment planning platform, one has the option of comparing different treatment planning solutions at once, including stereotactic intensity-modulated radiation therapy (IMRT). For selected skull base lesions, we have found that stereotactic IMRT yields greater conformality than FSR and we will therefore include its application among fractionation strategies.

Identification of occult prostate malignancy in a large patient cohort using a stereotactic transperineal prostate biopsy technique.

9 Background: Continued rising PSA, despite prior transrectal prostate biopsy (TRPB), can cause significant anxiety for patients and physicians. This study investigates the detection rate of non-palpable, isoechoic occult malignancy using a stereotactic transperineal prostate biopsy (STPB) technique in patients with previous negative TRPB. Methods: 2,565 men with continued rising prostate specific antigen (PSA) with a minimum of 1 prior benign TRPB, underwent STPB at a single out-patient institution between 04/04 - 02/17 (See table). Specimens were obtained according to x, y, and z coordinates from 8 equal octants with pathology reported accordingly. A greater number of specimens were obtained from the apical half than the basilar half of the prostate; this was attributed to smaller glands in which the apical specimens sufficiently sampled the anterior curvature of the gland. Results: STPB yielded adenocarcinoma in 965/2,565 (37.6%) patients. The number of biopsy cores obtained per patient approximated the prostate gland volume in cm3. Statistical analysis demonstrated there was a significant difference in detection rates with the apex having a higher incidence of malignancy than the base of the prostate gland (p=.000). Furthermore, the anterior apex harbored significantly more adenocarcinoma when compared to the posterior apex (p=.026). Conclusions: STPB is efficacious for diagnosis of non-palpable, isoechoic occult prostate malignancy. Repeated sequential analysis of malignancy identification has consistently resulted in approximately 40% positive yield. Furthermore, a possible explanation for the significant finding in this study that occult malignancies occupy a higher percentage of apical biopsies using STPB may be related to difficulty and limitations of apical sampling using a standard transrectal biopsy approach. [Table: see text]

Potential indications for deep brain stimulation in neurological disorders: an evolving field.

Deep brain stimulation (DBS) is an established therapy for appropriately selected patients with movement disorders and neuropsychiatric conditions. Although the exact mechanisms and biology of DBS are not fully understood, it is a safe and well-tolerated therapy for many refractory cases of neuropsychiatric disease. Increasingly, DBS has been explored in other conditions with encouraging results. In this paper, available data is reviewed and new DBS targets, challenges and future directions in neurological disorders are explored. A detailed search of the medical literature discussing the potential use of DBS for neurological disorders excluding accepted indications was conducted. All reports were analyzed individually for content and redundant articles were excluded by examining individual abstracts. The level of evidence for each indication was summarized. Multiple studies report promising preliminary data regarding the safety and efficacy of DBS for a variety of neurological indications including chronic pain, tinnitus, epilepsy, Tourette syndrome, Huntington's disease, tardive dyskinesia and Alzheimer's disease. The initial results of DBS studies for diverse neurological disorders are encouraging but larger, controlled, prospective, homogeneous clinical trials are necessary to establish long-term safety and effectiveness. The field of neuromodulation continues to evolve and advances in DBS technology, stereotactic techniques, neuroimaging and DBS programming capabilities are shaping the present and future of DBS research and use in practice.

Management of nonfunctioning pituitary tumors: radiotherapy.

External beam radiotherapy (RT) is an essential part of the management of intracranial tumors and has been used in treating pituitary adenomas for more than five decades. It has been demonstrated that conventional RT for postoperative residual or progressive nonfunctioning pituitary adenomas (NFAs) present an excellent long-term local tumor control, although its use has been limited because of the potential late toxicity related to radiation treatments. Recent advances in radiation techniques have led to more accurate treatments, rendering obsolete many commonly held views of the "old" radiotherapy. New techniques include intensity modulated radiotherapy, volumetric-modulated arc therapy, and stereotactic techniques, either stereotactic radiosurgery or fractionated stereotactic radiotherapy. New techniques allow the delivering of higher radiation doses to the target with rapid dose fall-off in the surrounding normal tissues, and potentially limiting the long term toxicity of radiation. In this review, we present a critical analysis of the most recent available literature on the use of radiation in patients with NFAs, focusing particularly on the efficacy and safety of radiation stereotactic techniques.

The stereotactic suboccipitaltranscerebellar approach to lesions of the brainstem and the cerebellum

ObjectiveThe stereotactic suboccipital-transcerebellar approach is widely regarded as technically demanding requiring substantial modifications of the standard stereotactic methods thus often making a transfrontal approach preferable.In this comprehensive series we aim to present our experience with the stereotactic suboccipital-transcerebellar approach to lesions of the brainstem or cerebellum using two standard stereotactic systems. Patients and MethodsIn the period of 2000–2015 overall 80 patients (mean age 43.95 ± 23.76 years) with lesions of the brainstem or cerebellum underwent stereotactic surgery for diagnostic or therapeutic purposes via a suboccipital approach. In 59 patients stereotactic surgery was performed using the Riechert-Mundinger Stereotactic Frame, the Leksell Stereotactic Frame was used in 21 patients. For both frames standard systems were used without modification. Retrospective analysis of intraoperative stereotactic technique, achievement of the predefined surgical objectives and perioperative complications was carried out. ResultsIn this series, the stereotactic suboccipital-transcerebellar approach proved to be feasible with two standard stereotactic systems. Using either frame the predefined surgical objective was achieved in 90.0%. A verified neuropathological diagnosis was obtained in 89.6%. Minor transient perioperative complications occurred in 8.75%. There was no surgery-related permanent morbidity or mortality. ConclusionIn this comprehensive series the stereotactic suboccipital-transcerebellar approach using a standard stereotactic system proved to be a favorable stereotactic approach with a high diagnostic success rate and no surgery-related permanent morbidity.