Cranial Vertex Research Articles

Early Bone and Suture Reformations in Different Cranial Regions After Cranial Vault Remodeling for Sagittal Craniosynostosis.

Cranial vault remodeling (CVR) is a common procedure for correcting sagittal craniosynostosis. Some approaches leave significant craniectomy defects. The authors investigated the reosteogenesis in different cranial defect areas after CVR. A cross-sectional study was conducted in nonsyndromic sagittal craniosynostosis. Available early postoperative computed tomography (CT) scans were analyzed. The segmentation of three-dimensional reconstructed images was performed. Different cranial defect areas, including coronal, vertex, and occipital regions, were further investigated using an automated three-dimensional analysis software for reosteogenesis percentage. Forty-four CT scans were included. The average age at CVR was 8.8 months. The median time of postoperative CT scans was 6.1 weeks. The median bone reformation percentage of the entire cranial defect was 56.7%. Given the similar postoperative CT timing, the median bone reformation at the coronal, vertex, and occipital areas demonstrated 44.21%, 41.13%, and 77.75%, respectively (P < 0.001). In the simultaneously removed coronal and lambdoid sutures, there were 45% with coronal and lambdoid sutures reformation, followed by lambdoid suture reformation alone, no suture reformation and coronal reformation alone in 35%, 20%, and 0%, respectively (P = 0.013). There was no coronal reformation in the removed coronal suture group. However, 40% demonstrated lambdoid suture reformation after the isolated lambdoid suture removal. The occipital region has the highest reosteogenesis compared with the other cranial defects after CVR in nonsyndromic sagittal craniosynostosis. Within the removed previous patent sutures, the lambdoid suture reformation showed a higher rate than the coronal suture.

Radiosynthesis automation, non-human primate biodistribution and dosimetry of K+ channel tracer [11C]3MeO4AP

Background4-Aminopyridine (4AP) is a medication for the symptomatic treatment of multiple sclerosis. Several 4AP-based PET tracers have been developed for imaging demyelination. In preclinical studies, [11C]3MeO4AP has shown promise due to its high brain permeability, high metabolic stability, high plasma availability, and high in vivo binding affinity. To prepare for the translation to human studies, we developed a cGMP-compatible automated radiosynthesis protocol and evaluated the whole-body biodistribution and radiation dosimetry of [11C]3MeO4AP in non-human primates (NHPs).MethodsAutomated radiosynthesis was carried out using a GE TRACERlab FX-C Pro synthesis module. One male and one female adult rhesus macaques were used in the study. A high-resolution CT from cranial vertex to knee was acquired. PET data were collected using a dynamic acquisition protocol with four bed positions and 13 passes over a total scan time of ~ 150 min. Based on the CT and PET images, volumes of interest (VOIs) were manually drawn for selected organs. Non-decay corrected time-activity curves (TACs) were extracted for each VOI. Radiation dosimetry and effective dose were calculated from the integrated TACs using OLINDA software.ResultsFully automated radiosynthesis of [11C]3MeO4AP was achieved with 7.3 ± 1.2% (n = 4) of non-decay corrected radiochemical yield within 38 min of synthesis and purification time. [11C]3MeO4AP distributed quickly throughout the body and into the brain. The organs with highest dose were the kidneys. The average effective dose of [11C]3MeO4AP was 4.0 ± 0.6 μSv/MBq. No significant changes in vital signs were observed during the scan.ConclusionA cGMP-compatible automated radiosynthesis of [11C]3MeO4AP was developed. The whole-body biodistribution and radiation dosimetry of [11C]3MeO4AP was successfully evaluated in NHPs. [11C]3MeO4AP shows lower average effective dose than [18F]3F4AP and similar average effective dose as other carbon-11 tracers.

Gravitational bullet injuries

Gravitational bullet injuries, prevalent in the Middle East, particularly in Iraq, are a critical public health concern, often resulting from celebratory gunfire. In our Neurosurgery Teaching Hospital in Baghdad, we've observed that these injuries differ significantly from high-velocity gunshot wounds, characterized by lower velocity and energy due to air resistance and gravity. Unlike high-velocity bullets, gravitational bullets cause less bone fragmentation and radial brain damage. These bullets often end up on the tentorium or within the skull base, rarely transgressing the cerebellar tentorium on a vertical trajectory. We've also noticed that the pediatric population, particularly younger children, are more susceptible to these injuries due to their thinner cranial vertex, leading to more penetrating injuries and aggressive brain bleeding. Our observations underline the need for focused studies, awareness, regulation, and tailored management strategies to combat this overlooked issue.

Enhancing cognitive control with transcranial magnetic stimulation in subject-specific frontoparietal networks

BackgroundCognitive control processes, including those involving frontoparietal networks, are highly variable between individuals, posing challenges to basic and clinical sciences. While distinct frontoparietal networks have been associated with specific cognitive control functions such as switching, inhibition, and working memory updating functions, there have been few basic tests of the role of these networks at the individual level. MethodsTo examine the role of cognitive control at the individual level, we conducted a within-subject excitatory transcranial magnetic stimulation (TMS) study in 19 healthy individuals that targeted intrinsic (“resting”) frontoparietal networks. Person-specific intrinsic networks were identified with resting state functional magnetic resonance imaging scans to determine TMS targets. The participants performed three cognitive control tasks: an adapted Navon figure-ground task (requiring set switching), n-back (working memory), and Stroop color-word (inhibition). ObjectiveHypothesis: We predicted that stimulating a network associated with externally oriented control [the “FPCN-B” (fronto-parietal control network)] would improve performance on the set switching and working memory task relative to a network associated with attention (the Dorsal Attention Network, DAN) and cranial vertex in a full within-subjects crossover design. ResultsWe found that set switching performance was enhanced by FPCN-B stimulation along with some evidence of enhancement in the higher-demand n-back conditions. ConclusionHigher task demands or proactive control might be a distinguishing role of the FPCN-B, and personalized intrinsic network targeting is feasible in TMS designs.

Evaluation of the clinical efficacy of minimally invasive endoscopic surgery in the treatment of isolated non-syndromic sagittal synostosis in infants

The current study aimed to evaluate the early efficacy in infants with isolated non-syndromic sagittal synostosis who underwent minimally invasive endoscopic-assisted surgery. The clinical data of infants with isolated non-syndromic sagittal synostosis who were admitted to the Department of Neurosurgery of the Children's Hospital of Nanjing Medical University and underwent endoscopic-assisted surgery from October 2018 to December 2021 were retrospectively analyzed. All the infants underwent minimally invasive endoscopic-assisted surgery, and were treated with supine sleeping position after surgery. Computer-aided reconstruction technique was used to reconstruct and measure the thin-slice CT scan images of the head before and 3 months after surgery, and the differences in cranial index (CI), cranial cavity volume and angle drawn between the cranial vertex, nasion, and opisthocranion (VNO angle) of preoperative and postoperative groups were analyzed. A total of 103 infants were included in the final analysis, including 85 males and 18 females. The age at surgery was (2.1±0.8) months, and the weight was (6.1±0.9) kg. The postoperative CI was (84±6)%, which increased obviously compared with the pre-operation [(70±5)%] (P<0.001). The cranial volume of post-operation was (947±130) cm³, which was larger than that of the pre-operation [(748±104) cm³] (P<0.001). The VNO angle after surgery was (45±4)°, which showed a significant reduction compared with the pre-operation [(55±4)°] (P<0.001). The correction of head shape was satisfactory. For the treatment of sagittal synostosis in infants, minimally invasive endoscopic-assisted surgery is safe and effective, and in the case of switching from an auxiliary helmet to a supine position, the postoperative correction efficacy of head shape is better.

Evoked mid-frontal activity predicts cognitive dysfunction in Parkinson’s disease

BackgroundCognitive dysfunction is a major feature of Parkinson’s disease (PD), but the pathophysiology remains unknown. One potential mechanism is abnormal low-frequency cortical rhythms which engage cognitive functions and are deficient...

Six degrees of freedom intrafraction cranial motion detection using a novel capacitive monitoring technique: evaluation with human subjects

The purpose of this work is to introduce and evaluate a capacitive monitoring array capable of continuous 6DOF cranial motion detection during high precision radiotherapy. The ring-shaped capacitive array consists of four equally sized conductive sensors positioned at the cranial vertex. The system is modular, non-contact, and provides continuous motion information through the thermoplastic immobilization mask without relying on skin monitoring or use of ionizing radiation. The array performance was evaluated through a volunteer study with a cohort of twenty-five individuals. The study was conducted in a linac suite and the volunteers were fitted with an S-frame thermoplastic mask. Each volunteer took part in one data acquisition session per day for three consecutive days. During the data acquisition, the conductive array was translated and rotated relative to their immobilized cranium in 1-millimetre and 1-degree steps to simulate cranial motion. Capacitive signals were collected at each position at a frequency of 20 Hz. The data from the first acquisition session was then used to train a classifier model and establish calibration equations. The classifier and calibration equations were then applied to data from the subsequent acquisition sessions to evaluate the system performance. The trained classifiers had an average success rate of 92.6% over the volunteer cohort. The average error associated with calibration had a mean value below 0.1 mm or 0.1 deg for all six motions. The capacitive array system provides a novel method to detect translational and rotational cranial motion through a thermoplastic mask.

Human biodistribution and radiation dosimetry of the demyelination tracer [18F]3F4AP

Purpose[18F]3F4AP is a novel PET radiotracer that targets voltage-gated potassium (K+) channels and has shown promise for imaging demyelinated lesions in animal models of neurological diseases. This study aimed to evaluate the biodistribution, safety, and radiation dosimetry of [18F]3F4AP in healthy human volunteers.MethodsFour healthy volunteers (2 females) underwent a 4-h dynamic PET scan from the cranial vertex to mid-thigh using multiple bed positions after administration of 368 ± 17.9 MBq (9.94 ± 0.48 mCi) of [18F]3F4AP. Volumes of interest for relevant organs were manually drawn guided by the CT, and PET images and time-activity curves (TACs) were extracted. Radiation dosimetry was estimated from the integrated TACs using OLINDA software. Safety assessments included measuring vital signs immediately before and after the scan, monitoring for adverse events, and obtaining a comprehensive metabolic panel and electrocardiogram within 30 days before and after the scan.Results[18F]3F4AP distributed throughout the body with the highest levels of activity in the kidneys, urinary bladder, stomach, liver, spleen, and brain and with low accumulation in muscle and fat. The tracer cleared quickly from circulation and from most organs. The clearance of the tracer was noticeably faster than previously reported in nonhuman primates (NHPs). The average effective dose (ED) across all subjects was 12.1 ± 2.2 μSv/MBq, which is lower than the estimated ED from the NHP studies (21.6 ± 0.6 μSv/MBq) as well as the ED of other fluorine-18 radiotracers such as [18F]FDG (~ 20 μSv/MBq). No differences in ED between males and females were observed. No substantial changes in safety assessments or adverse events were recorded.ConclusionThe biodistribution and radiation dosimetry of [18F]3F4AP in humans are reported for the first time. The average total ED across four subjects was lower than most 18F-labeled PET tracers. The tracer and study procedures were well tolerated, and no adverse events occurred.

Large Vertex Encephaloceles: Management and Outcomes.

Complex vertex and posterior encephaloceles containing brain tissue have uncertain prognosis and high operative risk. Patients may not be offered operative intervention depending on local and regional specialist expertise. The authors present their experience treating 5 such pediatric patients. This is a retrospective review of the surgical assessment, planning, and technique of cranial repairs, as well as surgical outcomes and developmental follow-up regarding adaptive functioning for patients presenting for second opinion for encephalocele of the cranial vertex after having been deemed too high risk at another institution. Five consecutive patients presented between January 2014 and June 2016. One patient was not offered repair. Of 4 patients who underwent reconstruction, average age at time of repair was 2.7 months (range, 0.9-6.7). One presented with ruptured encephalocele, whereas the remaining 3 underwent drainage of the encephalocele (average volume of 1200mL) at time of surgical resection. Operative time averaged 3.7 hours (range, 2.2-5.3). There were no deaths. One patient had a single seizure postoperatively. Two patients required placement of permanent shunt for hydrocephalus. Two patients completed developmental evaluations, both of whom exhibited delays in adaptive functioning relative to same-aged peers. Patients with large, complex encephalocele warrant evaluation by an experienced high-volume tertiary care pediatric craniofacial center. The decision to proceed with surgical management should include an interdisciplinary team of surgeons, anesthesiologists, neurologists, and social work. Further study of developmental outcomes in both operated and unoperated patients is necessary to better understand risks and benefits of reconstruction.

QS68. Making the Diagnosis in Sagittal Craniosynostosis—It’s Height, Not Length, That Matters

Purpose: This study assesses the diagnostic reliability of a novel photogrammetric measurement to distinguish sagittal craniosynostosis (SS) from control and false positive cases (SNS). Methods: All head CT imaging at our institution between 2014-2020 was reviewed for patients with sagittal synostosis (SS, n = 177), patients with suspected sagittal craniosynostosis based on clinical examination but normal head CT (SNS, n = 30), and controls (n = 100). A novel measurement reflecting the anterior-posterior location of the vertex was measured by an angle drawn between the cranial vertex, nasion, and opisthocranion (VNO) in profile view with the head in a neutral position. NilRead Enterprise Viewer (Hyland Software, Inc. Westlake, OH) and Microsoft PowerPoint (Microsoft Corp. Redmond, Wash.) were used to measure VNO angles on 3D Head CT Reconstructions (n = 307) and clinic photos (n = 172) respectively. Three masked raters measured VNO angle on clinic photos, and one author (DYC) reviewed all photos to binarily determine the presence or absence of frontal bossing (FB) and occipital bulleting (OCB). Patients’ medical charts were reviewed for demographic information, preoperative cephalic index (CI), and operative approach when indicated. To determine the best combination of clinical findings to distinguish sagittal synostosis, Receiver operating characteristic analysis (ROC) was conducted for the various permutations of VNO, FB, OCB, and CI. Results: Mean age at pre-operative head CT was 9.5 months for the SS cohort, 4.2 months for the SNS cohort, and 8.9 months for the control cohort (p =.327). Mean age at the time of pre-operative clinical photo was 9.5 months for the SS cohort and 4.2 months for the SNS cohort (p =.149). Pearson correlations revealed no significant association between age and VNO angle for any group. The average VNO angle measured on clinical photos was 54.7°±3.8° for the SS group, 43.1°± 2.2° for the SNS group, and 41.1°± 3.7° for controls (p<.001). Three-rater analysis yielded a moderate intraclass correlation coefficient of 0.742 (p=.004). ROC analysis yielded a cut-off of 50° to determine SS versus SNS and controls. AUC for the permutations of VNO angle, FB, OCB, and CI ranged from.187 to.956. The largest AUC value of.956 was obtained when for VNO angle alone, with a corresponding sensitivity and specificity of 96.6% and 99.2% respectively. Conclusion: Measurement of the VNO angle is a reliable screening tool to diagnose sagittal craniosynostosis, with an angle of 50° or more suggesting suture synostosis. This method relies on the relationship between the anterior displacement of the cranial vertex and occipital bulleting to approach the diagnostic accuracy of CT imaging.

Making the Diagnosis in Sagittal Craniosynostosis-It's Height, Not Length, That Matters.

This study assesses the diagnostic reliability of a novel photogrammetric measurement to distinguish sagittal craniosynostosis (SS) from control and false positive cases (SNS). Head CTs from 2014-2020 were reviewed for patients with sagittal synostosis (SS, n = 177), presumed sagittal synostosis with normal imaging (SNS, n = 30), and controls (n = 100). Using preoperative clinical photographs and CTs, a measurement reflecting the anterior-posterior location of the vertexwas measured using an angle drawn betweenthe cranial vertex, nasion, andopisthocranion(VNO)in profile view,with the head in a neutralposition. Mean age at pre-operative head CT was 9.5months for the SS cohort, 4.2months for the SNS cohort, and 8.9months for controls (p = .327). Mean age at pre-operative clinical photograph was 9.5months for the SS cohort and 4.2months for the SNS cohort (p = .149). Pearson correlations revealed no significant association between age and VNO angle. The average VNO angle measured on clinical photographs was 54.7° ± 3.8° for the SS group, 43.1° ± 2.2° for the SNS group, and 41.1° ± 3.7° for controls (p < .001). Receiver operating characteristic (ROC) analysis yielded a cut-off of ≥ 50° to identify SS. Diagnostic sensitivity and specificity were 96.6% and 99.2%, respectively. Three-rater analysis yielded an average ICC of 0.742 (p = .004). Measurement of the VNO angle is a reliable screening tool to diagnose sagittal craniosynostosis, with an angle of 50° or more suggesting suture synostosis. This method relies on the relationship between the anterior displacement of the vertex and occipital bulleting to approach the diagnostic accuracy of CT imaging.

Acutis Dermal Dysplasia: a review

Aplasia Dermal Dysplasia (ADD) is an etiologically heterogeneous congenital abnormality having a circumscribed area of absent skin that involves any region of the body mainly the cranial vertex. The condition may involve only the superficial skin but also the subcutaneous tissue, bone, or even the dura. ADD can be isolated or associated with other malformations in the context of a genetic disease. Numerous alterations of skin detectable at birth might be confused with aplasia cutis congenita. Birth trauma, injuries from obstetrical procedures and intrauterine trauma such as from mechanical deliveries are some examples. Histologic analysis can make the proper diagnosis. Here we describe the surgical strategies to treatment of ADD, including patient selection, properative preparation, the operative procedure and Post-operative management. A multidisciplinary team including neurosurgery and plastic surgery, among others, is optimal for the treatment of these patients. Nevertheless, intensive care must be undertaken during treatment to detect potential life-threatening complications.

BDNF Val66Met gene polymorphism modulates brain activity following rTMS-induced memory impairment

The BDNF Val66Met gene polymorphism is a relevant factor explaining inter-individual differences to TMS responses in studies of the motor system. However, whether this variant also contributes to TMS-induced memory effects, as well as their underlying brain mechanisms, remains unexplored. In this investigation, we applied rTMS during encoding of a visual memory task either over the left frontal cortex (LFC; experimental condition) or the cranial vertex (control condition). Subsequently, individuals underwent a recognition memory phase during a functional MRI acquisition. We included 43 young volunteers and classified them as 19 Met allele carriers and 24 as Val/Val individuals. The results revealed that rTMS delivered over LFC compared to vertex stimulation resulted in reduced memory performance only amongst Val/Val allele carriers. This genetic group also exhibited greater fMRI brain activity during memory recognition, mainly over frontal regions, which was positively associated with cognitive performance. We concluded that BDNF Val66Met gene polymorphism, known to exert a significant effect on neuroplasticity, modulates the impact of rTMS both at the cognitive as well as at the associated brain networks expression levels. This data provides new insights on the brain mechanisms explaining cognitive inter-individual differences to TMS, and may inform future, more individually-tailored rTMS interventions.

内因性脳梗塞が先行した外傷症例に対し急性期再灌流療法を施行した1例(A case of revascularization therapy for acute ischemic stroke with a chief complaint of traumatic injury)

要旨 標準的な外傷診療では生理学的機能の管理および安定化を重視しており，神経学的所見は見逃されやすい。内因性脳梗塞が先行した外傷症例の診療について検討した。症例は78歳の男性，階段2階の踊り場から転落した。右共同偏視，右片麻痺，Glasgow coma scale（GCS）12の意識障害を認めた。外傷全身computed tomography（CT）で頭蓋内に占拠性病変は認めず，動脈優位相で左中大脳動脈の造影欠損を認めた。急性期脳梗塞と診断し，機械的血栓回収療法を行った。外傷機転を介在する内因性脳梗塞では，見逃しや治療介入に時間を要する可能性がある。病院前脳卒中スケールが症状検出に役立つ可能性があり，頭頂部の動脈優位相を含む造影CT検査で主幹動脈閉塞の検索が可能である。画像評価には熟練を要するため，3次元画像処理を行うとともに，適切に専門医へコンサルトし早期診断治療へつなげることが重要である。

Posterior Cranial Vault Distraction Osteogenesis Utilizing a Posterior-Superior Distraction Vector in the Treatment of Mercedes Benz Pattern Craniosynostosis.

Bilateral lambdoid and sagittal synostosis, or Mercedes Benz Syndrome, is a rare complex craniosynostosis resulting in frontal bossing, a tapered posterior fossa, and an anteriorly displaced cranial vertex. Its ideal surgical correction must result in posterior expansion, skull elongation, and caudal repositioning of the vertex. We present a craniometric analysis of skull changes with posterior-superior distraction and introduce a novel craniometric measure: vertex position. In this study, a retrospective review was performed to analyze outcomes of posterior cranial vault distraction osteogenesis (PVDO) using a posterior-superior distraction vector from 2016 to 2019. Cranial vertex position was measured as a fraction of the occipitofrontal diameter from rostral to caudal (0-1.0). Four patients underwent PVDO at mean age 10.61 ± 3.16 months utilizing a posterior-superior distraction vector. Linear distraction distance averaged 30.30 ± 0.90 mm with a mean consolidation period of 3.98 ± 0.72 months. Mean corrected change in intra-cranial volume was 236.30 ± 3.71 mL, at an average rate of 7.81 ± 2.00 mL/mm of distraction. Increases in anterior cranial height (7.83 ± 2.51 mm), middle cranial height (8.43 ± 4.21 mm), posterior cranial height (13.15 ± 7.45 mm), and posterior cranial fossa height (21.99 ± 8.55 mm) were observed. Cranial vertex demonstrated a mean posterior movement of 0.18 ± 0.13. PVDO utilizing a posterior-superior distraction vector for management of nonsyndromic bilateral lambdoid and sagittal synostosis effectively increases intracranial volume and height and provides an esthetic outcome with posterior movement of the cranial vertex.

Dlx5-augmentation in neural crest cells reveals early development and differentiation potential of mouse apical head mesenchyme

Neural crest cells (NCCs) give rise to various tissues including neurons, pigment cells, bone and cartilage in the head. Distal-less homeobox 5 (Dlx5) is involved in both jaw patterning and differentiation of NCC-derivatives. In this study, we investigated the differentiation potential of head mesenchyme by forcing Dlx5 to be expressed in mouse NCC (NCCDlx5). In NCCDlx5 mice, differentiation of dermis and pigment cells were enhanced with ectopic cartilage (ec) and heterotopic bone (hb) in different layers at the cranial vertex. The ec and hb were derived from the early migrating mesenchyme (EMM), the non-skeletogenic cell population located above skeletogenic supraorbital mesenchyme (SOM). The ec developed within Foxc1+-dura mater with increased PDGFRα signalling, and the hb formed with upregulation of BMP and WNT/β-catenin signallings in Dermo1+-dermal layer from E11.5. Since dermal cells express Runx2 and Msx2 in the control, osteogenic potential in dermal cells seemed to be inhibited by an anti-osteogenic function of Msx2 in normal context. We propose that, after the non-skeletogenic commitment, the EMM is divided into dermis and meninges by E11.5 in normal development. Two distinct responses of the EMM, chondrogenesis and osteogenesis, to Dlx5-augmentation in the NCCDlx5 strongly support this idea.

Intracranial EEG Validation of Single-Channel Subgaleal EEG for Seizure Identification.

A device that provides continuous, long-term, accurate seizure detection information to providers and patients could fundamentally alter epilepsy care. Subgaleal (SG) EEG is a promising modality that offers a minimally invasive, safe, and accurate means of long-term seizure monitoring. Subgaleal EEG electrodes were placed, at or near the cranial vertex, simultaneously with intracranial EEG electrodes in 21 epilepsy patients undergoing intracranial EEG studies for up to 13 days. A total of 219, 10-minute single-channel SGEEG samples, including 138 interictal awake or sleep segments and 81 seizures (36 temporal lobe, 32 extra-temporal, and 13 simultaneous temporal/extra-emporal onsets) were reviewed by 3 expert readers blinded to the intracranial EEG results, then analyzed for accuracy and interrater reliability. Using a single-channel of SGEEG, reviewers accurately identified 98% of temporal and extratemporal onset, intracranial, EEG-verified seizures with a sensitivity of 98% and specificity of 99%. All focal to bilateral tonic--clonic seizures were correctly identified. Single-channel SGEEG, placed at or near the vertex, reliably identifies focal and secondarily generalized seizures. These findings demonstrate that the SG space at the cranial vertex may be an appropriate site for long-term ambulatory seizure monitoring.

Relative position of sacral base in the pelvis and its correlation with spino-pelvic parameters.

To investigate the relationship between relative location of the sacral base and spinal alignment in standing healthy adult volunteers. One hundred seventy-two volunteers (men = 83, mean age = 39.3years [20-70], women = 89, mean age = 39.6years [20-62]) with no history of spinal disease were imaged using a low-dose biplanar slot-scanning 3D X-ray imaging system. A circle was drawn around three points: cranial vertex of the iliac crest (A), caudal vertex of the ischium (B), and anterior vertex of the pubis. Pelvic height (PH) was defined as the diameter (A-B). A tangent line perpendicular to PH (C) was drawn by passing through (A). Sacral height (SH) was defined as the distance between (C) and the center of the sacral base parallel to PH. Relative SH (rSH) was calculated as SH/PH × 100. Mean (SD) rSH was 18.3 ± 3.2 (men 20.0 ± 2.9, women 16.7 ± 2.6). rSH significantly positively correlated with thoracic kyphosis (r = 0.20, p < 0.05), lumbar lordosis (r = 0.28, p < 0.05), pelvic incidence (r = 0.28, p < 0.05), and sacral slope (r = 0.32, p < 0.0001), and significantly negatively correlated with pelvic thickness (r = - 0.66, p < 0.0001). rSH did not correlate with pelvic tilt. The center of the sacral base is normally located 3.8 ± 0.8cm caudal to the cranial vertex of the iliac crest. The sacral base was located more caudally in men than in women, regardless of age. The more caudal the sacral base, the angle of the spino-pelvic parameters (TK, LL, PI, SS) progressively increases along with a decrease in the sacro-acetabular distance (Pth). Pelvic tilt did not correlate with the location of the sacrum.

A novel intra-fraction motion monitoring system for stereotactic radiosurgery: proof of concept

The purpose of this work is to develop a prototype system for continuous, three-dimensional (3D) monitoring of patient cranial motion during stereotactic radiosurgery. Using novel capacitive detector plates, the goal was to provide detection of cranial position inside a thermoplastic immobilizing mask, without relying on skin monitoring or use of ionizing radiation.A novel capacitive detector array was used to detect cranial translations with sub-millimeter accuracy. The array was comprised of four conductive plates arranged around the cranium. One superior plate was positioned at the cranial vertex, two lateral plates were positioned in sagittal planes at the lateral aspects of the cranium and one plate was located in a coronal plane anterior to the face. The system was calibrated by parameterizing a capacitive signal for each dimension as a function of spatial translation. The detector array performance was evaluated with the help of a volunteer in the absence of radiation. Separately, possible effects of electromagnetic interference and irradiation in the linac suite were assessed.Detector plates mounted at 1 cm original distance to the thermoplastic mask can detect sub-millimeter lateral and superior cranial motion. Detection of sub-millimeter anterior motion is possible when the plate is mounted closer to the patient (5–10 mm). No signal interference was observed when the capacitive array was irradiated.Our prototype detector array provides continuous, 3D translation detection with sub-millimeter precision. The signal provides sufficient signal to noise ratio and is stable in linac room environment and in direct radiation beam. The detector plate is sensitive to the position of the cranium inside a mask and offers the advantage of being insensitive to the mask itself. Future work will involve modifying the array to detect patient rotation.

First evaluation of PET-based human biodistribution and radiation dosimetry of 11C-BU99008, a tracer for imaging the imidazoline2 binding site

BackgroundWe measured whole body distribution of 11C-BU99008, a new PET biomarker for non-invasive identification of the imidazoline2 binding site. The purpose of this phase I study was to evaluate the biodistribution and radiation dosimetry of 11C-BU99008 in healthy human subjects.MethodsA single bolus injection of 11C-BU99008 (296 ± 10.5 MBq) was administered to four healthy subjects who underwent whole-body PET/CT over 120 min from the cranial vertex to the mid-thigh. Volumes of interest were drawn around visually identifiable source organs to generate time-activity curves (TAC). Residence times were determined from time-activity curves. Absorbed doses to individual organs and the whole body effective dose were calculated using OLINDA/EXM 1.1 for each subject.ResultsThe highest measured activity concentration was in the kidney and spleen. The longest residence time was in the muscle at 0.100 ± 0.023 h, followed by the liver at 0.067 ± 0.015 h and lungs at 0.052 ± 0.010 h. The highest mean organ absorbed dose was within the heart wall (0.028 ± 0.002 mGy/MBq), followed by the kidneys (0.026 ± 0.005 mGy/MBq). The critical organ was the heart wall. The total mean effective dose averaged over subjects was estimated to be 0.0056 ± 0.0004 mSv/MBq for an injection of 11C-BU99008.ConclusionsThe biodistribution of 11C-BU99008 has been shown here for the first time in humans. Our dosimetry data showed the total mean effective dose over all subjects was 0.0056 ± 0.0004 mSv/MBq, which would result in a total effective dose of 1.96 mSv for a typical injection of 350 MBq of 11C-BU99008. The effective dose is not appreciably different from those obtained with other 11C tracers.