Anterior To Posterior Research Articles

Part II: The 50°/60° fibular tunnel trajectory for posterolateral corner reconstruction in a cadaver model.

Using data from our MRI study, we found that a tunnel oriented 50° externally rotated and 60° cephalad would better connect the fibular collateral ligament (FCL) insertion to the popliteofibular ligament (PFL) insertion as compared to a traditional anterior-to-posterior (A-P) fibular tunnel. The purpose of this study was to test that finding in a cadaver model. In eight cadaver knee pairs (16 knees), a guide pin was driven from the fibular FCL insertion point in a 50° externally rotated and 60° cephalad trajectory in 8 knees, and in a traditional A-P trajectory in the contralateral 8 knees. Proximity of the pin to the native PFL insertion, the peroneal and tibial nerves was measured, followed by drilling over the guide pin and measuring the remaining fibular bone stock. In comparison with the A-P fibular tunnel technique, the 50°/60° technique resulted in a fibular exit point significantly closer to the native PFL insertion (p < 0.01). Both techniques were safe with regard to the tibial and peroneal nerves. There were no instances of fibular wall blowout in either technique; however, there was less superior bone remaining in the 50°/60° technique (p < 0.04). In a cadaveric model, the 50°/60° technique for PLC reconstruction resulted in a more anatomic-based tunnel than an A-P fibular tunnel.

The cortical and cerebellar representation of the lumbar spine

Eight decades after Penfield's discovery of the homunculus only sparse evidence exists on the cortical representation of the lumbar spine. The aim of our investigation was the description of the lumbar spine's cortical representation in healthy subjects during the application of measured manual pressure. Twenty participants in the prone position were investigated during functional magnetic resonance imaging (fMRI). An experienced manual therapist applied non-painful, posterior-to-anterior (PA) pressure on three lumbar spinous processes (L1, L3, and L5). The pressure (30 N) was monitored and controlled by sensors. The randomized stimulation protocol consisted of 68 pressure stimuli of 5 s duration. Blood oxygenation level dependent (BOLD) responses were analyzed in relation to the lumbar stimulations. The results demonstrate that controlled PA pressure on the lumbar spine induced significant activation patterns. The major new finding was a strong and consistent activation bilaterally in the somatosensory cortices (S1 and S2). In addition, bilateral activation was located medially in the anterior cerebellum. The activation pattern also included other cortical areas probably related to anticipatory postural adjustments. These revealed stable somatosensory maps of the lumbar spine in healthy subjects can subsequently be used as a baseline to investigate cortical and subcortical reorganization in low back pain patients.

Neural Responses of Posterior to Anterior Movement on Lumbar Vertebrae: A Functional Magnetic Resonance Imaging Study

ObjectiveThe purpose of this study was to develop and test a clinically relevant method to mechanically stimulate lumbar functional spinal units while recording brain activity by means of functional magnetic resonance imaging (MRI). MethodsSubjects were investigated in the prone position with their face lying on a modified stabilization pillow. To minimize head motion, the pillow was fixed to the MRI headrest, and supporting straps were attached around the shoulders. An experienced manual therapist applied controlled, nonpainful pressure stimuli to 10 healthy subjects at 3 different lumbar vertebrae (L1, L3, and L5). Pressure applied to the thumb was used as a control. The stimulation consisted of posterior to anterior (PA) pressure movement. The therapist followed a randomized stimulation protocol projected onto a screen in the MRI room. Blood oxygenation level–dependent responses were analyzed in relation to the lumbar and the thumb stimulations. The study was conducted by the Chiropractic Department, Faculty of Medicine, University of Zürich, Switzerland. ResultsNo participant reported any discomfort due to the prone-lying position or use of the pillow. Importantly, PA-induced pressure produced only minimal head movements. Stimulation of the lumbar spinous processes revealed bilateral neural responses in medial parts of the postcentral gyrus (S1). Additional activity was observed in the secondary somatosensory cortex (S2), posterior parts of the insular cortex, different parts of the cingulate cortex, and the cerebellum. Thumb stimulations revealed activation only in lateral parts of the contralateral S1. ConclusionThe current study demonstrates the feasibility of the application of PA pressure on lumbar spinous processes in an MRI environment. This approach may serve as a promising tool for further investigations regarding neuroplastic changes in chronic low back pain subjects.

Laryngeal and Pharyngeal Activity During Semioccluded Vocal Tract Postures in Subjects Diagnosed With Hyperfunctional Dysphonia

High vertical laryngeal position (VLP), pharyngeal constriction, and laryngeal compression are common features associated with hyperfunctional voice disorders. The present study aimed to observe the effect on these variables of different semioccluded vocal tract postures in 20 subjects diagnosed with hyperfunctional dysphonia. During observation with flexible endoscope, each participant was asked to produce eight different semioccluded exercises: lip trills, hand-over-mouth technique, phonation into four different tubes, and tube phonation into water using two different depth levels. Participants were required to produce each exercise at three loudness levels: habitual, soft, and loud. To determine the VLP, anterior-to-posterior (A-P) compression, and pharyngeal width, a human evaluation test with three blinded laryngologists was conducted. Judges rated the three endoscopic variables using a five-point Likert scale. An intraclass correlation coefficient to assess intrarater and interrater agreement was performed. A multivariate linear regression model considering VLP, pharyngeal width, and A-P laryngeal compression as outcomes and phonatory tasks and intensity levels as predictive variables were carried out. Correlation analysis between variables was also conducted. Results indicate that all variables differ significantly. Therefore, VLP, A-P constriction, and pharyngeal width changed differently throughout the eight semioccluded postures. All semioccluded techniques produced a lower VLP, narrower aryepiglottic opening, and a wider pharynx than resting position. More prominent changes were obtained with a tube into the water and narrow tube into the air. VLP significantly correlated with pharyngeal width and A-P laryngeal compression. Moreover, pharyngeal width significantly correlated with A-P laryngeal compression.

Anterior brain glucose hypometabolism predates dementia in progranulin mutation carriers

In this prospective cohort study, we investigated cerebral glucose metabolism reductions on [(18)F]-fluorodeoxyglucose (FDG)-PET in progranulin (GRN) mutation carriers prior to frontotemporal dementia (FTD) onset. Nine mutation carriers (age 51.5 ± 13.5 years) and 11 noncarriers (age 52.7 ± 9.5 years) from 5 families with FTD due to GRN mutations underwent brain scanning with FDG-PET and MRI and clinical evaluation. Normalized FDG uptake values were calculated with reference to the pons. PET images were analyzed with regions of interest (ROI) and statistical parametric mapping (SPM) approaches. Compared with noncarriers, GRN mutation carriers had a lowered anterior-to-posterior (AP) ratio of FDG uptake (0.86 ± 0.09 vs 0.92 ± 0.05) and less left-right asymmetry, consistent with an overall pattern of right anterior cerebral hypometabolism. This pattern was observed regardless of whether they were deemed clinically symptomatic no dementia or asymptomatic. Individual ROIs with lowered FDG uptake included right anterior cingulate, insula, and gyrus rectus. SPM analysis supported and extended these findings, demonstrating abnormalities in the right and left medial frontal regions, right insular cortex, right precentral and middle frontal gyri, and right cerebellum. Right AP ratio was correlated with cognitive and clinical scores (modified Mini-Mental State Examination r = 0.74; Functional Rating Scale r = -0.73) but not age and years to estimated onset in mutation carriers. The frontotemporal lobar degenerative process associated with GRN mutations appears to begin many years prior to the average age at FTD onset (late 50s-early 60s). Right medial and ventral frontal cortex and insula may be affected in this process but the specific regional patterns associated with specific clinical variants remain to be elucidated.

P 10. Acute state-dependent changes in corticomotor threshold in the absence of overt motor activity

The cortical motor threshold (CMT) is often used to individually adjust the intensity of transcranial magnetic stimulation (TMS). It reflects the integrated excitability of the corticomotor projection, including the excitability at the spinal level. The CMT reflects axonal and synaptic excitability as CMT can be modified by drugs that voltage-gated sodium channel blockers or non-NMDA glutamatergic drugs. The CMT is not a static measure but is subject to state-dependent fluctuations. To test this hypothesis we used an adaptive stair-case procedure to track acute changes in CMT associated with motor imagery (MI) or shifts in visuospatial attention (VA). Eight healthy subjects were asked to imagine a continuous thumb-index movement with the left or right hand (MI-left and MI-right), to shift their visuospatial attention to the left or right FDI (VA-left and VA-right) or to fixate a cross in the central visual field. Using a fast (<15 pulses) threshold-hunting procedure (Borckardt, 2006), we assessed task-dependent CMT changes in the left primary motor hand area (M1) during each task. CMT was defined as the stimulus intensity, at which a single TMS pulse elicited a MEP of 50 μV in the relaxed right first dorsal interosseus muscle (FDI) with a probability of 0.5. The CMT measurements during the VA and MI task were normalized to the control condition. All participants underwent two experimental sessions on separate days, in which the TMS pulse either induced a posterior-to-anterior (PA) or anterior-to-posterior (AP) current in M1. The number of pulses needed to determine rMT did not significantly differ across conditions (average: 13.5). Using the normalized CMT values as dependent variable, we computed a repeated measures ANOVA with the factors Current (AP/PA), Task (MI/VA) and Site (Left/Right). We found a significant Task-by-Site interaction ( p = 0.004). Post hoc testing confirmed that CMT during MI-right was significantly lower than during MI-left or during VA-right. This was the case for AP and PA current direction. The resting CMT is subject to rapid state-dependent changes in the absence of overt motor activity. We show that these acute CMT changes can be captured with a threshold-hunting procedure. The “CMT tracking” approach might be particularly useful to assess the temporal dynamics of corticomotor excitability changes induced by interventional brain stimulation protocols.

IS 18. Interneuron networks

Transcranial magnetic stimulation (TMS) is known to activate several populations of interneuron networks in cerebral cortex as demonstrated by the existence of the well-known early and later indirect wave (I-wave) pathways which can be differentially stimulated by changing the direction of induced current in the brain. The question we ask here is whether these “circuits” are epiphenomena that only function when activated by a non-physiological TMS pulse, or whether they represent activity in intrinsic collections of interneurons that contribute differentially to specific types of motor behaviour. That is, can the electroanatomy of TMS tell us something about the functional anatomy of the cerebral cortex? A series of experiments suggests that this may be the case. First, we have devised a new intracortical paired associative stimulation (icPAS), to show that the difference in synaptic inputs recruited by anterior-to-posterior (AP) and posterior-to-anterior (PA) stimulation determines the direction of change in presumed synaptic plasticity. Second, we have recently found that variation in response to plasticity probing protocols, such as theta burst stimulation (TBS), is strongly influenced by which neuronal networks are likely to be recruited by each TMS pulse. The responses to TBS protocols were highly variable between individuals: about 50% of this variation was predicted by our postulated marker for the efficiency of late I-wave recruitment. Finally, the differential modulation of these circuits can interact with motor practice, measured by enhancement of acceleration of ballistic finger movements. These findings highlights the importance of differential role of interneuron networks within primary motor cortex in stimulation induced plasticity as well as voluntary motor learning.

Gata4 Is Required for Formation of the Genital Ridge in Mice

In mammals, both testis and ovary arise from a sexually undifferentiated precursor, the genital ridge, which first appears during mid-gestation as a thickening of the coelomic epithelium on the ventromedial surface of the mesonephros. At least four genes (Lhx9, Sf1, Wt1, and Emx2) have been demonstrated to be required for subsequent growth and maintenance of the genital ridge. However, no gene has been shown to be required for the initial thickening of the coelomic epithelium during genital ridge formation. We report that the transcription factor GATA4 is expressed in the coelomic epithelium of the genital ridge, progressing in an anterior-to-posterior (A-P) direction, immediately preceding an A-P wave of epithelial thickening. Mouse embryos conditionally deficient in Gata4 show no signs of gonadal initiation, as their coelomic epithelium remains a morphologically undifferentiated monolayer. The failure of genital ridge formation in Gata4-deficient embryos is corroborated by the absence of the early gonadal markers LHX9 and SF1. Our data indicate that GATA4 is required to initiate formation of the genital ridge in both XX and XY fetuses, prior to its previously reported role in testicular differentiation of the XY gonad.

Nematodes from the caecum and colon of Pogonomys (Muridae: Anisomyini) from Papua New Guinea with the descriptions of a new genus of Oxyuridae (Nematoda: Oxyurida) and a new species of Trichuridae (Nematoda: Enoplida)

Nematodes, comprising 2 species, a new genus from the family Syphaciidae and a new species from the familyTrichuridae were collected from the lower digestive tracts of 4 species of Pogonomys; P. championi, Flannery (12individuals), P. loriae, Thomas (14 individuals), P. macrourus, (Milne Edwards) (19 individuals) and P. sylvestris,Thomas (27 individuals) from Papua, Indonesia and Papua New Guinea. Pogonomicola rugala n. gen., n. sp.differs from all other genera in the Sypaciidae in having cervical alae with numerous folds and a single weaklydefined mamelon. Trichuris germani n. sp. differs from all congeners, including the cosmopolitan T. muris, theonly other trichurid reported from the region, by the lengths of the spicules and vagina, the ratio of anterior toposterior body length and the number of convolutions of the testis. The genus Pogonomys, with four species fromfour nematode families had a relatively rich helminth fauna in the lower digestive tract compared to otheransomyins studied. The Oxyuridae, with three genera comprising 5 species was the dominant group found in thelower digestive tract of the Anisomyini, indicating the possibility that the isolation of the old endemic rodents inNew Guinea has been associated with a period of coevolution between anisomyin hosts and their syphaciineparasites.

Big intraocular foreign body: Case report

Penetrated injuries are most difficult injuries of the eye. Intraocular foreign body (IOFB) may lodge in any of the structures it encounters, from anterior chamber to the retina and choroid. Notable effects caused by foreign body injury include traumatic cataract, vitreous liquefaction, retinal and subretinal hemorrhages, retinal detachment and development of endophtalmitis. A 49-year-old man sustained injury of the right eye with a piece of metal wire. On admission visual acuity was VOD: 1.0 and lower intraocular tension TOD = 6 mmHg (10-22 mmHg). Corneal entry wound was noticed near limb on 11 h with a prominating foreign body of 18 mm in length that passed through the iris, lens and vitreous. X-ray findings confirmed existence of a large foreign body extending along the entire length of the globe. IOFB removal was done with anatomic forceps. On postoperative detailed clinical examination we observed retinal rupture in the upper temporal quadrant fitting in the area of the IOFB damaged retina. Laser photocoagulation of retinal tear (laser retinal barrage) was done. Visual acuity on discharge was the same (1.0) and intraocular tension was within normal limits (10 mmHg). Penetrated injury of eye requires detailed examination of all eye structures, beginning from the anterior to posterior segment. Timely diagnosed ruptures of the posterior segment of eye before the development of traumatic cataract, and adequate therapeutic procedures prevent serious complications of IOFB penetrated eye injury such as retinal detachment and permanent reduction of visual acuity.

Current direction specificity of continuous theta-burst stimulation in modulating human motor cortex excitability when applied to somatosensory cortex

The present study examines the influence of primary somatosensory cortex (SI) on corticospinal excitability within primary motor cortex (M1) using repetitive transcranial magnetic stimulation. Two groups of subjects participated and both received continuous theta-burst stimulation (cTBS) over SI. One group received cTBS oriented to induce anterior-to-posterior (AP) followed by posterior-to-anterior (PA) current flow in the cortex and the other group received cTBS in the opposite direction (PA-AP). Motor evoked potentials (MEPs) were measured from the first dorsal interosseous muscle of the left and right hand before and at three time points (5, 25, 45 min) following cTBS over left-hemisphere SI. CTBS over SI in the AP-PA direction increased contralateral MEPs at 5 and 45 min with a near significant increase at 25 min. In contrast, PA-AP cTBS decreased contralateral MEPs at 25 min. We conclude that cTBS over SI modulates neural output directed to the hand with effects that depend on the direction of induced current.

Transcranial magnetic stimulation with a half-sine wave pulse elicits direction-specific effects in human motor cortex

BackgroundTranscranial magnetic stimulation (TMS) commonly uses so-called monophasic pulses where the initial rapidly changing current flow is followed by a critically dampened return current. It has been shown that a monophasic TMS pulse preferentially excites different cortical circuits in the human motor hand area (M1-HAND), if the induced tissue current has a posterior-to-anterior (PA) or anterior-to-posterior (AP) direction. Here we tested whether similar direction-specific effects could be elicited in M1-HAND using TMS pulses with a half-sine wave configuration.ResultsIn 10 young participants, we applied half-sine pulses to the right M1-HAND which elicited PA or AP currents with respect to the orientation of the central sulcus.Measurements of the motor evoked potential (MEP) revealed that PA half-sine stimulation resulted in lower resting motor threshold (RMT) than AP stimulation. When stimulus intensity (SI) was gradually increased as percentage of maximal stimulator output, the stimulus–response curve (SRC) of MEP amplitude showed a leftward shift for PA as opposed to AP half-sine stimulation. Further, MEP latencies were approximately 1 ms shorter for PA relative to AP half-sine stimulation across the entire SI range tested. When adjusting SI to the respective RMT of PA and AP stimulation, the direction-specific differences in MEP latencies persisted, while the gain function of MEP amplitudes was comparable for PA and AP stimulation.ConclusionsUsing half-sine pulse configuration, single-pulse TMS elicits consistent direction-specific effects in M1-HAND that are similar to TMS with monophasic pulses. The longer MEP latency for AP half-sine stimulation suggests that PA and AP half-sine stimulation preferentially activates different sets of cortical neurons that are involved in the generation of different corticospinal descending volleys.

Computed tomography of the chest with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination: preliminary observations

The purpose of this study was to assess the diagnostic image quality of ultra-low-dose chest computed tomography (ULD-CT) obtained with a radiation dose comparable to chest radiography and reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard dose diagnostic CT (SDD-CT) or low-dose diagnostic CT (LDD-CT) reconstructed with FBP alone. Unenhanced chest CT images of 42 patients acquired with ULD-CT were compared with images obtained with SDD-CT or LDD-CT in the same examination. Noise measurements and image quality, based on conspicuity of chest lesions on all CT data sets were assessed on a five-point scale. The radiation dose of ULD-CT was 0.16 ± 0.006 mSv compared with 11.2 ± 2.7 mSv for SDD-CT (P < 0.0001) and 2.7 ± 0.9 mSv for LDD-CT. Image quality of ULD-CT increased significantly when using MBIR compared with FBP or ASIR (P < 0.001). ULD-CT reconstructed with MBIR enabled to detect as many non-calcified pulmonary nodules as seen on SDD-CT or LDD-CT. However, image quality of ULD-CT was clearly inferior for characterisation of ground glass opacities or emphysema. Model-based iterative reconstruction allows detection of pulmonary nodules with ULD-CT with radiation exposure in the range of a posterior to anterior (PA) and lateral chest X-ray.

Mapping the frontal sinus ostia using virtual endoscopy

To determine the relative location of the frontal sinus opening to other frontal cells using virtual endoscopy; and to assess whether the relative location of the frontal sinus ostium can be predicted. Retrospective analysis of high-resolution computed tomography scans from 50 adult patients without frontal sinus disease or previous sinus surgery. Using virtual endoscopy software, 100 frontal recesses were mapped for the presence and relative position of the frontal sinus ostium to the following cells: agger nasi (ANC); frontal bullar; frontal types 1, 2, and 3; supraorbital ethmoid; suprabullar; and intersinus septal cells. ANC and frontal type 3 cells were present in 92% and 45% of frontal recesses, respectively. All other cell types had a prevalence of ≤ 25%. Fifty percent of recesses had two rows of ostia anterior to posterior (AP), and the frontal opening was anterior in 52%. When there were three rows of cells AP (39%), the frontal opening was in the center in 64% of cases. Thirty-five percent of recesses had two rows of ostia medial to lateral (ML), and the frontal opening was medial 80% of the time. When there were three rows of openings ML (45%), the frontal opening was in the center 56% of the time. The frontal sinus recess is variable and complex. Virtual endoscopy can be used to analyze the frontal recess and assist in presurgical planning. Although there is variability in the ostial configuration present in the frontal recess, the probable position of the frontal sinus ostium can be predicted.

Shh goes multidirectional in axon guidance

Shh and Wnts, secreted by the floor and roof plate of the spinal cord, direct longitudinal growth of the axons from the adjacent ventral funiculus and cortico-spinal tract. Whether these midline cues influence the directionality of axons elongating in more lateral positions of the spinal cord is unexplored. Song and colleagues investigate this possibility and demonstrate that the location of descending raphe-spinal tract in the ventrolateral spinal cord is dictated by the simultaneous repellent activity of Shh gradients in both the anterior-to-posterior (A-P) and medial-to-lateral (M-L) axis.

Shh signaling guides spatial pathfinding of raphespinal tract axons by multidirectional repulsion

Relatively little is known about the molecular mechanisms underlying spatial pathfinding in the descending serotonergic raphespinal tract (RST) in the developing spinal cord, one of the most important nerve pathways for pain, sensory and motor functions. We provide evidence that ventral floor plate-secreted Sonic hedgehog (Shh) is responsible for the establishment of decreasing gradients in both the anterior-to-posterior (A-P) and the medial-to-lateral (M-L) directions in the ventral spinal cord during serotonergic RST axon projection. Downstream components of the Shh pathway, Patched 1 (Ptch1) and Smoothened (Smo), were expressed in the serotonergic caudal raphe nuclei and enriched in the descending serotonergic RST axons. Diffusible Shh repulsion of serotonergic RST axons was shown to be mediated by Shh-Ptch1 interactions and derepression of Smo. Using a co-culture assay, we showed that A-P graded repulsion mediated by Shh signaling pushed the serotonergic axons caudally through the ventral spinal cord and M-L graded repulsion mediated by Shh signaling simultaneously restricted the serotonergic axons to the ventral and ventral-lateral funiculus. Prominent pathfinding errors of serotonergic RST axons were observed in various Shh, Ptch1 and Smo mutants. We conclude that Shh signaling-mediated multidirectional repulsion is required to push descending serotonergic RST axons in the A-P direction, and to restrict these axons to the ventral and ventral-lateral funiculus in the M-L direction. This is the first demonstration that Shh signaling-mediated multidirectional repulsion of serotonergic RST axons maintains spatial axon pathfinding in the developing spinal cord.

Accuracy of in situ neck-shaft angle and shortening measurements of the anatomically reduced, varus malreduced and shortened proximal femur: Can we believe what we see on the postoperative films?

ObjectivesMeasuring the neck-shaft angle (NSA) and amount of shortening of the femoral neck on the anterior to posterior (AP) X-ray is important when treating proximal femur fractures. To compensate for proximal femoral external rotation, the X-rays need to be taken with the leg internally rotated, an act that cannot always be performed or verified. This study aims to define the utility of in situ AP X-ray in NSA and shortening measurements. MethodsComputed tomography (CT) scans of 50 patients undergoing abdominal CT scans were assessed for the in situ rotation of the femoral neck relative to the AP beam. Three proximal femur fracture Sawbones models were made and AP X-rays of the models were taken with changing proximal femur rotation. NSA and shortening were measured on all X-rays. ResultsIn situ femoral neck rotation averaged 25.4±10.6° of external rotation (range, 0.9–51.8°, 80% of measurements less than 35°). NSA measurements varied less than 5° with less than 35° of rotation in all models, and were always greater than the true value. Femoral neck vertical length (VL) measurement was independent of proximal femur rotation whereas the horizontal length component was found to be highly dependent on the same. ConclusionsNSA measured on AP X-ray will be accurate to within 5° in 80% of patients with the hip left in situ and in 100% of the patients if the hip is internally rotated 15°. Measurement of significant varus or loss of VL of the femoral neck can be considered accurate regardless of leg rotation at the time of X-rays being taken.

Post-prostatectomy image-guided radiation therapy: Evaluation of toxicity and inter-fraction variation using online cone-beam CT

The purpose of this study is to assess the acute and late genitourinary (GU) and gastrointestinal (GI) toxicities of cone-beam computed tomography (CBCT) guided conformal adjuvant and salvage post-prostatectomy radiotherapy (RT) compared with RT with port films. Sixty-eight patients (group 1) were treated with RT following radical prostatectomy (RP) using CBCT-guided conformal RT to a median dose of 68.4Gy. CBCT images were acquired three to five times weekly and were automatically co-registered to a reference CT. A comparative group (group 2) included 150 patients who received post-RP RT with weekly port films to a median dose of 64.8Gy. GU and GI toxicities were graded in both the acute and late settings using Radiation Therapy Oncology Group criteria. Associations between toxicity and study variables were evaluated by odds ratios (ORs) estimated by logistic regression. Grades 2 and 3 acute GU toxicity were experienced by 13% (n=9) and 2% (n=1) of patients in group 1, respectively, while 13% (n=19) had grade 2 acute GU toxicity in the control group (group 2). Grade 2 acute GI toxicity was experienced by 13% (n=9) and 15% (n=23) in groups 1 and 2, respectively. Acute GU (P=0.67) and GI (P =0.84) toxicities were not significantly different between the two groups. There were no associations detected between CBCT and acute GI toxicity (OR 0.76, P=0.57) or acute GU (OR 1.16, P=0.75). Increased odds of acute GU toxicity were observed for doses>68.4Gy (OR 12.81, P=0.04), which were only delivered in the CBCT group. CBCT mean variations (standard deviation) for 1053 fractions were 2.8mm (2.8), 2.0mm (2.4) and 3.1mm (2.9) in the left-to-right, anterior-to-posterior (AP) and superior-to-inferior (SI) axes, respectively. Corrective shifts for variance≥5mm were required for 15%, 6% and 19% of fractions in the left-to-right, anterior-to-posterior and superior-to-inferior axes, respectively. Rates of acute toxicity with CBCT-guided post-RP RT to 68.4Gy were similar to treatment to 64.8Gy without image-guidance RT. Acceptable early toxicity profiles suggest that CBCT is a reasonable strategy for image guidance, but the value of CBCT must be weighed against potential increased risk of secondary cancers due to increased radiation exposure.

ORGAN-SPECIFIC EXTERNAL DOSE COEFFICIENTS AND PROTECTIVE APRON TRANSMISSION FACTORS FOR HISTORICAL DOSE RECONSTRUCTION FOR MEDICAL PERSONNEL

While radiation absorbed dose (Gy) to the skin or other organs is sometimes estimated for patients from diagnostic radiologic examinations or therapeutic procedures, rarely is occupationally-received radiation absorbed dose to individual organs/tissues estimated for medical personnel; e.g., radiologic technologists or radiologists. Generally, for medical personnel, equivalent or effective radiation doses are estimated for compliance purposes. In the very few cases when organ doses to medical personnel are reconstructed, the data is usually for the purpose of epidemiologic studies; e.g., a study of historical doses and risks to a cohort of about 110,000 radiologic technologists presently underway at the U.S. National Cancer Institute. While ICRP and ICRU have published organ-specific external dose conversion coefficients (DCCs) (i.e., absorbed dose to organs and tissues per unit air kerma and dose equivalent per unit air kerma), those factors have been published primarily for mono-energetic photons at selected energies. This presents two related problems for historical dose reconstruction, both of which are addressed here. It is necessary to derive conversion factor values for (1) continuous distributions of energy typical of diagnostic medical x-rays (bremsstrahlung radiation), and (2) energies of particular radioisotopes used in medical procedures, neither of which are presented in published tables. For derivation of DCCs for bremsstrahlung radiation, combinations of x-ray tube potentials and filtrations were derived for different time periods based on a review of relevant literature. Three peak tube potentials (70 kV, 80 kV, and 90 kV) with four different amounts of beam filtration were determined to be applicable for historic dose reconstruction. The probabilities of these machine settings were assigned to each of the four time periods (earlier than 1949, 1949-1954, 1955-1968, and after 1968). Continuous functions were fit to each set of discrete values of the ICRP/ICRU mono-energetic DCCs and the functions integrated over the air-kerma weighted photon fluence of the 12 defined x-ray spectra. The air kerma-weighted DCCs in this work were developed specifically for an irradiation geometry of anterior to posterior (AP) and for the following tissues: thyroid, breast, ovary, lens of eye, lung, colon, testes, heart, skin (anterior side only), red bone marrow (RBM), and brain. In addition, a series of functional relationships to predict DT Ka-1 values for RBM dependent on body mass index [BMI (kg m-2) ≡ weight per height] and average photon energy were derived from a published analysis. Factors to account for attenuation of radiation by protective lead aprons were also developed. Because lead protective aprons often worn by radiology personnel not only reduce the intensity of x-ray exposure but also appreciably harden the transmitted fluence of bremsstrahlung x-rays, DCCs were separately calculated for organs possibly protected by lead aprons by considering three cases: no apron, 0.25 mm Pb apron, and 0.5 mm Pb apron. For estimation of organ doses from conducting procedures with radioisotopes, continuous functions of the reported mono-energetic values were developed, and DCCs were derived by estimation of the function at relevant energies. By considering the temporal changes in primary exposure-related parameters (e.g., energy distribution), the derived DCCs and transmission factors presented here allow for more realistic historical dose reconstructions for medical personnel when monitoring badge readings are the primary data on which estimation of an individual's organ doses are based.

Immediate effects of anterior to posterior talocrural joint mobilizations following acute lateral ankle sprain

Restrictions in ankle dorsiflexion range of motion (ROM) have been associated with decreased posterior talar glide in individuals with an acute lateral ankle sprain. Talocrural joint mobilizations may be used to restore joint arthrokinematics. Our purpose was to examine the effects of a single bout of anterior to posterior (AP) talocrural joint mobilization on self-reported function, dorsiflexion ROM, and posterior talar translation in individuals with an acute lateral ankle sprain. This single-blinded, randomized controlled trial utilized 17 volunteers (nine treatment and eight control) with an acute lateral ankle sprain (grade I/II) who were immobilized for a period of 1–7 days. The treatment group received a single 30-second bout of grade III AP talocrural joint mobilization the day their immobilization device was removed, while the control group did not receive any intervention. Active dorsiflexion ROM and posterior talar translation were assessed before, immediately after, and 24 hours after receipt of the treatment or control interventions. Self-reported function and pain were assessed before and 24 hours after the receipt of the treatment or control interventions using the foot and ankle disability index. Collectively all groups demonstrated improved dorsiflexion ROM and self-reported function. There was a significant decrease in pain perception at 24-hour follow-up for the treatment group. A single bout of AP talocrural joint mobilizations may not have an immediate effect on ankle dorsiflexion ROM, posterior talar translation, or self-reported function; however, they may have an immediate effect on pain perception in individuals with an acute lateral ankle sprain.