Image guided liver stereotactic body radiation therapy (SBRT) often relies on implanted fiducial markers. The target localization accuracy decreases with increased marker-target distance. This may ...occur partly because of liver rotations. The aim of this study was to examine time-resolved translations and rotations of liver marker constellations and investigate if time-resolved intrafraction rotational corrections can improve localization accuracy in liver SBRT.
Twenty-nine patients with 3 implanted markers received SBRT in 3 to 6 fractions. The time-resolved trajectory of each marker was estimated from the projections of 1 to 3 daily cone beam computed tomography scans and used to calculate the translation and rotation of the marker constellation. In all cone beam computed tomography projections, the time-resolved position of each marker was predicted from the position of another surrogate marker by assuming that the marker underwent either (1) the same translation as the surrogate marker; or (2) the same translation as the surrogate marker corrected by the rotation of the marker constellation. The localization accuracy was quantified as the root-mean-square error (RMSE) between the estimated and the actual marker position. For comparison, the RMSE was also calculated when the marker's position was estimated as its mean position for all the projections.
The mean translational and rotational range (2nd-98th percentile) was 2.0 mm/3.9° (right-left), 9.2 mm/2.9° (superior-inferior), 4.0 mm/4.0° (anterior-posterior), and 10.5 mm (3-dimensional). Rotational corrections decreased the mean 3-dimensional RMSE from 0.86 mm to 0.54 mm (P<.001) and halved the RMSE increase per millimeter increase in marker distance.
Intrafraction rotations during liver SBRT reduce the accuracy of marker-guided target localization. Rotational correction can improve the localization accuracy with a factor of approximately 2 for large marker-target distances.
Intrafraction motion can compromise the treatment accuracy in liver stereotactic body radiation therapy (SBRT). Respiratory gating can improve treatment delivery; however, gating based on external ...motion surrogates is inaccurate. The present study reports the use of Calypso-based internal electromagnetic motion monitoring for gated liver SBRT.
Fifteen patients were included in a study of 3-fraction respiratory gated liver SBRT guided by 3 implanted electromagnetic transponders. The planning target volume was created by a 5-mm axial and 7-mm (n = 12) or 10-mm (n = 3) craniocaudal expansion of the clinical target volume (CTV) and covered with 67% of the prescribed CTV mean dose. Treatment was gated to the end-exhale phase of the respiratory cycle with beam-on when the target deviated <3 mm (left-right/anteroposterior) and 4 mm (craniocaudal) from the planned position, according to the monitored (25-Hz) transponder centroid position. The couch was adjusted remotely if baseline drifts >1 to 2 mm occurred. Log files of transponder motion were used to determine the geometric error and reconstruct the delivered CTV dose in the actual gated treatments and in simulated nongated treatments.
No severe side effects were observed in relation to transponder implantation. All 45 treatment fractions were successfully guided using the Calypso system. The mean number of couch corrections during each gated fraction was 2.8 (range 0-7). The mean duty cycle during gated treatment was 62.5% (range 29.1%-84.9%). Without gating, the mean 3-dimensional geometric error during a fraction would have been 5.4 mm (range 2.7-12.1). Gating reduced this error to 2.0 mm (range 1.2-3.0). The patient mean reduction in minimum dose to 95% of the CTV relative to the planned dose was 6.0 percentage points (range 0.7-22.0) without gating and 0.8 percentage point (range 0.2-2.0) with gating.
Gating using internal motion monitoring was successfully applied for liver SBRT. It markedly improved the geometric and dosimetric accuracy compared with nongated standard treatment.
To investigate the time-resolved 3-dimensional (3D) internal motion throughout stereotactic body radiation therapy (SBRT) of tumors in the liver using standard x-ray imagers of a conventional linear ...accelerator.
Ten patients with implanted gold markers received 11 treatment courses of 3-fraction SBRT in a stereotactic body-frame on a conventional linear accelerator. Two pretreatment and 1 posttreatment cone-beam computed tomography (CBCT) scans were acquired during each fraction. The CBCT projection images were used to estimate the internal 3D marker motion during CBCT acquisition with 11-Hz resolution by a monoscopic probability-based method. Throughout the treatment delivery by conformal or volumetric modulated arc fields, simultaneous MV portal imaging (8 Hz) and orthogonal kV imaging (5 Hz) were applied to determine the 3D marker motion using either MV/kV triangulation or the monoscopic method when marker segmentation was unachievable in either MV or kV images. The accuracy of monoscopic motion estimation was quantified by also applying monoscopic estimation as a test for all treatments during which MV/kV triangulation was possible.
Root-mean-square deviations between monoscopic estimations and triangulations were less than 1.0 mm. The mean 3D intrafraction and intrafield motion ranges during liver SBRT were 17.6 mm (range, 5.6-39.5 mm) and 11.3 mm (2.1-35.5mm), respectively. The risk of large intrafraction baseline shifts correlated with intrafield respiratory motion range. The mean 3D intrafractional marker displacement relative to the first CBCT was 3.4 mm (range, 0.7-14.5 mm). The 3D displacements exceeded 8.8 mm 10% of the time.
Highly detailed time-resolved internal 3D motion was determined throughout liver SBRT using standard imaging equipment. Considerable intrafraction motion was observed. The demonstrated methods provide a widely available approach for motion monitoring that, combined with motion-adaptive treatment techniques, has the potential to improve the accuracy of radiation therapy for moving targets.
•The patient presented culture-proven aortitis due to Coxiella burnetii infection.•The patient also fulfilled the ACR criteria for giant cell arteritis (GCA).•A pathophysiological link between the ...two diseases is likely.•It should be avoided to retain a diagnosis of chronic Q fever on the sole basis of biological criteria without clinically evident infection.•The case was managed in collaboration with experts of the French Reference Centre for Coxiella infections (Dr Million and Prof. Raoult).
A case of proven Coxiella burnetii aortitis, possibly associated with giant cell arteritis (GCA), is reported. A 72-year-old man, who is a hunter, presented with weight loss, fever, jaw claudication, and hardened temporal arteries associated with a persistent inflammatory syndrome and arteritis of the whole aorta, including the brachiocephalic arteries, as seen on 18F-fluorodeoxyglucose positron emission tomography/computed tomography. The diagnosis of GCA was retained, and treatment with prednisolone was started. Given the aneurysm of the abdominal aorta, the patient underwent replacement of the abdominal aorta with an allograft. Histology showed intense chronic arteritis attributed to atherosclerosis with dissection. However, Coxiella burnetii infection was confirmed by serology and then by culture and molecular biology on the surgical specimen. A combination of hydroxychloroquine and doxycycline was added to tapered prednisolone and the outcome was favourable.
The protein parkin, encoded by the
gene, is vital for mitochondrial homeostasis, and although it has been implicated in Parkinson's disease (PD), the disease mechanisms remain unclear. We have ...applied mass spectrometry-based proteomics to investigate the effects of parkin dysfunction on the mitochondrial proteome in human isogenic induced pluripotent stem cell-derived neurons with and without
knockout (KO). The proteomic analysis quantified nearly 60% of all mitochondrial proteins, 119 of which were dysregulated in neurons with
KO. The protein changes indicated disturbances in oxidative stress defense, mitochondrial respiration and morphology, cell cycle control, and cell viability. Structural and functional analyses revealed an increase in mitochondrial area and the presence of elongated mitochondria as well as impaired glycolysis and lactate-supported respiration, leading to an impaired cell survival in PARK2 KO neurons. This adds valuable insight into the effect of parkin dysfunction in human neurons and provides knowledge of disease-related pathways that can potentially be targeted for therapeutic intervention.
Abstract Purpose To use intrafraction kilovoltage (kV) imaging during liver stereotactic body radiotherapy (SBRT) delivered by volumetric modulated arc therapy (VMAT) to estimate the intra-treatment ...target motion and to reconstruct the delivered target dose. Methods Six liver SBRT patients with 2–3 implanted gold markers received SBRT in three fractions of 18.75 Gy or 25 Gy. CTV-to-PTV margins of 5 mm in the axial plane and 10 mm in the cranio-caudal directions were applied. A VMAT plan was designed to give minimum target doses of 95% (CTV) and 67% (PTV). At each fraction, the 3D marker trajectory was estimated by fluoroscopic kV imaging throughout treatment delivery and used to reconstruct the actually delivered CTV dose. The reduction in D95 (minimum dose to 95% of the CTV) relative to the planned D95 was calculated. Results The kV position estimation had mean root-mean-square errors of 0.36 mm and 0.47 mm parallel and perpendicular to the kV imager, respectively. Intrafraction motion caused a mean 3D target position error of 2.9 mm and a mean D95 reduction of 6.0%. The D95 reduction correlated with the mean 3D target position error during a fraction. Conclusions Kilovoltage imaging for detailed motion monitoring with dose reconstruction of VMAT-based liver SBRT was demonstrated for the first time showing large dosimetric impact of intrafraction tumor motion.
Abstract To minimize the risk of marker migration in fiducial marker guided liver SBRT it is common to add a delay of a week between marker implantation and planning CT. This study found that such a ...delay is unnecessary and could be avoided to minimize the treatment preparation time.
Purpose
Young patients represent a particularly vulnerable group regarding vocational prognosis after an acquired brain injury (ABI). We aimed to investigate how sequelae and rehabilitation needs are ...associated with vocational prognosis up to 3 years after an ABI in 15–30-year-old patients.
Methods
An incidence cohort of 285 patients with ABI completed a questionnaire on sequelae and rehabilitation interventions and needs 3 months after the index hospital contact. They were followed-up for up to 3 years with respect to the primary outcome “stable return to education/work (sRTW)”, which was defined using a national register of public transfer payments. Data were analyzed using cumulative incidence curves and cause-specific hazard ratios.
Results
Young individuals reported a high frequency of mainly pain-related (52%) and cognitive sequelae (46%) at 3 months. Motor problems were less frequent (18%), but negatively associated with sRTW within 3 years (adjusted HR 0.57, 95% CI 0.39–0.84). Rehabilitation interventions were received by 28% while 21% reported unmet rehabilitation needs, and both factors were negatively associated with sRTW (adjusted HR 0.66, 95% CI 0.48–0.91 and adjusted HR 0.72, 95% CI 0.51–1.01).
Conclusions
Young patients frequently experienced sequelae and rehabilitation needs 3 months post ABI, which was negatively associated with long-term labor market attachment. The low rate of sRTW among patients with sequelae and unmet rehabilitation needs indicates an untapped potential for ameliorated vocational and rehabilitating initiatives targeted at young patients.
Abstract The Ultraviolet Transient Astronomy Satellite (ULTRASAT) is scheduled to be launched to geostationary orbit in 2027. It will carry a telescope with an unprecedentedly large field of view ...(204 deg 2 ) and near-ultraviolet (NUV; 230–290 nm) sensitivity (22.5 mag, 5 σ , at 900 s). ULTRASAT will conduct the first wide-field survey of transient and variable NUV sources and will revolutionize our ability to study the hot transient Universe. It will explore a new parameter space in energy and timescale (months-long light curves with minutes cadence), with an extragalactic volume accessible for the discovery of transient sources that is >300 times larger than that of the Galaxy Evolution Explorer (GALEX) and comparable to that of the Vera Rubin Observatory’s Legacy Survey of Space and Time. ULTRASAT data will be transmitted to the ground in real time, and transient alerts will be distributed to the community in <15 minutes, enabling vigorous ground-based follow up of ULTRASAT sources. ULTRASAT will also provide an all-sky NUV image to >23.5 AB mag, over 10 times deeper than the GALEX map. Two key science goals of ULTRASAT are the study of mergers of binaries involving neutron stars, and supernovae. With a large fraction (>50%) of the sky instantaneously accessible, fast (minutes) slewing capability, and a field of view that covers the error ellipses expected from gravitational-wave (GW) detectors beyond 2026, ULTRASAT will rapidly detect the electromagnetic emission following binary neutron star/neutron star–black hole mergers identified by GW detectors, and will provide continuous NUV light curves of the events. ULTRASAT will provide early (hour) detection and continuous high-cadence (minutes) NUV light curves for hundreds of core-collapse supernovae, including for rarer supernova progenitor types.
Abstract
Purpose. To investigate the stability of target motion amplitude and motion directionality throughout full stereotactic body radiotherapy (SBRT) treatments of tumors in the liver. Material ...and methods. Ten patients with gold markers implanted in the liver received 11 courses of 3-fraction SBRT on a conventional linear accelerator. A four-dimensional computed tomography (4DCT) scan was obtained for treatment planning. The time-resolved marker motion was determined throughout full treatment field delivery using the kV and MV imagers of the accelerator. The motion amplitude and motion directionality of all individual respiratory cycles were determined using principal component analysis (PCA). The variations in motion amplitude and directionality within the treatment courses and the difference from the motion in the 4DCT scan were determined. Results. The patient mean (± 1 standard deviation) peak-to-peak 3D motion amplitude of individual respiratory cycles during a treatment course was 7.9 ± 4.1 mm and its difference from the 4DCT scan was −0.8 ± 2.5 mm (max, 6.6 mm). The mean standard deviation of 3D respiratory cycle amplitude within a treatment course was 2.0 ± 1.6 mm. The motion directionality of individual respiratory cycles on average deviated 4.6 ± 1.6° from the treatment course mean directionality. The treatment course mean motion directionality on average deviated 7.6 ± 6.5° from the directionality in the 4DCT scan. A single patient-specific oblique direction in space explained 97.7 ± 1.7% and 88.3 ± 10.1% of all positional variance (motion) throughout the treatment courses, excluding and including baseline shifts between treatment fields, respectively. Conclusion. Due to variable breathing amplitudes a single 4DCT scan was not always representative of the mean motion amplitude during treatment. However, the motion was highly directional with a fairly stable direction throughout treatment, indicating a potential for more optimal individualized motion margins aligned to the preferred direction of motion.
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