Alexander Kirichenko

Modular, Multi-Function Digital-RF Receiver Systems

Superconductor digital receiver systems of increasing functionality, modularity and user-friendliness have been developed. The modular design methodology ensures that within its input-output and heat load capacity, the system can be reconfigured to perform a different function by changing the chip module and by reprogramming FPGA-based digital signal processors. One of the systems (ADR-004), originally equipped with a 10 × 10 mm2 channelizing receiver chip for signals intelligence application, was reconfigured with a 5 × 5 mm2 1.1-GHz bandpass ADC chip to perform worlds first multi-net Link-16 demonstration at a U.S. Navy facility. Substantial improvements in system integration have been obtained in each successive generation of digital-RF receiver systems. The latest (third) generation system (ADR-005), hosting a 5 × 5 mm2 7.5-GHz bandpass ADC chip and an FPGA channelizer, successfully repeated the over-the-air SATCOM demonstration performed previously using a 1-cm2 single-chip bandpass digital receiver with an on-chip superconductor channelizer. This system ran error-free for over 12 hours with and without a low-noise amplifier. To our knowledge, this is the first time an X-band SATCOM receiver has been operated without analog amplification and down-conversion in a military application.

Stereotactic body radiotherapy (SBRT) with or without surgery for primary and metastatic liver tumors

OBJECTIVES We report single center experience on the outcome and toxicity of SBRT alone or in combination with surgery for inoperable primary and metastatic liver tumors between 2007 and 2014. PATIENTS AND METHODS Patients with 1-4 hepatic lesions and tumor diameter ≤9 cm received SBRT at 46.8Gy ± 3.7 in 4-6 fractions. The primary end point was local control with at least 6 months of radiographic followup, and secondary end points were toxicity and survival. RESULTS Eighty-seven assessable patients (114 lesions) completed liver SBRT for hepatoma (39) or isolated metastases (48) with a median followup of 20.3 months (range 1.9-64.1). Fourteen patients underwent liver transplant with SBRT as a bridging treatment or for tumor downsizing. Eight patients completed hepatic resections in combination with planned SBRT for unresectable tumors. Two-year local control was 96% for hepatoma and 93.8% for metastases; it was 100% for lesions ≤4 cm. Two-year overall survival was 82.3% (hepatoma) and 64.3% (metastases). No incidence of grade >2 treatment toxicity was observed. CONCLUSION In this retrospective analysis we demonstrate that liver SBRT alone or in combination with surgery is safe and effective for the treatment of isolated inoperable hepatic malignancies and provides excellent local control rates.

Combination of IG-IMRT and permanent source prostate brachytherapy in patients with organ-confined prostate cancer: GU and GI toxicity and effect on erectile function

PURPOSE To assess toxicity outcomes of image-guided intensity-modulated radiation therapy (IG-IMRT) combined with permanent prostate seed implant in a cohort of patients with localized prostate cancer. METHODS AND MATERIALS A retrospective analysis was performed on 67 patients with the median pretreatment prostate-specific antigen level of 5.4. The Gleason score was less than 7 in 7 patients, 7 in 52 patients, and greater than 7 in 8 patients. The median followup was 28.2 months (range, 12-89.5 months). Treatment consisted of 45 (n=65) or 50.4 Gy (n=2) at 1.8 Gy/fraction of IG-IMRT to the prostate and seminal vesicles. Eight patients had simultaneous irradiation of pelvic lymph nodes to 45 (n=65) or 50.4 Gy (n=2). After IG-IMRT, patients received transperineal prostate implant boost with either (103)Pd (n=65, the prescribed D(90) of 100 Gy) or (125)I (n=2, D(90) of 110 Gy). Eleven patients received androgen deprivation therapy with radiotherapy. RESULTS Toxicity higher than Grade 3 was not observed. The combined incidence of acute and late Grade 3 genitourinary toxicity was 6%. The combined incidence of acute and late Grade 3 gastrointestinal toxicity was 3%. At least one episode of gastrointestinal bleeding on followup, which could be attributed to radiation, was recorded in 14.9% of patients. For patients achieving erections before radiation, the 3-year Kaplan-Meier potency preservation rate was 66.5%. CONCLUSIONS The early toxicity of the combination of IG-IMRT and low-dose rate brachytherapy boost in this study was favorable.

Use of implanted gold fiducial markers with MV-CBCT image-guided IMRT for pancreatic tumours

Visualisation of soft tissues such as pancreatic tumours by mega‐voltage cone beam CT (MV‐CBCT) is frequently difficult and daily localisation is often based on more easily seen adjacent bony anatomy. Fiducial markers implanted into pancreatic tumours serve as surrogates for tumour position and may more accurately represent absolute tumour position. Differences in daily shifts based on alignment to implanted fiducial markers vs. alignment to adjacent bony anatomy were compared.

SU‐E‐J‐152: Fluoroscopic Treatment Verification for Gated Stereotactic Body Radiation Therapy of a Tumor Located Near the Dome of the Liver: A

Purpose: To describe a method using pretreatment and intrafraction fluoroscopic verification of the gated treatment of a liver lesion located near the diaphragm. Methods: A 74‐year‐old female patient, who had previously received radiation to the lung, presented with a 13.8 cc tumor located 0.5 cm inferior to the superior border of the liver, moving 2 cm in the cranio‐caudal direction with breathing. A planning CT with contrast in full exhale breath hold (FEBH) was acquired to reduce motion artifact, followed by a 4‐dimensional (4D) CT. The gross target volume (GTV) was contoured on the FEBH CT and propagated only to the 25% inspiration (25In) and 25% expiration (25Ex) phases of the 4D‐CT, in order to reduce lung dose. An internal target volume (ITV) was created encompassing all 3 phases. A plan was created to deliver 50 Gy to the PTV (ITV+0.3cm laterally and inferiorly) in 5 fractions using 3D conformal planning gated on the FE, 25In and 25Ex phases. Digitally reconstructed radiographs (DRR) were created for each beam angle and for each of the 3 respiratory phases included in the gating window. Prior to treatment, a mega‐voltage (MV)‐CBCT was acquired and its projections were analyzed in cine‐mode. Intrafraction motion verification was monitored using MV‐fluoroscopy. On both cine and fluoroscopy movies, the respiratory phase was identified using the position of the diaphragm, and the frames were compared to the corresponding DRRs. Results: Qualitative analysis on both the pretreatment cine and intrafraction fluoroscopy movies showed a clinically acceptable agreement between plan and treatment position. Conclusion: We described a treatment verification method for gated SBRT of lesions near the dome of the liver, using pre‐treatment and intrafraction fluoroscopic movies. This method is a good gated treatment quality assurance tool allowing to confidently spare lung tissue.