Chia-Chun Kuo

An autotuning respiration compensation system based on ultrasound image tracking

The purpose of this study was to develop an ultrasound image tracking algorithm (UITA) for extracting the exact displacement of internal organs caused by respiratory motion. The program can track organ displacements in real time, and analyze the displacement signals associated with organ displacements via a respiration compensating system (RCS). The ultrasound imaging system is noninvasive and has a high spatial resolution and a high frame rate (around 32 frames/s), which reduces the radiation doses that patients receive during computed tomography and X-ray observations. This allows for the continuous noninvasive observation and compensation of organ displacements simultaneously during a radiation therapy session.This study designed a UITA for tracking the motion of a specific target, such as the human diaphragm. Simulated diaphragm motion driven by a respiration simulation system was observed with an ultrasound imaging system, and then the induced diaphragm displacements were calculated by our proposed UITA. These signals were used to adjust the gain of the RCS so that the amplitudes of the compensation signals were close to the target movements. The inclination angle of the ultrasound probe with respect to the surface of the abdomen affects the results of ultrasound image displacement tracking. Therefore, the displacement of the phantom was verified by a LINAC with different inclination-angle settings of the ultrasound probe. The experimental results indicate that the best inclination angle of the ultrasound probe is 40 degrees, since this results in the target displacement of the ultrasound images being close to the actual target motion. The displacement signals of the tracking phantom and the opposing displacement signals created by the RCS were compared to assess the positioning accuracy of our proposed ultrasound image tracking technique combined with the RCS.When the ultrasound probe was inclined by 40 degrees in simulated respiration experiments using sine waves, the correlation between the target displacement on the ultrasound images and the actual target displacement was around 97%, and all of the compensation rates exceeded 94% after activating the RCS. Furthermore, the diaphragm movements on the ultrasound images of three patients could be captured by our image tracking technique. The test results show that our algorithm could achieve precise point locking and tracking functions on the diaphragm. This study has demonstrated the feasibility of the proposed ultrasound image tracking technique combined with the RCS for compensating for organ displacements caused by respiratory motion.This study has shown that the proposed ultrasound image tracking technique combined with the RCS can provide real-time compensation of respiratory motion during radiation therapy, without increasing the overall treatment time. In addition, the system has modest space requirements and is easy to operate.

A CASE OF HEPATOCELLULAR CARCINOMA WITH TUMOR THROMBUS EXTENDING FROM THE INFERIOR VENA CAVA TOWARDS THE RIGHT ATRIUM SHOWS COMPLETE RESPONSE AFTER COMBINED TREATMENT WITH RADIATION THERAPY AND SORAFENIB

We report a case of advanced hepatocellular carcinoma (HCC) with tumor thrombosis extending from the inferior vena cava (IVC) towards the right atrium (RA) treated by radiation therapy (RT) and targeted therapy with sorafenib. A 55-year old man who had been a hepatitis C carrier eventually developed liver cirrhosis and primary HCC. Tumor thrombosis spanning across the IVC and the RA was noted at initial diagnosis. He received RT with 37.5 Gy in 15 fractions in addition to concurrent and sequential sorafenib therapy. Follow-up imaging studies showed complete response of IVC and RA thrombus.

Gene Sequencing for Selection of Chemotherapy Drugs Combined with Stereotactic Body Radiation Therapy for Stage IV Colon Cancer: A Case Report

Gene sequencing may be a feasible means of individualizing cancer treatment. By investigating the correlation between genetic profiles and treatment outcomes of chemotherapy, it may be possible to determine effective treatment strategies according to individual genotypes in cancer patients. Despite great advances in drugs for cancer treatment, treatment outcomes may be improved by analyzing genetic markers that indicate treatment efficacy. We report the treatment for a patient with metastatic colon cancer in which gene sequencing was used for the selection of an effective chemotherapy regimen. In addition, we describe the entire course of treatment, including the combination of surgical resection for local control and radiotherapy to eradicate distant metastases. This is a pilot report of the clinical use of gene sequencing for determining a treatment regimen. Further clinical trials are needed to optimize the personalization of cancer treatment.

Brainstem Cavernoma Treated with Cone-based Stereotactic Radiosurgery

The treatment of brainstem cavernoma includes neurosurgery and stereotactic radiosurgery (SRS). We reported two cases with brainstem cavernoma treated with linear accelerator (LlNAC) cone-based stereotactic radiosurgery.CASE 1: A 44 year-old female patient survived from brainstem cavernoma with bleeding into right pons. She recovered her neurological function gradually in months. Another growing cavernoma at left pons was noted by magnetic resonance imaging (MRI) of brain. It was treated with cone-based stereotactic radiosurgery. The prescribed radiation dose was 14 Gy in two fractions. No new neurological deficit was noted after radiosurgery. On the regular follow-up of brain MRI, the cavernoma over left pons remitted gradually, and no cerebral edema related to radiosurgery was observed.CASE 2: A 43 year-old male patient with history of left orbital cavernoma status post operation and radiation therapy in 1997 had a 0.7 cm cavernoma at left ambient cistern of the 4th ventricle roof. Cone-based stereotactic radiosurgery was performed. The prescribed radiation dose was 18 Gy in two fractions. On the regular follow-up brain MRI the cavernoma demonstrated very good treatment response.