Progress in the treatment of non-small cell lung cancer with brain metastases / 中国肿瘤临床

Lung cancer is a malignant tumor,leading to the highest morbidity and mortality worldwide.Non-small cell lung cancer (NSCLC)accounts for approximately 80% of all lung cancer types.Out of all the patients with advanced NSCLC,more than 40% develop brain metastasis,and lung cancer associated with brain metastasis indicates poor prognosis.Traditional treatment options,such as ra-diotherapy,chemotherapy and surgery,have an extremely limited role in improvement of prognosis of such patients.In recent years, with the development of stereotactic radiotherapy and targeted therapy,particularly chemotherapy combined with targeted therapy, radiotherapy combined with targeted therapy and other types of therapies,NSCLC patients with brain metastases could benefit from these therapies with an improved quality of life and prolonged median overall survival. However, the ideal treatment regimen for NSCLC patients with brain metastases remains controversial.Recent advances in NSCLC with brain metastases will be described elabo-rately in this paper,to provide a theoretical basis for selecting a reasonable treatment plan for non-small lung cancer patients with brain metastasis.

Measurement of Dosimetric Parameters and Dose Verifi cation in Stereotactic Radiosurgery (SRS) / Jurnal Sains Kesihatan Malaysia

The fi rst part of this study was about measurement of dosimetric parameters for small photon beams to be used as input data for treatment planning computer system (TPS) and to verify the dose calculated by TPS in Stereotactic Radiosurgery (SRS) procedure. The beam data required were percentage depth dose (PDD), off-axis ratio (OAR) and scattering factor. Small beams of 5 mm to 45 mm diameter from a circular cone collimator in SRS were used for beam data measurements. Measurements were made using pinpoint ionisation chamber (0.016cc). In the second part of this study, we reported the important of carrying out quality assurance (QA) procedures before SRS treatment which were found to infl uence the accuracy of dose delivery. These QA procedures consisted of measurements on the accuracy in target localization and treatment room laser alignment. The calculated TPS dose for treatment was verifi ed using pinpoint ionisation chamber and thermoluminescent detector (TLD) 100H. The deviation mean between measured and calculated dose was -3.28%. The measured dose obtained from pinpoint ionisation chamber is in good agreement with the calculated dose from TPS with deviation mean of 2.17%. In conclusion, pinpoint ionisation chamber gives a better accuracy in dose calculation compared to TLD 100H. The results are acceptable as recommended by International Commission on Radiation Units and Measurements (ICRU) Report No. 50 (1994) that dose delivered to the target volume must be within ± 5% error.

Clinical Results from Single-Fraction Stereotactic Radiosurgery (SRS) of Brain Arteriovenous Malformation: Single Center Experience / 의학물리

The purpose of this study was to analyze the effect of single-fraction stereotactic radiosurgery (SRS) for the treatment of 15 cases of cerebral arteriovenous malformations (AVMs). Between 2002 and 2009, of the 25 patients who had SRS for the treatment of cerebral AVM, 15 patients (6 men, 9 women) taken a digital subtraction angiography (DSA) over 12 months after SRS were included. We retrospectively evaluated the size, location, hemorrhage of nidus, angiographic changes on follow-up on the MR angiography and DSA, and clinical complications during follow-up periods. At a median follow-up of 24 months (range 12-89), complete obliteration of nidus was observed in all patients (100%) while residual draining veins was observed in 3 patients (20%). There was no clinical complication during the follow-up period except seizure in 1 patient. The mean nidus volume was 4.7cc (0.5~11.7 cc, SD 3.7 cc). The locations of nidus were in cerebral hemisphere in 11 patients, cerebellum in 2 patients, basal ganglia in 1 patient, and pons in 1 patient respectively. 9 cases were hemorrhagic, and 6 cases were non-hemorrhagic AVMs. The SRS with LINAC is a safe and effective treatment for cerebral AVMs when the follow up period is over 4 years. However, it is recommended to continue to follow up until the draining vein on arterial phase of follow up DSA disappears completely.

Estimation of CyberKnife Respiratory Tracking System Using Moving Phantom / 의학물리

In this study, we evaluated accuracy and usefulness of CyberKnife Respiratory Tracking System (SynchronyTM, Accuray, USA) about a moving during stereotactic radiosurgery. For this study, we used moving phantom that can move the target. We also used Respiratory Tracking System called Synchrony of the Cyberknife in order to track the moving target. For treatment planning of the moving target, we obtained an image using 4D-CT. To measure dose distribution and point dose at the moving target, ion chamber (0.62 cc) and gafchromic EBT film were used. We compared dose distribution (80% isodose line of prescription dose) of static target to that of moving target in order to evaluate the accuracy of Respiratory Tracking System. We also measured the point dose at the target. The mean difference of synchronization for TLS (target localization system) and Synchrony were 11.5+/-3.09 mm for desynchronization and 0.14+/-0.08 mm for synchronization. The mean difference between static target plan and moving target plan using 4D CT images was 0.18+/-0.06 mm. And, the accuracy of Respiratory Tracking System was less 1 mm. Estimation of usefulness in Respiratory Tracking System was 17.39+/-0.14 mm for inactivity and 1.37+/-0.11 mm for activity. The mean difference of absolute dose was 0.68+/-0.38% in static target and 1.31+/-0.81% in moving target. As a conclusion, when we treat about the moving target, we consider that it is important to use 4D-CT and the Respiratory Tracking System. In this study, we confirmed the accuracy and usefulness of Respiratory Tracking System in the Cyberknife.