Measurement of Cosmic-ray Muon-induced Spallation Neutrons in the Aberdeen Tunnel Underground Laboratory

AbstractMuon-induced neutrons are one of the major backgrounds to various underground experiments, such as dark matter searches, low-energy neutrino oscillation experiments and neutrino-less double beta-decay experiments. Previous experiments on the underground production rate of muon-induced neutrons were mostly carried out either at shallow sites or at very deep sites. The Aberdeen Tunnel experiment aims to measure the neutron production rate at a moderate depth of 611 meters water equivalent. Our apparatus comprises of six layers of plastic-scintillator hodoscopes for tracking the incident cosmic-ray muons, and 760 L of gadolinium-doped liquid-scintillator for both neutron production and detection targets. In this paper, we describe the design and the performance of the apparatus. The preliminary result on the measurement of neutron production rate is also presented

Male breast cancer in Hong Kong: 15-year experience from a tertiary institution

© 2015 Hong Kong College of Radiologists. Objective: Male breast cancer (MBC) is a rare disease entity and few data are available for the Chinese population. This study aimed to report MBC data from a single institution in Hong Kong to supplement existing evidence of this disease in our local population. Methods: Patients with histologically confirmed MBC treated between July 1997 and February 2012 were retrospectively identified from an institutional patient database. Clinical, pathological, treatment, and survival data were collected and subsequently analysed. Results: Within the captioned period, 52 cases of MBC were identified. The median age was 63 years, with evenly distributed tumour laterality. The majority of patients had invasive ductal carcinoma (84.6%), most of which were histologically grade II (50.0%). Almost all patients demonstrated hormone receptor positivity (oestrogen receptor-positive 98.0%, progesterone receptor-positive 96.0%), and HER2 amplification rate was 25.0%. Patients tended to present at an early stage of disease: approximately 85% presented as a T1 or T2 tumour, and 56.1 % had axillary nodal involvement. Surgery with curative intent was performed in 48 patients, with 13 (27.1 %) received adjuvant chemotherapy, and 35 (72.9%) underwent adjuvant radiotherapy. Almost all hormone receptor-positive patients received adjuvant tamoxifen. The median time to tamoxifen discontinuation was 60 months (range, 2-61 months). Discontinuation rate before 60 months was 15.9%. For those who underwent radical surgery, none developed loco-regional recurrence, and 5- and 10-year disease-free survival was 89.6% and 85.1%, respectively. The median overall survival for the entire population was 14.3 years. Conclusion: Our single-institutional data indicate that a good long-term survival outcome can be achieved in MBC following a treatment protocol similar to that established for females with breast cancer. Prospective data will be helpfid to further evaluate optimal treatment strategies as well as treatment tolerance for MBC in the Asian population.Link_to_subscribed_fulltex

Management of chordoma in a tertiary hospital in Hong Kong

© 2017 Hong Kong College of Radiologists. Objectives: To report the clinical characteristics, treatment, and outcome of 25 patients with chordoma. Methods: The medical records of 25 patients with chordoma treated in a regional hospital in Hong Kong between January 2000 and June 2016 were retrospectively reviewed. Their clinical, pathological, treatment, and survival data were collected and analysed. Results: Of the 25 patients, 14 had skull base and 11 had sacral tumours; 78.6% and 100% were conventional chordoma, respectively. Their median ages were 41 and 64 years, respectively. In the skull base cohort, all 14 patients underwent surgery but none achieved R0 resection, and 13 received adjuvant radiotherapy. In the sacral cohort, eight of 11 patients underwent surgery and three of them achieved R0 resection. Four patients received postoperative radiotherapy. The 5-year local control rates for skull base and sacral chordoma were 29.6% and 17.9%, respectively, with a median time to progression of 42 (range, 8-68) and 33 (range, 4-76) months, respectively. The 5-year overall survival rates were 64.3% and 72.2%, respectively. Conclusion: Treatment outcome of chordoma patients in our hospital was suboptimal. Strategies to improve outcome should be explored.Link_to_subscribed_fulltex

Selective internal radiation therapy for hepatocellular carcinoma: Experience from a hospital in Hong Kong

© 2017 Hong Kong College of Radiologists. Purpose: To report the outcomes and prognostic factors of overall survival after selective internal radiation therapy (SIRT) for hepatocellular carcinoma (HCC). Methods: Consecutive patients who underwent SIRT for HCC at Queen Elizabeth Hospital between December 2006 and February 2016 were retrospectively reviewed. Results: 51 male and 11 female patients aged 42 to 90 (median, 66) years were deemed suitable to receive SIRT. Most were hepatitis B carriers and had an Eastern Cooperative Oncology Group performance score of ≤1 and Child-Pugh class A cirrhosis. About half of the patients had portal vein thrombosis and an alpha-fetoprotein level of > 200 ng/ml. 30.7% of patients were at Barcelona Clinic Liver Cancer stage B and 64.5% at stage C. 50% of tumours were ≥8 cm at the longest diameter. The median dose received by the tumour was 130 Gy. Three months after SIRT, 1.7% had a complete response, 43.3% had a partial response, 26.7% had stable disease, and 28.3% had progressive disease. The 1-year local control rate was 12.3%. The 1-year overall survival was 30.6%. The median time to tumour progression was 3 months and the median overall survival was 6 months. In multivariate analysis, Child-Pugh class, portal vein thrombosis, and post-SIRT intervention were significant prognostic factors for overall survival. Conclusion: SIRT is an effective and safe treatment for intermediate- to advanced-stage HCC. It achieves good local control with minimal toxicity although the outcome is unsatisfactory in terms of new intrahepatic or distant recurrence. HCC patients with Child-Pugh class A cirrhosis, no portal vein thrombosis, and an ability to undergo subsequent treatments have longer survival.Link_to_subscribed_fulltex

Prevention of restenosis of central venous stricture after percutaneous transluminal angioplasty and endovascular stenting by brachytherapy [1]

Link_to_subscribed_fulltex

The Impact of the Oncotype DX Breast Cancer Assay on Treatment Decisions for Women With Estrogen Receptor-Positive, Node-Negative Breast Carcinoma in Hong Kong

© 2016 The Authors. Background: The Onco. type DX Breast Cancer Assay is validated to assess risk of distant recurrence and likelihood of chemotherapy (CT) benefit in estrogen receptor-positive ESBC in various populations. In Hong Kong, > 80% of breast cancers are early stage breast cancer (ESBC) and > 60% of these women receive CT. This prospective study measured changes in CT type and recommendations, as well as physician impression of assay impact in a homogenous Chinese population. Methods: Consecutive patients with estrogen receptor-positive, T1-3 N0-1mi M0 ESBC were offered enrollment. After surgery, physicians discussed treatment options with patients, then ordered the assay, then reassessed treatment recommendation considering assay results. Changes in treatment recommendation, CT utilization, physician confidence, and physician rating of influence on their treatment recommendations were measured. Results: A total of 146 evaluable patients received pre- and post-testing treatment recommendations. CT recommendations (including changes in intensity of CT) were changed for 34 of 146 patients (23.3%; 95% confidence interval, 16.7%-31.0%); change in intensity occurred in 7 of 146 (4.8%). There were 27 changes in treatment recommendations of adding or removing CT altogether (18.5% change; 95% confidence interval, 12.6%-25.8%). CT recommendations decreased from 52.1% to 37.7%, a net absolute reduction of 14.4% (P < .001; 27.6% net relative reduction). Pre-assay, 96% of physicians agreed/strongly agreed that they were confident in their treatment recommendation; post-assay, 90% of physicians agreed/strongly agreed with the same statement. Thirty percent of physicians agreed/strongly agreed that the test had influenced their recommendation, similar to the proportion of changed recommendations. Conclusions: The Onco. type DX Assay appears to influence physician ESBC adjuvant treatment recommendations in Hong Kong.Link_to_subscribed_fulltex