Medical radiation exposures for diagnostic radiology in Malaysia

The medical radiation usage for diagnostic radiology in Malaysia (a Level II country) for 1990-1994 is reported, enabling a comparison to be made for the first time with the United Nations Scientific Committee on the Effects of Atomic Radiation Report. In 1994, the number of physicians, radiologists, x-ray units, and x-ray examinations per 1,000 population was 0.45, 0.005, 0.065, and 183, respectively. (Level I countries had averages of 2.6, 0.072, 0.35, and 860, respectively). In 1994, a total of 3.6 million x-ray examinations were performed; the annual effective dose per capita to the population was 0.05 mSv, and the collective effective dose aas 1,000 person-Sv. Chest examinations contributed 63 of the total. Almost all examinations experienced increasing frequency from 1990 to 1994 except for barium studies, cholecystography, and intravenous urography (-23, -36, -51). These decreases are related to the increasing use of ultrasound and greater availability of fiberoptic endoscopy. Notable increases during the same period were observed in computed tomography (161), cardiac procedures (190), and mammography (240). In order to progress from Level II to Level I status Malaysia needs to expand and upgrade radiological service in tandem with the health care development of the country

Samarium-153 labelled microparticles for liver tumour targeted therapy with imaging functionality

Samarium-153 (153Sm) are widely used in radia-tion synovectomy and pain management for patients with bone metastases. However, its therapeutic application has not been fully explored. 153Sm has been proven to be useful for imaging purposes. This provides a beneficial alternative for therapy with pure beta emitter especially for liver radioembolization with Yttrium-90 (90Y). This study aimed to develop an alterna-tive radioembolic agent using 153Sm and biocompatible resin microparticles for liver cancer therapy. The ion-exchange resin; Amberlite IR-120 H+ commercially available in large beads were crushed and sieved to 20 – 40 μm and labelled with 152SmCl3 salt prior to neutron activation. Administered activity of 3 GBq 153Sm was aimed based on the standard activity used by the 90Y SIR-Spheres. 6 hours irradiation in 1.494 x 1012 n.cm-2.s-1 flux produced 3.1 GBq.g-1 immediately after activa-tion. Characterization of the microparticles, gamma spectros-copy, and in-vitro radiolabelling studies were carried out and compared to a commercially available resin readily made in 20 – 40 μm, Fractogel EMD SO3- (S). 153Sm-Amberlite micropar-ticles possess a superior and suitable characteristics for liver radioembolization with added imaging capabilities

A new mechanism of thermal sensitivity for rapid drug release and low systemic toxicity in hyperthermia and thermal ablation temperature ranges

Purpose: The aim of this paper was to introduce a new mechanism of thermal sensitivity in nanocarriers that results in a relatively low drug release at physiological temperature and rapid release of the encapsulated drug at hyperthermia and thermal ablation temperature range (4060 degrees C). Materials and methods: The nanocarriers were synthesised by coating mesoporous silica nanoparticles with a thin layer of polyacrylamide. The low gelation temperature of the protective shell provides preferred routes for drug diffusion when the nanocarriers are heated within the hyperthermia temperature range. In order to determine the gelation point of polyacrylamide shell, differential scanning calorimetry was used. Various chemical, morphological, thermal, as well as drug loading capacities of these nanocarriers were characterised and their drug release behaviour was examined using magnetic resonance - guided focused ultrasound (MRgFUS). Results: Drug release measurements at different temperatures using doxorubicin showed 11.5 +/- 2.4% leakage in aqueous solution at 37 degrees C after 30 min, while this value was significantly increased to 67.6 +/- 2.5% at 60 degrees C. A 39.2 +/- 2.2% release of doxorubicin was also obtained due to the sonication of drug-loaded nanoparticles for 5 x 20 s using MRgFUS. Conclusion: The nanocarriers developed do not exhibit a sharp transition temperature. However, a relatively high loading efficiency as well as rapid drug release at thermal ablation temperature range makes these nanostructures promising candidates for application as adjuvants to various thermal modalities such as radiofrequency and high intensity focused ultrasound

Long-term survival of nasopharyngeal carcinoma patients treated with adjuvant chemotherapy subsequent to conventional radical radiotherapy

Purpose: To assess the long-term survival of patients with nasopharyngeal carcinoma (NPC) who were treated with conventional radical radiotherapy (RT) followed by adjuvant chemotherapy. Methods and Materials: Ninety-one newly diagnosed patients with Stage III and IV (American Joint Committee on Cancer, 1988) NPC, seen at the University of Malaya Medical Center, Kuala Lumpur, Malaysia between January 1992 and May 1997, were treated with RT followed by adjuvant chemotherapy. The tumor dose was 70 Gy delivered in 35 fractions, 5 fractions weekly. Three cycles of chemotherapy, each consisting of 5-fluorouracil, 1 g/m(2)/d on Days 1-4 and cisplatin 100 mg/m(2) on Day 1, were administered 3 weeks after RT completion. Thirty-six patients had Stage 11, 10 had Stage III, and 45 had Stage IV disease (AJCC 1997 staging system). Results: After a median follow-up of 61 months, the 5-year overall survival rate for all 91 patients was 80.1, the disease-free survival rate was 76, and the locoregional control rate was 85. The 3-year overall survival rate for Stage II was 94.3; it was 80 for Stage III and 79.8 for Stage IV (p = 0.0108). The 3-year DFS rate for Stage II was 90; it was 80 for Stage H and 65 for Stage IV. The rate of distant failure for Stage IV was 8.9. Conclusion: Radical RT followed by adjuvant chemotherapy was effective in our patients with locoregionally advanced NPC. The long-term results appear encouraging, even for patients with Stage IV disease. This single institution experience deserves further investigation in prospective trials

Production and first use of (SmCl3)-Sm-153-ion exchange resin capsule formulation for assessing gastrointestinal motility

We produced an enteric-coated gelatine capsule containing neutron-activated Sm-153-labelled resin beads for use in gastrointestinal motility studies. In vitro test in simulated gastrointestinal environment and in vivo study on volunteers were performed. Scintigraphic images were acquired from ten volunteers over 24 h while blood and urine samples were collected to monitor the presence of Sm-153. All the capsules remained intact in stomach. This proved to be a safe and practical oral capsule formulation for whole gut transit scintigraphy. (C) 2011 Elsevier Ltd. All rights reserved