Implementation of Beam Matching Concept for the New Installed Elekta Precise Treatment System Medical LINACs in Indonesia

A concept of radiation beam matching of some medical linear accelerators (LINACs) that have identical characteristics of the models, radiation quality, and multileaf collimator features may be implemented as long as the manufacturer provides complete specifications so that a Treatment Planning System (TPS) can be used for many beam-matched LINACs. This paper describes a preliminary study on the implementation of the beam matching concept for five units Elekta Precise Treatment System LINACs that have recently been installed in Indonesia. The beam matching criteria were based on the percentage depth dose (PDD) and beam profile for photon and electron beams. Dosimetry measurements were carried out by using an SNC 125 ionization chamber of 0.125 cm3 in volume, PTW Pinpoint 3D of  0.016 cm3 in volume, and PTW Farmer Chamber of 0.6 cm3 in volume. The results indicated that the PDD10 of 6 and 10 MV photon beams among installed five units LINACs have excellent compatibility each others with a maximum deviation of less than 0.4 %, while the maximum deviation for dose depth of 80 % (R80) for the electron beams with nominal energies of 4, 6, 8, 10, 15 and 18 MeV is 1 mm. The measurement results for the flatness profile were less than 6 %, and symmetry profiles were less than 3 %. It also outlines the determination of the absorbed dose to water under reference conditions. The results of the calibration of output doses show that the absorbed dose in the water was 1 cGy ≈ 1 MU. The data obtained from measurements for each LINAC conform with the requirements of the beam matching process set by the manufacturer

Detection and Identification of Detonation Sounds in an Internal Combustion Engine Using Wavelet and Regression Analysis

Improving efficiency and power in an internal combustion engine is always impeded by detonation (knock) problems. This detonation problem has not been explained fully yet. Quick and accurate detection of detonation is also in the development stage. This research used a new method of detonation sound detection which uses microphone sensors, analysis of discrete wavelet transform (DWT), and analysis of the regression function envelope to identify the occurrence of detonation. The engine sound was captured by the microphone; it was recorded on a computer; it was proceeded using a DWT decomposition filtering technique; it was then subjected to normalization and regression function envelope to get the shape of the wave pattern for the vibration. Vibrational wave patterns were then compared to a reference using the Euclidean distance calculation method, in order to identify and provide an assessment decision as to whether or not detonation had occurred. The new method was applied using Matlab and it has yielded results which are quite effective for the detection and identification of detonation and it is also capable of producing an assessment decision about the occurrance of detonation

Addition of Lead (Pb)-Nitrate Filler on Polymer Composite Aprons for X-Ray Radiation Shielding

Radiation shielding aprons are needed by radiation workers to minimize radiation exposure to the body. The aprons at present use fabric-coated lead plates which are heavy and rigid materials and therefore are not comfortable to use. Polymer aprons from cassava starch and glycerin with addition of Pb-nitrate filler at 0 %, 2 %, 4 %, and 6 % have been synthesized. Mixtures for synthesizing the polymer apron composites were heated using a magnetic stirrer at a speed of 800 rpm at 160 °C for 25 minutes. Then, the polymer apron composites were dried in an oven for 24 hours at 70 °C. The effectiveness of the apron was determined by calculating the attenuation coefficient (μ), half-value layer (HVL), and radiation absorption. The mechanical properties of the aprons were characterized by testing their tensile strengths using anA&D MCT-2150 universal tester. The result shows that the optimal addition of Pb-nitrate filler of as much as 6 % produced aprons with an attenuation coefficient of 1248 cm‑1, HVL of 0.54 cm, and radiation absorption of 25 %, while the aprons’ tensile strength was obtained as28.244 MPa. The addition of Pb-nitrate as a filler in apron composites proportionally improves the quality of materials used as radiation shields. More detailed research is still needed to obtain the best apron

Analisis Penentuan Pdd Berkas Foton 6 dan 10 Mv Free Flattening Filter (Fff) pada Lapangan Kecil Menggunakan Tiga Detektor yang Berbeda

ANALISIS PENENTUAN PDD BERKAS FOTON 6 DAN 10 MV FREE FLATTENING FILTER (FFF) PADA LAPANGAN KECIL MENGGUNAKAN TIGA DETEKTOR YANG BERBEDA. Analisis penentuan persentase dosis kedalaman untuk berkas foton 6 dan 10 MV flattening filter free (FFF) pada lapangan kecil menggunakan variasi detektor. Makalah ini menguraikan penentuan persentase dosis kedalaman dari berkas foton 6 dan 10 MV FFF yang dipancarkan pesawat pemercepat linier medik Versa HD. Pengukuran dilakukan menggunakan 3 jenis detektor yaitu IBA Razor dioda, PTW PinPoint 3D dan IBA CC13 yang dihubungkan dengan elektrometer IBA Dose 1. Pengukuran dilakukan di dalam fantom air Blue Fantom IBA yang dilengkapi dengan perangkat lunak MyQA Accept pada jarak sumber radiasi ke permukaan 100 cm dengan variasi lapangan radiasi 1 x 1 cm2, 2 x 2 cm2, 3 x 3 cm2 dan 4 x 4 cm2. Berdasarkan data yang didapatkan deviasi pengukuran antara detektor IBA Razor terhadap detektor PinPoint 3D didapatkan rentang deviasi 1.8% - 2.1%. Berbeda dengan deviasi pengukuran antara detektor IBA CC13 terhadap dektektor PinPoint 3D yang mendapatkan rentang deviasi 0,15% - 0,21%. Maka dapat disimpulkan bahwa pengukuran menggunakan tiga tipe detektor ini menunjukkan adanya kesesuaian dengan deviasi terbesar lebih kecil dari 3,5%. Detektor PinPoint 3D, Detektor IBA Razor, dan IBA CC13 dapat digunakan untuk melakukan pengukuran relatif pada lapangan kecil hingga 1 x 1 cm2 pesawat pemercepat linier medik

Randomized Trial of Probiotics and Calcium on Diarrhea and Respiratory Tract Infections in Indonesian Children

OBJECTIVE: To investigate the effects of calcium and probiotics on the incidence and duration of acute diarrhea and acute respiratory tract infections (ARTIs) in low-socioeconomic communities of Jakarta, Indonesia. METHODS: We conducted a 6-month, double-blind, placebo-controlled study in 494 healthy children aged 1 to 6 years who received low-lactose milk with low calcium content (LC; ~50 mg/day; n = 124), regular calcium content (RC; ~440 mg/day; n = 126), RC with 5.108 colony-forming units per day of Lactobacillus casei CRL431 (casei; n = 120), or RC with 5.108 colony-forming units per day of Lactobacillus reuteri DSM17938 (reuteri; n = 124). Number and duration of diarrhea and ARTIs episodes were primary and secondary outcomes, respectively. RESULTS: Incidence of World Health Organization–defined diarrhea (=3 loose/liquid stools in 24 hours) was not significantly different between RC and LC (relative risk [RR]: 0.99 [95% confidence interval (CI): 0.62–1.58]), between casei and RC (RR: 1.21 [95% CI: 0.76–1.92]), or between reuteri and RC (RR: 0.76 [95% CI: 0.46–1.25]) groups. Incidence of all reported diarrhea (=2 loose/liquid stools in 24 hours) was significantly lower in the reuteri versus RC group (RR: 0.68 [95% CI: 0.46–0.99]). Irrespective of the definition used, reuteri significantly reduced diarrhea incidence in children with lower nutritional status (below-median height-and-weight-for-age z score). None of the interventions affected ARTIs. CONCLUSIONS: RC milk, alone or with L casei, did not reduce diarrhea or ARTIs in Indonesian children. L reuteri may prevent diarrhea, especially in children with lower nutritional statu

Randomized Trial of Probiotics and Calcium on Diarrhea and Respiratory Tract Infections in Indonesian Children

OBJECTIVE: To investigate the effects of calcium and probiotics on the incidence and duration of acute diarrhea and acute respiratory tract infections (ARTIs) in low-socioeconomic communities of Jakarta, Indonesia. METHODS: We conducted a 6-month, double-blind, placebo-controlled study in 494 healthy children aged 1 to 6 years who received low-lactose milk with low calcium content (LC; ~50 mg/day; n = 124), regular calcium content (RC; ~440 mg/day; n = 126), RC with 5.108 colony-forming units per day of Lactobacillus casei CRL431 (casei; n = 120), or RC with 5.108 colony-forming units per day of Lactobacillus reuteri DSM17938 (reuteri; n = 124). Number and duration of diarrhea and ARTIs episodes were primary and secondary outcomes, respectively. RESULTS: Incidence of World Health Organization–defined diarrhea (=3 loose/liquid stools in 24 hours) was not significantly different between RC and LC (relative risk [RR]: 0.99 [95% confidence interval (CI): 0.62–1.58]), between casei and RC (RR: 1.21 [95% CI: 0.76–1.92]), or between reuteri and RC (RR: 0.76 [95% CI: 0.46–1.25]) groups. Incidence of all reported diarrhea (=2 loose/liquid stools in 24 hours) was significantly lower in the reuteri versus RC group (RR: 0.68 [95% CI: 0.46–0.99]). Irrespective of the definition used, reuteri significantly reduced diarrhea incidence in children with lower nutritional status (below-median height-and-weight-for-age z score). None of the interventions affected ARTIs. CONCLUSIONS: RC milk, alone or with L casei, did not reduce diarrhea or ARTIs in Indonesian children. L reuteri may prevent diarrhea, especially in children with lower nutritional statu

Probiotics lactobacillus reuteri DSM 17938 and lactobacillus casei CRL 431 modestly increase growth, but non iron and zinc status, among Indonesian children aged 1-6 years

Probiotics and milk calcium may increase resistance to intestinal infection, but their effect on growth and iron and zinc status of Indonesian children is uncertain. We investigated the hypotheses that cow milk with added probiotics would improve growth and iron and zinc status of Indonesian children, whereas milk calcium alone would improve growth but reduce iron and zinc status. A 6-mo randomized trial was conducted in low-socioeconomic urban communities of Jakarta. Healthy children (n = 494) were randomly assigned to receive low-lactose milk with a low calcium content of similar to 50 mg/d (LC; n = 124), a regular calcium content of similar to 440 mg/d (RC group; n = 126), regular calcium with 5 x 10(8) CFU/d Lactobacillus casei CRL 431 (casei; n = 120), or regular calcium with 5 x 10(8) CFU/d Lactobacillus reuteri DSM 17938 (reuteri; n = 124). Growth, anemia, and iron and zinc status were assessed before and after the intervention. Compared with the RC group, the reuteri group had significantly greater weight gain [0.22 (95% CI: 0.02, 0.42) kg], weight-for-age Z-score (WAZ) changes [0.09 (95% CI: 0.01, 0.17)], and monthly weight [0.03(95% CI: 0.002, 0.05) kg/mo] and height [0.03(95% Cl: 0.01, 0.05) cm/mo] velocities. Casei significantly increased monthly weight velocity [0.03 (95% CI: 0.001, 0.05) kg/mo], but not height. However, the changes in underweight, stunting, anemia prevalence, and iron and zinc status were similar between groups. In conclusion, L. reuteri DSM 17938 modestly improved growth by increasing weight gain, WAZ changes, and weight and height velocity, whereas L. casei CRL 431 modestly improved weight velocity. Independent from probiotics supplementation, regular milk calcium did not affect growth or iron and zinc status