Dose delivery accuracy on helical tomotherapy for 4-dimensional tumor motion — a phantom study

BACKGROUND: The advances in image guidance and capability of highly conformal dose deliveries made possible the use of helical tomotherapy (HT) for lung cancer treatment. To determine the effect of respiratory motion on the delivered dose in HT, film dosimetry using a dynamic phantom was performed. This was a phantom study to determine the effect of motion on the delivered dose in HT. MATERIALS AND METHODS: 4D computed tomography (4DCT) was acquired for various target motions of CIRS dynamic phantom (CIRS Inc., Norfolk, USA) with 2.5cm diameter spherical target of volume 8.2 cc moving in the COS4 motion pattern. AveIP images and treatment plans were generated in the HT planning system. Target excursions during treatment delivery were changed in the superior-inferior, anteroposterior and lateral directions. The breathing cycle time was varied from 4 to 5 sec. and also the delivery interruptions were introduced. A film was exposed for each delivery and gamma analysis was performed. RESULTS: The gamma pass rate (GPR) with 3%, 2 mm criteria for the target motion in the S-I direction showed a significant reduction from 97.5% to 54.4% as the motion increased from 3 mm to  8 mm (p = 0.03). For the target motion in S-I = 8 mm, L-R = A-P = 3 mm, the percentage decrease in the GPR was 74% (p = 0.001) for three interruptions. CONCLUSION: The ITV based approach in HT is ideal for a shallow breathing situation when the tumor excursions were confined to 5 mm in the S-I and 3 mm in L-R and A-P directions

A STUDY ON SWOC ANALYSIS OF RELIANCE JIO

Reliance Jio Infocomm Limited, started business as Jio, is a LTE type of mobile network operator in India. It is a subsidiary fully owned by Reliance Industries.Its headquarters situated in Navi Mumbai, Maharashtra; it provides wireless 4G LTE service network without 2G or 3G based services and it’s became countries first 100% VoLTE operator, plus it covers nearly 22 telecom circles coverage in India. Jio's partners and employees enjoyed services of first beta-launched to on 27 December 2015 on the eve of 83rd birth anniversary of late Dhirubhai Ambani, founder of Reliance Industries, and later on 5 September 2016 services were commercially launched. Jio subsidiary is LYF mobiles launched in beginning of 2016. India is a largest internet user’s country. Most of the communication companies arealready utilizing the benefit of countries population. In India, Airtel, Idea, Vodafone, Reliance, Docomo, Aircel and BSNL are major mobile operators. In that, Airtel holds largest market share by providing free internet services, lowest data 2G, 3G and 4G data packs with high speed of internet, low call rate packs etc. Secondly, Vodafone is a second largest market share holding mobile operator company. When android operating system launched the new revolution began in mobile industry, smart phones pulled high demand overmobile market segment. Due to Social media like Whatsapp, Facebook, Instagrametcdemad for smart phones increased continuously. Internet is a heart of smart phones by this reason operators took an advantage and hiked the rate of data packs. In the name of 2G, 3G and 4G packs network providers continuously fleeced money of customers. Any way demand for data packs are connected with different types of apps available in App market. So, mobile operators started race towards high speed internet. Now CEO of Reliance Industries Mukesh Ambani launched high speed internet 4G service in the name of JIO Digital life. Jio is wireless telecommunication includes Mobile telephony and Wireless broadband products. In 25th January 2016, Jio launched its LYF smartphone series starting with Water 1, to supply 4G handsets enabled with voice over LTE (VoLTE) feature. Jio has started providing free Wi-Fi hotspot services in cities throughout India. At present Jio offers 90 days of free internet, free call, free SMS and Jio app services till December 31st 2016 in the name of Jio welcome offer. Youths are highly attracted with this offer. This paper aim is to provide strengths, weakness, opportunities and challenges are to be faced by Reliance Jio

Treatment planning and dosimetric comparison study on two different volumetric modulated arc therapy delivery techniques

AimTo compare and evaluate the performance of two different volumetric modulated arc therapy delivery techniques.BackgroundVolumetric modulated arc therapy is a novel technique that has recently been made available for clinical use. Planning and dosimetric comparison study was done for Elekta VMAT and Varian RapidArc for different treatment sites.Materials and methodsTen patients were selected for the planning comparison study. This includes 2 head and neck, 2 oesophagus, 1 bladder, 3 cervix and 2 rectum cases. Total dose of 50[[ce:hsp sp="0.25"/]]Gy was given for all the plans. All plans were done for RapidArc using Eclipse and for Elekta VMAT with Monaco treatment planning system. All plans were generated with 6[[ce:hsp sp="0.25"/]]MV X-rays for both RapidArc and Elekta VMAT. Plans were evaluated based on the ability to meet the dose volume histogram, dose homogeneity index, radiation conformity index, estimated radiation delivery time, integral dose and monitor units needed to deliver the prescribed dose.ResultsRapidArc plans achieved the best conformity (CI95%[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]1.08[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]0.07) while Elekta VMAT plans were slightly inferior (CI95%[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]1.10[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]0.05). The in-homogeneity in the PTV was highest with Elekta VMAT with HI equal to 0.12[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]0.02[[ce:hsp sp="0.25"/]]Gy when compared to RapidArc with 0.08[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]0.03. Significant changes were observed between the RapidArc and Elekta VMAT plans in terms of the healthy tissue mean dose and integral dose. Elekta VMAT plans show a reduction in the healthy tissue mean dose (6.92[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]2.90)[[ce:hsp sp="0.25"/]]Gy when compared to RapidArc (7.83[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]3.31)[[ce:hsp sp="0.25"/]]Gy. The integral dose is found to be inferior with Elekta VMAT (11.50[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]6.49)[[ce:hsp sp="0.25"/]]×[[ce:hsp sp="0.25"/]]104[[ce:hsp sp="0.25"/]]Gy[[ce:hsp sp="0.25"/]]cm3 when compared to RapidArc (13.11[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]7.52)[[ce:hsp sp="0.25"/]]×[[ce:hsp sp="0.25"/]]104[[ce:hsp sp="0.25"/]]Gy[[ce:hsp sp="0.25"/]]cm3. Both Varian RapidArc and Elekta VMAT respected the planning objective for all organs at risk. Gamma analysis result for the pre-treatment quality assurance shows good agreement between the planned and delivered fluence for 3[[ce:hsp sp="0.25"/]]mm DTA, 3% DD for all the evaluated points inside the PTV, for both VMAT and RapidArc techniques.ConclusionThe study concludes that a variable gantry speed with variable dose rate is important for efficient arc therapy delivery. RapidArc presents a slight improvement in the OAR sparing with better target coverage when compared to Elekta VMAT. Trivial differences were noted in all the plans for organ at risk but the two techniques provided satisfactory conformal avoidance and conformation

On the Decidability of Model-Checking Information Flow Properties

Current standard security practices do not provide substantial assurance about information flow security: the end-to-end behavior of a computing system. Noninterference is the basic semantical condition used to account for information flow security. In the literature, there are many definitions of noninterference: Non-inference, Separability and so on. Mantel presented a framework of Basic Security Predicates (BSPs) for characterizing the definitions of noninterference in the literature. Model-checking these BSPs for finite state systems was shown to be decidable in [8]. In this paper, we show that verifying these BSPs for the more expressive system model of pushdown systems is undecidable. We also give an example of a simple security property which is undecidable even for finite-state systems: the property is a weak form of non-inference called WNI, which is not expressible in Mantel’s BSP framework

Third time re-irradiation of liver metastasis with robotic radiosurgery: a case series

Re-irradiation (Re-RT) in liver tumours is rarely reported owing to poor tolerance of liver and high incidence of radiation induced liver disease incidence. Fiducial based robotic radiosurgery allows to deliver high dose radiation to the liver tumour and restricts the dose to healthy uninvolved liver, thereby increasing the potential for Re-RT. Tolerance to radiation is low for entire liver and hence re-radiation is a challenge. On the other hand, as regenerative potential of hepatocytes is rapid, replacement of necrotic liver tissue occurs with regenerated hepatocytes. These regenerated hepatocytes are radiation naïve, do not have “memory” of radation therapy treatment and hence have potential of Re-RT. We are reporting a series of two breast cancer patients presented with liver oligometastasis treated with fiducial based CyberKnife system (CK). Both the patients were treated multiple times with CK and had long-term survival (> 2 years) without any clinical features of radiation induced liver injury. Appropriately selected patients are suitable for multiple sessions of CK for liver lesions with long-term outcome

A comparative study of set up variations and bowel volumes in supine versus prone positions of patients treated with external beam radiation for carcinoma rectum

Purpose: A prospective study was undertaken to evaluate the influence of patient positioning on the set up variations to determine the planning target volume (PTV) margins and to evaluate the clinical relevance volume assessment of the small bowel (SB) within the irradiated volume. Materials and Methods: During the period of months from December 2011 to April 2012, a computed tomography (CT) scan was done either in supine position or in prone position using a belly board (BB) for 20 consecutive patients. All the patients had histologically proven rectal cancer and received either post- or pre-operative pelvic irradiation. Using a three-dimensional planning system, the dose-volume histogram for SB was defined in each axial CT slice. Total dose was 46-50 Gy (2 Gy/fraction), delivered using the 4-field box technique. The set up variation of the study group was assessed from the data received from the electronic portal imaging device in the linear accelerator. The shift along X, Y, and Z directions were noted. Both systematic and random errors were calculated and using both these values the PTV margin was calculated. Results: The systematic errors of patients treated in the supine position were 0.87 (X-mm), 0.66 (Y-mm), 1.6 (Z-mm) and in the prone position were 1.3 (X-mm), 0.59 (Y-mm), 1.17 (Z-mm). The random errors of patients treated in the supine positions were 1.81 (X-mm), 1.73 (Y-mm), 1.83 (Z-mm) and in prone position were 2.02 (X-mm), 1.21 (Y-mm), 3.05 (Z-mm). The calculated PTV margins in the supine position were 3.45 (X-mm), 2.87 (Y-mm), 5.31 (Z-mm) and in the prone position were 4.91 (X-mm), 2.32 (Y-mm), 5.08 (Z-mm). The mean volume of the peritoneal cavity was 648.65 cm 3 in the prone position and 1197.37 cm 3 in the supine position. Conclusion: The prone position using BB device was more effective in reducing irradiated SB volume in rectal cancer patients. There were no significant variations in the daily set up for patients treated in both supine and prone positions