Therapy Facility Research Articles

Constructing a National Database to Perform a Modern Analysis of Radiation Therapy Facilities in the United States

Prior literature suggests that the geographic availability of radiation therapy (RT) has a significant effect on whether patients receive radiation and may be associated with better outcomes. However, these studies rely on imperfect proxies to determine the location of RT facilities. The American Medical Association (AMA) Masterfile relies on the location of radiation oncologists, and the American Hospital Association (AHA) relies on survey data from a subset of US hospitals. However, patients receive treatments where RT facilities are located, not just the primary hospitals from which physicians may bill. In this study, we attempted to compile and analyze a more comprehensive modern database of RT facilities in the United States and compared it to existing datasets. We contacted regulatory departments from all 50 states from March to June of 2015 to obtain data on RT facility locations across the US. We mapped the facilities by address and then aggregated the data to the county level to characterize the geographic distribution of RT and to compare this dataset with popular proxies. In our dataset, a county was flagged as providing RT if there was at least 1 RT facility in it. For the AMA data, a county was flagged as having RT if there was at least 1 radiation oncologist working there. For the AHA data, a county was flagged as having RT if there was at least one hospital that performed at least one of the RT modalities. We also performed a linear regression to determine which counties would be less likely to contain an RT facility based on county-level covariates in the Area Health Resources File. 2069 unique radiation treatment facilities in 41 states were included in our new database. 31.1% (815/2614) of total counties in the 41 states that reported data contained a radiation therapy site. Only 18.5% (483/2614) of counties in reporting states were flagged as having RT by all three data sources. 115 counties in reporting states were identified as having RT in the new database but not in AHA nor AMA. 169 counties were flagged in at least one other database but not in the new database. Counties with the most unique RT addresses included Chicago, Houston, and Phoenix. Counties that were urban, had a higher total population, higher income, and a lower median age were more likely to contain a RT facility (p<0.001). Our analysis suggests that existing data sources cataloguing RT availability are incomplete and can be improved by incorporating state-managed data. Our compiled dataset allows for a more comprehensive and detailed analysis of RT distribution in the US than prior studies relying on proxy measures. Future investigations improved by a more comprehensive dataset include specifying regions of greatest need for RT facility expansion and correlation with treatment or outcomes data.

RADIATION PROTECTION MEASUREMENTS WITH THE VARIANCE-COVARIANCE METHOD IN THE STRAY RADIATION FIELDS FROM PHOTON AND PROTON THERAPY FACILITIES.

The microdosimetric variance-covariance method was used to study the stray radiation fields from the photon therapy facility at the Technical University of Denmark and the scanned proton therapy beam at the Skandion Clinic in Uppsala, Sweden. Two TEPCs were used to determine the absorbed dose, the dose-average lineal energy, the dose-average quality factor and the dose equivalent. The neutron component measured by the detectors at the proton beam was studied through Monte Carlo simulations using the code MCNP6. In the photon beam the stray absorbed dose ranged between 0.3 and 2.4 μGy per monitor unit, and the dose equivalent between 0.4 and 9 μSv per monitor unit, depending on beam energy and measurement position. In the proton beam the stray absorbed dose ranged between 3 and 135 μGy per prescribed Gy, depending on detector position and primary proton energy.

Measurement of the energy spectrum of secondary neutrons in a proton therapy environment

Abstract Measurement of the energy spectrum of secondary neutrons were carried out at the OncoRay Proton Therapy facility in Dresden, following an approach originating in neutron metrology which is well suited for both the characterization of secondary neutron fields at proton therapy facilities and the validation of Monte Carlo simulations. For the experiment, a brass target was placed in the proton beam and Bonner spheres measurements were made at a distance of 2 m from the target and at different angles, 15° to 120°, with respect to the incoming proton beam. The measured spectra were compared to Monte Carlo simulations.

Neutron and photon scattering properties of high density concretes used in radiation therapy facilities: A Monte Carlo study

Abstract In the current study the neutron and photon scattering properties of some newly developed high density concretes (HDCs) were calculated by using MCNPX Monte Carlo code. Five high-density concretes including Steel-Magnetite, Barite, Datolite-Galena, Ilmenite-ilmenite, Magnetite-Lead with the densities ranging from 5.11 g/cm3 and ordinary concrete with density of 2.3 g/cm3 were studied in our simulations. The photon beam spectra of 4 and 18 MV from Varian linac and neutron spectra of clinical 18 MeV photon beam was used for calculations. The fluence of scattered photon and neutron from all studied concretes was calculated in different angles. Overall, the ordinary concrete showed higher scattered photons and Datolite-Galena concrete (4.42 g/cm3) had the lowest scattered photons among all studied concretes. For neutron scattering, fluence at the angle of 180 was higher relative to other angles while for photons scattering fluence was maximum at 90 degree. The scattering fluence for photons and neutrons was dependent on the angle and composition of concrete. The results showed that the fluence of scattered photons and neutrons changes with the composition of high density concrete. Also, for high density concretes, the variation of scattered fluence with angle was very pronounced for neutrons but it changed slightly for photons. The results can be used for design of radiation therapy bunkers.

Radiation Therapy Deficiencies Identified During On-Site Dosimetry Visits by the Imaging and Radiation Oncology Core Houston Quality Assurance Center

To review the dosimetric, mechanical, and programmatic deficiencies most frequently observed during on-site visits of radiation therapy facilities by the Imaging and Radiation Oncology Core Quality Assurance Center in Houston (IROC Houston). The findings of IROC Houston between 2000 and 2014, including 409 institutions and 1020 linear accelerators (linacs), were compiled. On-site evaluations by IROC Houston include verification of absolute calibration (tolerance of ±3%), relative dosimetric review (tolerances of ±2% between treatment planning system [TPS] calculation and measurement), mechanical evaluation (including multileaf collimator and kilovoltage-megavoltage isocenter evaluation against Task Group [TG]-142 tolerances), and general programmatic review (including institutional quality assurance program vs TG-40 and TG-142). An average of 3.1 deficiencies was identified at each institution visited, a number that has decreased slightly with time. The most common errors are tabulated and include TG-40/TG-142 compliance (82% of institutions were deficient), small field size output factors (59% of institutions had errors ≥3%), and wedge factors (33% of institutions had errors ≥3%). Dosimetric errors of ≥10%, including in beam calibration, were seen at many institutions. There is substantial room for improvement of both dosimetric and programmatic issues in radiation therapy, which should be a high priority for the medical physics community. Particularly relevant was suboptimal beam modeling in the TPS and a corresponding failure to detect these errors by not including TPS data in the linac quality assurance process.

Progress in charged particle therapy

Charged particle therapy offers a better effect and obvious dosimetric and biological advantages over conventional radiotherapy in tumor control. Charged particles form Bragg peak in the dose distribution in tissue, enable most of energy to be deposited in the target region, and thus enhance tumor control and reduce the damage to normal tissues surrounding the tumor. With the increasing demand for charged particle therapy and the advances in particle accelerator, particle therapy technology is developing rapidly. The core apparatus of particle therapy facility is particle accelerator, and the accelerator type, particle type, and implementation technique determine the performance and therapeutic effect of the facility. This article provides a detailed comparative analysis of various particle therapies. Statistical data show that proton therapy is dominant in particle therapy, and high construction difficulty, large facility size, and extremely high cost have limited the development of heavy ion therapy. Nowadays, there are still some technical problems regarding charged particle therapy, and more clinical trials are required. Key words: Particle accelerator; Proton therapy; Carbon ion therapy

Simulation study of slow extraction for the Shanghai Advanced Proton Therapy facility

The Shanghai Advanced Proton Therapy facility employs third-integer slow extraction. In order to achieve accurate treatment, high-quality spill is needed. Therefore, parameters that may affect slow extraction should be investigated by simulation. A computer model of the synchrotron operation slow extraction was constructed with MATLAB®. By simulating the motion of the circulating protons, we could quantify the influence of machine and initial beam parameters on properties of the extracted beam, such as ripple, uniformity, stability, on- and off-time of the spill and spill width in the synchrotron. Suitable design parameters including the horizontal tunes, power supply ripple, longitudinal RF cavity voltage, RF-KO and the chromaticities were determined.

Conceptual Design of Scanning Magnets for Superconducting Proton Therapy Facility

The performance of scanning magnets is the key to the treatment of proton accelerator in nozzle of the Superconducting Proton Therapy System (SPTS), which directly affects the quality of the proton beam and the size of the radiation field. The scanning magnets set at the entrance of the beam irradiation system are two dipole magnets to scan the beam in both horizontal and vertical directions and form the irradiation field to be tumor shape. In this paper, the theoretical calculation and software simulation have carried out to design scanning magnets for the SPTS in brief. The distribution of magnetic field is improved by structure optimization of scanning magnet and comparative analysis of magnetic induction intensity distribution curve in medium plane. The optimum structures of scanning magnets are got, which can meet the beam integral field uniformity and improve scanning accuracy. The study provides the key technical support to proton therapy of the SPTS.

PUSAT TERAPI OKSIGEN DENGAN PENERAPAN KONSEP GREEN BUILDING DI PULAU GILI IYANG MADURA

&lt;p&gt;&lt;strong&gt;&lt;em&gt;Abstract: &lt;/em&gt;&lt;/strong&gt;&lt;em&gt;Gili Iyang Island has high oxygen level potential which is more than 20% with lower pollution percentage compared to other regions in Indonesia. The result of oxygen in Gilli Iyang Island was done by LAPAN in 2006 and BBTKL-PP in 2013. It reached 20,9% up to 21,5%. The oxygen level affects Gili Iyang Island becoming tourist destination to take oxygen therapy. However, the activity isn’t supported by adequate facilities, so that an oxygen therapy center is necessary to meet those needs. The design proposal rises a problem is designing a healthy oxygen therapy facility that hold the local natural circumstance. Environmental issues in Gili Iyang Island which is still pure and healthy responded by Green Building concept application in Oxygen Therapy Center. The Oxygen Therapy Center focusing on the application of green building concept to respond the environmental issue of Gili Iyang Island. The Green Building concept based on six criterias in accordance with the Greenship: Green Building Council Indonesia (GBCI): appropriate land use, energy efficiency and conservation, water conservation, resource and material cycle, health and comfort in space, and environmental management building. The concept is trying to afford a healthy and nature-synergy building design so than it can support oxygen therapy process and energy-saving building. The main design concepts are site cultivation, mass system, shape and appearance of the building, material selection, exterior of the building, also building utilities.&lt;/em&gt;&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Keywords&lt;/em&gt;&lt;/strong&gt;&lt;em&gt;: Gili Iyang Island, Oxygen Therapy, Green Building Concept, Greenship: Green Building Council Indonesia (GBCI)&lt;/em&gt;&lt;/p&gt;

Proton beam characterization in the experimental room of the Trento Proton Therapy facility

As proton therapy is becoming an established treatment methodology for cancer patients, the number of proton centres is gradually growing worldwide. The economical effort for building these facilities is motivated by the clinical aspects, but might be also supported by the potential relevance for the research community. Experiments with high-energy protons are needed not only for medical physics applications, but represent also an essential part of activities dedicated to detector development, space research, radiation hardness tests, as well as of fundamental research in nuclear and particle physics.Here we present the characterization of the beam line installed in the experimental room of the Trento Proton Therapy Centre (Italy). Measurements of beam spot size and envelope, range verification and proton flux were performed in the energy range between 70 and 228 MeV. Methods for reducing the proton flux from typical treatments values of 106–109 particles/s down to 101–105 particles/s were also investigated. These data confirm that a proton beam produced in a clinical centre build by a commercial company can be exploited for a broad spectrum of experimental activities. The results presented here will be used as a reference for future experiments.

Modelling PET radionuclide production in tissue and external targets using Geant4

The Proton Therapy Facility in TRIUMF provides 74 MeV protons extracted from a 500 MeV H- cyclotron for ocular melanoma treatments. During treatment, positron emitting radionuclides such as 1C, 15O and 13N are produced in patient tissue. Using PET scanners, the isotopic activity distribution can be measured for in-vivo range verification. A second cyclotron, the TR13, provides 13 MeV protons onto liquid targets for the production of PET radionuclides such as 18F, 13N or 68Ga, for medical applications. The aim of this work was to validate Geant4 against FLUKA and experimental measurements for production of the above-mentioned isotopes using the two cyclotrons. The results show variable degrees of agreement. For proton therapy, the proton-range agreement was within 2 mm for 11C activity, whereas 13N disagreed. For liquid targets at the TR13 the average absolute deviation ratio between FLUKA and experiment was 1.9±2.7, whereas the average absolute deviation ratio between Geant4 and experiment was 0. 6±0.4. This is due to the uncertainties present in experimentally determined reaction cross sections.

Simulations and measurements of proton beam energy spectrum after energy degradation

At the proton therapy facility PROSCAN of the Paul Scherrer Institute the energy modulation of the cyclotron generated proton beam is performed via material insertion into the beam trajectory. The energy spectrum of the particles propagating forwards after such procedure has been simulated and measured. The current paper summarizes the results of these simulations and measurements and illustrates their significance for the future developments of a gantry for proton therapy at the Paul Scherrer Institute.

Internal Dose Analysis for Radiation Worker in Cancer Therapy Based on Boron Neutron Capture Therapy with Neutron Source Cyclotron 30 MeV Using Monte Carlo N Particle Extended Simulator

Based Studies were carried out to analyze internal dose for radiation worker at Boron Neutron Capture Therapy (BNCT) facility base on Cyclotron 30 MeV with BSA and room that actually design before. This internal dose analyze include interaction between neutron and air. The air contains N2 (72%), O&lt;sub&gt;2 &lt;/sub&gt;(20%), Ar (0.93%), CO&lt;sub&gt;2&lt;/sub&gt;, Neon, Kripton, Xenon, Helium and Methane. That internal dose to the worker should be bellow limit dose for radiation worker amount of 20 mSv/years. From the particle that are present in the air, only Nitrogen and Argon can change into radioactive element. Nitrogen-14 activated to Carbon-14, Nitrogen-15 activated to Nitrogen-16, and Argon-40 activated to Argon-41. Calculation using tally facility in Monte Carlo N Particle Version Extended (MCNPX) program for calculated flux Neutron in the air 3,16x10&lt;sup&gt;7&lt;/sup&gt; Neutron/cm&lt;sup&gt;2&lt;/sup&gt;s. room design in cancer facility have a measurement of length 200 cm, width 200 cm and high 166,40 cm. flux neutron can be used to calculated the reaction rate which is 80,1x10&lt;sup&gt;-2&lt;/sup&gt; reaction/cm&lt;sup&gt;3&lt;/sup&gt;s for carbon-14 and 8,75x10&lt;sup&gt;-5&lt;/sup&gt; reaction/cm&lt;sup&gt;3&lt;/sup&gt;s. Internal dose exposed to the radiation worker is 9.08E-9 µSv.

Simulations of mass attenuation coefficients for shielding materials using the MCNP-X code

In this paper, mass attenuation coefficients of concrete, bricks and cement plaster, as shielding materials, are calculated at 59.5, 356, 662, 1173, 1274 and 1333 keV by using the MCNP-X (version 2.4.0) code. The numerical simulation results are compared with previous Monte Carlo studies, experimental results and XCOM data. The effects of barite on mass attenuation coefficients are investigated. The mass attenuation coefficients increase with the barite content. Thus, our results agree well with experimental studies on gamma ray shielding of barite. It is flexible for the MN method to change the barite rates in material by small increments, which is experimentally difficult. Also, modeled geometry can be used for future approaches such as new designs and new structures especially in investigating new barite-containing materials to build nuclear reactors or high-energy radiation therapy facilities.

A case report of zinc phosphide poisoning: complicated by acute renal failure and tubulo interstitial nephritis

BackgroundRun Rat® is a rodenticide widely used against small mammals. It comprises of a minimum of 32% zinc phosphide which is highly toxic in acute exposures to humans. It may be consumed accidentally or intentionally. It enters the body via skin, respiratory and gastrointestinal tracts. Zinc phosphide is hydrolyzed by the gastric acid and is transformed into phosphine gas. Phosphine is a respiratory toxin that inhibits cytochrome C oxidase system resulting in renal failure and liver failure.Case presentationA 35 year old Sri Lankan female presented following ingestion of 2.5 g of Run Rat®, which is a branded preparation of zinc phosphide, resulting in 61 mg/kg poison load. She developed severe acute kidney injury with acute tubular necrosis, subnephrotic ranged proteinuria and tubulointerstitial nephritis for which she underwent haemodialysis three times along with other measures of resuscitation. She also developed elevated liver enzymes with hyperblirubinaemia, hypoalbuminaemia, acute pancreatitis and mild myocarditis. She improved with supportive therapy over a period of 3 weeks.ConclusionRun Rat® is a commonly used rodenticide and the toxic effects are mediated through conversion of phosphide to phosphine gas. The majority of the deaths had occurred in the first 12 to 24 h and the main causes identified are refractory hypotension and arrhythmias. The late deaths (beyond 24 h) had been commonly due to adult respiratory distress syndrome, liver and renal failure. The outcome is poorer with delayed presentation, development of coagulopathy, hyperglycaemia and multiorgan failure with elevated liver enzymes. In our patient, Zinc phosphide poisoning caused severe acute kidney injury, abnormal liver profile, pancreatitis and possible myocarditis. The patient improved with repeated haemodialysis. The renal biopsy revealed acute tubulointerstitial nephritis with acute tubular necrosis.In tropical countries, the rural population engaged in agriculture has easier access to the compound, as it is available at a lower cost. Furthermore, the lack of an antidote and advanced resuscitative measures such as inotropic supportive therapy and renal replacement facilities at most of the peripheral hospitals pose a major challenge in providing timely interventions to prevent deaths.

Beam-on imaging of short-lived positron emitters during proton therapy

In vivo dose delivery verification in proton therapy can be performed by positron emission tomography (PET) of the positron-emitting nuclei produced by the proton beam in the patient. A PET scanner installed in the treatment position of a proton therapy facility that takes data with the beam on will see very short-lived nuclides as well as longer-lived nuclides. The most important short-lived nuclide for proton therapy is 12N (Dendooven et al 2015 Phys. Med. Biol. 60 8923–47), which has a half-life of 11 ms. The results of a proof-of-principle experiment of beam-on PET imaging of short-lived 12N nuclei are presented. The Philips Digital Photon Counting Module TEK PET system was used, which is based on LYSO scintillators mounted on digital SiPM photosensors. A 90 MeV proton beam from the cyclotron at KVI-CART was used to investigate the energy and time spectra of PET coincidences during beam-on. Events coinciding with proton bunches, such as prompt gamma rays, were removed from the data via an anti-coincidence filter with the cyclotron RF. The resulting energy spectrum allowed good identification of the 511 keV PET counts during beam-on. A method was developed to subtract the long-lived background from the 12N image by introducing a beam-off period into the cyclotron beam time structure. We measured 2D images and 1D profiles of the 12N distribution. A range shift of 5 mm was measured as 6 ± 3 mm using the 12N profile. A larger, more efficient, PET system with a higher data throughput capability will allow beam-on 12N PET imaging of single spots in the distal layer of an irradiation with an increased signal-to-background ratio and thus better accuracy. A simulation shows that a large dual panel scanner, which images a single spot directly after it is delivered, can measure a 5 mm range shift with millimeter accuracy: 5.5 ± 1.1 mm for 1 × 108 protons and 5.2 ± 0.5 mm for 5 × 108 protons. This makes fast and accurate feedback on the dose delivery during treatment possible.

Eddy current analysis and optimization of fast scanning magnet for a proton therapy system

Proton therapy is now recognized as one of the most effective radiation therapy methods for cancers. A proton therapy facility with multiple gantry treatment rooms is under development in HUST (Huazhong University of Science and Technology), which is based on isochronous superconducting cyclotron scheme. In the beam line, the scanning system spreads out the proton beam on the target according to the complex tumour shape by two scanning magnets for horizontal and vertical scanning independently. Since these two magnets are excited by alternating currents and the maximum repetition frequency is up to 100Hz, eddy currents and losses are expected to be significant. Slits are proven to be an effective way to reduce the eddy currents. To evaluate the heat distribution due to eddy losses in the pole end of the scanning magnet, the transient electromagnetic analysis and steady-state thermal analysis are performed. This paper describes design considerations of the scanning system and mainly analyses the eddy current effect of the scanning magnets. Different coil shapes and slit arrangements are simulated and compared to obtain the optimal configuration. The maximum temperatures of two magnets are optimized below 70°C. In addition, the lag effect due to eddy currents is also discussed.

The front-end electronics design of dose monitors for beam delivery system of Shanghai Advanced Proton Therapy Facility

A front-end electronics of dose monitor has been developed for measuring irradiation dose to the patient in Shanghai Advanced Proton Therapy Facility. The parallel plate ionization chamber is used for the dose monitoring. Unlike the traditional method of recycling capacitor integration and voltage-to-frequency conversion, this dose monitor electronics uses the trans-impedance amplifier and analog-to-digital conversion method. It performs satisfactorily, with the integral nonlinearity of less than ±0.04 nA in the range of −400 to 50 nA and the resolution of about ±0.6 nA.

134 - Implementation of a program for the external audit of contracted suppliers by AusCord—The Australian Public Cord Blood Collection and Banking Network

Contracted suppliers of critical materials, reagents, services and equipment must be audited and qualified to verify compliance with written agreements and relevant standards. External audits may be challenging for cellular therapy facilities faced with large numbers of contracted suppliers and often limited resources. As part of an operational alignment project, AusCord created a system to integrate and coordinate the audit of external suppliers. A master register was established and included a list of suppliers and services provided, a uniform process for risk assessment and an audit schedule. A procedure and forms were developed to manage the process. Each cord blood bank (CBB) registered their suppliers to identify common contractors and performed risk assessment of individual suppliers. Results were compared between the three CBBs to develop consensus on a single scale and risk rating matrix. Each supplier was then rated based on the degree of regulatory oversight, criticality of their service and the presence of prior non-conformances. The level of risk was used to determine whether an audit was required and if so the type of audit to be performed (on-site audit, desk-top audit or a questionnaire). Audits were allocated to each CBB and scheduled. A total of 27 audits were allocated in the first year. The results of completed audits are reviewed at face to face AusCord meetings. To date we have had 100% compliance with respect to supplier cooperation. Audit outcome will be used to determine the frequency and type of subsequent audits for individual suppliers. The AusCord coordinated system has provided significant benefits to the various stakeholders. The use of a standardized integrated approach to risk assessment and audit of suppliers and the consolidation of audits has resulted in increased surveillance of suppliers, improved supplier response rate, CBB access to a more comprehensive and concise summary of supplier performance and effective and efficient utilization of resources.

SP-0019: Scaling down proton therapy facilities to fit into photon vaults

SP-0019: Scaling down proton therapy facilities to fit into photon vaults