Neutron induced brachytherapy: A combination of neutron capture therapy and brachytherapy

Shih, Jing‐Luen A.; Brugger, R.M.

doi:10.1118/1.596869

Cited by 5 publications

(3 citation statements)

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“…Since the gamma emission spectra of the various neutron-activated lanthanide elements are both unique and nonoverlapping, these elements can be quantified simultaneously in the presence of other lanthanides. This property allows the design of experiments where similar colloids labeled with different lanthanides are used either sequentially or simultaneously in labeling and tracking cells (16).…”

Section: Discussionmentioning

confidence: 99%

“…Since the chemistry among the lanthanides is so similar , one would anticipate that introducing one lanthanide element would serve as a guide, through judicious substitutions, for introducing the entire lanthanide series into the iron oxide core of magnetic nanoparticles. Among the informational properties that lanthanide atoms possess (Table ) are sensitive and quantitative detection by neutron activation (NA) , detection by time resolved fluorescence (TRF) , detection by combined X-ray fluorescence/scanning electron microscopy (EM) , and applications involving neutron capture therapy – .…”

Section: Introductionmentioning

confidence: 99%

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Ultrasmall Mixed Ferrite Colloids as Multidimensional Magnetic Resonance Imaging, Cell Labeling, and Cell Sorting Agents

et al. 2007

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One area that has been overlooked in the evolution of magnetic nanoparticle technology is the possibility of introducing informational atoms into the iron oxide core of the coated colloid. Introduction of suitable atoms into the iron oxide core offers an opportunity to produce a quantifiable probe, thereby adding one or more dimensions to the magnetic colloid's informational status. Lanthanide-doped iron oxide nanoparticles have been synthesized to introduce informational atoms through the formation of colloidal mixed ferrites. These colloids are designated ultrasmall mixed ferrite iron oxides (USMIOs). USMIOs containing 5 mol % europium exhibit superparamagnetic behavior with an induced magnetization of 56 emu/g Fe at 1.5 T, a powder X-ray diffraction pattern congruent with magnetite, and R1 and R2 relaxivity values of 15.4 (mM s) (-1) and 33.9 (mM s) (-1), respectively, in aqueous solution at 37 degrees C and 0.47 T. USMIO can be detected by five physical methods, combining the magnetic resonance imaging (MRI) qualities of iron with the sensitive and quantitative detection of lanthanide metals by neutron activation analysis (NA), time-resolved fluorescence (TRF), X-ray fluorescence, along with detection by electron microscopy (EM). In addition to quantitative detection using neutron activation analysis, the presence of lanthanides in the iron oxide matrix confers attractive optical properties for long-term multilabeling studies with europium and terbium. These USMIOs offer high photostability, a narrow emission band, and a broad absorption band combining the high sensitivity of time-resolved fluorescence with the high spatial resolution of MRI. USMIO nanoparticles are prepared through modifications of traditional magnetite-based iron oxide colloid synthetic methods. A 5 mol % substitution of ferric iron with trivalent europium yielded a colloid with nearly identical magnetic, physical, and chemical characteristics to its magnetite colloid parent.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ultrasmall Mixed Ferrite Colloids as Multidimensional Magnetic Resonance Imaging, Cell Labeling, and Cell Sorting Agents

et al. 2007

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“…In situ activation radiation therapy (InSituArt TM ) is a therapy modality built around the principles of neutron capture therapy (Coderre et al 1997). However, instead of relying on expensive nuclear reactor facilities (Shih and Brugger 1992) or specifically designed accelerators (Burlon et al 2001), InSituArt TM uses the neutrons that are already present in the photon beam of a high-energy electron accelerator or linac (AAPM 1986). Since the linac's introduction to the clinic some 30 years ago, numerous reports have been published on the contribution of these neutrons, usually referred to as photoneutrons, to the patient dose (Gur et al 1978, Bading et al 1982.…”

Section: Introductionmentioning

confidence: 99%

Dosimetry ofin situactivated dysprosium microspheres

Adnani¹

2004

Phys. Med. Biol.

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This paper presents the results of a study aimed at investigating the dosimetry of stable dysprosium microspheres activated, in situ, by a linac generated photon beam. In phantom measurements of the neutron flux within an 18 MV photon beam were performed using CR-39 detectors and gold activation. The results were used in conjunction with a Monte Carlo computer simulation to investigate the dose distribution resulting from the activation of dysprosium (Dy) microspheres using an 18 MV photon beam. Different depths, lesion volumes and volume concentrations of microspheres are investigated. The linac lower collimator jaws are assumed completely closed to shield the tumour volume from the photon dose. Using a single AP field with 0 x 0 cm2 field size (closed jaws), a photon dose rate of 600 MU min(-1) and 80 cm SSD for 10 min, an average dose exceeding 1 Gy can be delivered to spherical lesions of 0.5 cm and higher diameter. The variation of the average dose with the size of the lesion reaches saturation for tumour volumes exceeding 1 cm in diameter. This report shows that the photon beam of a high-energy linac can be used to activate Dy microspheres in situ and, as a result, deliver a significant dose of beta radiation. Non-radioactive Dy microspheres do not have the toxicity and imaging problems associated with commercially available yttrium-90 based products.

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Gadolinium as an Element for Neutron Capture Therapy

Brugger

Liu

Laster

et al. 1993

Advances in Neutron Capture Therapy

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Gadolinium is being studied as an alternate active elementto B for Neutron Capture Therapy (NCT). The advantages of Gd-157 as compared to B-10 arethat Gd-|57 has a very large thermalneutroncrosssection(455,000 b), and Gd containingcompounds that targetto tumorsare beingdevelopedasMR] contrast agents. A disadvantage is thatthe products of the Gd + n reaction,gammaraysand Augerelectrons, do notappearto be aswell suitedto NCT as the productsof the B + n reaction,but thesestill may be effectivein destroyingtumors. Because of the advantages of Gd, an investigation of Gd as an elementfor NCT is proceeding at BNLt.The oneGd loadedMR! contrast agent, Gd-DTPA, thatisnowaccepted for imagingdoes target brain tumorsand will not be toxic at the levelsof injectionthat will be neededfor GdNCT'. Calculations andmeasurements of the physical doseshowthatwith 150 ppmin a 50 cctumor anda source of 5 x 10li neutrons, greaterthan 30 Gy of dosefromthe promptgamma rayswill be deliveredto the tumor 2. The dosedropsoff rapidlyawayfrom thetumor similar tothedosedistribution in brachytherapy. Measurements of thisdosewith a biological dosimeter agree with calculations, in addition,the biologicaldosimetershowsthat the dosecan be enhancedwith the additionof IdUrd to the treatment.Thusfar, for the compounds tried, the biologicaleffectobservedfrom Augerelectrons hasbeenmodest. In anotherstudy,a different deliverysystem wasexamined.Calculations showthaiGd metalseeds canbe usedwith GdNCT in a combination of brachytherapy andNCT3.At BNL, preparations are beingmadeto test in _ compounds containingGd and comparetheir response to the response of Gd-DTPA todetermineif one or severalcompounds canbe located that enterthe cellsandenhance theAugereffect. Figure I showsthe shapeof the • two similar rotatorswith positions for cell vials that havebeenconstructed for thesetests. The first rotatoris madeof onlyparaffinwhichsimulates healthytissueandprovidescontrolcurves.The secondrotatorhas 135ppmof Gd-157in the paraffinto simulate a Gd loadedtumor. Cells are irradiatedin vialsin the paraffinrotato_andJntheGd-paraffin rotatorat the epithermal beam of the Brookhaven MedicalResearch Reactor(BMRR). This produces an irradiationsimilar to whata patient weuldreceivein anactualtreatment.A combination of irradiations aremadewith both rotators; with no Gd compoundor ldUrd in the cell media,with only Gd compoundin the cell mediaand withboth Gd compoundand ldUrd in the cell media. The first set showsthe effectsof gammaraysfromthe H(n,gamma)reactionandthe promptgammaraysfrom capture of neutrons by Gd. The second setshowsif thereis anyeffectof Gd beingin the cell mediaor insidethe cells,i.e., an Auger effect. The third set showsthe effectof enhancement by the idUrd producedby the gammaraysfromneutrons captured by eitherH or Gd. The fourthset _ombinesali of the reactionsand enhancements. Preliminarycalculationsand physical ,neasurements of thedosesthatthe cellswill receivein theserotatorshavebeenmade. Figure 2 showspreliminary cell survival measurements and Table I lists b...

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Neutron induced brachytherapy: A combination of neutron capture therapy and brachytherapy

Cited by 5 publications

References 0 publications

Ultrasmall Mixed Ferrite Colloids as Multidimensional Magnetic Resonance Imaging, Cell Labeling, and Cell Sorting Agents

Ultrasmall Mixed Ferrite Colloids as Multidimensional Magnetic Resonance Imaging, Cell Labeling, and Cell Sorting Agents

Dosimetry ofin situactivated dysprosium microspheres

Gadolinium as an Element for Neutron Capture Therapy

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