X-ray phototherapy for canine brain masses

Norman, Amos; Ingram, Marylou; Skillen, R.G.; Freshwater, Donald B.; Iwamoto, Keisuke S.; Solberg, Timothy D.

doi:10.1002/(sici)1520-6823(1997)5:1<8::aid-roi2>3.0.co;2-1

Cited by 63 publications

(47 citation statements)

References 9 publications

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“…Binary radiation therapy targets cells at the biological level with a noncytotoxic agent that is "activated" by low-energy radiation, thereby destroying cancer cells wherever they may reside, while sparing normal cells in proximity to the diseased cells. A number of binary radiation therapies have been and are being explored (9,(34)(35)(36); one of the more promising approaches is based on dose enhancement through Auger electron emission secondary to the photoelectric effect dominant at low photon energies. Auger electron emission generates a cascade of low-energy electrons that travel very short distances and deposit their energy locally.…”

Section: Discussionmentioning

confidence: 99%

Enhancement of radiation effect on cancer cells by gold-pHLIP

Antosh

Wijesinghe

Shrestha

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Previous research has shown that gold nanoparticles can increase the effectiveness of radiation on cancer cells. Improved radiation effectiveness would allow lower radiation doses given to patients, reducing adverse effects; alternatively, it would provide more cancer killing at current radiation doses. Damage from radiation and gold nanoparticles depends in part on the Auger effect, which is very localized; thus, it is important to place the gold nanoparticles on or in the cancer cells. In this work, we use the pH-sensitive, tumor-targeting agent, pH Low-Insertion Peptide (pHLIP), to tether 1.4-nm gold nanoparticles to cancer cells. We find that the conjugation of pHLIP to gold nanoparticles increases gold uptake in cells compared with gold nanoparticles without pHLIP, with the nanoparticles distributed mostly on the cellular membranes. We further find that gold nanoparticles conjugated to pHLIP produce a statistically significant decrease in cell survival with radiation compared with cells without gold nanoparticles and cells with gold alone. In the context of our previous findings demonstrating efficient pHLIP-mediated delivery of gold nanoparticles to tumors, the obtained results serve as a foundation for further preclinical evaluation of dose enhancement.

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Section: Discussionmentioning

confidence: 99%

Enhancement of radiation effect on cancer cells by gold-pHLIP

Antosh

Wijesinghe

Shrestha

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…The latter techniques include photon activation therapy (40,41) and the use of dose-enhancing contrast agents, such as iodine (42,43), platinum (41), and gold (44,45). A disadvantage of the interlaced method would be the limited number of beam entrance portals around the tumor, which reduce the ability to conform the dose to the target.…”

Section: Discussionmentioning

confidence: 99%

Interlaced x-ray microplanar beams: A radiosurgery approach with clinical potential

Dilmanian

Zhong²,

Bacarian³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

175

214

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Studies have shown that x-rays delivered as arrays of parallel microplanar beams (microbeams), 25-to 90-m thick and spaced 100 -300 m on-center, respectively, spare normal tissues including the central nervous system (CNS) and preferentially damage tumors. However, such thin microbeams can only be produced by synchrotron sources and have other practical limitations to clinical implementation. To approach this problem, we first studied CNS tolerance to much thicker beams. Three of four rats whose spinal cords were exposed transaxially to four 400-Gy, 0.68-mm microbeams, spaced 4 mm, and all four rats irradiated to their brains with large, 170-Gy arrays of such beams spaced 1.36 mm, all observed for 7 months, showed no paralysis or behavioral changes. We then used an interlacing geometry in which two such arrays at a 90°angle produced the equivalent of a contiguous beam in the target volume only. By using this approach, we produced 90-, 120-, and 150-Gy 3.4 ؋ 3.4 ؋ 3.4 mm 3 exposures in the rat brain. MRIs performed 6 months later revealed focal damage within the target volume at the 120-and 150-Gy doses but no apparent damage elsewhere at 120 Gy. Monte Carlo calculations indicated a 30-m dose falloff (80 -20%) at the edge of the target, which is much less than the 2-to 5-mm value for conventional radiotherapy and radiosurgery. These findings strongly suggest potential application of interlaced microbeams to treat tumors or to ablate nontumorous abnormalities with minimal damage to surrounding normal tissue.

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“…27,37 It is important to note that recent surgical works focusing on improved tumor removal by ultrasonic aspiration and neuroendoscopy reported median survival times of 40-70 months, which appears to be better than our study results. [38][39] For a correct comparison, longer follow-up and better patient statistics are needed, but further stratification is probably necessary of both surgery and our work outcomes to better evaluate small differences.…”

Section: Follow-up:-mentioning

confidence: 99%

Stereotactic Volume Modulated Arc Radiotherapy Protocol for Canine Intracranial Meningioma.

Dolera¹,

Malfassi²,

Carrara³

et al. 2017

IJAR

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Objective: to assess High Dose Hypofractionated Volume Modulated Arc Radiotherapy (HDH-VMAT) feasibility and clinical efficacy in canine meningiomas. Design: a prospective study was conducted on thirty-three patients with a presumptive diagnosis of encephalic meningiomas assumed from Magnetic Resonance Imaging (MRI) findings. Methods: all dogs, whose neurological status was scored through the use of an innovative evaluation scale (Romanengo Veterinary Neurological Scale -RVNS), received HDH-VMAT by a Linear Accelerator (LINAC) equipped with an external beam modulator micro-multileaf collimator and an XVI Cone Beam Computed Tomography system (CBCT). The prescribed mean dose was 33 Gy delivered in 5 fractions. The treatment feasibility was tested through planned and delivered dose agreement checks. Regular clinical examinations were performed during and after irradiation time with regard to mentation, deambulation, cranial nerve dysfunction and seizures. Serial MRI exams were done 60 days after irradiation and after 4, 6, 12, 18, 24 months. Volumetric disease reduction criteria implemented with clinical neurological systematic evaluation were adopted to assess the course and to categorize patients' response. Results: complete and partial responses were observed on the whole in 65,5% of alive patients 24 months after irradiation. Two-year overall and disease-specific survival rates were 74.3% and 97.4%, respectively, and the putative radiotoxic effects were found to be few and slight. Conclusions: HDH-VMAT is a valid therapeutic option for encephalic canine meningioma. Volumetric MRI evaluation together with the hereby proposed RVNS should be considered for the evaluation of the post-treatment response.Copy Right, IJAR, 2017,. All rights reserved.

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X-ray phototherapy for canine brain masses

Cited by 63 publications

References 9 publications

Enhancement of radiation effect on cancer cells by gold-pHLIP

Enhancement of radiation effect on cancer cells by gold-pHLIP

Interlaced x-ray microplanar beams: A radiosurgery approach with clinical potential

Stereotactic Volume Modulated Arc Radiotherapy Protocol for Canine Intracranial Meningioma.

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