Phantom development and implementation for gamma knife dosimetry. Nine gamma knife centers in six states participated in a round robin intercomparison w four phantoms, two ionization chambers and one electrometer comparing and contrasting three different calibration protocols results. Gamma knife gamma knife is a radiation therapy that uses computerized treatment planning software to help physicians locate and irradiate small targets within the head and brain with very high precision. Cureus aapm tg 178 gamma knife dosimetry intercomparison. Instead, the gamma knife uses up to 192 precisely focused beams of radiation to control malignant and nonmalignant tumors, as well as vascular and functional disorders in the brain, without harming surrounding healthy tissue. The new phantom is suitable for gamma knife reference and relative dosimetry. The gamma knife also known as the leksell gamma knife, a creation of elekta ab, a swedish public company, is used to treat brain tumors by administering highintensity gamma radiation therapy in a manner that concentrates the radiation over a small volume. Choice of phantom materials for dosimetry of leksell gamma knife unit. The results of this work aim to contribute to the implementation of the trs 483, mainly in the area of gamma knife dosimetry and the use of small volume ionization chambers. Mark perera5 department of radiation oncology,1 columbia university, 622 w168th st. Arndt 4 to illustrate this hypothetical discussion above with reality, off axis ratios oar. The solid water phantom leksell gamma knife dosimetry phantom, elekta, stockholm, sweden represents an alternative because it should have a response to radiation equivalent to water. As part of full calibration of the gamma knife in meeting 10 cfr 35. Dosimetry for small fields in stereotactic radiosurgery.
Gamma knife treatment for avms spetzlermartin grade i or ii 97 dural arteriovenous fistulas 97 effect of gamma knife on seizure activity in avm patients 98 pediatric avm 99 thalamicbasal ganglia and brainstem avm 101 volumestaged gamma knife radiosurgery in large avm 103. Development of a pmma phantom as a practical alternative for quality control of gamma knife dosimetry jae pil chung1, young min seong1, tae yeon kim2, yona choi2, tae hoon kim3, hyun joon choi4, chul hee min4, hamza benmakhlouf5, kook jin chun2 and hyuntai chung6 abstract. Calibration of the gamma knife perfexion using tg21 and the solid water leksell dosimetry phantom. A gamma knife center,2 takanobashi central hospital, 2416. Absorbed dose to water rate was determined in nine small radiation fields with diameters between 4 and 35 mm in a leksell gamma knife lgk and a modified linear accelerator linac for stereotactic radiosurgery treatments. The qf 12 of gamma knife dosimetry has an inverse correlation with target shape complexity independent of target volume. Dosimetry of small static fields used in external beam radiotherapy an international code of practice for reference and relative dose determination. Pdf a microchamber, ptw pinpoint 31006, was used to measure transverse. Max number of lesions that can reasonably be treated in a single session 30. This study showed that both md55 and gd302m had good dose linearity from 3 to 120 gy.
Profiles in the three directions were also measured for the 4 mm beam to evaluate full width at half maximum fwhm and penumbra and to compare them with the corresponding leksell gammaplan profiles. Allison and diana campos, booktitlejournal of applied clinical medical physics, year2010. Evaluation of a synthetic singlecrystal diamond detector for. Since its inception, doses applied using gamma knife radiosurgery gkr have been calculated using a simple tmr algorithm, which assumes the patients head is of even density, the same as water. In 1975, a series of surgical pioneers at the karolinska hospital, stockholm began to utilize a re. The treatment delivers intense radiation doses to the target area while sparing surrounding tissue.
The use of small volume ionization chamber has become required for the dosimetry of equipments that use small radiation fields such as the gamma. Particularly for small and round targets the gamma knife plan quality is significantly higher qf 12. Purpose the effectiveness of gamma knife stereotactic radiosurgery to obliterate brain arteriovenous malformations avms may be diminished by the preoperative adjunctive use of endovascular liquid embolic agents. E045 the effect of liquid embolic agents on gamma knife. Introduction increased uncertainties in dosimetry measurements of small photon fields have been reported in a considerable body of literature and summarized in ipem report 103 aspradakis et al 2010. Gamma knife treatment is traditionally limited to tumours with a diameter not exceeding 33. It is solely focused on the brain, and only the brain. This work investigated the suitability of passive dosimeters for reference dosimetry in small fields with acceptable accuracy. Cureus dosimetry and treatment descriptions using the. Physics and dosimetry of the gamma knife sciencedirect. It uses 192 highactivity cobalt60 sources collimated to a common focus to impart radiological damage to the target structure while minimizing dose to adjacent healthy tissue. Measured dors were compared to the new output factor reference values for gamma knife perfexion 0. Pdf investigation of dosimetric differences between the.
Ho gamma knife centre hk, canossa hospital, 1 old peak road, hong kong. Tungsten collimators are organized into eight sectors of 24. Zoros e, pappas e p, zourari k, pantelis e, moutsatsos a, kollias g, hourdakis c i and karaiskos p 2017 ep1438 experimental determination of correction factors for reference dosimetry in gamma knife perfexion radiother. Development of a 3dimensional dosimetry system for. Dec 07, 2014 presage dosimetry is an accurate solution for measuring gamma knife output factors and performing quality assurance measurements for gamma knife treatment systems. Evaluation of dose delivery accuracy of gamma knife by. Presage dosimetry is an accurate solution for measuring gamma knife output factors and performing quality assurance measurements for gamma knife treatment systems. Three adapters for measuring with ionization chamber or other detectors are included. Despite its name, this procedure does not involve a surgical incision into the brain. Precision dosimetry for narrow photon beams used in. Evaluation of dose delivery accuracy of gamma knife by polymer gel dosimetry yoichi watanabe,1 tomohide akimitsu, 2 yutaka hirokawa, 3 rob b.
The gamma knife system is a co60 based medical device for treatment target irradiations in the radiosurgery 14. We carried out a retrospective comparative study on dosimetric parameters of the treatments delivered with xknife and gamma knife techniques at. Comparative clinical dosimetry with xknife and gamma knife. Comparative clinical dosimetry with xknife and gamma. The dosimetry phantom is used for accurately measure absorbed dose and dose rate in leksell gamma knife. Aapm task group 178 gamma stereotactic radiosurgery dosimetry and quality assurance aapm 58th annual meeting august, 2016 steven j. The particular presage formulation used in these experiments possessed a very linear relationship between optical density and irradiated dose within the dose ranges of these.
The gamma knife perfexion is a radiosurgical treat ment device used to irradiate targets in the head. Aapm task group 178 gamma stereotactic radiosurgery dosimetry. Methods dosimetry tests were conducted by our institution using the standard of examination and calibration and the intelligent. Radiometer of the china research institute of measurement. Treatment units for radiosurgery, like leksell gamma knife and adapted, or dedicated, linear accelerators use small circular beams of ionizing radiation down to 4 mm in diameter at the isocenter. Complete your entire cyberknife qa quickly and easily while minimizing downtime so you can treat more patients. Dosimetric comparison of the leksell gamma knife perfexion. We carried out a retrospective comparative study on dosimetric parameters of the treatments delivered with x knife and gamma knife techniques at our centre. Gamma knife radiosurgery, also known as stereotactic radiosurgery, is a form of radiation used to treat brain disorders. Monte carlo and experimental determination of correction.
Pdf investigation of dosimetric differences between the tmr. Pdf study of a spherical phantom for gamma knife dosimetry. Gamma knife using gamma radiation to treat the tumor cells especially in the brain. Clinical work with the gamma knife began in 1967 in sweden. The phantom consists of a hemispherical outer phantom, one exchangeable cylindrical chamberhosting inner phantom, and two.
Development of a pmma phantom as a practical alternative for. Request pdf dosimetric comparison of the leksell gamma knife perfexion and 4c the recently introduced leksell gamma knife lgk perfexion is an entirely new system with a different beam. That means building on the treatment experience of over 1. Dosimetry and treatment descriptions using the first. However, because of its high price, this option is not likely to be generally accepted. Pdf calibration of the gamma knife perfexion using tg21. The dosimetry phantom can also be used to verify dose 3d distributions by means of film dosimetry. A multipurpose pmma phantom was developed to measure the absorbed dose rate to water and the dose distribution of a gk.
This results in a significant approximation of the dose delivered by the gamma knife. Pdf comparative clinical dosimetry with xknife and gamma. Aapm task group 178 gamma stereotactic radiosurgery. Phantom development and implementation for gamma knife. The current paper presents 97 patients with meningiomas with a minimum volume of 10 cm3, treated with a prescription dose of 12 gy or sometimes less to protect neighbouring structures. Comparative clinical dosimetry with x knife and gamma knife. Study of a spherical phantom for gamma knife dosimetry. Leksell gamma knife perfexion offers protocol reproducibility with full backward compatibility to existing gamma knife surgery protocols. A synthetic diamond diode in volumetric modulated arc therapy dosimetry med. The x knife facility was the first to be commissioned which now mostly is used for srt after the commissioning of the gamma knife facility. The xknife facility was the first to be commissioned which now mostly is used for srt after the commissioning of the gamma knife facility. Cureus dosimetry and treatment descriptions using the first. The posttreatment assessment of these patients, the early response to treatment and the complications. Introduction the objective is to report the dosimetry and safety profiles of the first fully automatized rotating gamma ray unit for intracranial radiosurgery in america.
Thus, doses were measured and recorded relative to this standard calibration point. Dose measurements for gamma knife with radiophotoluminescent. Yua department of physics and materials science, city university of hong kong, tat chee avenue, kowloon tong, hong kong c. We investigated how gkr dose calculations varied when using a new convolution algorithm clinically available for. Request pdf study of a spherical phantom for gamma knife dosimetry four 16 cm diameter spherical phantoms were modeled in this study. Robotic efficiency with leksell gamma knife perfexion, the multiple helmets of the previous. Gamma knife surgery is a nearly painless computerguided procedure that delivers highly focused radiation to tumors in the brain. Pdf ion chamber measurements of transverse gamma knife beam. The leksell gamma knife lgk is a complete system for radiosurgery marketed. Leksell gamma knifeperfexion lgkp elekta, norcross, ga is equipped with three, different collimator sizes. Request pdf comparative clinical dosimetry with xknife and gamma knife xknife and gamma knife techniques are wellestablished for cranial stereotactic radiosurgery srs.
The first gamma knife created a discoidshaped lesion suitable for neurosurgical treatment of movement disorder surgery and intractable pain management. Development of a 3dimensional dosimetry system for leksell. During the 1990s, other companies in asia begun developing intracranial stereotactic gamma ray machines that rotated the cobalt 60 sources in relation to the isocenter, needing a significantly lower number of sources 25 or 30 with similar dosimetry characteristics than the static gamma knife units 45 of the time. Verifying the accuracy of dose distribution in gamma knife unit in. Evaluation of a synthetic singlecrystal diamond detector. Towards the recommendation of a standard dosimetry protocol for gamma knife stereotactic radiosurgery paula l. To measure relative dose rate, both types of tlds were also placed at the center of the 16 cm diameter phantom elekta, norcross, ga and at least two 3minute irradiations were.
Evaluation of dose delivery accuracy of gamma knife by polymer. Use of the leksell gamma knife for localized small field. Dosimetry of small static fields used in external beam. Adaptation and validation of a commercial head phantom for. Development of a pmma phantom as a practical alternative. Gamma knife, model b, and compared with profiles measured with film dosimetry. The purpose of the present investigation was to determine if commercially available liquid embolic agents reduce the radiation dose to the target owing to. Describe results of aapm task group 178 on gamma knife dosimetry and quality assurance round robin dosimetry intercomparison methods. Choice of phantom materials for dosimetry of leksell gamma. This article describes the basic physical characteristics of the gamma knife, patient setup procedures, the existing treatmentplanning system, the measurements. Gamma knife is a noninvasive stereotactic radiosurgery instrument that involves no scalpel or incision its not a knife at all.
Pdf comparative clinical dosimetry with xknife and. In fact, gamma knife is the only noninvasive radiosurgery. The phantom was manually moved across the beam, using the gamma knife. Dosimetry for small fields in stereotactic radiosurgery using. As target volume and complexity increase, the imrt beak qf 12 approaches that of the gamma knife.
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