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TheraSeed (TheraSeed)

✓ Approved

Theragenics · 治疗药物

什么是 TheraSeed？

TheraSeed 是一种治疗药物，由Theragenics研发。该药已获批，用于治疗相关适应症，给药途径：Injectable (Others)、Surgical Implantation。

药物档案

商品名TheraSeed
公司Theragenics
给药途径Injectable (Others), Surgical Implantation
状态Approved
来源： ClinicalTrials.gov, Theragenics

治疗适应症

TheraSeed 针对 1 个适应症，涉及 1 个治疗领域。

治疗领域疾病/病症分期
Neoplasms benign, malignant and unspecified (incl cysts and polyps)Prostate cancer✓ Approved

相关研究文献

PubMedInternational journal of radiation oncology, biology, physics2017-11-06

Microdosimetric Evaluation of Current and Alternative Brachytherapy Sources-A Geant4-DNA Simulation Study.

Famulari Gabriel G, Pater Piotr P, Enger Shirin A SA

Radioisotopes such as 75Se, 169Yb, and 153Gd have photon energy spectra and half-lives that make them excellent candidates as alternatives to 192Ir for high-dose-rate brachytherapy. The aim of the present study was to evaluate the relative biological effectiveness (RBE) of current (192Ir, 125I, 103Pd) and alternative (75Se, 169Yb, 153Gd) brachytherapy radionuclides using Monte Carlo simulations of lineal energy distributions. Brachytherapy sources (microSelectron v2 [192Ir, 75Se, 169Yb, 153Gd], SelectSeed [125I], and TheraSeed [103Pd]) were placed in the center of a spherical water phantom with a radius of 40 cm using the Geant4 Monte Carlo simulation toolkit. The kinetic energy of all primary, scattered, and fluorescence photons interacting in a scoring volume were tallied at various depths from the source. Electron tracks were generated by sampling the photon interaction spectrum and tracking all the interactions down to 10 eV using the event-by-event capabilities of the Geant4-DNA models. The dose mean lineal energy (y¯D) values were obtained through random sampling of transfer points and overlaying spherical scoring volumes within the associated volume of the tracks. The scoring volume diameter was determined by fitting the y¯D ratio for 125I to its observed RBE. y¯D increased with the increasing distance from the source for 192Ir, 75Se, and 169Yb, remained constant for 153Gd and 125I, and decreased for 103Pd. The diameter at which the y¯D ratio coincided with the RBE of 1.15 to 1.20 for 125I was ∼25 to 40 nm. The RBE (reference 1 MeV photons) at high doses and dose rates for 192Ir, 75Se, 169Yb, 153Gd, 125I, and 103Pd was 1.028 to 1.034, 1.05 to 1.07, 1.12 to 1.15, 1.16 to 1.21, 1.15 to 1.20, and 1.17 to 1.22, respectively. The radiation quality of the radionuclides under investigation was greater than that of high-energy photons. The present study has provided a set of values to modify the prescription doses for brachytherapy to account for the variation in radiation quality among radionuclides.

PMID 29102279
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PubMedMedical physics2017-07-22

Technical Note: Empirical altitude correction factors for well chamber measurements of permanent prostate and breast seed implant sources.

Watt Elizabeth E, Spencer David P DP, Meyer Tyler T

Previous studies in the literature have measured an altitude effect for low-energy brachytherapy seeds; a correction factor applied in addition to PTP to account for the breakdown of Bragg-Gray cavity theory at low energies in well-type ionization chambers. In clinical practice, many centers use altitude correction factors that are not seed-model-specific. The purpose of this work is to present altitude correction factors for several seed models without documented factors in the literature. An in-house constructed pressure vessel was used with a well-type ionization chamber to measure the air-kerma strength of the IsoAid Advantage (Pd-103), Theragenics AgX100 (I-125), and Nucletron selectSeed (I-125) at a pressure range representative of those encountered worldwide. The TheraSeed 200 (Pd-103) was also measured for comparison to the originally published correction factor for validation of the experimental process. When correction factors derived in this work were within experimental uncertainties of those published, no new correction factors were proposed. The three seed models measured herein all demonstrated a similar response to change in pressure as previously documented in the literature with the HDR 1000 Plus well-type ionization chamber. Correction factors of the functional form PA=k1(P[torr])k2, consistent with those previously published, were found to be appropriate for these seed models. A new correction factor is proposed for the Theragenics AgX100 and Nucletron selectSeed (k1  = 0.0417, k2  = 0.479). The IsoAid Advantage, however, agreed to within uncertainty with the published altitude correction factor for the TheraSeed 200; thus the application of the same correction factor is appropriate (k1  = 0.0241, k2  = 0.562). This work presents altitude correction factors for three permanent implant brachytherapy seed models in clinical use. This will allow clinics to utilize model-specific factors, reducing systematic errors in their air-kerma strength verifications.

PMID 28730606
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PubMedMedical physics2011-09-21

Changes in dose with segmentation of breast tissues in Monte Carlo calculations for low-energy brachytherapy.

Sutherland J G H JG, Thomson R M RM, Rogers D W O DW

To investigate the use of various breast tissue segmentation models in Monte Carlo dose calculations for low-energy brachytherapy. The EGSnrc user-code BrachyDose is used to perform Monte Carlo simulations of a breast brachytherapy treatment using TheraSeed Pd-103 seeds with various breast tissue segmentation models. Models used include a phantom where voxels are randomly assigned to be gland or adipose (randomly segmented), a phantom where a single tissue of averaged gland and adipose is present (averaged tissue), and a realistically segmented phantom created from previously published numerical phantoms. Radiation transport in averaged tissue while scoring in gland along with other combinations is investigated. The inclusion of calcifications in the breast is also studied in averaged tissue and randomly segmented phantoms. In randomly segmented and averaged tissue phantoms, the photon energy fluence is approximately the same; however, differences occur in the dose volume histograms (DVHs) as a result of scoring in the different tissues (gland and adipose versus averaged tissue), whose mass energy absorption coefficients differ by 30%. A realistically segmented phantom is shown to significantly change the photon energy fluence compared to that in averaged tissue or randomly segmented phantoms. Despite this, resulting DVHs for the entire treatment volume agree reasonably because fluence differences are compensated by dose scoring differences. DVHs for the dose to only the gland voxels in a realistically segmented phantom do not agree with those for dose to gland in an averaged tissue phantom. Calcifications affect photon energy fluence to such a degree that the differences in fluence are not compensated for (as they are in the no calcification case) by dose scoring in averaged tissue phantoms. For low-energy brachytherapy, if photon transport and dose scoring both occur in an averaged tissue, the resulting DVH for the entire treatment volume is reasonably accurate because inaccuracies in photon energy fluence are compensated for by inaccuracies in localized dose scoring. If dose to fibroglandular tissue in the breast is of interest, then the inaccurate photon energy fluence calculated in an averaged tissue phantom will result in inaccurate DVHs and average doses for those tissues. Including calcifications necessitates the use of proper tissue segmentation.

PMID 21928657
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PubMedAnnals of nuclear medicine2011-03-16

Investigation of dose distribution of TheraSeed 200 103Pd brachytherapy seed on coaxial cylindrical phantom shells using Monte Carlo simulation.

Camgöz Berkay B, Kumru Mehmet Nurullah MN

In this study, radial dosimetric characterization for specific internal geometry of seed source was determined. In this study, the separate contribution of radioactive components of the seed's unlikely single radioactive rod on dose distribution was investigated using model seed TheraSeed 200 source at parallel shells in a water phantom. TheraSeed 200 brachytherapy seed was modeled using EGSnrc-MP Monte Carlo simulation code. Dose contributions of radioactive components inside the seed were calculated on coaxial shells with different radii in a water phantom. Dose calculation points on shells were determined as only spatial. The study's spatial geometrical approach was considered. Dose distributions of two radiation emitters were compared on plotted data. In 0°-90° rotation area, left emitter's efficiency varied with distance. On shells with small radius, dose contribution (D1) of left emitter was weakly effective on total distribution; right emitter was the determinant factor on the total dose. By increasing shell radius, efficiency of two emitters comes close. It seems that geometrical specification of a seed is markedly effective on dose distribution. Differences between doses of two radioactive materials decrease rapidly beyond the seed borders. Consideration of this study can be applied for other seeds that have multiple radiation emitters to research the effects of their geometrical specification on dose distributions.

PMID 21404137
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PubMedBrachytherapy2005-12-14

Variability of prostate brachytherapy pre-implant dosimetry: a multi-institutional analysis.

Merrick Gregory S GS, Butler Wayne M WM, Wallner Kent E KE, Blasko John C JC et al.

To conduct a multi-institutional comparison of prostate brachytherapy pre-implant dosimetry of Pd-103 and I-125. Eight experienced brachytherapists submitted Pd-103 and I-125 monotherapeutic and boost pre-implant dosimetry plans for central review. All 32 plans were calculated using the same transrectal ultrasound volumetric study. Seeds of any strength were acceptable, but were restricted to Theraseed Model 200 (Theragenics Inc., Buford, GA) and Oncura Oncoseed Model 6711 (Oncura, Plymouth Meeting, PA). The dosimetric analysis included evaluation of target volume, target to prostate ratio, target length, number of needles, seed activity, number of seeds, total activity, total activity divided by treatment planning volume, the use of extracapsular seeds, and average treatment margins (defined as the perpendicular distance between the prostate capsule and the 100% isodose line). Prostate coverage was defined in terms of V(100)/V(150)/V(200)/V(300) and D(100)/D(90)/D(50), whereas urethral dosimetry consisted of UV(100)/UV(150)/UV(200) and UD(90)/UD(50). The mean planning target volume to prostate volume ratio varied dramatically (mean 1.29, range 0.99-1.76) with the target length ranging from 3.5 to 4.5 cm. Although the prostate V(100) was >95% in all cases, the V(150) ranged from 29.9% to 92.1% and the V(200) from 6.72% to 52.5%. The urethral V(100) was 100% in all cases with six of the eight brachytherapists limiting the UV(150) to <3%. However, the median urethral dose varied by up to 50%. Treatment margins also varied significantly (average 3.98 mm, range 0.32-7.68 mm). All brachytherapists used extracapsular seeds with five implanting >25% of the seeds in extracapsular locations (range 6.4-58.2%). In addition, significant variability existed in the number of needles, number of seeds, and seed strength. This study highlights the substantial variability that exists regarding target volume, seed strength, dose homogeneity, treatment margins, and extracapsular seed placement, although prostate brachytherapy prescription doses are uniform. The standardization of pre-implant dosimetry is essential for meaningful multi-institutional comparisons of biochemical outcomes and morbidity.

PMID 16344253
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PubMedBrachytherapy2005-03-02

103Pd brachytherapy versus radical prostatectomy in patients with clinically localized prostate cancer: a 12-year experience from a single group practice.

Sharkey Jerrold J, Cantor Alan A, Solc Zucel Z, Huff William W et al.

In an effort to shed light on the continuing debate over the best treatment options for patients with localized prostate cancer, we present a retrospective review of patients from a single group community urology practice. Data from 1707 patients were reviewed. These patients, with T1 or T2 adenocarcinoma of the prostate, were treated from 1992 to 2004 with either brachytherapy or radical retropubic prostatectomy (RRPP); 81% were aged over 65 years. Patients were classified into risk groups based on initial prostate-specific antigen (PSA) and Gleason score. Time to PSA-indicated recurrence was used as the measure of disease control and cure. Time to PSA-indicated recurrence was used as a measure of efficacy. Brachytherapy with 103Pd exclusively and RRPP were found to provide equivalent control (<0.4 ng/mL for prostatectomy and <3 successive rises in PSA as defined by the American Society for Therapeutic Radiology and Oncology [ASTRO]) in low-risk groups (89% seeds vs. 94% RRPP). In intermediate (89% seeds vs. 58% RRPP) and high-risk (88% seeds vs. 43% RRPP) groups, brachytherapy patients had better control rates. The addition of external radiation, with or without luteinizing hormone-releasing hormone therapy, improved biochemical control rates in intermediate and high-risk brachytherapy groups. The results failed to show any superiority of prostatectomy over brachytherapy with 103Pd (TheraSeed; Theragenics Corp., Buford, GA) regarding time until relapse as indicated by PSA level increase (>0.4 ng/mL for prostatectomy and >3 successive rises in PSA as defined by ASTRO). We recently reviewed our techniques and improved equipment from 1995 to present and found major gains with both brachytherapy and surgery. Low risk brachytherapy resulted in 99% freedom from PSA failure while surgery showed results of 97%. Brachytherapy and prostatectomy should be offered without bias to all men with stage T1 and T2 organ-confined prostate cancer.

PMID 15737905
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