Does escalation of the apical dose change treatment outcome in β-radiation of posterior choroidal melanomas with 106Ru plaques?

Hermann, Robert Michael; Pradier, Olivier; Lauritzen, Katharina; Ott, Marcel; Schmidberger, Heinz; Hess, Clemens F.

doi:10.1016/s0360-3016(01)02763-8

Cited by 15 publications

(7 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Although the dose in the sclera was up to 19 Gy, the sclera is radioresistant, and a dose of less than 20 Gy does not result in any significant morbidity. Indeed, experience with ocular melanomas has shown the absence of clinical effects at doses into the hundreds of Gy (Missotten et al 1998, Hermann et al 2002, van Ginderdeuren et al 2005). We also found that for realistic motion in the anterior–posterior direction, the displacement of the fovea would have minimal impact on the overlap of the beam and would not pose a threat to the optic disc.…”

Section: Discussionmentioning

confidence: 99%

Assessment of targeting accuracy of a low-energy stereotactic radiosurgery treatment for age-related macular degeneration

Taddei¹,

Chell²,

Hansen³

et al. 2010

Phys. Med. Biol.

View full text Add to dashboard Cite

Age-related macular degeneration (AMD), a leading cause of blindness in the United States, is a neovascular disease that may be controlled with radiation therapy. Early patient outcomes of external beam radiotherapy, however, have been mixed. Recently, a novel multimodality treatment was developed, comprising external beam radiotherapy and concomitant treatment with a vascular endothelial growth factor inhibitor. The radiotherapy arm is performed by stereotactic radiosurgery, delivering a 16 Gy dose in the macula (clinical target volume, CTV) using three external low-energy x-ray fields while adequately sparing normal tissues. The purpose of our study was to test the sensitivity of the delivery of the prescribed dose in the CTV using this technique and of the adequate sparing of normal tissues to all plausible variations in the position and gaze angle of the eye. Using Monte Carlo simulations of a 16 Gy treatment, we varied the gaze angle by ±5° in the polar and azimuthal directions, the linear displacement of the eye ±1 mm in all orthogonal directions, and observed the union of the three fields on the posterior wall of spheres concentric with the eye that had diameters between 20 and 28 mm. In all cases, the dose in the CTV fluctuated <6%, the maximum dose in the sclera was <20 Gy, the dose in the optic disc, optic nerve, lens and cornea were <0.7 Gy and the three-field junction was adequately preserved. The results of this study provide strong evidence that for plausible variations in the position of the eye during treatment, either by the setup error or intrafraction motion, the prescribed dose will be delivered to the CTV and the dose in structures at risk will be kept far below tolerance doses.

show abstract

Section: Discussionmentioning

confidence: 99%

Assessment of targeting accuracy of a low-energy stereotactic radiosurgery treatment for age-related macular degeneration

Taddei¹,

Chell²,

Hansen³

et al. 2010

Phys. Med. Biol.

View full text Add to dashboard Cite

show abstract

“…Censored study also is reported by some studies in the literature. Hermann et al observed that in 56% of cases, the tumors were localized in the left eye (20) . However, this difference was not observed in studies involving a higher number of cases (18) .…”

Section: Time (Months)mentioning

confidence: 99%

“…A study describing the Dutch experiment with ruthenium for uveal melanoma utilized doses up to 160 Gy delivered to the tumor apex, and doses to the sclera from 220 Gy to 950 Gy (3) . Hermann et al, analyzing the effect of the dose-assignment in relation to results from ruthenium-106 plaque brachytherapy, utilized doses of 120 Gy to the apex of the tumor (20) . Shields et al, in a study with concomitant transpupillary thermotherapy and brachytherapy, describe a dose to the apex ranging between 55 Gy and 124 Gy (median, 90 Gy), and 254 Gy to the base (11) .…”

Section: Time (Months)mentioning

confidence: 99%

Braquiterapia com rutênio-106 em melanomas uveais - resultados preliminares: experiência uni-institucional

et al. 2007

View full text Add to dashboard Cite

OBJETIVO: Analisar os resultados preliminares da braquiterapia com rutênio-106 em pacientes portadores de melanomas uveais. MATERIAIS E MÉTODOS: No período de abril de 2002 a julho de 2003, 20 pacientes com diagnóstico de melanoma uveal foram tratados com braquiterapia com rutênio-106. A dose calculada no ápice tumoral variou de 55 Gy a 100 Gy. Pacientes com lesões com altura maior que 5 mm foram submetidos a termoterapia transpupilar concomitante à colocação da placa oftálmica. RESULTADOS: Quanto à localização da lesão, esta se encontrava na coróide em 75% dos casos, na íris em 15% e no corpo ciliar em 10% dos pacientes. Com seguimento mediano de 19 meses, a sobrevida livre de progressão para a braquiterapia e para a associação com a termoterapia transpupilar foi de 69% e 87%, respectivamente. Observou-se redução significante da altura tumoral após o tratamento. Nenhum dos pacientes foi submetido a enucleação. CONCLUSÃO: Nossos resultados preliminares mostram que a braquiterapia com rutênio-106 é uma opção adequada para o tratamento conservador de melanomas uveais em termos de controle local, manutenção do globo ocular e visão útil, com índice aceitável de complicações.

show abstract

“…106 Ru/ 106 Rh episcleral plaques produced by Eckert & Ziegler BEBIG (Berlin, Germany) are commonly used to treat intraocular tumors with an apical height up to 5 mm. 1 The majority of clinical studies report on outcomes for ocular melanoma [2][3][4][5][6][7][8][9] and retinoblastoma 10,11 treatments. All plaques feature a 0.1-lm-thick metallic layer of 106 Ru uniformly distributed on a gold foil with an approximate thickness of 1.4 lm.…”

Section: Introductionmentioning

confidence: 99%

A convex windowless extrapolation chamber to measure surface dose rate from ¹⁰⁶Ru/¹⁰⁶Rh episcleral plaques

2019

View full text Add to dashboard Cite

Purpose A convex windowless extrapolation chamber was developed as a primary measurement device to determine surface dose rate from curved 106Ru/106Rh episcleral plaques. Methods A convex extrapolation chamber without an entrance window was constructed for this work, and surface dose rate measurements were performed with two curved CCB‐type 106Ru/106Rh plaques (S/N 2545 and 2596) manufactured by Eckert & Ziegler BEBIG. FARO® Gage measurements were performed to verify the radius of curvature for the convex electrode and the concave plaque surface. Furthermore, the collecting electrode area was verified through capacitance measurements. Chamber correction factors for divergence and backscatter were generated using the EGSnrc cavity user code. For each source, surface dose rate was measured with the convex extrapolation chamber and compared with on‐contact measurements made with curved un‐laminated EBT3 film strips. A Monte Carlo correction was generated for radiochromic film measurements to account for volume averaging within the active layer and effects of phantom scatter. Additionally, extrapolation chamber results for each plaque were compared with scintillation detector measurements performed by the manufacturer. For the second source (S/N 2596), a comparison was also made with the Monte Carlo‐corrected surface dose rate measured at the National Physical Laboratory (NPL) using cylindrical alanine pellets. Finally, source measurements were performed using conventional ionization chambers (Exradin A26, A1SL, and A20) within a custom fixture to investigate the transfer of extrapolation chamber surface dose rate to clinics. Results For the first 106Ru/106Rh plaque (S/N 2545), average surface dose rate from the convex windowless extrapolation chamber was found to be 1.5% higher than the corresponding value from curved un‐laminated EBT3 film measurements and 5.6% lower than the manufacturer value. For the second source (S/N 2596), the extrapolation chamber surface dose rate was 2.5% higher than the un‐laminated EBT3 film result, 4.5% lower than the manufacturer value, and 3.9% higher compared to corrected alanine measurements made at NPL. Total uncertainty in the extrapolation chamber measurement was estimated to be approximately ± 7.0% (k = 2). For the plaque measurements made using conventional ionization chambers with a custom fixture, surface dose rate from the transfer technique was found to agree within 3.8% with the expected convex extrapolation chamber result for S/N 2596. Conclusions A convex windowless extrapolation chamber was developed as a primary measurement device for 106Ru/106Rh plaques. Through comparison with the extrapolation chamber, the accuracy of surface dose rate measurements from current dosimetry techniques was assessed and agreement was seen within 5.6%. Finally, it was found that conventional ionization chambers could be calibrated with a reference 106Ru/106Rh plaque in order to transfer the extrapolation chamber result for surface dose rate to clinics.

show abstract

Does escalation of the apical dose change treatment outcome in β-radiation of posterior choroidal melanomas with 106Ru plaques?

Cited by 15 publications

References 21 publications

Assessment of targeting accuracy of a low-energy stereotactic radiosurgery treatment for age-related macular degeneration

Assessment of targeting accuracy of a low-energy stereotactic radiosurgery treatment for age-related macular degeneration

Braquiterapia com rutênio-106 em melanomas uveais - resultados preliminares: experiência uni-institucional

A convex windowless extrapolation chamber to measure surface dose rate from ¹⁰⁶Ru/¹⁰⁶Rh episcleral plaques

Contact Info

Product

Resources

About

Does escalation of the apical dose change treatment outcome in β-radiation of posterior choroidal melanomas with 106Ru plaques?

Cited by 15 publications

References 21 publications

Assessment of targeting accuracy of a low-energy stereotactic radiosurgery treatment for age-related macular degeneration

Assessment of targeting accuracy of a low-energy stereotactic radiosurgery treatment for age-related macular degeneration

Braquiterapia com rutênio-106 em melanomas uveais - resultados preliminares: experiência uni-institucional

A convex windowless extrapolation chamber to measure surface dose rate from 106Ru/106Rh episcleral plaques

Contact Info

Product

Resources

About

A convex windowless extrapolation chamber to measure surface dose rate from ¹⁰⁶Ru/¹⁰⁶Rh episcleral plaques