Markus Buchgeister

Stereotactic fractionated radiotherapy in patients with optic nerve sheath meningioma.

PURPOSE To evaluate the effectiveness of stereotactic fractionated radiotherapy (SFRT) in the treatment of optic nerve sheath meningioma (ONSM). METHODS AND MARERIALS: Between 1994 and 2000, a total of 39 patients with either primary (n = 15) or secondary (n = 24) ONSM were treated with SFRT and received a median total tumor dose of 54 Gy using 1.8 Gy/fraction. RESULTS The radiographic response to SFRT was documented in all patients as stable disease (no change) except for 1 patient with a partial response. After a median follow-up of 35.5 months, all patients with ONSM were alive without recurrence. The visual fields and visual acuity were improved in 6 of 15 and 1 of 16 examined eyes in patients with primary ONSM, respectively, and in 6 of 24 and 7 of 26 examined eyes in patients with secondary ONSM, respectively. Stable visual fields and visual acuity was observed in 8 of 14 and 15 of 16 patients with primary ONSM, respectively, and in 17 of 24 and 19 of 26 patients with secondary ONSM, respectively. Except for reversible alopecia and erythema, no other SFRT-related toxicity was observed. CONCLUSION SFRT represents a very effective and low-toxic treatment modality for ONSM. Despite a median follow-up of 3 years, this series of primary ONSM holds promise for future studies. It adds substantial evidence that SFRT may definitely become a standard treatment approach in selected cases of ONSM.

Radiosurgery for brain metastases: the Tuebingen experience

PURPOSE To retrospectively investigate the effectiveness of linear accelerator based radiosurgery (RS) in the treatment of brain metastases (BM). MATERIAL AND METHODS Of 55 patients with a total of 72 BM, 41 patients had a single brain metastasis and 14 patients had two or three metastases. Median tumour dose of 15Gy (range 8-20Gy) was prescribed to a median isodose surface of 90% (range 70-100%) encompassing the target volume. RESULTS The median survival time (MST) for all 55 patients was 7 months [95% confidence interval (CI), 5-10 months] and 2-year survival is 18%. There was no significant difference between patients who had one brain metastasis and those with either two or three metastases (log rank P=0.7565). Multivariate analysis in patients with a single BM showed that interval between primary diagnosis (PD) to BM, maximum size of metastasis, and histology (renal cell carcinoma and melanoma versus others) were independent prognostic factors influencing survival. Local control was obtained in 66/72 (92%) metastases. Actuarial local control at 24 months was 52%. Only age (<or=50 years vs >50 years) and histology (renal cell versus others) influenced local control in the univariate analysis in patients with a single BM. In multivariate analysis, size, histology (renal cell and melanoma versus others), activity of extracranial metastatic disease, age, interval from PD to BM and location (midline versus other) independently influenced local control, while the dose was not significant for our patient group. Only one patient developed radiographically suspected RS-induced necrosis after previous whole brain RT. CONCLUSION RS was effective and little toxic in BM. Identification of prognostic factors must be performed to gain knowledge on patients most likely to benefit from this procedure.

Retrospective Evaluation of Patients With Uveal Melanoma Treated by Stereotactic Radiosurgery With and Without Tumor Resection

IMPORTANCE The present study intended to analyze the suitability of single-dose stereotactic radiotherapy in the treatment of uveal melanoma that cannot be handled with ruthenium-brachytherapy and therefore is a challenge for ophthalmologists concerning local tumor control, as well as preservation of the eye and visual function. OBJECTIVES To evaluate local tumor control, eye preservation, visual course, radiation complications, metastases, and death after single-dose stereotactic radiotherapy (SDRT) applied exclusively or combined with tumor resection in uveal melanomas that are neither suitable nor favorably located for ruthenium brachytherapy. DESIGN Retrospective, observational case series. SETTING Primary care center. PARTICIPANTS Seventy-eight patients with uveal melanoma were treated. INTERVENTION Between June 3, 2003, and March 18, 2008, patients with uveal melanoma received SDRT monotherapy (group 1, 60 patients) or SDRT combined with tumor resection (group 2, 18 patients). Radiotherapy was performed with a tumor-surrounding dose of 25 Gy on a linear accelerator. MAIN OUTCOME MEASURES Local tumor control, eye preservation, visual results, and radiation complications. RESULTS Within a median follow-up of 33.7 months (range, 0.13-81.13 months), 6 recurrences occurred in group 1; none recurred in group 2. The Kaplan-Meier estimate for local control was 85% at 3 years in group 1 and 100% in group 2 (P = .22). Eye preservation rate was 77% vs 87% at 3 years (groups 1 and 2, respectively) (P = .82). Visual acuity decreased with a median loss of -18 Snellen lines (group 1) and -22 Snellen lines (group 2). More retinopathies (P = .07), opticopathies (P = .27), and rubeotic glaucomas (P = .10) occurred in group 1. No significant difference was observed in the development of metastases (P = .33). The groups differed in overall survival because of 2 deaths occurring shortly after surgery in group 2 for unexplained reasons (P = .06). CONCLUSIONS AND RELEVANCE Survival analysis suggested that SDRT with combined tumor resection might be associated with increased tumor control and fewer radiation complications than SDRT as monotherapy. Both groups had similar eye retention rates and were comparable concerning the decrease in visual function in most eyes. However, the protocol was stopped after 3 unexplainable deaths after surgery.

A new fixation aid for the radiotherapy of eye tumors.

A modified swim goggle holding a light spot as an optical guide for actively aligning the eye in a reproducible orientation has been constructed to perform radiotherapy of ocular tumors. This device is compatible with computed tomography (CT) and magnetic resonance imaging systems. Image fusion of these data sets yielded clinically acceptable results. The reproducibility of the eyes positioning is tested by repeated CT. The eyes alignment during radiotherapy is monitored by an infrared TV camera with individual markings of the eyes position on the TV-monitor screen. From 2003-2006, 50 patients were treated with this fixation aid by radiosurgery with good patient compliance.

A special radiation shielding for the radiotherapy of a pregnant patient

PURPOSE Measurement of the radiation dose of different radiotherapy techniques with a phantom at the position of the uterus of a pregnant patient with and without a special radiation shielding. MATERIAL AND METHODS A special radiation shielding for the radiation therapy of a pregnant patient was constructed in the shape of a tunnel over the abdomen from 1 cm thick lead to reduce scatter radiation to the uterus and the fetus therein. The reduction of the scatter radiation to the lower abdomen was measured for three typical cases (cerebrum with lateral opposed fields, 6-MV photons; tangential fields for mamma irradiation, 6 MV; and anteroposterior-posteroanterior [AP-PA] opposed fields of 15 MV for treatment of the mediastinum) at an anthropomorphic Alderson phantom with thermoluminescence dosimeters in different depths and with an ionization chamber positioned in an RW3 solid water phantom. In the case of lateral opposed fields, a movable lead wall was additionally positioned next to the accelerators head to reduce the scatter radiation from this source. RESULTS Depending on the geometry of the radiation fields and on the photon energy, a reduction of the dose to the lower abdomen averaged over the depths of 6, 9, and 12 cm from 16% (15 MV, mediastinum case) to 51% (6 MV, cerebrum with additional lead wall) was achieved. The absolute scattered dose with shielding in place for a 2-Gy fraction dose results to 3.85 mGy and 0.27 mGy, respectively. CONCLUSION National and international recommendations on the radiation dose to a fetus of a pregnant patient state limits of 200 mSv (DGMP report no. 7) and 100 mGy (ICRP 84), below which an abortion should not be considered and above which an indication for termination of the pregnancy could be given, respectively. The dose to the fetus can be kept below these limits with the shielding described in this work. Therefore, a radiation therapy of a pregnant patient is possible when these special precautions to reduce the scatter radiation to the fetus are met.Ziel:Messung der Strahlendosis mit einem Phantom am Ort des Uterus einer Schwangeren für verschiedene Bestrahlungstechniken mit und ohne Einsatz einer Spezialabschirmung.Material und Methodik:Zur Bestrahlung einer schwangeren Patientin wurde ein Tunnel aus 1 cm dickem Walzblei zur Reduktion der Streustrahlendosis auf den Unterleib konstruiert. Die Reduktion der Streustrahlendosis im Unterleib wurde für drei typische Bestrahlungssituationen (Cerebrum mit lateralen Gegenfeldern, 6-MV-Photonen; Mammatangente, 6 MV, mit Einsatz von motorischen Keilfeldern; Mediastinum mit anteroposterior-posteroanterioren [a.p.-p.a.] Gegenfeldern, 15 MV) an einem anthropomorphen Alderson-Phantom mittels Thermolumineszenzdosimetern in verschiedenen Tiefen bzw. mittels Ionisationskammer in einem Phantom aus RW3-Platten gemessen. Bei lateralen Gegenfeldern wurde eine fahrbare Bleiwand zur zusätzlichen Reduktion der Durchlassstrahlung des Beschleunigerkopfes eingesetzt.Ergebnisse:In Abhängigkeit von der Bestrahlungsgeometrie und Photonenenergie lässt sich eine Dosisreduktion der Streustrahlung im Unterleib über die Tiefen von 6, 9 und 12 cm gemittelt von 16% (15 MV, Mediastinum) bis 51% (6 MV, Cerebrum, zusätzliche Bleiwand) erreichen. Die absolute Dosis der Streustrahlung mit Abschirmung liegt dabei für eine Fraktionsdosis von 2 Gy über die verwendeten Tiefen gemittelt bei 3,85 mGy bzw. 0,27 mGy.Schlussfolgerung:Die in nationalen und internationalen Empfehlungen zur Dosisbelastung von Schwangeren und Feten genannten Richtwerte von 200 mSv (DGMP-Bericht Nr. 7) bzw. 100 mGy (ICRP 84), unterhalb deren ein Schwangerschaftsabbruch aufgrund der Bestrahlung nicht erwogen werden sollte bzw. ab denen eine Indikation nach individueller Dosisberechnung gestellt werden kann, können durch die Verwendung der hier vorgestellten Abschirmvorrichtungen unterschritten werden. Eine Bestrahlung von Schwangeren ist unter dem Gesichtspunkt der Strahlenbelastung daher bei entsprechenden besonderen Vorsorgemaßnahmen möglich.Purpose:Measurement of the radiation dose of different radiotherapy techniques with a phantom at the position of the uterus of a pregnant patient with and without a special radiation shielding.Material and Methods:A special radiation shielding for the radiation therapy of a pregnant patient was constructed in the shape of a tunnel over the abdomen from 1 cm thick lead to reduce scatter radiation to the uterus and the fetus therein. The reduction of the scatter radiation to the lower abdomen was measured for three typical cases (cerebrum with lateral opposed fields, 6-MV photons; tangential fields for mamma irradiation, 6 MV; and anteroposterior-posteroanterior [AP-PA] opposed fields of 15 MV for treatment of the mediastinum) at an anthropomorphic Alderson phantom with thermoluminescence dosimeters in different depths and with an ionization chamber positioned in an RW3 solid water phantom. In the case of lateral opposed fields, a movable lead wall was additionally positioned next to the accelerators head to reduce the scatter radiation from this source.Results:Depending on the geometry of the radiation fields and on the photon energy, a reduction of the dose to the lower abdomen averaged over the depths of 6, 9, and 12 cm from 16% (15 MV, mediastinum case) to 51% (6 MV, cerebrum with additional lead wall) was achieved. The absolute scattered dose with shielding in place for a 2-Gy fraction dose results to 3.85 mGy and 0.27 mGy, respectively.Conclusion:National and international recommendations on the radiation dose to a fetus of a pregnant patient state limits of 200 mSv (DGMP report no. 7) and 100 mGy (ICRP 84), below which an abortion should not be considered and above which an anzuindication for termination of the pregnancy could be given, respectively. The dose to the fetus can be kept below these limits with the shielding described in this work. Therefore, a radiation therapy of a pregnant patient is possible when these special precautions to reduce the scatter radiation to the fetus are met.

Eine Spezialabschirmung für die Strahlentherapie von Schwangeren

PURPOSE Measurement of the radiation dose of different radiotherapy techniques with a phantom at the position of the uterus of a pregnant patient with and without a special radiation shielding. MATERIAL AND METHODS A special radiation shielding for the radiation therapy of a pregnant patient was constructed in the shape of a tunnel over the abdomen from 1 cm thick lead to reduce scatter radiation to the uterus and the fetus therein. The reduction of the scatter radiation to the lower abdomen was measured for three typical cases (cerebrum with lateral opposed fields, 6-MV photons; tangential fields for mamma irradiation, 6 MV; and anteroposterior-posteroanterior [AP-PA] opposed fields of 15 MV for treatment of the mediastinum) at an anthropomorphic Alderson phantom with thermoluminescence dosimeters in different depths and with an ionization chamber positioned in an RW3 solid water phantom. In the case of lateral opposed fields, a movable lead wall was additionally positioned next to the accelerators head to reduce the scatter radiation from this source. RESULTS Depending on the geometry of the radiation fields and on the photon energy, a reduction of the dose to the lower abdomen averaged over the depths of 6, 9, and 12 cm from 16% (15 MV, mediastinum case) to 51% (6 MV, cerebrum with additional lead wall) was achieved. The absolute scattered dose with shielding in place for a 2-Gy fraction dose results to 3.85 mGy and 0.27 mGy, respectively. CONCLUSION National and international recommendations on the radiation dose to a fetus of a pregnant patient state limits of 200 mSv (DGMP report no. 7) and 100 mGy (ICRP 84), below which an abortion should not be considered and above which an indication for termination of the pregnancy could be given, respectively. The dose to the fetus can be kept below these limits with the shielding described in this work. Therefore, a radiation therapy of a pregnant patient is possible when these special precautions to reduce the scatter radiation to the fetus are met.Ziel:Messung der Strahlendosis mit einem Phantom am Ort des Uterus einer Schwangeren für verschiedene Bestrahlungstechniken mit und ohne Einsatz einer Spezialabschirmung.Material und Methodik:Zur Bestrahlung einer schwangeren Patientin wurde ein Tunnel aus 1 cm dickem Walzblei zur Reduktion der Streustrahlendosis auf den Unterleib konstruiert. Die Reduktion der Streustrahlendosis im Unterleib wurde für drei typische Bestrahlungssituationen (Cerebrum mit lateralen Gegenfeldern, 6-MV-Photonen; Mammatangente, 6 MV, mit Einsatz von motorischen Keilfeldern; Mediastinum mit anteroposterior-posteroanterioren [a.p.-p.a.] Gegenfeldern, 15 MV) an einem anthropomorphen Alderson-Phantom mittels Thermolumineszenzdosimetern in verschiedenen Tiefen bzw. mittels Ionisationskammer in einem Phantom aus RW3-Platten gemessen. Bei lateralen Gegenfeldern wurde eine fahrbare Bleiwand zur zusätzlichen Reduktion der Durchlassstrahlung des Beschleunigerkopfes eingesetzt.Ergebnisse:In Abhängigkeit von der Bestrahlungsgeometrie und Photonenenergie lässt sich eine Dosisreduktion der Streustrahlung im Unterleib über die Tiefen von 6, 9 und 12 cm gemittelt von 16% (15 MV, Mediastinum) bis 51% (6 MV, Cerebrum, zusätzliche Bleiwand) erreichen. Die absolute Dosis der Streustrahlung mit Abschirmung liegt dabei für eine Fraktionsdosis von 2 Gy über die verwendeten Tiefen gemittelt bei 3,85 mGy bzw. 0,27 mGy.Schlussfolgerung:Die in nationalen und internationalen Empfehlungen zur Dosisbelastung von Schwangeren und Feten genannten Richtwerte von 200 mSv (DGMP-Bericht Nr. 7) bzw. 100 mGy (ICRP 84), unterhalb deren ein Schwangerschaftsabbruch aufgrund der Bestrahlung nicht erwogen werden sollte bzw. ab denen eine Indikation nach individueller Dosisberechnung gestellt werden kann, können durch die Verwendung der hier vorgestellten Abschirmvorrichtungen unterschritten werden. Eine Bestrahlung von Schwangeren ist unter dem Gesichtspunkt der Strahlenbelastung daher bei entsprechenden besonderen Vorsorgemaßnahmen möglich.Purpose:Measurement of the radiation dose of different radiotherapy techniques with a phantom at the position of the uterus of a pregnant patient with and without a special radiation shielding.Material and Methods:A special radiation shielding for the radiation therapy of a pregnant patient was constructed in the shape of a tunnel over the abdomen from 1 cm thick lead to reduce scatter radiation to the uterus and the fetus therein. The reduction of the scatter radiation to the lower abdomen was measured for three typical cases (cerebrum with lateral opposed fields, 6-MV photons; tangential fields for mamma irradiation, 6 MV; and anteroposterior-posteroanterior [AP-PA] opposed fields of 15 MV for treatment of the mediastinum) at an anthropomorphic Alderson phantom with thermoluminescence dosimeters in different depths and with an ionization chamber positioned in an RW3 solid water phantom. In the case of lateral opposed fields, a movable lead wall was additionally positioned next to the accelerators head to reduce the scatter radiation from this source.Results:Depending on the geometry of the radiation fields and on the photon energy, a reduction of the dose to the lower abdomen averaged over the depths of 6, 9, and 12 cm from 16% (15 MV, mediastinum case) to 51% (6 MV, cerebrum with additional lead wall) was achieved. The absolute scattered dose with shielding in place for a 2-Gy fraction dose results to 3.85 mGy and 0.27 mGy, respectively.Conclusion:National and international recommendations on the radiation dose to a fetus of a pregnant patient state limits of 200 mSv (DGMP report no. 7) and 100 mGy (ICRP 84), below which an abortion should not be considered and above which an anzuindication for termination of the pregnancy could be given, respectively. The dose to the fetus can be kept below these limits with the shielding described in this work. Therefore, a radiation therapy of a pregnant patient is possible when these special precautions to reduce the scatter radiation to the fetus are met.

Stereotactic Radiation Therapy in Primary Optic Nerve Sheath Meningioma

SFRT is an interesting treatment approach of patients with pONSM which combines advantages of stereotaxy and fractionation. Several institutions used SFRT in patients with progressive visual loss to achieve impressive improvements in both visual fields and visual acuity using relatively modest doses of irradiation (mostly 45–54 Gy, using 1.8- to 2.0-Gy daily fractionation). Excellent visual outcome was almost always accompanied by low toxicity and low tumour reduction on follow-up imaging. Owing to these results, SFRT can be suggested as the new standard treatment approach in patients with pONSM and progressive visual loss.

Cyclo-oxygenase-2 expression in photon-radiated and non-radiated uveal melanomas

Purpose:  To determine and compare cyclo‐oxygenase‐2 (COX‐2) expression in photon‐radiated and non‐radiated malignant uveal melanomas and to analyse the correlation between COX‐2 expression and prognosis.

Automated Analysis of Film Checks for QA of Stereotactic Treatment Setup

Stereotactic radiotherapy with high doses per treatment strongly depends among other factors on the mechanical accuracy of the setup of the patient at the linear accelerator. A commonly used quality assurance tool for radiosurgery with circular collimators is a film check introduced by Winston and Lutz [1] to evaluate the positional accuracy of the gantry and couch rotation around a radiopaque target ball that is positioned in the isocenter by means of the stereotactic setup. There are different manual methods to determine the shift between the center of the exposures of the circular collimator and the sometimes hardly recognizable target ball on the film that naturally depend on the individual skills of the analyzing person to estimate the appropriate centers. Since stereotactic radiotherapy as well as radiosurgery steadily gain importance in cancer treatment, an automated tool to speed up and standardize the analysis of Winston-Lutz film QA checks would be very helpful.