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Purpose Risk management (RM) is a key component of patient safety in radiation oncology (RO). We investigated current approaches on RM in German RO within the framework of the Patient Safety in German Radiation Oncology (PaSaGeRO) project. Aim was not only to evaluate a status quo of RM purposes but furthermore to discover challenges for sustainable RM that should be addressed in future research and recommendations. Methods An online survey was conducted from June to August 2021, consisting of 18 items on prospective and reactive RM, protagonists of RM, and self-assessment concerning RM. The survey was designed using LimeSurvey and invitations were sent by e‑mail. Answers were requested once per institution. Results In all, 48 completed questionnaires from university hospitals, general and non-academic hospitals, and private practices were received and considered for evaluation. Prospective and reactive RM was commonly conducted within interprofessional teams; 88% of all institutions performed prospective risk analyses. Most institutions (71%) reported incidents or near-events using multiple reporting systems. Results were presented to the team in 71% for prospective analyses and 85% for analyses of incidents. Risk conferences take place in 46% of institutions. 42% nominated a manager/committee for RM. Knowledge concerning RM was mostly rated “satisfying” (44%). However, 65% of all institutions require more information about RM by professional societies. Conclusion Our results revealed heterogeneous patterns of RM in RO departments, although most departments adhered to common recommendations. Identified mismatches between recommendations and implementation of RM provide baseline data for future research and support definition of teaching content.

To evaluate radiation exposure and image quality in thoracic computed tomography (CT) using a new dose-saving algorithm to protect radiosensitive organs.For dose measurements, an Alderson RANDO phantom equipped with thermoluminescent dosimeters was used. The effective dose was calculated according to the International Commission on Radiologic Protection 103. Exposure was performed on a second-generation dual-source CT. The following parameters for thoracic CT were used: 160 effective mAs, 120 kV, scan range of 30 cm, collimation of 128 × 0.6 mm. For the acquisition, the tube current modulation type XCare was used, which reduces the tube current for anterior tube position to minimize direct exposure to anterior located organs. To compare differences, scans with and without XCare were performed. Objective signal-to-noise measurements were evaluated, and the subjective noise perception was rated in a 3-point scale (1: excellent, 3: affecting diagnostic accuracy) in 30 patients with a standard thoracic examination and a follow-up using XCare.A substantial dose reduction in radiosensitive tissues was evident using the dose-saving algorithm XCare. Specifically, reductions of 35.2% for the female breast and 20.1% for the thyroid gland were measured, resulting in a decreasing effective whole-body dose of 8.0% and 14.3% for males and females, respectively. The objective and subjective evaluation of image quality showed no significant differences between both scan protocols (P0.05). Mean signal-to-noise ratio was 1.3 ± 0.2 and 1.2 ± 0.2 in scan protocols without and with XCare, respectively. The subjective scores at the level of the pulmonary trunk were 1.2 ± 0.4 and 1.4 ± 0.5 in standard chest scan and scans with the dose-saving algorithm XCare, respectively.The XCare technique protects radiosensitive organs like the female breast and the thyroid gland without affecting image quality. Therefore, this dose-saving algorithm may be used in thoracic CT examinations in male and female patients.

Background CT has become an important role in the differential diagnosis of acute chest pain to exclude an aortic dissection, pulmonary embolism and acute coronary artery syndrome. However, the additional radiation exposure is a cause of concern and dose saving strategies should be applied, if possible. Purpose To estimate effective dose of retrospective gated and prospective ECG-triggered triple-rule-out computed tomography angiography (TRO-CTA). Material and Methods An Alderson-Rando-phantom equipped with thermoluminescent dosimeters was used for dose measurements. Exposure was performed on a 128-slice single source scanner. The following scan parameters were used (retrospective ECG-gated): 120 kV, 190 mAs/rot., collimation 128x0.6 mm, rotation time 0.3 s. Protocols with a simulated heart rate (HR) of 60 and 100 bpm were performed using the standard ECG-pulsing as well as MinDose. Additionally, a prospective triggered TRO-CTA was acquired (HR 60 bpm). Results The estimated effective dose of retrospective ECG-gated TRO-CTA ranged from 7.4–13.4 mSv and from 10.1–17.5 mSv for men and women, respectively. Due to radiosensitive breast tissue, women received a significant increased effective dose of up to 64.7% ± 0.03% (p = 0.028) compared to men. MinDose reduces radiation exposure of up to 33.0% ± 6.5% in comparison to standard ECG-pulsing (p < 0.001). The effective dose increased significantly with lower heart rates (p < 0.001). Prospective ECG-triggered TRO-CTA showed an effective dose of 5.9 mSv and 8.2 mSv for men and women, respectively. Compared to retrospective ECG-gated TRO-CTA a significant dose reduction was observed (p < 0.001). Conclusion Due to the significant different dose exposure, scan protocols should be specifically adapted in a patient- and problem-oriented manner.

Introduction Risks are naturally also present in radiotherapy, where the patient is subject of the application of high doses of ionizing radiation. For the case of radiotherapy already exist extensive quality assurance procedures that have been developed for the imaging and treatment equipment and software involved. Nevertheless, all quality assurance measures on e.g. the dose applied focuses only on the technical side of the risk linked to the administration of radiation. The personal operating these machines or software follow usually organized procedures and are faced by the workload given in relation to the workforce provided by the institution. Actions and decisions are taken, that may impose also risks to patients not covered by the above mentioned quality assurance systems of the machines. The goal of risk analysis in radiotherapy is to reduce all possible kind of risks linked to patients during their treatment, but this is also part of the risk management which seeks to continuously improve the quality of the treatment and safety of the patient. Additionally, this includes also the prevention of the institution as well as the people working there from unjustified claims of patients. This is of economical value to the institution as insurance premiums are calculated according the level of risk of insurance claims. Materials and Methods The risk analysis is usually following the proactive method of “healthcare failure mode and error analysis” (hFMEA) [1] . This starts with the identification of possible sources of risks in all procedures involved. This is best done by a internal team of experts from the institution itself knowing all related facts, that is accompanied by an external expert for risk analysis. Risks are then categorised according their potential frequency of occurrence, detectability and severity of consequences in form of a risk or hazard scoring matrix, where scoring values can be used to classify the associated risk. From this risk matrix priorities have to be set for measures to control and reduce these risks if possible. Practical examples of risk analysis in radiotherapy are used to illustrate this procedure.

Medical Physics can be taught to a variety of audiences: medical physics students, physicians, technical assistants, nurses and maybe also to the interested public. Teaching in the past and maybe still today uses often a lecture style: one is speaking, using the black board or Powerpoint presentations, all others are listening, trying to follow. Modern educational methods employ audience activating methods to pick up the individuals at their starting knowledge level and get them practically involved with the subject. Therefore, it is important to evaluate the starting knowledge of the participants and to adjust the course for the persons present accordingly. This can be done by anonymous introductory written tests or online feedback tools. Besides providing basic theoretical input at the start, by experience the intended subjects are best taught in a problem based style. This means to give one or a set of problems to individuals and groups formed from audience present. This can be done e.g. with the help of an online questionnaire in learning management systems like moodle to optimize the mixture of group members for best peer interaction. It is now the discussion within the groups, that get them actively in touch with the subject on way to the solution. It is no longer having all eyes watching one person, but have this person watch and accompany all other persons present on their way of discovering steps to one or more solutions of the problem given. Naturally, for this purpose they use information from the internet as well as one would do in real live, too. This can even be done in a competitive manner to enhance the emotional level of involvement. It is now the task of the teacher to provide basic knowledge, guide to good sources of information and to come up with appropriate problems and tasks. To facilitate this, a network of interested teachers in Medical Physics could exchange their set of concepts as “open educational resources” (OER) as well as collections of slides, images, graphs, animations and videos produced under GPL licence under the coordination of the EFOMP Education and Training Committee.

Objective: We aimed to estimate the effective dose of 4D-Perfusion-CT proto-cols of the lung, liver, and pelvis for the assessment of tumor vascularity.Materials and Methods: An Alderson-Rando phantom equipped with thermo-luminescent dosimeters was used to determine the effective dose values of 4D-Perfusion-CT. Phantom measurements were performed on a 128-slice single-source scanner in adaptive 4D-spiral-mode with bidirectional table movementand a total scan range of 69 mm over a time period of nearly 120 seconds (26scans). Perfusion measurements were simulated for the lung, liver, and pelvisunder the following conditions: lung (80 kV, 60 mAs), liver (80 kV/80 mAs and 80kV/120 mAs), pelvis (100 kV/80 mAs and 100 kV/120 mAs).Results: Depending on gender, the evaluated body region and scan protocol,an effective whole-body dose between 2.9 -12.2 mSv, was determined. The radi-ation exposure administered to gender-specific organs like the female breast tis-sue (lung perfusion) or to the ovaries (pelvic perfusion) led to an increase in thefemale specific dose by 86% and 100% in perfusion scans of the lung and thepelvis, respectively. Conclusion: Due to a significant radiation dose of 4D-perfusion-CT protocols,the responsible use of this new promising technique is mandatory. Gender- andorgan-specific differences should be considered for indication and planning oftumor perfusion scans. erfusion CT was introduced several years ago as an adjunct to morpho-logical imaging in tumor patients. Considering tumor perfusion as an

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. Methods: Immunohistochemical staining for COX-2 was performed on 21 uveal melanomas that were endoresected after prior stereotactic radiotherapy with photons and on 22 tumours that were treated by endoresection without prior radiotherapy. COX-2 staining was further analysed in respect to cell type, maximal prominence, time interval between radiotherapy and surgery, apoptotic index (AI), proliferative index (PI) and the development of metastatic disease. Results: There was no difference in COX-2 expression between radiated and non-radiated melanomas (P > 0.15). COX-2 staining correlated with neither the tumour prominence (P > 0.40) nor the AI or the PI (both P > 0.35). Tumours with high COX-2 expression were significantly more likely to develop metastasis (P = 0.022). Conclusion: Radiotherapy with photons does not induce COX-2 expression in malignant melanomas of the uvea. But high COX-2 expression may be a marker for poor prognosis.

Messung der Strahlendosis mit einem Phantom am Ort des Uterus einer Schwangeren fur verschiedene Bestrahlungstechniken mit und ohne Einsatz einer Spezialabschirmung. 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 fur 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 zusatzlichen Reduktion der Durchlassstrahlung des Beschleunigerkopfes eingesetzt. In Abhangigkeit von der Bestrahlungsgeometrie und Photonenenergie lasst sich eine Dosisreduktion der Streustrahlung im Unterleib uber die Tiefen von 6, 9 und 12 cm gemittelt von 16% (15 MV, Mediastinum) bis 51% (6 MV, Cerebrum, zusatzliche Bleiwand) erreichen. Die absolute Dosis der Streustrahlung mit Abschirmung liegt dabei fur eine Fraktionsdosis von 2 Gy uber die verwendeten Tiefen gemittelt bei 3,85 mGy bzw. 0,27 mGy. 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, konnen durch die Verwendung der hier vorgestellten Abschirmvorrichtungen unterschritten werden. Eine Bestrahlung von Schwangeren ist unter dem Gesichtspunkt der Strahlenbelastung daher bei entsprechenden besonderen Vorsorgemasnahmen moglich.

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 eye's positioning is tested by repeated CT. The eye's alignment during radiotherapy is monitored by an infrared TV camera with individual markings of the eye's position on the TV-monitor screen. From 2003-2006, 50 patients were treated with this fixation aid by radiosurgery with good patient compliance.

The radiation exposure of four different 64-slice MDCT-colonography (CTC) protocols was evaluated using an Alderson-Rando phantom. Protocols using 30 mAs (collimation 20 × 1.2mm), 50 mAs (collimation 20 × 1.2 and 64 × 0.6mm) and 80 mAs (20 × 1.2 mm) representing screening low-dose, routine, narrow collimation and oncologic staging setups were measured with an Alderson-Rando phantom (Alderson Research Laboratories Inc.). Scans were performed on a 64-row MDCT (SOMATOM Sensation 64, Siemens) simulating the prone and supine positions with a constant voltage of 120 kV. Dose values (male/female) were 2.5/2.9, 3.8/4.2, 4.2/4.5 and 5.7/6.4 mSv for 30, 50 (20 × 1.2 and 64 × 0.6 mm) and 80 mAs, respectively. Measurements showed an elevated dose for females (11.5% mean; compared to males). Use of narrow collimation combined with 50 mAs resulted in a small increase of dose exposure of 10.5 (male) and 7.1% (female). Gonad doses ranged from 0.9 to 2.6 mSv (male) and from 1.5 to 3.5 mSv (female). In all protocols, the stomach wall, lower colon, urinary bladder and liver were slightly more highly exposed (all

The present paper presents the results of a survey on radiotherapy-treatment planning systems conducted in the summer of 2000. A total of 263 questionnaires of 108 German, 6 Austrian, and 4 Swiss radiotherapy clinics or practices have been evaluated. Most treatment planning systems are used for teletherapy, with nearly all sites using at least one commercial system. The planning systems are mostly networked with CT, partially also with MRI, simulator and R&V systems of the treatment equipment. For brachytherapy planning, usually orthogonal X-ray images are used, but some systems allow already the use of CT data as well. Stereotactic planning dominates the specialized treatment planning, followed by total body irradiation techniques. Commercial systems are well established for stereotactic planning systems, whereas in-house systems are still predominant for total body irradiation. In-house systems predominate also in the case of simple treatment planning systems and plausibility check programs. These simpler dose-calculation programs usually offer variable degrees of correction options.

Purpose: To assess the accuracy of field alignment in patients undergoing three-dimensional (3D) conformal radiotherapy of brain tumors, and to evaluate the impact on the definition of planning target volume and control procedures. Methods and Materials: Geometric accuracy was analyzed in 20 patients undergoing fractionated stereotactic conformal radiotherapy for brain tumors. Rigid head fixation was achieved by using cast material. Transfer of stereotactic coordinates was performed by an external positioning device. The accuracy during treatment planning was quantitatively assessed by using repeated computed tomography (CT) examinations in treatment position (reproducibility of isocenter). Linear discrepancies were measured between treatment plan and CT examination. In addition, for each patient, a series of 20 verifications were taken in orthogonal projections. Linear discrepancies were measured between first and all subsequent verifications (accuracy during treatment delivery). Results: For the total group of patients, the distribution of deviations during treatment setup showed mean values between −0.3–1.2 mm, with standard deviations (SD) of 1.3–2.0 mm. During treatment delivery, the distribution of deviations revealed mean values between 0.7–0.8 mm, with SDs of 0.5–0.6 mm, respectively. For all patients, deviations for the transition to the treatment machine were similar to deviations during subsequent treatment delivery, with 95% of all absolute deviations between less than 2.8 and 4.6 mm. Conclusion: Random fluctuations of field displacements during treatment planning and delivery prevail. Therefore, our quantitative data should be considered when prescribing the safety margins of the planning target volume. Repeated CT examination are useful to detect operator errors and large random or systematic deviations before start of treatment. Control procedures during treatment delivery appear to be of limited importance. In addition, our findings should help to determine “cut-off points” for corrective actions in stereotactic conformal radiotherapy of brain tumors.

Purpose. To estimate effective dose and organ equivalent doses of prospective ECG-triggered high-pitch CTCA.Materials and Methods. For dose measurements, an Alderson-Rando phantom equipped with thermoluminescent dosimeters was used. The effective dose was calculated according to ICRP 103. Exposure was performed on a second-generation dual-source scanner (SOMATOM Definition Flash, Siemens Medical Solutions, Germany). The following scan parameters were used: 320 mAs per rotation, 100 and 120 kV, pitch 3.4 for prospectively ECG-triggered high-pitch CTCA, scan range of 13.5 cm, collimation mm with z-flying focal spot, gantry rotation time 280 ms, and simulated heart rate of 60 beats per minute.Results. Depending on the applied tube potential, the effective whole-body dose of the cardiac scan ranged from 1.1 mSv to 1.6 mSv and from 1.2 to 1.8 mSv for males and females, respectively. The radiosensitive breast tissue in the range of the primary beam caused an increased female-specific effective dose of % compared to males. Decreasing the tube potential, a significant reduction of the effective dose of 35.8% and 36.0% can be achieved for males and females, respectively ().Conclusion. The radiologist and the CT technician should be aware of this new dose-saving strategy to keep the radiation exposure as low as reasonablly achievable.

We evaluated two mobile cone beam computed tomographs (mCBCT) comparing image quality with respect to radiation dosage. Image quality was analyzed by using different scanning modes.The skulls of three human cadavers were scanned by use of conventional Computed Tomography (CT) as well as with two mobile cone beam computed tomographs (Siemens Arcadis Orbic 3D and Ziehm Vision Vario 3D). Six different acquisition modes with different radiation dosages were used. The axial views of all scans were evaluated by five medical doctors regarding image quality by identifying predefined anatomical structures of the skull. A five-point ranking scale was used. The inter-rater reliability was statistically depicted by Cohen's Kappa coefficient. A Wilcoxon signed rank test was used to evaluate the rater's results. For evaluating the signal-to-noise ratio (SNR) a Catphan 600 reference body with two different inlays was used.Comparing the mCBCTs, the image quality of the Siemens Arcadis Orbic 3D in high-dosage mode received the best score (median: 2.27). The inter-rater reliability was fair (Kappa=-0.030 to 0.328). The Wilcoxon test showed significant (p0.05) different median rating values in 18 out of 21 imaging modes. The SNR was higher (better) in the high-dosage modes.Intra-operative 3D imaging by using mCBCT for maxillofacial surgery in low-dose mode acquisition is adequate in terms of signal-to-noise ratio and image quality. The image quality does not correlate in a linear manner with a higher radiation dosage. Surgeons using this technique should gather their own experience with the different acquisition modes.

Purpose To estimate the effective dose of prospectively triggered computed tomography coronary angiography (CTCA) in step-and-shoot (SAS) mode, depending on the tube current and tube voltage modulation. Materials and methods For dose measurements, an Alderson-Rando-phantom equipped with thermoluminescent dosimeters was used. The effective dose was calculated according to ICRP 103. Exposure was performed on a 128-slice single source scanner providing a collimation of 128 × 0.6 mm and a rotation time of 0.38 seconds. CTCA in the SAS mode was acquired with variation of the tube current (160, 240, 320 mAs) and tube voltage (100, 120, 140 kV) at a simulated heart rate of 60 beats per minute and a scan range of 13.5 cm. Results Depending on gender, tube current and tube voltage, the effective dose of a CTCA in SAS mode varies from 2.8 to 10.8 mSv. Due to breast tissue in the primary scan range, exposure in the case of females showed an increase of up to 60.0 ± .4% compared to males. The dose reduction achieved by a reduction of tube current showed a significant positive, linear correlation to effective dose with a possible decrease in the effective dose of up to 60.4% (r = 0.998; p = 0.044). Disproportionately high, the estimated effective dose can be reduced by using a lower tube voltage with a dose reduction of up to 52.4%. Conclusion Further substantial dose reduction of low-dose CTCA in SAS mode can be achieved by adapting the tube current and tube voltage and should be implemented in the clinical routine, i. e. adapting those protocol parameters to patient body weight.

Purpose To estimate the effective dose of cardiac CT with different dose saving strategies dependent on varying heart rates. Materials and methods For dose measurements, an Alderson-Rando-phantom equipped with thermoluminescent dosimeters was used. The effective dose was calculated according to ICRP 103. Exposure was performed on a 128-slice single source scanner providing a rotation time of 0.30 s and standard protocols with 120 kV and 160 mA s/rot. Protocols were evaluated without ECG-pulsing, with two different ECG-pulsing techniques, and automated exposure control with a simulated heart rate of 60 and 100 beats per minute. Results Depending on different dose saving techniques and heart rate, the effective whole-body dose of a cardiac scan ranged from 2.8 to 9.5 mSv and from 4.3 to 16.0 mSv for males and females, respectively. The radiation-sensitive breast tissue in the primary scan range results in an increased female dose of 66.7 ± 6.0%. Prospective triggering has the greatest potential to reduce the effective dose to 27.8%, compared to a comparable scan protocol with retrospective ECG-triggering with no ECG-pulsing. Furthermore, the heart rate influences the radiation exposure by increasing significantly at lower heart rates. Conclusion Due to this broad variability in radiation exposure of a cardiac CT, the radiologist and the CT technician should be aware of the different dose reduction strategies.

The aim of the study was to estimate radiation exposure of coronary calcium scoring and angiography using ECG-gated and ECG-triggered dual-source computed tomography.An Alderson Rando phantom equipped with thermoluminescent dosimeters was used for all dose measurements. Effective dose was calculated according to ICRP 103. Radiation exposure was performed on a dual-source computed tomography (DSCT) scanner with standard protocols for calcium scoring (DSCT-Ca) and coronary angiography (DSCTA) at different heart rates (40-100 beats/min). Furthermore, a scanning protocol with ECG-triggering as well as a standard chest CT scan were evaluated.Depending on gender, heart rate and ECG-pulsing, the effective dose of a complete cardiac DSCT (DSCT-Ca and DSCTA) scan varies from 10.2 to 32.6mSv. The effective radiation dose increased significantly with lower heart rates (p0.035). ECG-pulsing reduced the radiation exposure significantly in DSCTA (p0.001). Due to breast tissue in the primary scan range, females' doses showed an increase up to 69.9% compared to males in scan protocols without ECG-pulsing. Prospective ECG-triggered DSCTA resulted in estimated effective doses from 2.8mSv (males) to 4.1mSv (females).The ECG-pulsing technique has proven its effectiveness to reduce effective dose in coronary CT angiography and is recommended for all patients with regular heart rates. The patient's heart rate influences the radiation exposure with a significant decrease at higher heart rates. Due to its lower dose, ECG-triggered DSCTA should be implemented for special indications, i.e. for diagnosis of pathologies of the aortic root and the ascending aorta.

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.

The efficiency and radiation dose of a low-dose dual-energy (DE) CT protocol for the evaluation of urinary calculus disease were evaluated. A low-dose dual-source DE-CT renal calculi protocol (140 kV, 46 mAs; 80 kV, 210 mAs) was derived from the single-energy (SE) CT protocol used in our institution for the detection of renal calculi (120 kV, 75 mAs). An Alderson-Rando phantom was equipped with thermoluminescence dosimeters and examined by CT with both protocols. The effective doses were calculated. Fifty-one patients with suspected or known urinary calculus disease underwent DE-CT. DE analysis was performed if calculi were detected using a dedicated software tool. Results were compared to chemical analysis after invasive calculus extraction. An effective dose of 3.43 mSv (male) and 5.30 mSv (female) was measured in the phantom for the DE protocol (vs. 3.17/4.57 mSv for the SE protocol). Urinary calculi were found in 34 patients; in 28 patients, calculi were removed and analyzed (23 patients with calcified calculi, three with uric acid calculi, one with 2,8-dihyxdroxyadenine-calculi, one patient with a mixed struvite calculus). DE analysis was able to distinguish between calcified and non-calcified calculi in all cases. In conclusion, dual-energy urinary calculus analysis is effective also with a low-dose protocol. The protocol tested in this study reliably identified calcified urinary calculi in vivo.

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 eye's positioning is tested by repeated CT. The eye's alignment during radiotherapy is monitored by an infrared TV camera with individual markings of the eye's position on the TV-monitor screen. From 2003-2006, 50 patients were treated with this fixation aid by radiosurgery with good patient compliance.

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.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 accelerator's head to reduce the scatter radiation from this source.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.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.

Purpose We sought to evaluate the radiation exposure of cardiac CT scans with 16-row multidetector computed tomography (MDCT). Additionally the possibility of dose reduction by using a ECG-controlled tube current modulation technique was evaluated. Methods and material An Alderson Rando phantom equipped with thermoluminescent dosimeters was used for dose measurements. Effective dose was calculated according to ICRP 60. Exposure was performed on a 16-row MDCT scanner with standard protocols for CT coronary calcium scoring (120 kV, 133 mAs, 12 x 1.5 mm) and CT coronary angiography (120 kV, 400 mAs, 12 x 0.75 mm). Exposure was repeated at a simulated heart rate of 60 bpm with ECG-pulsed tube current modulation. Results Effective dose was 2.9 mSv (male) and 3.6 mSv (female) for the calcium scoring protocol. CT coronary angiography resulted in an effective dose of 8.1 mSv (male) and 10.9 mSv (female). Using ECG-pulsed tube current modulation radiation exposure can significant reduced: by 46 % (1.6 mSv) in calcium scoring and by 47 % (4.3 mSv) in CT coronary angiography. Conclusion MDCT of the heart shows a significant radiation exposure, which can significantly be reduced by ECG-pulsed tube current modulation. Radiation exposure of cardiac MDCT is comparable to CT-examinations of chest or abdomen, but seem to be slightly higher compared to conventional coronary angiography.

Purpose: To evaluate the effectiveness of stereotactic fractionated radiotherapy (SFRT) in the treatment of optic nerve sheath meningioma (ONSM). Methods and Materials: 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.

The present paper presents the results of a survey on radiotherapy-treatment planning systems conducted in the summer of 2000. A total of 263 questionnaires of 108 German, 6 Austrian, and 4 Swiss radiotherapy clinics or practices have been evaluated. Most treatment planning systems are used for teletherapy, with nearly all sites using at least one commercial system. The planning systems are mostly networked with CT, partially also with MRI, simulator and RV systems of the treatment equipment. For brachytherapy planning, usually orthogonal X-ray images are used, but some systems allow already the use of CT data as well. Stereotactic planning dominates the specialized treatment planning, followed by total body irradiation techniques. Commercial systems are well established for stereotactic planning systems, whereas in-house systems are still predominant for total body irradiation. In-house systems predominate also in the case of simple treatment planning systems and plausibility check programs. These simpler dose-calculation programs usually offer variable degrees of correction options.

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 (≤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.

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.

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.