Risk of cancer incidence before the age of 15 years after exposure to ionising radiation from computed tomography: results from a German cohort study.

The aim of this cohort study was to assess the risk of developing cancer, specifically leukaemia, tumours of the central nervous system and lymphoma, before the age of 15 years in children previously exposed to computed tomography (CT) in Germany. Data for children with at least one CT between 1980 and 2010 were abstracted from 20 hospitals. Cancer cases occurring between 1980 and 2010 were identified by stochastic linkage with the German Childhood Cancer Registry (GCCR). For all cases and a sample of non-cases, radiology reports were reviewed to assess the underlying medical conditions at time of the CT. Cases were only included if diagnosis occurred at least 2 years after the first CT and no signs of cancer were recorded in the radiology reports. Standardised incidence ratios (SIR) using incidence rates from the general population were estimated. The cohort included information on 71,073 CT examinations in 44,584 children contributing 161,407 person-years at risk with 46 cases initially identified through linkage with the GCCR. Seven cases had to be excluded due to signs possibly suggestive of cancer at the time of first CT. Overall, more cancer cases were observed (O) than expected (E), but this was mainly driven by unexpected and possibly biased results for lymphomas. For leukaemia, the SIR (SIR = O/E) was 1.72 (95 % CI 0.89-3.01, O = 12), and for CNS tumours, the SIR was 1.35 (95 % CI 0.54-2.78, O = 7). Despite careful examination of the medical information, confounding by indication or reverse causation cannot be ruled out completely and may explain parts of the excess. Furthermore, the CT exposure may have been underestimated as only data from the participating clinics were available. This should be taken into account when interpreting risk estimates.

[Radiology and pregnancy : Part 2: clinical recommendations]. / Radiologie und Schwangerschaft : Teil 2: Klinische Empfehlungen.

In spite of a growing number of radiological scans in pregnant women there is still a high level of uncertainty concerning radiation exposure to the fetus. At the same time, the risk of fetal radiation injury is frequently overestimated. This entails an avoidable fear in the pregnant patient and may delay urgently required imaging and thus lead to an increased risk for maternal and fetal health. As a consequence, radiological scans in pregnant patients do not only require a thorough medical check but also a careful estimate of the specific radiation exposure to the fetus. The previous first part of the article described the legal requirements in Germany, the technical exposure and pharmacological risks for the pregnant woman and the fetus. The current second article focuses on the risk analysis for examinations with ionizing radiation and will provide recommendations for typical indications for maternal and fetal imaging.

[Current requirements for image management in radiotherapy]. / Aktuelle Anforderungen an das Bildmanagement in der Strahlentherapie.

AIMS AND METHODS: Treatment techniques of increasing complexity such as dynamic/rotational techniques mandate digital management and increasingly image guidance. This constantly increases requirements for image management and archiving. This article discusses the current status of these requirements and will present potential image administration strategies. RESULTS: Fundamentals of image administration and storage/archiving are presented (DICOM Standard, radiotherapy-specific issues) along the typical patient pathway (demographic data, radiotherapy treatment planning, signatures/approval of plan and image data, archiving of plan and image data). Different strategies for image management are presented (archiving centered on individual application vs. integral approach with central archiving in a DICOM-RT-PACS governed by a radiation oncology information system (ROCIS)). Infrastructural requirements depending on the amount of image data generated in the department are discussed. CONCLUSION: Application-centered image management provides access to image data including all relevant RT-specific elements. This approach, however, is not migration-safe, requires significant administrative work to ensure a redundancy level that protects against data loss and does not provide datasets that are linked to respective therapeutic interventions. Therefore, centralized image management and archiving that links images to patients and individual steps in the treatment pathway within a standardized DICOM(-RT) environment is preferable despite occasional problems with visualization of specific data elements.

[Radiology and pregnancy. Principles, general requirements and exposure]. / Radiologie und Schwangerschaft. Grundlagen, Rahmenbedingungen und Belastungen.

In a radiology department there are frequently asked questions associated with pregnant and breast feeding women. These are related to either pregnant patients or staff members or the questions are centered on the fetus as a patient. For pregnant patients the potential exposure to the mother and the fetus related to the imaging modality selected as well as the effects of the necessary contrast media must be taken into account. Even for methods without ionizing radiation possible limitations in the use for pregnant women must be discussed. Finally, this medical check defines the imaging modality and the necessary protocol and contrast media. The present article describes the legal requirements in Germany, the technical exposure and pharmacological risks for the pregnant woman and the fetus regarding imaging modalities with and without ionizing radiation. The forthcoming second article will address the risk analysis for examinations with ionizing radiation and will present recommendations for typical clinical imaging problems.

Computed tomography in children: multicenter cohort study design for the evaluation of cancer risk.

Exposure to ionizing radiation is a known risk factor for cancer. Cancer risk is highest after exposure in childhood. The computed tomography is the major contributor to the average, individual radiation exposure. Until now the association has been addressed only in statistical modeling. We present the first feasible study design on childhood cancer risk after exposure to computed tomography.

[Diagnostic value of electron-beam computed tomography (EBT). I. Cardiac applications]. / Diagnostische Wertigkeit der Elektronenstrahl-Computertomographie (EBT). I. Kardiale Anwendungen.

Electron beam tomography (EBT) directly competes with other non-invasive imaging modalities, such as multislice computed tomography, magnetic resonance imaging, and echocardiography, in the diagnostic assessment of cardiac diseases. EBT is the gold standard for the detection and quantification of coronary calcium as a preclinical sign of coronary artery disease (CAD). Its standardized examination protocols and the broad experience with this method favor EBT. First results with multislice CT indicate that this new technology may be equivalent to EBT for coronary calcium studies. The principal value of CT-based coronary calcium measurements continues to be an issue of controversy amongst radiologists and cardiologists due to lack of prospective randomized trials. Coronary angiography with EBT is characterized by a high negative predictive value and, in addition, may be indicated in some patients with manifest CAD. It remains to be shown whether coronary angiography with multislice CT is reliable and accurate enough to be introduced into the routine work-up, to replace some of the many strictly diagnostic coronary catheterizations in Germany and elsewhere. Assessment of coronary stent patency with EBT is associated with several problems and in our opinion cannot be advocated as a routine procedure. EBT may be recommended for the evaluation of coronary bypasses to look for bypass occlusions and significant stenoses, which, however, can be equally well achieved with multislice CT. Quantification of myocardial perfusion with EBT could not replace MRI or other modalities in this field. EBT has proven to be accurate, reliable and in some instances equivalent to MRI, which is the gold standard for the quantitative and qualitative evaluation of cardiac function. Some disadvantages, not the least of which is the limited distribution of electron beam scanners, favor MRI for functional assessment of the heart.

Quantification of color Doppler for the evaluation of tissue vascularization.

Assessment of tissue vascularization with color Doppler (CD) can improve differential diagnosis of tumors. Until now, measurement of flow velocities is restricted to conventional duplex ultrasound of single vessels or semiquantitative scoring of the vessel distribution in CD. We developed a new method for quantification of CD data in organs or tumors by statistical image analysis. Based on standardized image recording, data is acquired from the video output of any ultrasound scanner using a 24-bit color framegrabber in a personal computer. The digitized colors are recognized according to their position in the CD palette bar resulting in an 8-bit color image (number of identified pixels > 99.9%). Within the region of interest, statistics of the detected flow patterns are calculated. The color pixel density and the mean color value varies between recordings of the same image during subsequent systolic peaks with a SD of 10% and 2%, respectively, and within different sections of the same organ or tumor with 25% and 10-50%. This analysis can be used for comparative or longitudinal studies and an objective evaluation of CD in complex vascular formations such as tumors. Its diagnostic impact has already been demonstrated in clinical studies.

[MR tomography of lung metastases with rapid gradient echo sequences. Initial results in diagnostic applications]. / MR-Tomographie von Lungenmetastasen mit schnellen Gradientenechosequenzen. Erste Ergebnisse in der diagnostischen Anwendung.

Rapid gradient echo sequences enable MR imaging (MRI) of pulmonary metastases with acquisition times of less than 1 s per slice. By optimization of this technique, density, T1- and T2-weighted images can be obtained (FLASH: TR 6.5 ms, TE2 = 3 ms, alpha = 10 degrees; T1w-Turbo-FLASH: TI 200 ms, TR 6.5 ms, TE2 = 3 ms, alpha = 10 degrees; T2w-Turbo-FLASH: TE1 = 50 ms, TR = 6.5 ms, TE2 = 3.5 ms; alpha = 10 degrees). In a prospective study 25 patients in whom pulmonary metastases were suspected were examined with three techniques in all three anatomical planes prior to surgery. All lung metastases revealed a high signal intensity on the FLASH as well as the T2w-Turbo-FLASH images, whereas vascular structures revealed a low signal intensity on the T2-weighted Turbo-FLASH images. Analysis regarding detection and correct number of lung metastases per patient with MRI compared with the histology revealed (n = 25): sensitivity of 82%, specificity 67%, positive predictive value of 95% and negative predictive value of 33%. While MRI does not currently have any diagnostic advantages over CT, the excellent differentiation of parenchymal lesions and vascular structures without the use of contrast medium and the variability of imaging planes are significant methodological advantages.

[The color-coded duplex sonography and contrast-enhanced magnetic resonance tomography of scintigraphically cold thyroid nodules]. / Farbkodierte Duplexsonographie und kontrastverstärkte Magnetresonanztomographie szintigraphisch kalter Schilddrüsenknoten.

In order to establish diagnostic criteria, colour-coded duplex sonography was performed on 40 patients who had a total of 43 operatively confirmed thyroid lesions which were scintigraphically "cold" (28 adenomas, 8 carcinomas, 4 cases of thyroiditis and 3 cysts). 32 of these patients also had MRT with T2- and T1-weighted images before and after injection of Gd-DTPA (0.1 mmol/kg). Adenomatous nodules and adenomas showed a peripheral vascular halo on colour-coded duplex sonography with a sensitivity of 96% and a specificity of 93%. Malignant lesions showed marked central vascularisation and on B-images irregular marginal structures. Adenomas and adenomatous nodules showed hyperintense areas on T1-weighted unenhanced MR images and/or homogeneous uptake in the lesion (sensitivity 100%, specificity 77%). Malignant lesions typically showed an irregular margin with increased contrast uptake on MRT. If sonography and colour-coded duplex sonography is unable to classify a lesion with any degree of assurance then MRT with Gd-DTPA enhancement should be performed.

3D MPRAGE evaluation of lesions in the posterior cranial fossa.

Standard spin-echo images of the posterior cranial fossa are usually impaired by pulsation artifacts. We evaluated a heavily T1 weighted MPRAGE sequence (TR/TE/alpha/TI = 10/4/10-15 degrees/200-350) for detection of intracerebral lesions in the posterior fossa in 11 patients. Overall quality of the MPRAGE images was superior due to the lack of pulsation artifacts, high S/N and excellent gray-white matter contrast. Lesion detection was better in one patient, equal in six and inferior in four patients compared to SE technique. A cerebellar metastasis (8 mm) in one patient was completely blurred from pulsation artifacts on the SE images. Whereas multiple small lesions (< or = 4 mm) with discrete contrast enhancement were missed on the MPRAGE images in three patients. We conclude, that the MPRAGE sequence yields high quality images with isotropic spatial resolution in a reasonable time. But MPRAGE with these parameters can not replace standard SE images in screening the posterior fossa, because of a decreased sensitivity in the detection of small contrast-enhancing lesions.

[Radiation treatment of plastic induration of the penis]. / Die Strahlenbehandlung der Induratio penis plastica.

Between 1969 and 1984, a group of 54 patients with plastic induration of the penis was treated at the Medical Radiation Institute of the University of Tübingen. During the first years conventional X-ray irradiation was applied, and since 1974 patients were submitted to 3 or 5 MeV electron irradiation of a linear accelerator, until a total focal dose of 20 Gy was accumulated. 78% of these patients were between 50 and 60 years old. Sixteen patients suffered from a simultaneous Dupuytren contracture, one patient had a fibrosis of mamma virilis. The treatment results reached from satisfactory until very good in 69% of all cases. Complete regression or a considerable improvement was obtained for indurations in 59%, for deviations in 69%, and for erection algesia in 79%. Radiogenic damages can be excluded in case of a gonad exposition of 0.2 Gy. There were no permanent cutaneous lesions after a total focal dose of 20 Gy. The prognostic importance of an early treatment is underlined; late stages presenting ossifications can be treated only by surgery. For routine diagnosis of site, extent, and possible mineralization of the regions involved, soft ray phallography performed with the technique of mammography can be used.

[Neuroradiology of the normal and pathological anatomy of the rat brain.--III Morphology and growth behaviour of experimental brain tumours following radiation therapy (author's transl)]. / Neuroradiologie der normalen und pathologischen Anatomie des Rattenhirnes. III. Morphologie und Wachstumsverhalten experimenteller Hirntumoren nach Strahlenbehandlung.

Radiation induced (30 Gy) morphological changes of experimental malignant brain tumors, which were produced by chemical carcinogenesis, were investigated by microangiography and correlated with the histological findings in 62 BD-IX-rats. In randomized groups the investigations were performed 2, 3, 6 and 8 weeks after the radiation was finished. Morphologically different reactions could be differentiated: remissions or partial recovery of the tumors, rest or recurrent tumor and uninfluenced tumor growth. The characteristic findings, the reasons for different courses and possible conclusions concerning the radiotherapeutical effect are discussed.

[Neuroradiology of the normal and pathological anatomy of the rat brain. II Microangiographic investigations of the vascularisation of transplanted malignant brain tumors (author's transl)]. / Neuroradiologie der normalen und pathologischen Anatomie des Rattenhirnes. II. Mikroangiographische Untersuchungen zur Vaskularisation transplantierter maligner.

70 BD-IX rats, in which chemically induced mixed gliomas have been transplanted intracerebrally, were investigated by microangiography. The pattern and the degree of tumor vascularisation of all animals was correlated with the histological findings. Depended on the type of the tumor different localisations of tumor growth could be found: G XII-gliomas preferred the juxtaventricular region and subarachnoid space whereas GL 2.2-gliomas mainly grew as solid intracerebral space occupying lesions. Microangiograms of all tumor stages from the 14th to 42nd day after transplantation revealed a typical vascular pattern consisting of lacunar, glomerulose and netlike vessels. Further, necrosis, bleedings into the tumor, and irregularities of the capillary network could be demonstrated. The volume, age and vascularisation of the tumors are correlated and the results are discussed with regard to the principles of tumor growth and malignancy.