[The impact of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) on planning of radiotherapy]. / Vliianie pozitronnoi émissionnoi tomografii s 18F-ftorodeoksigliukozoi na planirovanie luchevoi terapii.

AIM: To determine the impact of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) on patient management in radiotherapy. MATERIAL AND METHODS: One hundred sixty-nine consecutive patients with different malignant tumors were analyzed. Whole-body FDG-PET was performed for staging before radiotherapy. The strategy of radiotherapy before and after PET scanning was compared and the change in the treatment management determined. RESULTS: In 47(28%) of 169 patients PET results changed patient management in radiotherapy. In 19 patients (11%) radiotherapy was not performed after PET. In 16 patients (10%) PET results changed the intention of radiation treatment (curative/palliative). Correction of radiation dose was made in 16 patients (10%). Correction of the volume of the exposure area was made in 12 patients (7%). Tumor outside the field of view was missed in only 2 patients with a regional PET scan. CONCLUSION: In this retrospective analysis the information provided by FDG-PET contributes to a substantial change in radiotherapy strategy.

Theory and practice of predictive assays in radiation therapy.

PURPOSE: An overview of the field of predictive assays is presented. It has been written with the many clinicians and scientists in mind who would like to become better acquainted with the general scope, principles and themes in the field. RESULTS: Predictive assays have yielded much valuable information about the radiobiology of tumors e.g. the overall treatment time for rapidly proliferating tumors should be kept to a minimum. However, alteration of current treatment protocols based on results from predictive assays is still a matter of debate. What justification do we have to change established treatment protocols? A necessary and sufficient justification would be when the test value indicated an alternative treatment producing a better outcome, i.e. higher survival, improved local control, etc. Necessary but not always sufficient justification is correlation between the parameter measured and clinical outcome, if insufficient clinical benefit can be derived even when this is known. It is not sufficient that a test be demonstrated to be discriminatory. It must discriminate a sufficient number of patients, and its use must provide the patient with useful therapeutic alternatives. These parameters measured by predictive assays may well interact radiobiologically, and restricting observations to just one assay is probably insufficient for reliable indications. In the future, it is more likely that a panel of tests will be performed, and clinical decisions based on multi-parametric analysis of biopsy material. CONCLUSION: In the following overview general predictive assay theory is presented followed by a brief introduction to some of the more established assays and finally some guidelines are suggested for the development of new assays.

Langerhans'-cell histiocytosis in adults.

Guided by a long-term retrospective observation, the clinical course and treatment of Langerhans'-cell histiocytosis (LCH) in adult patients are represented. The series included 19 patients meeting the histopathologic criteria of presumptive LCH who were followed for 1.5-20 years (average 7.7 years). Most frequently, skeletal lesions (16 patients), diffuse interstitial lung infiltrates (seven patients), and pituitary gland involvement with diabetes insipidus (four patients) were present. Bone lesions of the skull and axial skeleton were associated with an infiltration of adjacent soft tissues in 10 of 16 patients. Liver, lymph node, and bone marrow involvement appeared sporadically. LCH was divided into localized or multifocal form. Localized disease took a benign course with remission of bone (n = 4) or lymph node lesions (n = 2). Also, in isolated pulmonary LCH (n = 2), spontaneous transition to inactive disease occurred. With the exception of isolated bone lesions (n = 27), which remained asymptomatic or showed a remission to treatment, multifocal LCH had a more aggressive course. Osseous lesions with adjacent soft tissue infiltration (n = 20) showed a relapse rate in excess of 80% independent of the treatment applied. Pulmonary involvement led to a more marked functional impairment compared to the isolated form, and systemic treatment yielded no convincing effect. In three patients with liver or bone marrow involvement, LCH showed a persistent, serious disease activity. One patient died of transition into acute monomyelocytic leukemia 18 months after diagnosis without preceding chemotherapy. In adults, LCH seems to be limited to a few organ systems. Multifocal LCH represents the more aggressive form with unfavorable prognosis in patients with bone lesions spreading into the adjacent soft tissue and liver or bone marrow involvement.

[Myocardial scintigraphy with thallium 201 in assessing revascularization procedures by aortocoronary bypass or coronary dilatation]. / La scintigraphie du myocarde au thallium 201 dans l'évaluation du succès d'une intervention revascularisatrice soit par pontage aorto-coronarien soit par dilatation coronarienne.

40 patients underwent aortocoronary bypass surgery for coronary artery disease involving a single vessel in 2 cases, 2 vessels in 10 cases, and all 3 vessels in 28 cases. Preoperative exercise Thallium 201 scanning showed one or several zones of hypofixation (80 p. 100 of maximum myocardial fixation) which were not present at rest. After surgery, exercise scanning was normal in 22 out of 24 patients with normalised or improved vascularisation on control angiography, but remained pathological in 2 cases. However, comparable areas of hypoperfusion were observed in 16 patients with no improvement or worsening of vascularisation after operation. The exercise EG remained pathological in 6 out of 24 patients with normalised or improved vascularisation and in 11 out of 16 patients with identical or worsened vascularisation. In addition, 10 of the 24 patients with improved or normalised vascularisation, and 12 of 16 patients with identical or worsened vascularisation, continued to have chest pain after operation. A zone of hypoactivity was observed in the preoperative exercise scan in 18 out of 20 patients with isolated stenosis treated by catheter dilatation. Normalised exercise scans were recorded in all patients in the month following dilatation, but the exercise ECG remained pathological in 3 patients. In conclusion, 201 Thallium scanning gives a good assessment of myocardial vascularisation after revascularisation procedures. It helps identify patients with non-anginal post-operative chest pain, and detects residual ischaemia in patients without ischaemic signs on electrocardiography.