Data-driven RBE parameterization for helium ion beams.

Helium ion beams are expected to be available again in the near future for clinical use. A suitable formalism to obtain relative biological effectiveness (RBE) values for treatment planning (TP) studies is needed. In this work we developed a data-driven RBE parameterization based on published in vitro experimental values. The RBE parameterization has been developed within the framework of the linear-quadratic (LQ) model as a function of the helium linear energy transfer (LET), dose and the tissue specific parameter (α/ß)ph of the LQ model for the reference radiation. Analytic expressions are provided, derived from the collected database, describing the RBEα = αHe/αph and Rß = ßHe/ßph ratios as a function of LET. Calculated RBE values at 2 Gy photon dose and at 10% survival (RBE10) are compared with the experimental ones. Pearson's correlation coefficients were, respectively, 0.85 and 0.84 confirming the soundness of the introduced approach. Moreover, due to the lack of experimental data at low LET, clonogenic experiments have been performed irradiating A549 cell line with (α/ß)ph = 5.4 Gy at the entrance of a 56.4 MeV u(-1)He beam at the Heidelberg Ion Beam Therapy Center. The proposed parameterization reproduces the measured cell survival within the experimental uncertainties. A RBE formula, which depends only on dose, LET and (α/ß)ph as input parameters is proposed, allowing a straightforward implementation in a TP system.

Vertigo in patients with cervical spine dysfunction.

To our knowledge, quantitative studies on the significance of disorders of the upper cervical spine as a cause of vertigo or impaired hearing do not exist. We examined the cervical spines of 67 patients who presented with symptoms of dizziness. Prior to the orthopaedic examination, causes of vertigo relating to the field of ENT and neurology had been ruled out. Fifty patients of the above-mentioned group were studied. They followed the outlined treatment protocol with physical therapy and were available for 3 months of follow-up. Thirty-one patients, hereinafter referred to as group A, were diagnosed with dysfunctions of the upper cervical spine. Nineteen patients, hereinafter referred to as group B, did not show signs of dysfunction. Cervical spine dysfunctions were documented as published by Bischoff. In group A dysfunctions were found at level C1 in 14 cases, at level C2 in 6 cases and at level C3 in 4 cases. In seven cases more than one upper cervical spine motion segment was affected. Dysfunctions were treated and resolved with mobilising and manipulative techniques of manual medicine. Regardless of cervical spine findings seen at the initial visit, group A and B patients received intensive outpatient physical therapy. At the final 3-month follow-up, 24 patients of group A (77.4%) reported an improvement of their chief symptom and 5 patients were completely free of vertigo. Improvement of vertigo was recorded in 5 group B patients (26.3%); however, nobody in group B was free of symptoms. We concluded that a functional examination of motion segments of the upper cervical spine is important in diagnosing and treating vertigo, because a non-resolved dysfunction of the upper cervical spine was a common cause of long-lasting dizziness in our population.

Sacroiliac joint dysfunction in patients with imaging-proven lumbar disc herniation.

A dysfunction of a joint is defined as a reversible functional restriction of motion presenting with hypomobility according to manual medicine terminology. The aim of our study was to evaluate the frequency and significance of sacroiliac joint (SIJ) dysfunction in patients with low back pain and sciatica and imaging-proven disc herniation. We examined the SIJs of 150 patients with low back pain and sciatica; all of these patients had herniated lumbar disks, but none of them had sensory or motor losses. Forty-six patients, hereinafter referred to as group A, were diagnosed with dysfunction of the SIJ. The remaining 104 patients, hereinafter referred to as group B, had no SIJ dysfunction. Dysfunctions were resolved with mobilizing and manipulative techniques of manual medicine. Regardless of SIJ findings, all patients received intensive physiotherapy throughout a 3-week hospitalisation. At the 3 weeks follow-up, 34 patients of group A (73.9%) reported an improvement of lumbar and ischiadic pain, 5 patients were pain free. Improvement was recorded in 57 of the group B patients (54.8%); however, nobody in group B was free of symptoms. We conclude that in the presence of lumbar and ischiadic symptoms our presented data suggest consideration of SIJ dysfunction, requiring manual medicine examination and, in the presence of SIJ dysfunction, appropriate therapy, regardless of intervertebral disc pathomorphology. This could avoid wrong indications for nucleotomy.

[Total femur replacement following multiple periprosthetic fractures between ipsilateral hip and knee replacement in chronic rheumatoid arthritis. Case report of 2 patients]. / Totaler Femurersatz nach mehrfachen periprothetischen Frakturen zwischen ipsilateralem Hüft- und Kniegelenksersatz bei chronischer Polyarthritis. Falldarstellung von 2 Patienten.

Periprosthetic femur fractures are one of the most severe complications in hip surgery. Osteoporosis as seen in patients with rheumatoid arthritis could favour such fractures, which are located mostly between the stems of the hip and knee prostheses. A traumatic event is not even required. The fracture rate increases with predisposing factors, such as preliminary changes of the prosthesis or osteoporosis. This paper reports two patients with rheumatoid arthritis (males, 54 and 71 years old) with femur fractures after total hip and knee replacements. Both had a severe osteoporosis caused by a long-term steroid therapy. Consecutively, both patients showed refractures of the femur with loosening of the osteosynthetic material, so that a total femur replacement was required. However, both patients are able to walk. To reduce the risk of femur fractures between the tips of knee and hip prostheses it is advisable to use knee prostheses without a proximal intramedullary stem. In this way pressure stress is reduced.