Ion recombination correction factor in scanned light-ion beams for absolute dose measurement using plane-parallel ionisation chambers.

Based on international reference dosimetry protocols for light-ion beams, a correction factor (k s) has to be applied to the response of a plane-parallel ionisation chamber, to account for recombination of negative and positive charges in its air cavity before these charges can be collected on the electrodes. In this work, k s for IBA PPC40 Roos-type chambers is investigated in four scanned light-ion beams (proton, helium, carbon and oxygen). To take into account the high dose-rates used with scanned beams and LET-values, experimental results are compared to a model combining two theories. One theory, developed by Jaffé, describes the variation of k s with the ionization density within the ion track (initial recombination) and the other theory, developed by Boag, describes the variation of k s with the dose rate (volume recombination). Excellent agreement is found between experimental and theoretical k s-values. All results confirm that k s cannot be neglected. The solution to minimise k s is to use the ionisation chamber at high voltage. However, one must be aware that charge multiplication may complicate the interpretation of the measurement. For the chamber tested, it was found that a voltage of 300 V can be used without further complication. As the initial recombination has a logarithmic variation as a function of 1/V, the two-voltage method is not applicable to these scanned beams.

Diagnosis of vascular cognitive impairment and its main categories.

OBJECTIVE: A review of current criteria for the diagnosis of categories related with vascular cognitive impairment, in particular the nomenclature, diagnostic criteria, and differential clinical-radiological findings. DEVELOPMENT: The criteria for the diagnosis of vascular cognitive impairment have evolved, but available criteria were designed basically for differentiating between vascular dementia and dementia due to Alzheimer disease, and for research purposes. Nevertheless, in clinical practice precise elements are required for: 1) Clinical diagnosis of dementia and mild cognitive impairment; 2) Clinical and neuroimaging criteria for identification of the various cerebrovascular lesions associated with cognitive dysfunction, and 3) A formulation of the aetiogenic-pathogenic relationship between cognitive impairment and cerebrovascular lesions. For this reason, a review was carried out on the diagnostic elements of vascular cognitive impairment categories, classification, and their most relevant characteristics. It highlights the characteristic for the diagnosis of multi-infarction dementia, strategic single infarct dementia, small vessel disease with dementia, mixed dementia, and vascular mild cognitive impairment. CONCLUSIONS: Standardisation is required, by a multidisciplinary expert team, as regards nomenclature and criteria for the diagnosis of the full spectrum associated with vascular cognitive impairment and especially for vascular dementia and its categories.

[Diagnosis of delayed cerebral ischaemia and cerebral vasospasm in subarachnoid haemorrhage]. / Diagnóstico de la isquemia cerebral tardía y el vasospasmo cerebral en la hemorragia subaracnoidea.

OBJECTIVE: A review of current foundations for the medical diagnosis of vasospam and delayed cerebral ischaemia due to spontaneous subarachnoid haemorrhage. DEVELOPMENT: A review of available tests for the investigation of vasospasm (transcraneal Doppler, angiographic methods) and delayed cerebral ischaemia (clinical exam, computerised tomography by X rays, magnetic resonance, emission computerised tomography, electroencephalography, microdialysis) based on type and quality of information, advantages and limitations. Grading and trends for application were also considered for differential diagnosis. CONCLUSIONS: In current clinical practice the most advisable guideline for screening and diagnosis monitoring of vasospasm and delayed cerebral ischaemia is in the first place, based on clinical examination and transcraneal Doppler. The electroencephalographic monitoring, computerised tomography techniques and multi-modal magnetic resonance are justified in specific situations. Digital subtraction angiography is the current gold standard for diagnosis of cerebral vasospasm. There is a need for more and higher quality articles about the utility of diagnostic tests in this context.

[Clinical techniques for use in neurological physical examinations. III. Sensory functions]. / Técnicas clínicas para el examen físico neurológico. III. Función sensitiva.

AIMS: The purpose of this work is to focus on the main practical aspects of the techniques used for the neurological physical examination of the sensory functions and to present an approach for the practice of this study. DEVELOPMENT: Despite the difficulty often involved in interpreting its results, today the formal examination of sensation is still an important part of a complete neurological evaluation and remains valid in the search for a correct diagnosis and suitable treatment. We recommend clinicians to carry out a brief but consistent and effective exploration in a systematic, flexible and orderly manner to check for abnormalities in the sensory functions. Should any anomalies be detected, then a more detailed and thorough neurological exploration must be performed selectively. We present a detailed review of the practical aspects of the main techniques used in the physical examination of this neurological category. In addition to the tests used to examine the peripheral and cortical sensory systems, we also describe other techniques designed to trigger pain or other sensory symptoms due to radicular lesions or injury to the median nerve. CONCLUSIONS: We present a detailed description of the main clinical techniques used in the neurological physical examination of the sensory functions, as well as an approach that allows them to be performed on adult patients. In addition, we underline the importance of physically examining the sensory functions in contemporary medicine and the need to continually perfect the way these techniques are performed in order to achieve an efficient clinical practice.

[Clinical techniques for use in neurological physical examinations. II. Motor and reflex functions]. / Técnicas clínicas para el examen físico neurológico. II. Función motora y refleja.

AIMS: The aim of this study is to highlight the chief practical aspects of the techniques used in the neurological physical examination of the motor and reflex functions. DEVELOPMENT: We recommend clinicians to carry out a brief but consistent and effective exploration in a systematic, flexible and orderly manner to check for abnormalities in the motor and reflex functions of the nervous system. Should any anomalies be detected, then a more detailed and thorough neurological exploration must be performed selectively. We present a detailed review of the practical aspects of the main techniques used in the physical examination of these neurological categories. The motor function is explored using techniques that examine muscle tone, muscle strength, muscle fatigability, hypokinesia, tremor, coordination and gait. Lastly, in this category several manoeuvres that are useful in hysterical or mimicking paralyses are also dealt with. Reflexes to examination are usually divided into: 1. Myotatic reflexes; 2. Cutaneomucous reflexes; 3. Spinal cord or defence automatism reflexes; 4. Posture and attitude reflexes. We also add the study of primitive pathological reflexes, remote reflexes, synkinesias and signs of meningeal irritation. CONCLUSIONS: We present a detailed description of the main clinical techniques used in the neurological physical examination of motility and reflexes, as well as an approach that allows them to be performed on adult patients. In addition, we underline the importance of physically examining the nervous system in contemporary medicine and the need to continually perfect the way these techniques are performed in order to achieve an efficient clinical practice.

[Clinical techniques for use in neurological physical examinations. I. General organisation, cranial and peripheral spinal nerves]. / Técnicas clínicas para el examen físico neurológico. I. Organización general, nervios craneales y nervios raquídeos periféricos.

AIMS: The purpose of this work is to focus on the main practical aspects of the techniques used for the physical examination of the nervous system and to present an approach for the practice of this study in adult patients. DEVELOPMENT: We recommend clinicians to carry out a brief but consistent and effective exploration in a systematic, flexible and orderly manner to check for alterations in the functioning of the nervous system. Should any anomalies be detected, then a more detailed and thorough neurological exploration must be performed selectively. The techniques and data from this examination are organised into five broad categories: mental status, cranial nerves, motor function, reflex function and sensory function. The practical aspects of the main techniques used in the physical exploration are reviewed and we also describe the technique to be employed for palpating the main peripheral nerves. CONCLUSIONS: The study offers a detailed description of the chief clinical techniques used in the physical exploration of the cranial nerves and for the palpation of the peripheral nerves; we also present an approach to performing the neurological examination. Furthermore, we highlight the importance of physically examining the nervous system in contemporary medicine and the need to continually perfect the way these techniques are performed in order to achieve an efficient clinical practice.