Search

Report Committee 26 of the ICRU proposes a set of operational quantities for radiation protection for external radiation, directly based on effective dose and for an extended range of particles and energies. It is accompanied by quantities for estimating deterministic effects to the eye lens and the local skin. The operational quantities are designed to overcome the conceptual and technical shortcomings of those presently in use. This paper describes the proposed operational quantities, and highlights the improvements with respect to the present, legal monitoring quantities.

The new recommendation issued by the International Commission on Radiological Protection (ICRP) introducing a 20-mSv annual dose limit for the eye lens stimulated an interesting debate among the radiation protection community. In the present work the problem of estimating Hp(3) for neutron realistic workplace spectra is treated, employing the recently published Hp(3)/Φ conversion coefficients with the aim of establishing a workplace-dependent relationship between Hp(10) and Hp(3). The results demonstrate that, whilst the two quantities can differ by less than 10 %, in general, Hp(10) cannot be considered a conservative estimate of Hp(3)., (© The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: This retrospective study was performed to assess the effectiveness of active immunostimulation therapy with bacterial immunotherapy (BIT) in treatment for chronic osteomyelitis (COM)., Materials and Methods: We analyze 154 patients affected by COM and treated with BIT from 1995 to 2009 at our Institution. Using Cierny and Mader classification, patients were divided according to their clinical status and anatomic nature of septic process. The data were analyzed considering several confounding factors, such as antibiotic therapy and hyperbaric oxygen therapy combined with the administration of BIT. According to clinical and radiographic parameters, patients were considered as unchanged, improved, or healed., Results: After a mean follow-up of 40.4 months (median 38 months), healing was achieved in 41.6 % of cases. Multivariate statistical analysis showed that patient's clinical status is the most important prognostic factor of responding (p < 0.0005) and healing (p = 0.008) after therapy. The best healing rate (62 % of cases) was achieved in patients with a normal clinical condition (Cierny-Mader group A); it was worse (20 % of cases) in those patients with a compromised clinical status (Cierny-Mader group B). There was no healing case in group C., Conclusions: The results show the effectiveness of BIT in treatment of patients affected by COM with uncompromised clinical status. The use of this therapy must be assessed critically in patients with alterations in clinical conditions.

The recent statement on tissue reactions issued by the International Commission on Radiological Protection in April 2011 recommends a very significant reduction in the equivalent dose annual limit for the eye lens from 150 to 20 mSv y(-1); this has stimulated a lot of interest in eye lens dosimetry in the radiation protection community. Until now no conversion coefficients were available for the operational quantity Hp(3) for neutrons. The scope of the present work was to extend previous evaluations of H*(10) and Hp(10) performed at the PTB in 1995 to provide also Hp(3) data for neutrons. The present work is also intended to complete the studies carried out on photons during the last 4 y within the European Union-funded ORAMED (optimisation of radiation protection for medical staff) project.

In the framework of the ORAMED project (Optimization of RAdiation protection for MEDical staff), funded by the European Union Seventh Framework Programme, different studies were aimed at improving the quality of radiation protection in interventional radiology and nuclear medicine. The main results of the project were presented during a final workshop held in Barcelona in January 2011, the proceedings of which are available in the open literature. One of the ORAMED tasks was focused on the problem of eye-lens photon exposure of the medical staff, a topic that gained more importance especially after the ICRP decision to lower the limiting equivalent dose to 20 mSv per year. The present technical note has the scope, besides briefly summarising the physical reasons of the proposal and the practical implications, to provide, in tabular form, a set of air kerma to Hp(3) conversion coefficients based on the adoption of a theoretical cylindrical model that is well suited for reproduction of the mass and the shape of a human head.

Since the first developments of Monte Carlo radiation transport codes, the importance of solving deep penetration problems in the phase space was pointed out. Whilst natural Monte Carlo radiation transport models are rather easy and straightforward to be implemented, apart from geometry extreme complexities that could limit the modelling capabilities of the user, the possibility to obtain results with high precision and reasonable CPU time, when the scored events contributing to the response of interest are characterised by a low probability of occurrence, can be guaranteed only through biased games for which the user needs a robust expertise. The present paper wanted to present in a concise way the main aspects of the variance reduction techniques and some practical application to help the users in becoming more familiar with such a necessary tool.

The ORAMED (Optimization of RAdiation protection for MEDical staff) project is funded by EU-EURATOM within the 7° Framework Programme. Task 2 of the project is devoted to study the dose to the eye lens. The study was subdivided into various topics, starting from a critical revision of the operational quantity H(p)(3), with the corresponding proposal of a cylindrical phantom simulating as best as possible the head in which the eyes are located, the production of a complete set of air kerma to dose equivalent conversion coefficients for photons from 10 keV to 10 MeV, and finally, the optimisation of the design of a personal dosemeter well suited to respond in terms of H(p)(3). The paper presents some preliminary results.

Recent epidemiological studies suggest a rather low-dose threshold (<0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimised and current dose limits for the eye lens may be reduced in the future. ICRP Publication 103 on H(p)(d), in §(136), reads that '… a depth d = 3 mm has been proposed for the rare case of monitoring the dose to the lens of the eye. In practice, however, H(p)(3) has rarely been monitored and H(p)(0.07) can be used for the same monitoring purpose… '. As recommended on the EU 'Technical recommendations for monitoring individuals occupationally exposed to external radiation', a test on the ENEA TL extremity dosemeter is herein reported. The results within the actual EU founded Optimization of RAdiation protection for MEDical staff (ORAMED) Project, whose WP2 is aimed at the quantity H(p)(3) and eye lens dosimetry in practice, are taken into account. The paper summarises the main aspects of the study carried out at ENEA-Radiation Protection Institute (Bologna, Italy) to provide practical solutions (in the use and the design) to evaluate the response of the ENEA TL extremity dosemeter in terms of H(p)(3).

The work package two of the ORAMED project--Collaborative Project (2008-2011) supported by the European Commission within its seventh Framework Programme--is devoted to the study of the eye lens dosimetry. A first approach is to implement the use of H(p)(3) by providing new sets of conversion coefficients and well suited calibration and type test procedures. This approach is presented in other papers in the proceedings of this conference. Taking into account that the eye lens is an organ close to the surface of the body, another approach would be to directly estimate the absorbed dose to the eye lens, D(lens,est) through a special calibration procedure although this quantity is not directly measurable. This paper is a methodological paper that tries to identify the critical aspects of a dosimetry in terms of D(lens).

The Work Package 4 of the ORAMED project, a collaborative project (2008-11) supported by the European Commission within its seventh Framework Programme, is concerned with the optimisation of the extremity dosimetry of medical staff in nuclear medicine. To evaluate the extremity doses and dose distributions across the hands of medical staff working in nuclear medicine departments, an extensive measurement programme has been started in 32 nuclear medicine departments in Europe. This was done using a standard protocol recording all relevant information for radiation exposure, i.e. radiation protection devices and tools. This study shows the preliminary results obtained for this measurement campaign. For diagnostic purposes, the two most-used radionuclides were considered: (99m)Tc and (18)F. For therapeutic treatments, Zevalin(®) and DOTATOC (both labelled with (90)Y) were chosen. Large variations of doses were observed across the hands depending on different parameters. Furthermore, this study highlights the importance of the positioning of the extremity dosemeter for a correct estimate of the maximum skin doses.

Interventional radiology, among guided X-rays procedures, is a methodology characterised by high level of doses, both for the patient and for the medical staff. The aim of the present study is to estimate the dose associated with coronary angiography procedures by means of numerical models (simplified and anthropomorphic) and MCNPX Monte Carlo code. Numerical estimates were supported by measurement performed with a dose area product meter that is commonly employed in such kind of studies. In the present work the main considerations and the preliminary results are presented.

The need of organ absorbed dose evaluation for radiation protection purposes stimulated, since the late 1960s, the development of anthropoid models to be used with radiation transport codes. Very significant improvements were introduced during the years, passing from stylised analytical human models to realistic voxel models based on computed tomography scans or MRI scans, and finally to advanced surface-geometry models. Besides illustrating the main contributions in this field from various international laboratories, this paper illustrates some applications of voxel models to internal (including in vivo monitoring) and external dosimetry for radiation protection.

Background: The authors report the results of femoral-tibial fusion with an Ilizarov circular external fixator following septic loosening of knee prosthesis., Materials and Methods: The series included 17 patients with a mean age of 62.9 years, treated from 1990 to 2007 with femoral-tibial fusion. The Cierny-Mader classification was used for clinical and anatomopathological evaluation; the Engh classification was used to assess the bone defect. Surgical treatment differed according to these criteria., Results: Healing was achieved in 13 out of 17 patients at the first surgical attempt in a mean time of 9.3 months. Mean follow-up was 30 months. Of the four complications, two patients had an intolerance to the external fixator that led to its early removal, and the other two had a septic intraarticular nonunion., Conclusions: The Ilizarov circular external fixator is a very reliable fixation system due to its low cost, versatility, stability under load, and low risk of septic dissemination. Nevertheless, an appropriate patient selection and a good surgeon's experience are necessary.

Chronic recurrent multifocal and unspecific osteomyelitis (CRMUO) is a severe form of chronic nonbacterial osteomyelitis. Lesions can be found anywhere in the skeleton, in young patients, such as children or adolescents, chronic nonbacterial osteomyelitis often affects the metaphyses of the long bones. Furthermore, other organs like skin, eyes and gastrointestinal tract can also be affected. Because of symptoms and course of disease vary in significant way, a clinical diagnosis is often difficult. The radiographic appearance suggests subacute or chronic osteomyelitis. CRMUO may mimic acute hematogenous osteomyelitis, but bacterial culture are usually negative and nonspecific histopathological and laboratory findings are present. This kind of osteomyelitis is often diagnosed by exclusion of the two main differential diagnoses-bacterial infections and tumor-by assessing for a characteristic course and the findings by conventional radiography, if necessary supplemented by scintigraphy and magnetic resonance imaging (MRI). The MRI appearance of CRMUO lesions in tubular bones and the spine is often rather characteristic and can support the diagnosis. It is important to diagnose CRMUO to avoid unnecessary diagnostic procedures or therapy, and initiate an appropriate one. We present a case report of a 44-year-old woman diagnosed with CRMUO involving both femurs.

In the frame of the EU Coordination Action CONRAD (coordinated network for radiation dosimetry), WP4 was dedicated to work on computational dosimetry with an action entitled 'Uncertainty assessment in computational dosimetry: an intercomparison of approaches'. Participants attempted one or more of eight problems. This paper presents the results from problems 4-8-dealing with the overall uncertainty budget estimate; a short overview of each problem is presented together with a discussion of the most significant results and conclusions. The scope of the problems discussed here are: the study of a (137)Cs calibration irradiator; the manganese bath technique; the iron sphere experiment using neutron time-of-flight technique; the energy response of a RADFET detector and finally the sensitivity and uncertainty analysis for the recoil-proton telescope discussed in the companion paper.

This communication briefly summarises the results obtained from the 'International comparison on MC modeling for in vivo measurement of Americium in a knee phantom' organised within the EU Coordination Action CONRAD (Coordinated Network for Radiation Dosimetry) as a joint initiative of EURADOS working groups 6 (computational dosimetry) and 7 (internal dosimetry). Monte Carlo simulations using the knee voxel phantom proved to be a viable approach to provide the calibration factor needed for in vivo measurements.

Within the scope of CONRAD (A Coordinated Action for Radiation Dosimetry) Work Package 4 on Computational Dosimetry jointly collaborated with the other research actions on internal dosimetry, complex mixed radiation fields at workplaces and medical staff dosimetry. Besides these collaborative actions, WP4 promoted an international comparison on eight problems with their associated experimental data. A first set of three problems, the results of which are herewith summarised, dealt only with the expression of the stochastic uncertainties of the results: the analysis of the response function of a proton recoil telescope detector, the study of a Bonner sphere neutron spectrometer and the analysis of the neutron spectrum and dosimetric quantity H(p)(10) in a thermal neutron facility operated by IRSN Cadarache (the SIGMA facility). A second paper will summarise the results of the other five problems which dealt with the full uncertainty budget estimate. A third paper will present the results of a comparison on in vivo measurements of the (241)Am bone-seeker nuclide distributed in the knee. All the detailed papers will be presented in the WP4 Final Workshop Proceedings.

The radiation doses received by individuals from radionuclides which enter the human body cannot be measured directly but must be inferred. In these calculations, several measurable quantities (such as the internal whole body burden or urine daily excretion) and quantities derived from models are employed. The Radiation Protection Quantities for internal dosimetry are, in principle, the same as for external dosimetry with the addition of quantities taking into account that the doses in the body are protracted. Other parameters are also necessary for the dose assessment, such as the SAFs (Specific Absorbed Fractions). All these quantities are calculated using Monte Carlo codes and complex anthropomorphic phantoms. Monte Carlo codes are also widely employed as useful tools during the calibration procedure for in vivo measurements. This paper summarises the role played by Monte Carlo modelling in these fields.

Effective dose is the main radiation protection quantity. Progresses in radiation studies brought ICRP to revise ICRP 60 recommendations. A new publication, already circulated in form of draft, is expected to change some aspects of effective dose evaluation method. The organ absorbed doses for neutrons at various energies and incidence angles, necessary to estimate the effective dose, have been published in ICRU 57 and ICRP 74 reports for ADAM and EVA analytical male and female phantoms and similar calculations were also performed, based on the MCNP code, for VIP-MAN voxel phantom. The NORMAN voxel phantom, developed on the basis of magnetic resonance data of an adult male at HPA (formerly NRPB), is an accurate model (with a voxel element of approximately 8 mm(3)), which well approximates the standard man and has been already employed for radiation protection studies with photons. In the present paper, a modified version, called NORMAN-05, including a new organ, the salivary glands (as suggested in the mentioned ICRP draft), and a more detailed skeletal description, especially devoted to red bone marrow dose evaluation, has been employed with the Monte Carlo code MCNPX to calculate neutron conversion coefficients from thermal energies to 20 MeV. Some preliminary results, for antero-posterior and postero-anterior irradiation conditions, are presented and compared with the available published data.

Hp(3) has been defined as the operational quantity for eye lens dosimetry. Hp(3)/ka conversion coefficients were evaluated at the GSF (Germany) in a 30x30x15 cm3 4-elements ICRU slab phantom for various energies and incident angles through Monte Carlo. The ISO report 12,794 suggests to employ a PMMA water filled phantom, of the same dimensions, for dosemeter calibration in terms of Hp(3). The present paper briefly summarises the main aspects of a study carried out at ENEA-Radiation Protection Institute (Bologna, Italy) to provide practical procedures for the calibration of dosemeters in terms of Hp(3). Tabulations of a new set conversion coefficients and air kerma backscatter factors are provided as a function of energy and incident angle. The paper demonstrates that a more accurate approach to the dosimetric assessment in terms of Hp(3) could be rather simply introduced employing a reduced phantom.

Boron neutron capture therapy (BNCT) is an experimental technique for the treatment of certain kinds of tumors. Research in BNCT is performed utilizing both thermal and epithermal neutron beams. Epithermal neutrons (0.4 eV-10 keV) penetrate more deeply into tissue and are thus used in non-superficial clinical applications such as the brain glioma. In the last few years, the fast reactor TAPIRO (ENEA-Casaccia Rome) has been employed as a neutron source for research into BNCT applications. Recently, an 'epithermal therapeutic column' has been designed and its construction has been completed. The Monte Carlo code MCNPX was employed to optimize the design of the column and to evaluate the dose profiles and the therapeutic parameters in the cranium of the anthropomorphic phantom ADAM. In the same context, some preliminary evaluations of the undesirable doses to the patient were performed with MCNPX. A hermaphrodite phantom derived from ADAM and EVA was employed to evaluate the energy deposition in some organs during a standard BNCT treatment. The total dose consists of the contributions from the primary neutron beam, the neutron interactions with boron and the neutron induced photons generated in the epithermal column structures and in the patient's tissues. The paper summarizes the computational procedure and provides a general dosimetric framework of the patient radiological protection aspects related to a BNCT treatment scenario at the TAPIRO reactor.

The general criteria and the scientific approach adopted for an 'International comparison on Monte Carlo modelling for in vivo measurement of Americium in a knee phantom' that is being organised within the EU Coordination Action CONRAD (Coordinated Network for Radiation Dosimetry) are described her. Detection system and a knee voxel phantom based on a computerised axial tomography of the Spitz anthropometric knee phantom with a homogeneous distribution of 241Am in bone have been considered for the simulation of three specific situations: (a) a single Low Energy Germanium detector for a point 241Am source in air; (b) the calculation of photon fluence spectra in air around the voxel phantom; and (c) the calculation of the energy distribution of pulses and peak detection efficiency in the real detection system geometry.

The question of Monte Carlo simulation of radiation transport in voxel geometries is addressed. Patched versions of the MCNP and MCNPX codes are developed aimed at transporting radiation both in the standard geometry mode and in the voxel geometry treatment. The patched code reads an unformatted FORTRAN file derived from DICOM format data and uses special subroutines to handle voxel-to-voxel radiation transport. The various phases of the development of the methodology are discussed together with the new input options. Examples are given of employment of the code in internal and external dosimetry and comparisons with results from other groups are reported.

Anthropomorphic computational models coupled with radiation transport codes are valuable tools in radiation protection dosimetry. In particular, they are very reliable for the estimate of the energy absorbed by different organs due to an incorporated radionuclide. MIRD-based stylised analytical models are widely accepted as standards but the recent generation of voxel phantoms, developed on real anatomical data derived from tomographic images, can represent a valid alternative for radiation protection and dosimetry purposes. Specific absorbed fraction evaluation and patient-specific dose estimate in nuclear medicine and radiotherapy could be considered as the optimal area for their implementation and use. On the other hand, the accuracy of organ and body structure representation guarantees an improved dose evaluation system also for radiation protection purposes in the workplace in case of accidental internal contamination. In the present work the voxel model NORMAN-05, a modified version of NORMAN (HPA, UK) model, has been employed with the Monte Carlo code MCNPX. Some preliminary investigations were carried out to evaluate the absorbed fractions for a series of source-target organ couples in case of gamma emitters and the organ absorbed doses in case of 90Sr incorporation. The paper summarises the main preliminary outcomes of such studies.

Photons conversion coefficients from 20 keV to 100 MeV have been calculated with the voxel model NORMAN-05 using the MCNPX code. Both kerma approximation and electronic transport were employed and the results compared with published data. In the near future, ICRP group DOCAL will issue a new computational model, based on the GSF-GOLEM, which is intended to be the reference adult male voxel model for ICRP. NORMAN-05 well approximates the western-caucasian standard man characteristics, in terms of body height (176 cm) and mass (73 kg) and masses of the organs. It is not intended to substitute, or to be an alternative, to the future official ICRP voxel model, but thanks to its accuracy and its "standard man structure" can be useful to evaluate the intrinsic uncertainties associated with the dose quantities evaluated adopting different voxel models. For such reason data obtained with NORMAN-05 could be easily compared with those that will be derived from the future ICRP model.

Thanks to the continuously increasing computer power, Monte Carlo techniques are progressively playing a key role in radiation dosimetry, in the field of dose assessment from internal and external exposures. Internal dosimetry aspects are presented in a separate paper in the same issue. For external exposure, individual monitoring techniques provide suitable tools to estimate the personal dose equivalent Hp(d), that should be a conservative estimate of the effective dose. Personal dosemeters should be designed and type tested in terms of Hp(d) and also irradiations facilities should be characterised in terms of the same operational quantity. This paper provides a concise overview on the role played by monte Carlo techniques in the field.

The QUADOS EU cost shared action conducted an intercomparison on the usage of numerical methods in radiation protection and dosimetry. The eight problems proposed were intended to test the usage of Monte Carlo and deterministic methods by assessing the accuracy with which the codes are applied and also the methods used to evaluate uncertainty in the answer gained through these methods. The overall objective was to spread good practice through the community and give users information on how to assess the uncertainties associated with their calculated results.

Microdosimetry with tissue-equivalent proportional counters (TEPC) has proven to be an ideal dosimetry technique for mixed radiation fields as those ones used in boron neutron capture therapy (BNCT). A new counter, composed of two twin cylindrical mini TEPCs inserted in a slim titanium sleeve of 2.7 mm external diameter, has been constructed. The detector has been designed to perform dosimetry and microdosimetry in intense radiation fields. The two mini TEPCs work in gas flow mode. They have right cylinder sensitive volumes of 0.9 mm. In spite of gas line tiny sizes, the gas pressure inside the two counters is well established with <1% of uncertainty. The counter has been calibrated in a secondary standard photon fields. The mean of the effective sensitive volume sizes has been measured to be 0.86 mm. The twin TEPC acquisition system processes properly the signals up to about 30 kHz of counting rate. Therefore, twin TEPC can perform dosimetric measurements in photon field with intensities of some tens of Gy h(-1).

'QUADOS', a concerted action of the European Commission, has promoted an intercomparison aimed at evaluating the use of computational codes for dosimetry in radiation protection and medical physics. This intercomparison was open to all users of radiation transport codes. Eight problems were selected for their relevance to the radiation dosimetry community, five of which involved photon and proton transport. This paper focuses on a discussion of lessons learned from the participation in solving the photon and charged particle problems. The lessons learned from the participation in solving the neutron problems are presented in a companion paper (in this issue).

In recent years voxel phantoms have been developed on the basis of tomographic data of real individuals allowing new sets of conversion coefficients to be calculated for effective dose. Progress in radiation studies brought ICRP to revise its recommendations and a new report, already circulated in draft form, is expected to change the actual effective dose evaluation method. In the present paper the voxel phantom NORMAN developed at HPA, formerly NRPB, was employed with MCNP Monte Carlo code. A modified version of the phantom, NORMAN-05, was developed to take into account the new set of tissues and weighting factors proposed in the cited ICRP draft. Air kerma to organ equivalent dose and effective dose conversion coefficients for antero-posterior and postero-anterior parallel photon beam irradiations, from 20 keV to 10 MeV, have been calculated and compared with data obtained in other laboratories using different numerical phantoms. Obtained results are in good agreement with published data with some differences for the effective dose calculated employing the proposed new tissue weighting factors set in comparison with previous evaluations based on the ICRP 60 report.

Whole-body counters (WBCs) are used for the assessment of the internal contamination of actinides in the human body. WBCs require adequate calibration procedures that rely on the use of suitable calibration phantoms. A previous study carried out at the ENEA-Radiation Protection Institute was aimed at designing a head calibration phantom in which a heterogeneous distribution of 241Am point sources could satisfactorily approximate an assumed homogeneous contamination throughout the head bones. Suitable correction factors for the WBC detection efficiencies were evaluated with Monte Carlo. The present paper summarises the main aspects and implications of an advanced modelling technique based on a VOXEL approach. The methodology could be extended to other bone-seeker radionuclides.

It was the purpose of the study to evaluate morcellized bone with cement and antibiotic release mixed with vancomycin and methylmethacrylate cement (PMMA). The aim of the study is part of a wider one aimed at verifying the possibility of using this composite for the treatment of chronic septic pathologies of the bone. Five cylinders 1 cm in height by 1 cm in diameter, formed by morcellized bone with cement and vancomycin were immersed in plasma and 5 in physiological solution. Three cylinders equal in size but formed by cement and antibiotic alone were immersed in plasma and 3 in physiological solution. All of the cylinders remained in immersion for 28 days at a temperature of 37 degrees C. The immersion fluids were changed every day during the first week and on days 14, 21 and 28. The quantity of vancomycin released was dosed in each specimen. The greatest and most constant release of antibiotic took place in the cylinders of morcellized bone, cement and antibiotic immersed in plasma.

QUADOS, a Concerted Action of the European Commission, has promoted an intercomparison aimed at evaluating the use of computational codes for dosimetry in radiation protection and medical physics. This intercomparison was open to all users of radiation transport codes. Eight problems were selected for their relevance to the radiation dosimetry community, five of which involved photon and proton transport. This paper focuses on the analysis of the photon and charged particle problems. The neutron problems were presented in a paper at the NEUDOS9 conference.

At the ENEA Radiation Protection Institute in Bologna a thermal neutron irradiation facility is available for the calibration of neutron dosemeters. It consists of a 1 m x 1 m x 1 m polyethylene cube containing three 241Am-Be sources of about 185 GBq. The cube contains three co-axial cylindrical calibration cavities of different dimension. Due to their limited dimensions, the cavities do not allow the calibration of thermal neutron personal dosemeters in terms of Personal Dose Equivalent Hp(d), that should be carried out on the 30 cm x 30 cm x 15 cm ISO phantom. The study herewith presented was addressed at adapting the facility for external irradiation of personal dosemeters on the ISO phantom. Extensive Monte Carlo studies were carried out to characterise the neutron fluence spatial distribution along the front face of the phantom. A satisfying neutron field homogeneity within the measurement area has been obtained by means of a pyramidal polyethylene fluence flattening filter and the selection of the proper cube to phantom distance. This new irradiation set-up was experimentally tested through measurements with activation foils, according to the spatial mapping array taken from the calculations.

The present paper summarises the activity carried out at the ENEA Radiation Protection Institute for updating the methodologies employed for the evaluation of the neutron and photon dose to the exposed workers in case of a criticality accident, in the framework of the 'International Intercomparison of Criticality Accident Dosimetry Systems' (Silène reactor, IRSN-CEA-Valduc June 2002). The evaluation of the neutron spectra and the neutron dosimetric quantities relies on activation detectors and on unfolding algorithms. Thermoluminescent detectors are employed for the gamma dose measurement. The work is aimed at accurately characterising the measurement system and, at the same time, testing the algorithms. Useful spectral information were included, based on Monte Carlo simulations, to take into account the potential accident scenarios of practical interest. All along this exercise intercomparison a particular attention was devoted to the 'traceability' of all the experimental and computational parameters and therefore, aimed at an easy treatment by the user.

'QUADOS', a Concerted Action of the European Commission, has run an intercomparison aimed at evaluating the use of computational codes for dosimetry in radiation protection and medical physics. This intercomparison was open to all users of Monte Carlo, analytic and semi-analytic codes or deterministic methods. Its main aim was to provide a snapshot of the methods and codes currently in use. It also intended to furnish information on the methods used to assess the reliability of computational results and disseminate 'good practice' throughout the radiation dosimetry community. Eight problems were selected for their relevance to the radiation dosimetry community, three of which involve neutron transport. This paper focuses on the analysis of the neutron problems.

From 1988 to 2000, 21 patients with infected nonunion were treated by wide resection of the nonunion site and fixation with Ilizarov's external ring fixator. Of the 21 cases, 2 are still under treatment. 18 cases resolved. In two cases iterative fracture occurred, which was successfully treated by internal fixation. One case treated by external fixator failed; any further attempts at surgery were abandoned, and the patient was put in a brace. The ring fixator enabled a sufficiently wide resection to remove the infection. It also provided stability for long periods of time, unrestricted weight bearing, and, after resolution, the same set up was used to restore the femur to its original length by corticotomy and distraction according to Ilizarov.

We studied a teleconsulting service for second opinions in orthopaedics. Three units of the national insurance organization for accidents at work were connected to a large orthopaedic hospital in Bologna. During a 20-month study, 65 consultations were provided: 51 (78%) by asynchronous (store-and-forward) consulting and 14 (22%) by realtime videoconferencing. All the consultations made use of radiology images (radiographs, computerized tomography scans, magnetic resonance imaging scans and ultrasound scans). Video-messages and still images were commonly used to support the asynchronous consultations. More data were transmitted on average for an asynchronous teleconsultation (8 MByte) than in a videoconference (5 MByte). The average time spent by orthopaedic specialists was slightly longer in videoconferences (21 min, SD 8) than in asynchronous teleconsultations (19 min, SD 8). The clinicians confidence in their diagnosis was generally good but was lower in asynchronous consultations. The main problem affecting the telemedicine service was the lack or the low quality of the information received from the referring sites. The clinical complexity of the case and the organizational requirements were declared to be the main factors affecting the choice of consulting procedure. The study showed that the asynchronous method was preferred in the majority of cases and could be easily integrated into clinical practice, although there were some concerns about the diagnostic quality of the information transmitted.

Eight patients with infected nonunion of the humerus were treated surgically by removal of the instrumentation, surgical debridement or wide resection of the fracture site and stabilization in compression with an external fixator. A monoaxial external fixator was used in 5 patients, a circular external one in 3. The amount of time between trauma and treatment described was a mean of 13 months. Consolidation occurred in all of the patients after an average of 5.5 months. Long-term follow-up was obtained after a mean of 18 months (minimum 14, maximum 35). There was postoperative paralysis of the radial nerve in 2 of the cases, with complete recovery after 3 months. One case consolidated despite the persistence of a fistula.

The investigation of actinides' internal contamination in human body makes use of a variety of techniques. In large scale screening the technique of "in vivo" evaluation of bone 241Am burden via the determination of the nuclide activity in the skull is often used. For this purpose, adequate calibration procedures and standard phantoms are needed. The present paper summarises the studies and technical procedures followed for the development of a calibration phantom based on a commercial Alderson angiographic head in which a set of 24 241Am point sources were embedded. A theoretical study was first carried out, at the ENEA Institute for Radiation Protection, using the MCNP4-B Monte Carlo code to determine the point source distribution that closely approximates a homogeneous bone contamination. The numerical models were also used to evaluate the resulting degree of approximation. The point sources were prepared at the ENEA National Metrology Institute for ionising radiation quantities and were traceable to the Italian national standard of radionuclide activity. The sources were prepared by quantitatively dispensing a liquid solution onto a plastic disc. The activity of each source was checked by gamma-ray spectrometry and the reproducibility of the activity values was determined. Each source was then placed in the optimum position in the skull, given by the Monte Carlo modelling, by a precision mechanical device. The phantom was finally used to calibrate a whole body counter operating at the ENEA Institute for Radiation Protection. The paper reports the main theoretical and experimental aspects of this work, and also discusses the results of the first calibrations.

The authors comment on the experience acquired in the treatment of chronic osteomyelitis of the long bones with intramedullary reaming. The procedure is reserved for the femur and tibia with stage I chronic osteomedullary infection according to the Cierny-Mader classification. 2 A total of 36 patients were treated. Surgical treatment consists in reaming of the medullary canal and in its contra-opening with antiseptic solutions. Mean time for lavage is 6 days. Criteria for healing involves the absence of clinical, humoral, and radiologic signs of active medullary sites of infection. The percentage of healing was 83.2%, mean long-term follow-up was 2.9 years.

Unlabelled: Radioiodine-131 is used in differentiated thyroid cancer (DTC) for ablation of postsurgical thyroid remnants and destruction of metastases. The question may be raised of whether 131I treatment of DTC in male patients may give an irradiation dose to the testes that could impair fertility. Few data in the literature concern the dose absorbed by the testes after 1311 therapy for DTC. Because 131I kinetics may be altered by the hypothyroid condition commonly present at the time of treatment and by the radioiodinated iodoproteins released by the damaged thyroid tissue, the dose values reported in the International Commission on Radiological Protection (ICRP) tables for euthyroid men may not be appropriate. To clarify this problem, three male subjects undergoing 131I therapy for ablation of thyroid remnants shortly after thyroidectomy for DTC were studied., Methods: The mean administered activity was 1256 MBq, and the duration of the study was 2 wk. The gamma dose was measured by thermoluminescent dosimeters (TLDs) applied to the lower poles of the testes. Correction factors were calculated for the distance of the TLD from the center of the testes and for attenuation by the testes of the gamma rays reaching the TLD. After correction, the gamma dose to the testes ranged from 21 to 29 mGy. The gamma dose calculated by the Medical Internal Radiation Dose (MIRD) method from blood and urine samples was similar (18-20 mGy) to that measured by TLDs. The beta dose was estimated by the MIRD method from blood activity and testicular volume and ranged between 14 and 31 mGy., Results: The total (beta and gamma) doses to testes were 30, 33 and 43 microGy/MBq in the three subjects., Conclusion: These values are close to those derived from the ICRP tables (26-37 microGy/MBq 131I) for euthyroid subjects. The present data indicate that significant irradiation is delivered to the testes after the administration of the 131I ablative dose to thyroidectomized patients. The relevance of the radiation absorbed by testes on fertility remains to be established.

The authors conducted a study to evaluate the effects of cigarette smoke on the healing of septic pseudarthrosis of the tibia treated by ilizarov external fixator. A total of 31 patients of both sexes were chosen, and the healing time in relation to the habit of smoking was examined. The results have shown that the healing time in non-smokers as compared to smokers was shorter by 33%. The difference is highly significant. This shows that abstention from smoking during treatment should be given maximum importance in prevention.

The authors report 52 cases of aseptic nonunion of the tibia treated by intramedullary osteosynthesis. The means of synthesis used were the Küntscher nail, the Eiffel Tower Rush nail, and the Grosse-Kempf nail. Which means of synthesis was used depended on the site and the features of the nonunion. Healing occurred in all of the cases after an average of 5 months. Mean follow-up was 4.5 years.

An original system used to measure torque of pin insertion and extraction in external fixation is presented. The system is made up of an electronic dynamometric key and an analogic/digital switchboard that may be linked up to a personal computer. The in vitro results show the simplicity of use and the versatility of the system, that is capable of providing the surgeon with accurate indicative values as to the mechanical resistance of the bone-pin interface during implantation of any fixator.

Between 1985 and 1990 a total of 35 cases of infected pseudarthrosis of the tibia were treated by radical resection of the pseudarthrosis and corticotomy-distraction-compression. In 5 patients there was severe lesion of the soft tissues with extensive loss of substance. It is the purpose of the present study to evaluate the effects of the use of this method on lesions of the soft tissues in these 5 patients.

Vertebral deformity in neurofibromatosis can present in two basic forms which determine the prognosis and treatment. In the first form, which is rare, there are no gross dystrophic changes, while in the second, which is the more common, such changes are widespread. Neurofibromatosic scoliosis where there are no signs of bone dystrophy poses no particular therapeutic problems. However, the surgical treatment of the dystrophic form is much more complex and the results far more uncertain. There is a high incidence of pseudarthrosis following posterior arthrodesis and fixation with Harrington rods, and this has shown the need for combined posterior and anterior arthrodesis in all cases of neurofibromatosic kyphoscoliosis. Furthermore, posterior arthrodesis alone does not provide protection against future relapse even when kyphosis is initially absent. Delayed kyphosis, due to subsidence of the vertebral bodies, frequently appears after six months and necessitates a second operation to reinforce the posterior arthrodesis. However, a greater guarantee of stability can be achieved simply by performing combined anterior and posterior arthrodesis at the outset.