The ICRU Proposal for New Operational Quantities for External Radiation.

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.

Hp(3)/Φ conversion coefficients for neutrons: discussion on the basis of the new ICRP recommended limit for the eye lens.

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 role of active immunization therapy as preoperative treatment for chronic osteomyelitis.

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.

Fluence to Hp(3) conversion coefficients for neutrons from thermal to 15 MeV.

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.

Air kerma to HP(3) conversion coefficients for photons from 10 keV to 10 MeV, calculated in a cylindrical phantom.

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.

Monte Carlo variance reduction techniques: an overview with some practical examples.

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.

Principles for the design and calibration of radiation protection dosemeters for operational and protection quantities for eye lens dosimetry.

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.

Eye lens dosimetry: task 2 within the ORAMED project.

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).

Extremity exposure in nuclear medicine: preliminary results of a European study.

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.

ENEA extremity dosemeter based on LiF(Mg,Cu,P) to evaluate Hp(3,alpha).

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.

Evaluation of the dose to the patient and medical staff in interventional cardiology employing computational models.

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.

Knee arthrodesis with the Ilizarov external fixator as treatment for septic failure of knee arthroplasty.

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.

A review of voxel model development and radiation protection applications at ENEA.

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.

Chronic recurrent multifocal and aspecific osteomyelitis: a case report.

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.

Analysis of computational problems expressing the overall uncertainties: photons, neutrons and electrons.

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.

Analysis of a computational problem involving complex voxel geometries.

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.

Monte Carlo modelling for in vivo measurements of Americium in a knee voxel phantom: general criteria for an international comparison.

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.

Preliminary evaluations of the undesirable patient dose from a BNCT treatment at the ENEA-TAPIRO reactor.

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.

MCNPX internal dosimetry studies based on the NORMAN-05 voxel model.

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.

Monte Carlo evaluated parameters for internal dosimetry.

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.

Monte Carlo modeling for individual monitoring.

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.

Preliminary studies on neutron conversion coefficients calculated with MCNPX in NORMAN voxel phantom.

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.

Personal dosimetry in terms of HP(3): Monte Carlo and experimental studies.

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).

Two miniaturised TEPCS in a single detector for BNCT microdosimetry.

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.