Tissue mimicking materials for imaging and therapy phantoms: a review

Tissue mimicking materials (TMMs), typically contained within phantoms, have been used for many decades in both imaging and therapeutic applications. This review investigates the specifications that are typically being used in development of the latest TMMs. The imaging modalities that have been investigated focus around CT, mammography, SPECT, PET, MRI and ultrasound. Therapeutic applications discussed within the review include radiotherapy, thermal therapy and surgical applications. A number of modalities were not reviewed including optical spectroscopy, optical imaging and planar x-rays. The emergence of image guided interventions and multimodality imaging have placed an increasing demand on the number of specifications on the latest TMMs. Material specification standards are available in some imaging areas such as ultrasound. It is recommended that this should be replicated for other imaging and therapeutic modalities. Materials used within phantoms have been reviewed for a series of imaging and therapeutic applications with the potential to become a testbed for cross-fertilization of materials across modalities. Deformation, texture, multimodality imaging and perfusion are common themes that are currently under development

Dose estimation after a mixed field exposure: Radium-223 and intensity modulated radiotherapy

Included in a special edition on ‘Radiobiology of Molecular Radionuclide Therapy’.This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Public Health England, PHE PhD studentship scheme; Movember Prostate Cancer UK Centre of Excellence (CEO13_2-004); Research and Development Division of the Public Health Agency of NI (COM/4965/14)

Clinically relevant safety issues associated with St. John's wort product labels

<p>Abstract</p> <p>Background</p> <p>St. John's wort (SJW), used to treat depression, is popular in the USA, Canada, and parts of Europe. However, there are documented interactions between SJW and prescription medications including warfarin, cyclosporine, indinavir, and oral contraceptives. One source of information about these safety considerations is the product label. The aim of this study was to evaluate the clinically relevant safety information included on labeling in a nationally representative sample of SJW products from the USA.</p> <p>Methods</p> <p>Eight clinically relevant safety issues were identified: drug interactions (SJW-HIV medications, SJW-immunosupressants, SJW-oral contraceptives, and SJW-warfarin), contraindications (bipolar disorder), therapeutic duplication (antidepressants), and general considerations (phototoxicity and advice to consult a healthcare professional (HCP)). A list of SJW products was identified to assess their labels. Percentages and totals were used to present findings.</p> <p>Results</p> <p>Of the seventy-four products evaluated, no product label provided information for all 8 evaluation criteria. Three products (4.1%) provided information on 7 of the 8 criteria. Four products provided no safety information whatsoever. Percentage of products with label information was: SJW-HIV (8.1%), SJW-immunosupressants (5.4%), SJW-OCPs (8.1%), SJW-warfarin (5.4%), bipolar (1.4%), antidepressants (23.0%), phototoxicity (51.4%), and consult HCP (87.8%). Other safety-related information on labels included warnings about pregnancy (74.3%), lactation (64.9%), discontinue if adverse reaction (23.0%), and not for use in patients under 18 years old (13.5%). The average number of <it>a priori </it>safety issues included on a product label was 1.91 (range 0–8) for 23.9% completeness.</p> <p>Conclusion</p> <p>The vast majority of SJW products fail to adequately address clinically relevant safety issues on their labeling. A few products do provide an acceptable amount of information on clinically relevant safety issues which could enhance the quality of counseling by HCPs and health store clerks. HCPs and consumers may benefit if the FDA re-examined labeling requirements for dietary supplements.</p

Practical collimator optimization in the management of prostate IMRT planning: A feasibility study

AbstractThe objective of this study was to evaluate the delivery efficiency of intensity modulated radiation therapy (IMRT) with a non-zero collimator rotation approach compared to conventional planning IMRT in the management of prostate carcinoma. Inverse plans, created using conventional collimator angle 0° (CA0) for eight prostate patients, were compared to plans using collimator angle 70° (CA70) for all fields and also with plans utilizing an automatic collimator angle optimization tool (CAopt) for each field. Results demonstrate that IMRT plans created with rotational collimator techniques can produce comparable dose distributions to standard CA0 plans. The rotational collimator approach significantly reduced the total number of monitor units (MU) by 6% (p value = 0.027) and 9% (p value = 0.003) for CA70 and CAopt, respectively. The mean monitor units for CA0, CA70 and CAopt were 635 ± 107 MU, 597 ± 96 MU and 587 ± 104 MU, respectively. The mean peripheral dose was significantly increased with CA70 against CA0 (p value &lt; 0.001) despite reduced monitor units. Collimator optimization resulted in reduction in monitor units and peripheral dose. The number of monitor units are reduced with the rotational collimator approach, which results in reduced delivery time. However, we conclude that peripheral dose should be analyzed when assessing monitor unit differences in IMRT plans.</jats:p