Construction and validation of an infant chest phantom for paediatric computed tomography.

Paediatric imaging protocols should be carefully optimised to maintain the desired image quality while minimising the delivered patient dose. A paediatric chest phantom was designed, constructed and evaluated to optimise chest CT examinations for infants. The phantom was designed to enable dosimetry and image quality measurements within the anthropomorphic structure. It was constructed using tissue equivalent materials to mimic thoracic structures of infants, aged 0-6 months. The phantom materials were validated across a range of diagnostic tube voltages with resulting CT numbers found equivalent to paediatric tissues observed via a survey of clinical paediatric chest studies. The phantom has been successfully used to measure radiation dose and evaluate various image quality parameters for paediatric specific protocols.

Establishment of a local diagnostic reference level for dental intraoral bitewing X-rays.

A state-based local diagnostic reference level (LDRL) for dental intraoral X-rays has been established. LDRL values of 2.0 mGy incident air kerma (IAK) and 57 mGy•cm2 air kerma-area product (KAP) for an adult posterior bitewing X-ray were determined based on 811 X-ray units surveyed. This IAK LDRL value is greater than those established in several other nations and regions around the world in similar studies. Analyses of radiographic technique and equipment usage are included to provide broad guidance as to ways that imaging could be optimised, such as in the selection of exposure factors, collimators, image receptors, and X-ray unit models.

Cosmetic outcomes following wide local excision of impalpable breast cancer: is radioguided occult lesion localization using iodine-125 seeds better than hookwire localization?

BACKGROUND: Hookwire localization (HWL) is the gold standard for localizing impalpable tumours for breast conserving surgery. An alternative technique, radioguided occult lesion localization using iodine-125 seeds (ROLLIS), has been associated with lower re-excision rates. This paper investigates if cosmetic outcomes differ in women undergoing breast conserving surgery with HWL or ROLLIS. METHODS: Women who had ROLLIS or HWL guided excision for impalpable breast cancer within a multicentre randomized controlled trial (RCT) (ANZCTR 12613000655741) were recruited. Exclusions were level 2 oncoplasty and mastectomy. Cosmetic outcome was calculated using BCCT.core, the Hopwood Body Image Scale and estimated percentage breast volume excised. Chi-squared analysis was used to determine the difference between the intervention groups. RESULTS: Analysis was performed for 123 participants (66 ROLLIS and 57 HWL). The cosmetic outcome determined by BCCT.core for all participants was good with no significant difference between the ROLLIS and HWL groups. When reviewing the number of patients who experienced either a good or excellent result, there was a significantly higher number of patients in the ROLLIS group (n = 53, 82%) compared to the HWL group (n = 42, 74%, P = 0.02. There were no differences in Hopwood Body Image Scale or estimated percentage breast volume excised between groups. There was a reduction in the frequency of re-excision in the ROLLIS group (n = 3, 4.5%) versus HWL group (n = 8, 14%); however, this was not significant (P = 0.06). CONCLUSION: Pre-operative localization of impalpable breast lesions using either ROLLIS or HWL resulted in a good cosmetic outcome with no significant difference between localization techniques.

Direct in vivo comparison of [18F]PSMA-1007 with [68Ga]Ga-PSMA-11 and [18F]AlF-PSMA-11 in mice bearing PSMA-expressing xenografts.

The aim of this preclinical study was to directly compare [18F]PSMA-1007 with both [68Ga]Ga-PSMA-11 and [18F]AlF-PSMA-11 in mice bearing PSMA-positive tumor xenografts. Uptake was assessed by PET/CT at 1, 2 and 4 h post-injection, and by ex vivo measurement after 4 h. [18F]PSMA-1007 demonstrated the highest tumor uptake of the three tracers. The high uptake in bone for mice injected with [18F]AlF-PSMA-11 suggested rapid in vivo decomposition. This was confirmed by an in vitro plasma stability study.