SU‐GG‐I‐79: Effective Doses to Pediatric Cystic Fibrosis Patients Undergoing Chest CT Examinations
Bibliographic record
Abstract
Purpose: To compare radiation doses to five year old pediatric patients with Cystic Fibrosis (CF) undergoing chest CT examinations at five North American imaging centers. Method and Materials: A questionnaire was sent to five facilities participating in a CF research study (Chapel Hill NC; Washington WA; St Louis Mo; Denver Co; Toronto ON) to obtain their protocols for chest CT examinations on a five year old child with Cystic Fibrosis. The ImPACT CT dose calculator was used to determine adult effective doses for techniques used at each facility (i.e., kV/mAs/pitch). Adult effective doses were scaled to those for five year olds to account for differences in scan length, patient size and energy imparted. Results: The five facilities used four different models of CT scanner from two vendors. CT techniques for five year old patients with CF were generally 120 kV, 60 mAs, and an average pitch ratio of ∼ 1.2. Adult scan lengths were 30 cm whereas those for 5 year olds were 15 cm. Adults weigh 70 kg compared to 18.5 kg for a 5 year old. For a single 360 ° x‐ray tube rotation, energy absorbed in the chest region of a five year old is only 55% of that for an adult. Three facilities had effective doses of ∼ 2.4 mSv, whereas two facilities had lower doses of ∼1.25 mSv. The main reasons for the lower doses were the use of lower x‐ray technique (i.e., 30 mAs) or a lower x‐ray tube voltage (i.e., 100 kV). Conclusion: Effective doses to 5 year old CF patients can be obtained by scaling adult effective doses, and average to 2 mSv per patient examination.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".