From standard to stratified: Modeling NTCP and EAR to personalize daily MV‐CBCT in radiotherapy
Bibliographic record
Abstract
PURPOSE: To evaluate the cumulative radiobiological impact of daily megavoltage cone-beam computed tomography (MV-CBCT) imaging dose based on normal tissue complication probability (NTCP) and excess absolute risk (EAR) of secondary malignancies among radiotherapy patients treated for breast, pelvic, and head & neck cancers. This study investigated whether MV-CBCT imaging dose warrants protocol personalization according to patient age, anatomical treatment site, and organ-specific radiosensitivity. METHODS: This retrospective study included cohorts of breast (n = 30), pelvic (n = 17), and head & neck (n = 20) cancer patients undergoing radiotherapy with daily MV-CBCT. Imaging dose distributions employing two common MV-CBCT protocols (5 and 10 MU per fraction) were analyzed. NTCP values were estimated using logistic models, while EAR were calculated using Schneider's organ equivalent dose (OED)-based model, integrating organ-specific dose, patient age, and established tissue-specific risk coefficients. Comparative statistical analyses were conducted using paired t-tests, and results were further stratified by patient age (< 40, 40-60, > 60 years). RESULTS: In breast cancer patients, NTCP values increased significantly for lung tissue when comparing the 10 MU protocol to the 5 MU one (p < 0.001), while those for heart and breast tissues showed minimal and insignificant differences. EAR estimations revealed substantial risk increases among younger breast cancer patients (< 40 years), with some exceeding 15 cases per 10 000 person-years under the 10 MU protocol. Conversely, pelvic and head & neck cohorts demonstrated consistently low NTCP and EAR values (< 1%), with no meaningful differences observed between the two imaging protocols. Across all cancer sites, younger age consistently correlated with higher secondary cancer risks. CONCLUSION: Routine daily MV-CBCT imaging at the 10 MU protocol possesses minimal additional risk in pelvic and head & neck radiotherapy. However, among breast cancer patients, particularly those under 40 years, the 10 MU protocol significantly elevates the theoretical secondary cancer risk estimates and lung NTCP. These findings support transitioning from conventional uniform imaging approach toward personalized MV-CBCT protocols, tailored according to patient age, anatomical site, and organ radiosensitivity. A stratified imaging framework is proposed to optimize clinical outcomes, balancing treatment accuracy, and long-term patient safety.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".