Structuring medication signeturs as a language regression task: comparison of zero- and few-shot GPT with fine-tuned models.

Importance: Electronic health record textual sources such as medication signeturs (sigs) contain valuable information that is not always available in structured form. Commonly processed through manual annotation, this repetitive and time-consuming task could be fully automated using large language models (LLMs). While most sigs include simple instructions, some include complex patterns. Objectives: We aimed to compare the performance of GPT-3.5 and GPT-4 with smaller fine-tuned models (ClinicalBERT, BlueBERT) in extracting the average daily dose of 2 immunomodulating medications with frequent complex sigs: hydroxychloroquine, and prednisone. Methods: Using manually annotated sigs as the gold standard, we compared the performance of these models in 702 hydroxychloroquine and 22 104 prednisone prescriptions. Results: GPT-4 vastly outperformed all other models for this task at any level of in-context learning. With 100 in-context examples, the model correctly annotates 94% of hydroxychloroquine and 95% of prednisone sigs to within 1 significant digit. Error analysis conducted by 2 additional manual annotators on annotator-model disagreements suggests that the vast majority of disagreements are model errors. Many model errors relate to ambiguous sigs on which there was also frequent annotator disagreement. Discussion: Paired with minimal manual annotation, GPT-4 achieved excellent performance for language regression of complex medication sigs and vastly outperforms GPT-3.5, ClinicalBERT, and BlueBERT. However, the number of in-context examples needed to reach maximum performance was similar to GPT-3.5. Conclusion: LLMs show great potential to rapidly extract structured data from sigs in no-code fashion for clinical and research applications.

Image Guided Energy Ablation for Palliation of Painful Bony Metastases - A Systematic Review.

PURPOSE: To analyze the effectiveness of image-guided energy ablation techniques with and without concurrent therapies in providing palliative pain relief in patients with bone metastases. MATERIALS AND METHODS: OVID Embase, OVID Medline, and Pubmed were searched from inception to April 14th, 2023 using search terms relating to bone lesions and MeSH terms regarding ablation therapy. English peer-reviewed primary articles were included that reported pain scores following image-guided energy-based ablation of bone metastases. Exclusion criteria included 1) non-palliative treatment, 2) pain scores associated with specific treatment modalities not reported, and 3) non-metastatic bone lesions. Mean percentage reduction in pain score was calculated. RESULTS: 1396 studies were screened and 54 were included. All but one study demonstrated decreased pain scores at final follow-up. Mean reduction in pain scores at final follow-up were 49% for radiofrequency ablation (RFA), 58% for radiofrequency ablation and adjunct (RFA-A), 54% for cryoablation (CA), 72% for cryoablation and adjunct (CA-A), 48% for microwave ablation (MWA), 81% for microwave ablation and adjunct (MWA-A), and 64% for high-intensity focused ultrasound (HIFU). Post-procedural adverse event rates were 4.9% for RFA, 34.8% for RFA-A, 9.6% for CA, 12.0% for CA-A, 48.9% for MWA, 33.5% for MWA-A and 17.0% for HIFU. CONCLUSION: Image-guided energy ablation demonstrated consistently strong reduction in pain across all modalities, with variable post-procedural adverse event rates. Due to heterogeneity of included studies, quantitative analysis was not appropriate. Future primary research should focus on creating consistent prospective studies with established statistical power, explicit documentation and comparison to other techniques.

Development of UV-Vis Imaging Compatible Chromatographic Matrix with Application for Injectable Formulation Characterization.

Transport within human tissue matrices, e.g., the subcutaneous tissue, exhibits some resemblance to chromatographic processes. Here, a porous matrix comprising agarose beads compatible with UV-vis imaging was developed for a parallel piped rectangular flow cell (4 mm light path). Introduction of high-molecular weight dextrans (Mr ∼ 200000 and ∼500000) at 10% (w/v) rendered imaging possible by providing optical clearing of the turbid porous matrix, resulting in improved transmittance as well as resolution (from 400 to 180 µm) at 280 nm, as well as 520 nm. The interplay between diffusive and convective transport at 0 < Pe ≤ 28 was visualized at 280 nm upon injection of dexamethasone suspensions. Real-time UV-vis imaging showed in-flow cell the effect of incorporating ion-exchange resins on the retention of infliximab, lysozyme, and α-lactalbumin. The ion-exchange matrix may serve as a surrogate for polyelectrolytes in the subcutaneous tissue, assessing the potential role of electrostatic interactions of biotherapeutics upon injection. UV-vis imaging of size-exclusion chromatographic matrixes may be of interest in its own right and potentially develop into a characterization tool for injectables.

Impact of Lenalidomide Treatment on Overall Survival in Patients With Lower-Risk, Transfusion-Dependent Myelodysplastic Syndromes.

BACKGROUND: For patients with lower-risk (LR) myelodysplastic syndromes (MDS), overall survival (OS) is rarely a primary clinical trial endpoint. Treatments such as lenalidomide can reduce red blood cell (RBC) transfusion burden (TB) and serum ferritin, but the long-term impact on OS remains undetermined. PATIENTS AND METHODS: Data from 3 trials evaluating lenalidomide in patients with LR-MDS (the phase 2 MDS-003 and phase 3 MDS-004 trials in del[5q]; the phase 3 trial MDS-005 in non-del[5q] patients) were pooled. Predictors of OS were assessed by multivariate analysis using time-dependent models for TB and RBC transfusion independence (RBC-TI), and a landmark analysis of RBC-TI at 17 weeks. Separate analyses using MDS-004 and MDS-005 data determined the relationship between OS and serum ferritin. RESULTS: Median follow-up for MDS-003, MDS-004, and MDS-005 was 3.2, 3.0, and 1.7 years, respectively. In multivariate analyses, transfusion of ≥6 RBC units over 8 weeks was a significant predictor of shorter OS vs. 0 units in the time-dependent TB model (hazard ratio [HR] 4.65; 95% confidence interval [CI] 3.32-6.52; P < .0001). RBC-TI achievement was associated with prolonged OS in the time-dependent (HR 0.48; 95% CI 0.37-0.62; P < .0001) and landmark model (HR 0.57; 95% CI 0.44-0.75; P < .0001). Increased serum ferritin was associated with shorter OS (P < .0001). CONCLUSION: This analysis of prospective trial data in patients with LR-MDS confirms lenalidomide may improve OS by reducing TB and serum ferritin. OS should be considered as an endpoint in future lower risk MDS clinical trials.

Contextualizing temporal arterial magnetic resonance angiography in the diagnosis of giant cell arteritis: a retrospective cohort study.

OBJECTIVES: Imaging modalities have become common in evaluating patients for a possible diagnosis of GCA. This study seeks to contextualize how temporal arterial magnetic resonance angiography (TA-MRA) can be used in facilitating the diagnosis of GCA. METHODS: A retrospective cohort study was performed on patients who had been previously referred to a rheumatologist for evaluation of possible GCA in Hamilton, Ontario, Canada. Data including clinical features, inflammatory markers, imaging, and biopsy results were extracted. Multivariable logistic regression model to predict the diagnosis of GCA. Using these models, the utility of TA-MRA in series with or in parallel to clinical evaluation was demonstrated across the cohort as well as in subgroups defined by biopsy and imaging status. RESULTS: In total 268 patients had complete data. Those diagnosed with biopsy- and/or imaging-positive GCA were more likely to demonstrate classic features including jaw claudication and vision loss. Clinical multivariable modelling allowed for fair discriminability [receiver operating characteristic (ROC) 0.759, 95% CI: 0.703, 0.815] for diagnosing GCA; there was excellent discriminability in facilitating the diagnosis of biopsy-positive GCA (ROC 0.949, 0.898-1.000). When used in those with a pre-test probability of 50% or higher, TA-MRA had a positive predictive value of 93.0%; in those with a pre-test probability of 25% or less TA-MRA had a negative predictive value of 89.5%. CONCLUSION: In those with high disease probability, TA-MRA can effectively rule in disease (and replace temporal artery biopsy). In those with low to medium probability, TA-MRA can help rule out the disease, but this continues to be a challenging diagnostic population.

A Gene Mutation Signature Predicting Immunotherapy Benefits in Patients With NSCLC.

INTRODUCTION: Identification of patients who can benefit from immune checkpoint blockade (ICB) therapy is key for improved clinical outcome. Recently, U.S. Food and Drug Administration approved tumor mutational burden (TMB) high (TMB-H or TMB ≥ 10) as a biomarker for pembrolizumab treatment of solid tumors. We intend to test the hypothesis that mutations in select genes may be a better predictor of NSCLC response to ICB therapy than TMB-H. METHODS: We compiled a list of candidate genes that may predict for benefits from ICB treatment by use of data from a recently published cohort of 350 patients with NSCLC. We then evaluated the influences of different mutation signatures in the candidate genes on ICB efficacy. They were also compared with TMB-H. The predictive powers of different mutation signatures were then evaluated in an independent cohort of patients with NSCLC treated with ICB. RESULTS: A compound mutation signature, in which two or more of the 52 candidate genes were mutated, accounted for 145 of 350 patients with NSCLC and was associated with considerable ICB treatment benefits. Specifically, the median duration of overall survival was 36 versus 8 months in NSCLC in those with two or more versus none of the 52 genes mutated. Moreover, those patients with the compound mutation signature but had low TMB (<10) achieved significant overall survival benefits when compared with those without the signature but had TMB-H (≥10). Finally, in an independent cohort of 156 patients with ICB-treated NSCLC, the median duration of progression-free survival was 8.3 months versus 3.5 months in those with the compound mutation signature versus those with none mutated in the 52 genes. CONCLUSIONS: A genetic signature with mutations in at least two of 52 candidate genes was superior than TMB-H in predicting clinical benefits for ICB therapy in patients with NSCLC.

Neural network and logistic regression diagnostic prediction models for giant cell arteritis: development and validation.

PURPOSE: To develop and validate neural network (NN) vs logistic regression (LR) diagnostic prediction models in patients with suspected giant cell arteritis (GCA). Design: Multicenter retrospective chart review. METHODS: An audit of consecutive patients undergoing temporal artery biopsy (TABx) for suspected GCA was conducted at 14 international medical centers. The outcome variable was biopsy-proven GCA. The predictor variables were age, gender, headache, clinical temporal artery abnormality, jaw claudication, vision loss, diplopia, erythrocyte sedimentation rate, C-reactive protein, and platelet level. The data were divided into three groups to train, validate, and test the models. The NN model with the lowest false-negative rate was chosen. Internal and external validations were performed. RESULTS: Of 1,833 patients who underwent TABx, there was complete information on 1,201 patients, 300 (25%) of whom had a positive TABx. On multivariable LR age, platelets, jaw claudication, vision loss, log C-reactive protein, log erythrocyte sedimentation rate, headache, and clinical temporal artery abnormality were statistically significant predictors of a positive TABx (P≤0.05). The area under the receiver operating characteristic curve/Hosmer-Lemeshow P for LR was 0.867 (95% CI, 0.794, 0.917)/0.119 vs NN 0.860 (95% CI, 0.786, 0.911)/0.805, with no statistically significant difference of the area under the curves (P=0.316). The misclassification rate/false-negative rate of LR was 20.6%/47.5% vs 18.1%/30.5% for NN. Missing data analysis did not change the results. CONCLUSION: Statistical models can aid in the triage of patients with suspected GCA. Misclassification remains a concern, but cutoff values for 95% and 99% sensitivities are provided (https://goo.gl/THCnuU).

Erratum: Disruption of Myc-Max Heterodimerization with Improved Cell-Penetrating Analogs of the Small Molecule 10074-G5.

[This corrects the article DOI: 10.18632/oncotarget.1108.].

Undergraduate Dermatology Education in Canada: A National Survey.

BACKGROUND: Canadian dermatology curriculum was reviewed in 1983, 1987, 1996, and 2008. All these surveys highlighted the disproportionately low level of dermatology teaching in relation to the significant amount of skin disease seen by physicians. Since the official adoption and dissemination of the Canadian Professors of Dermatology (CPD) core curriculum and competencies, there has been no assessment of how these changes have influenced dermatology curriculum. OBJECTIVE: This survey gathered information on the current status of undergraduate dermatology education across Canadian medical schools. METHODS: A survey was sent electronically to all undergraduate dermatology directors at each of the 17 Canadian medical schools. RESULTS: Between 2008 and 2017, dermatology teaching has increased 25% to 25.6 ± 17.2 hours of teaching. However, 75% of this teaching is delivered in preclinical years. The number of faculty members, both dermatologists and nondermatologists, has also increased. A growing number of schools are now using electronic formats of teaching. Most schools (59%) are covering all the CPD core curriculum topics. CONCLUSION: Dermatology education is demonstrating positive trends with regards to teaching hours and faculty members. Nevertheless, a more even distribution of content so that students have increased clinical exposure should be achieved. Furthermore, an online atlas of resources would be helpful in standardising curriculum.

Repurposing Lesogaberan to Promote Human Islet Cell Survival and ß-Cell Replication.

The activation of ß-cell's A- and B-type gamma-aminobutyric acid receptors (GABAA-Rs and GABAB-Rs) can promote their survival and replication, and the activation of α-cell GABAA-Rs promotes their conversion into ß-cells. However, GABA and the most clinically applicable GABA-R ligands may be suboptimal for the long-term treatment of diabetes due to their pharmacological properties or potential side-effects on the central nervous system (CNS). Lesogaberan (AZD3355) is a peripherally restricted high-affinity GABAB-R-specific agonist, originally developed for the treatment of gastroesophageal reflux disease (GERD) that appears to be safe for human use. This study tested the hypothesis that lesogaberan could be repurposed to promote human islet cell survival and ß-cell replication. Treatment with lesogaberan significantly enhanced replication of human islet cells in vitro, which was abrogated by a GABAB-R antagonist. Immunohistochemical analysis of human islets that were grafted into immune-deficient mice revealed that oral treatment with lesogaberan promoted human ß-cell replication and islet cell survival in vivo as effectively as GABA (which activates both GABAA-Rs and GABAB-Rs), perhaps because of its more favorable pharmacokinetics. Lesogaberan may be a promising drug candidate for clinical studies of diabetes intervention and islet transplantation.

Direct inhibition of c-Myc-Max heterodimers by celastrol and celastrol-inspired triterpenoids.

Many oncogenic signals originate from abnormal protein-protein interactions that are potential targets for small molecule inhibitors. However, the therapeutic disruption of these interactions has proved elusive. We report here that the naturally-occurring triterpenoid celastrol is an inhibitor of the c-Myc (Myc) oncoprotein, which is over-expressed in many human cancers. Most Myc inhibitors prevent the association between Myc and its obligate heterodimerization partner Max via their respective bHLH-ZIP domains. In contrast, we show that celastrol binds to and alters the quaternary structure of the pre-formed dimer and abrogates its DNA binding. Celastrol contains a reactive quinone methide group that promiscuously forms Michael adducts with numerous target proteins and other free sulfhydryl-containing molecules. Interestingly, triterpenoid derivatives lacking the quinone methide showed enhanced specificity and potency against Myc. As with other Myc inhibitors, these analogs rapidly reduced the abundance of Myc protein and provoked a global energy crisis marked by ATP depletion, neutral lipid accumulation, AMP-activated protein kinase activation, cell cycle arrest and apoptosis. They also inhibited the proliferation of numerous established human cancer cell lines as well as primary myeloma explants that were otherwise resistant to JQ1, a potent indirect Myc inhibitor. N-Myc amplified neuroblastoma cells showed similar responses and, in additional, underwent neuronal differentiation. These studies indicate that certain pharmacologically undesirable properties of celastrol such as Michael adduct formation can be eliminated while increasing selectivity and potency toward Myc and N-Myc. This, together with their low in vivo toxicity, provides a strong rationale for pursuing the development of additional Myc-specific triterpenoid derivatives.

Perturbation of the c-Myc-Max protein-protein interaction via synthetic α-helix mimetics.

The rational design of inhibitors of the bHLH-ZIP oncoprotein c-Myc is hampered by a lack of structure in its monomeric state. We describe herein the design of novel, low-molecular-weight, synthetic α-helix mimetics that recognize helical c-Myc in its transcriptionally active coiled-coil structure in association with its obligate bHLH-ZIP partner Max. These compounds perturb the heterodimer's binding to its canonical E-box DNA sequence without causing protein-protein dissociation, heralding a new mechanistic class of "direct" c-Myc inhibitors. In addition to electrophoretic mobility shift assays, this model was corroborated by further biophysical methods, including NMR spectroscopy and surface plasmon resonance. Several compounds demonstrated a 2-fold or greater selectivity for c-Myc-Max heterodimers over Max-Max homodimers with IC50 values as low as 5.6 µM. Finally, these compounds inhibited the proliferation of c-Myc-expressing cell lines in a concentration-dependent manner that correlated with the loss of expression of a c-Myc-dependent reporter plasmid despite the fact that c-Myc-Max heterodimers remained intact.

Discovery of methyl 4'-methyl-5-(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)-[1,1'-biphenyl]-3-carboxylate, an improved small-molecule inhibitor of c-Myc-max dimerization.

c-Myc is a basic helix-loop-helix-leucine zipper (bHLH-ZIP) transcription factor that is responsible for the transcription of a wide range of target genes involved in many cancer-related cellular processes. Over-expression of c-Myc has been observed in, and directly contributes to, a variety of human cancers including those of the hematopoietic system, lung, prostate and colon. To become transcriptionally active, c-Myc must first dimerize with Myc-associated factor X (Max) via its own bHLH-ZIP domain. A proven strategy towards the inhibition of c-Myc oncogenic activity is to interfere with the structural integrity of the c-Myc-Max heterodimer. The small molecule 10074-G5 is an inhibitor of c-Myc-Max dimerization (IC50 =146 µM) that operates by binding and stabilizing c-Myc in its monomeric form. We have identified a congener of 10074-G5, termed 3jc48-3 (methyl 4'-methyl-5-(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)-[1,1'-biphenyl]-3-carboxylate), that is about five times as potent (IC50 =34 µM) at inhibiting c-Myc-Max dimerization as the parent compound. 3jc48-3 exhibited an approximate twofold selectivity for c-Myc-Max heterodimers over Max-Max homodimers, suggesting that its mode of action is through binding c-Myc. 3jc48-3 inhibited the proliferation of c-Myc-over-expressing HL60 and Daudi cells with single-digit micromolar IC50 values by causing growth arrest at the G0 /G1 phase. Co-immunoprecipitation studies indicated that 3jc48-3 inhibits c-Myc-Max dimerization in cells, which was further substantiated by the specific silencing of a c-Myc-driven luciferase reporter gene. Finally, 3jc48-3's intracellular half-life was >17 h. Collectively, these data demonstrate 3jc48-3 to be one of the most potent, cellularly active and stable c-Myc inhibitors reported to date.

Novel therapy for non-cirrhotic hyperammonemia due to a spontaneous splenorenal shunt.

Spontaneous splenorenal shunts in the absence of cirrhosis have rarely been reported as a cause hyperammonemia with encephalopathy. Several closure techniques of such lesions have been described. Here we report a case of a patient with no history of liver disease who developed significant confusion. After an extensive workup, he was found to have hyperammonemia and encephalopathy due to formation of a spontaneous splenorenal shunt. There was no evidence of cirrhosis on biopsy or imaging and no portal hypertension when directly measured. The shunt was 18 mm and too large for embolization so the segment of the splenic vein between the portal vein and the shunt was occluded using an Amplatzer plug. Thus, the superior mesenteric flow was directed entirely to the liver. After interventional radiology closure of the shunt using this technique there was complete resolution of symptoms. The case represents the first report of a successful closure of splenorenal shunt via percutaneous embolization of the splenic vein with an amplatzer plug using a common femoral vein approach.

Information and communication needs of Chinese American breast cancer patients: perspectives on survivorship care planning.

BACKGROUND: The existing knowledge on the survivorship experiences of Chinese American breast cancer survivors (CABCS) has arisen largely from aggregated data across multiethnic or multicancer studies that have focused on quality of life. Little is known about Chinese American perspectives and preferences for survivorship care. OBJECTIVE: To examine the experiences of CABCS to better understand their information and communication needs and their preferences for survivorship care plans (SCPs). METHODS: 16 CABCS, aged 37-72 years, were recruited through community-based organizations in the Northeast United States to participate in one-on-one telephone interviews about their breast cancer survivorship experience. The semistructured interviews were conducted in Mandarin, Cantonese, or English. Two investigators transcribed and translated the audio recordings into English and analyzed the interview transcripts using established methods of qualitative content analysis. RESULTS: Three main themes were identified through analysis of interview transcripts: the need for evidence-based and culturally and linguistically appropriate health information; the role of language or communication barriers and culture in accessing care and communicating with providers; and preferences for SCP elements and format. LIMITATIONS: The sample may not be representative of the entire population of CABCS. CONCLUSIONS: The findings provide insight into the information and communication needs and SCP preferences of CABCS. Understanding the cultural nuances that underlie these needs and preferences is critical for improving CABCS's quality of life after treatment for cancer. SCPs that incorporate Chinese-language resources and address the unique cultural needs of this population should be developed and they should include information about diet and nutrition as well as traditional Chinese medicine.

Disruption of Myc-Max heterodimerization with improved cell-penetrating analogs of the small molecule 10074-G5.

The c-Myc (Myc) oncoprotein is a high-value therapeutic target given that it is deregulated in multiple types of cancer. However, potent small molecule inhibitors of Myc have been difficult to identify, particularly those whose mechanism relies on blocking the association between Myc and its obligate heterodimerization partner, Max. We have recently reported a structure-activity relationship study of one such small molecule, 10074-G5, and generated an analog, JY-3-094, with significantly improved ability to prevent or disrupt the association between recombinant Myc and Max proteins. However, JY-3094 penetrates cells poorly. Here, we show that esterification of a critical para-carboxylic acid function of JY-3-094 by various blocking groups significantly improves cellular uptake although it impairs the ability to disrupt Myc-Max association in vitro. These pro-drugs are highly concentrated within cells where JY-3-094 is then generated by the action of esterases. However, the pro-drugs are also variably susceptible to extracellular esterases, which can deplete extracellular reservoirs. Furthermore, while JY-3-094 is retained by cells for long periods of time, much of it is compartmentalized within the cytoplasm in a form that appears to be less available to interact with Myc. Our results suggest that persistently high extracellular levels of pro-drug, without excessive susceptibility to extracellular esterases, are critical to establishing and maintaining intracellular levels of JY-3-094 that are sufficient to provide for long-term inhibition of Myc-Max association. Analogs of JY-3-094 appear to represent promising small molecule Myc inhibitors that warrant further optimization.

Pharmacophore identification of c-Myc inhibitor 10074-G5.

A structure-activity relationship (SAR) study of the c-Myc (Myc) inhibitor 10074-G5 (N-([1,1'-biphenyl]-2-yl)-7-nitrobenzo[c][1,2,5]oxadiazol-4-amine, 1) - which targets a hydrophobic domain of the Myc oncoprotein that is flanked by arginine residues - was executed in order to determine its pharmacophore. Whilst the 7-nitrobenzofurazan was found to be critical for inhibitory activity, the ortho-biphenyl could be replaced with a para-carboxyphenyl group to furnish the new inhibitor JY-3-094 (3q). Around five times as potent as the lead with an IC(50) of 33 µM for disruption of the Myc-Max heterodimer, JY-3-094 demonstrated excellent selectivity over Max-Max homodimers, with no apparent effect at 100 µM. Importantly, the carboxylic acid of JY-3-094 improves the physicochemical properties of the lead compound, which will facilitate the incorporation of additional hydrophobicity that might enhance Myc inhibitory activity further still.

Perforin-dependent CD4+ T-cell cytotoxicity contributes to control a murine poxvirus infection.

CD4(+) T cells are generally regarded as helpers and regulators of the immune response. Although cytolytic CD4(+) T cells have been described, whether those generated during the course of a viral infection play a role in virus control remains unknown. Here we show that during acute infection with ectromelia virus, the mouse homolog of the human virus of smallpox, large numbers of CD4(+) T cells in the draining lymph node and liver of resistant mice have a cytotoxic phenotype. We also show that these cells kill targets in vivo in a perforin-dependent manner and that mice with specific deficiency of perforin in CD4(+) T cells have impaired virus control. Thus, perforin-dependent CD4(+) T-cell killing of infected cells is an important mechanism of antiviral defense.

Respiration induced heart motion and indications of gated delivery for left-sided breast irradiation.

PURPOSE: To investigate respiration-induced heart motion for left-sided breast irradiation using a four-dimensional computed tomography (4DCT) technique and to determine novel indications to assess heart motion and identify breast patients who may benefit from a gated treatment. METHODS AND MATERIALS: Images of 4DCT acquired during free breathing for 20 left-sided breast cancer patients, who underwent whole breast irradiation with or without regional nodal irradiation, were analyzed retrospectively. Dose distributions were reconstructed in the phases of 0%, 20%, and 50%. The intrafractional heart displacement was measured in three selected transverse CT slices using D(LAD) (the distance from left ascending aorta to a fixed line [connecting middle point of sternum and the body] drawn on each slice) and maximum heart depth (MHD, the distance of the forefront of the heart to the line). Linear regression analysis was used to correlate these indices with mean heart dose and heart dose volume at different breathing phases. RESULTS: Respiration-induced heart displacement resulted in observable variations in dose delivered to the heart. During a normal free-breathing cycle, heart-induced motion D(LAD) and MHD changed up to 9 and 11 mm respectively, resulting in up to 38% and 39% increases of mean doses and V(25.2) for the heart. MHD and D(LAD) were positively correlated with mean heart dose and heart dose volume. Respiratory-adapted gated treatment may better spare heart and ipsilateral-lung compared with the conventional non-gated plan in a subset of patients with large D(LAD) or MHD variations. CONCLUSION: Proposed indices offer novel assessment of heart displacement based on 4DCT images. MHD and D(LAD) can be used independently or jointly as selection criteria for respiratory gating procedure before treatment planning. Patients with great intrafractional MHD variations or tumor(s) close to the diaphragm may particularly benefit from the gated treatment.