SU-E-J-47: Evaluation of the Mismatches Between DRR's and Port Films for IMRT Fields.

PURPOSE: To quantify the frequency and magnitude of mismatches between the MLC shape on the DRR created by the Pinnacle planning system and the corresponding port film MLC shape generated by the Mosaiq record-and-verify system for IMRT fields. METHODS: A retrospective review was made of the most recent 60 patients to receive IMRT at our clinic. The MLC shape on the DRR created by the Philips Pinnacle planning system for each treatment field was reviewed (573 fields total) and compared with the MLC shape of the port film image, which was generated by the Mosaiq treatment planning system. RESULTS: Of the 60 patients studied, 20 had at least one leaf mismatched between the MLC shape on the DRR and port film (142 of the 573 fields). Of the affected cases, on average 59% of the fields had a mismatch. The affected fields had an average of 6.7 leaves mismatched with a mean discrepancy of 27mm. The average maximum discrepancy for each affected patient was 69mm. Discrepancies were most common for head and neck cancers. CONCLUSIONS: The MLC shape Mosaiq generates for the port film is the CIAO, or Complete Irradiated Area Outline, which is the area that is actually treated. The Pinnacle DRR displays the maximum leafmotion, which can be different for larger fields in which the MLC leaves abut within the collimator jaw opening. The discrepancy can create substantially different MLC shapes. The problem can be solved by not filming the MLC shape and only using the films for isocenter placement; however, displaying the area receiving treatment can be a useful safety check, possibly preventing a treatment error. The persons assessing the films must be aware of this issue and evaluate the films carefully.

Prospective evaluation of an outpatient heart failure management program.

BACKGROUND: Although considerable effort has been devoted to the follow-up of hospitalized patients, the effectiveness and process of heart failure outpatient management have not been well demonstrated. METHODS AND RESULTS: All new patients referred to the program from April 1997 to September 1998 were followed and managed by comprehensive strategies including preemptive hospitalization. Quality of life (QOL) and patients' self-care adherence behaviors were measured at baseline, 3 months, and 6 months. Clinical outcomes were compared for the 6 months before and 6 months after referral. A total of 108 patients were recruited. Patients' self-care knowledge score was improved over time (difference score = 0.9, P <.01). The proportion of patients weighing themselves daily increased by 24% (P =.02). The proportion of patients with New York Heart Association (NYHA) class III to IV was 67.6% at baseline and 49.1% at 6 months (P =.01). Compared with 6 months before referral, the program intervention was accompanied by a 52% reduction in the risk of hospitalization for cardiovascular causes (56.1% v 27.2%, P <.001) and a 72% reduction in emergency room visits (53.6% v 14.5%, P <.01). The total hospital admissions for cardiovascular causes decreased by 59% from 94 to 39; the total emergency room visits decreased by 77% from 83 to 19. The patients' QOL was improved over time with a change score of 11.2 (P <.001) at 3 months and 10.7 (P <.001) at 6 months. CONCLUSION: Our study shows the effectiveness of this heart failure outpatient management program.

A generic off-axis energy correction for linac photon beam dosimetry.

Cooperative clinical trial group protocols frequently require off-axis point dose calculations. The Radiological Physics Center uses the calculative technique developed by Hanson et al. [Med. Phys. 7, 145-146 (1980); 7, 147-150 (1980)] to verify these calculations. In order to correct for off-axis energy changes, this technique requires off-axis half-value layer data, HVL, as a function of off-axis ray angle for the specific beam. This paper presents a formulism based on HVL mesurements on a limited number of therapy beams, which allows the calculation of an off-axis energy-correction factor for any clinical photon beam created by a linear accelerator using conventional flattening filters.

cAMP activates MAP kinase and Elk-1 through a B-Raf- and Rap1-dependent pathway.

Cyclic adenosine monophosphate (cAMP) has tissue-specific effects on growth, differentiation, and gene expression. We show here that cAMP can activate the transcription factor Elk-1 and induce neuronal differentiation of PC12 cells via its activation of the MAP kinase cascade. These cell type-specific actions of cAMP require the expression of the serine/threonine kinase B-Raf and activation of the small G protein Rap1. Rap1, activated by mutation or by the cAMP-dependent protein kinase PKA, is a selective activator of B-Raf and an inhibitor of Raf-1. Therefore, in B-Raf-expressing cells, the activation of Rap1 provides a mechanism for tissue-specific regulation of cell growth and differentiation via MAP kinase.

Detection of a circulating tumor-associated antigen with a murine monoclonal antibody, LISA 101, selected by reversed indirect enzyme-linked immunosorbent assay.

In the presence of a characterized monoclonal antibody recognizing a soluble molecule, additional monoclonal antibodies reactive with unknown antigenic determinants on the molecule can be easily selected by reversed indirect enzyme-linked immunosorbent assay. A novel murine monoclonal antibody, LISA 101, was selected by reversed indirect enzyme-linked immunosorbent assay against soluble antigens, which exist in sera and in pleural effusions derived from lung adenocarcinoma patients and which bear determinants recognized by the previously characterized murine monoclonal antibody KL-6. Antigenic determinants recognized by the LISA 101 antibody appear to be sialylated carbohydrate in nature and different from those recognized by previously reported monoclonal antibodies against sialylated carbohydrates, such as NS 19-9, FH-6, and KL-6, suggested by competitive inhibition assay and immunostaining of tissues. A circulating antigen, LISA 1-6, was detected by a bimonoclonal bideterminant assay using immobilized LISA 101 antibody and enzyme-labeled KL-6 antibody. It was found that serum LISA 1-6 levels were elevated in 63% (25 of 40) of patients with lung adenocarcinoma and in 92% (11 of 12) of patients with pancreatic carcinoma, but only in 6.5% (2 of 31) of patients with benign lung diseases and in 7.1% (1 of 14) of patients with pancreatitis. The present observations indicate that the LISA 1-6 antigen may serve as a new tumor marker for adenocarcinomas of the lung and the pancreas. Additionally, the reversed indirect enzyme-linked immunosorbent assay may be a widely applicable method for selecting new monoclonal antibodies against as yet unknown antigenic determinants on soluble molecules.

Tyrosyl and phosphatidylinositol kinases of human erythrocyte membranes.

The tyrosyl kinase and phosphatidylinositol (PI) kinase activities of human red cells have been partially purified and characterized. Although the PI kinase required detergent for solubilization, the major tyrosyl kinase of the red cell could be extracted by high salt. A very small residual activity remained associated with the membranes, however, that was solubilized with the PI kinase and copurified through an ammonium sulfate precipitation and diethylaminoethyl (DEAE) ion-exchange step gradient elution. However, the two activities were found to differ with respect to their apparent KmS for ATP and Mg2+; they showed different half-lives for temperature inactivation, possessed different relative activities in the presence of Mn2+ and Ca2+, and were separable by elution from a DEAE-Trisacryl ion exchange column using a linear NaCl gradient. The kinetic parameters of the membrane-associated tyrosyl kinase differed from those of the salt-extracted enzyme. PI kinase was not activated by pretreatment with the tyrosyl kinase p68v-ros or by addition of the phosphotyrosyl phosphatase inhibitor, vanadate, to intact membranes, and was not competitively inhibited by the tyrosyl kinase substrate poly(Glu4, Tyr). We conclude that the human red cell phosphatidylinositol and tyrosyl kinases are distinct and separate activities, and that at least two separable tyrosyl kinases are present in human erythrocytes.