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J Pouliot

Publications and source records attributed to J Pouliot.

33 records · Page 2Linked to original sources
PubMed1996

Verification and correction of setup deviations in tangential breast irradiation using EPID: gain versus workload.

PURPOSE: When a deviation in the treatment setup is identified, when or how should it be corrected? With the aim of improving the precision and reducing the systematic errors while maintaining the workload to a minimum, a study was performed to define the proper set of actions for the correction of tangential breast setup deviations during the course of the treatment. PATIENTS AND METHODS: Clinical data were taken from a prospective study of more than 2200 on-line Electronic Portal Images (EPI) from 20 patients treated with tangential irradiation following a partial mastectomy for an early stage (I and II) breast cancer. The values of the central lung distance were then entered in the verification/correction procedure and modified to correct only the portion of the deviation most likely attributed to systematic errors according to the maximum likelihood. The verification/ correction procedure uses an action level equal to FML x alpha/square root of N, where alpha is proportional to the standard deviation (alpha = n sigma) and N is the number of consecutive fractions delivered after the start of the treatment. FML is the fraction of the deviation due to the systematic errors estimated from the maximum likelihood of the two distributions. In addition to n, one needs to specify Nmax, the maximum number of consecutive measurements without correction, to apply the procedure. The combination of these two parameters C(n,Nmax) will determine the reduction of systematic errors (gain) and the number of measurements and corrections (workload) associated to the procedure. RESULTS: The effects of three combinations, C(1,1), C(2,2), and C(3,4) were studied. Also, the analysis of the results after application of the procedure with and without the factor of maximum likelihood made individually for each patient demonstrates the importance of the FML. CONCLUSIONS: The verification/correction procedure with the inclusion of the FML can effectively improve the accuracy when applied to clinical data. With the specific workload related to measurements and corrections performed at our institution, we have found that in the case of the tangential breast treatment, the optimum combination uses an action level equal to 2 sigma and a maximum of two consecutive measurements without correction.

Breast Neoplasms↗
PubMed1995

The role of electronic portal imaging in tangential breast irradiation: a prospective study.

Side effects due to irradiation of normal tissues and local failure can be associated with deviations in the patient positioning in radiation therapy. In particular, tangential breast irradiation may include normal lung tissue or even a small portion of the heart in the field. A prospective study was performed to assess the precision and the reproducibility of the tangential breast irradiation technique with the help of on-line electronic portal imaging devices (EPID). The influence of respiration on the treatment set-up was evaluated. Also, a comparison was made with simulation films to study the degree of concordance with the intended treatment. Twenty patients with early breast cancer receiving post-operative radiotherapy were entered in the study. Geometrical parameters were measured from daily on-line portal images taken for approximately 17 fractions of each tangential fields. Multiple images were also acquired (six per field) for six fractions for all patients, yielding a total of 2120 images including the simulator films. Random and systematic errors were obtained. Variations of the parameters between various fractions and within the same fraction were about 3 mm (1 SD) or less. Variation between simulation and treatment set-up was 4.3 mm or less. Large maximum deviations, reaching 22.9 mm, were observed in rare cases. This confirms the need to implement daily verification procedures and to correct deviations in the treatment set-up. The study has shown that EPID can help reaching a high accuracy in patient treatment.

Breast Neoplasms↗
PubMed1995

Standardized pain flowsheet: impact on patient-reported pain experiences after cardiovascular surgery.

BACKGROUND: Administration of analgesics per patient request or random pain assessments may provide inadequate pain management. OBJECTIVE: To examine the impact of nurses' use of a standardized pain flowsheet to document pain assessment and pharmacologic management on patient-reported pain intensity. METHODS: A pre-post intervention design was used to compare 61 patients. In the preimplementation group, traditional charting of pain presence or absence was documented in the narrative notes and pharmacologic management was recorded on the medication profile. In the postimplementation group, the intensity of pain and pharmacologic management were documented on a pain flowsheet. Within 24 hours after transfer to the step-down unit, patients were interviewed regarding pain intensity experienced in the surgical heart unit and at the time of questioning. The distribution of these pain intensity scores was compared. RESULTS: The postimplementation group reported significantly lower pain intensity ratings for the average amount of pain experienced while in the surgical heart unit, the least amount of pain experienced while in the surgical heart unit, and the pain experienced at the moment of questioning. CONCLUSIONS: Use of a standardized pain flowsheet to assess pain intensity and document pharmacologic intervention may improve pain management in postsurgical cardiovascular patients.

Cardiac Surgical Procedures↗
PubMed1992

High pentamidine levels associated with hypoglycemia and azotemia in a patient with Pneumocystis carinii pneumonia.

We report on a patient who presented with a Pneumocystis carinii pneumonia. Intravenous pentamidine (4 mg/kg/day) was given for 14 days without the occurrence of adverse effects. During this treatment, the mean (+/- SD) serum pentamidine trough concentration was 94 +/- 16 ng/ml. Three days later, the patient was admitted because of fever, and pentamidine (4 mg/kg/day) was again started. Fasting hypoglycemia and azotemia then occurred; the mean serum trough pentamidine level was 190 +/- 10 ng/ml during this week of treatment. We conclude that the occurrence of hypoglycemia and azotemia during pentamidine therapy may not be idiosyncrasic, but seemed associated in our patient with high levels of serum pentamidine.

AIDS-Related Opportunistic Infections↗
PubMed1992

Higher pentamidine levels in AIDS patients with hypoglycemia and azotemia during treatment of Pneumocystis carinii pneumonia.

Trimethoprim-sulfamethoxazole (TMP-SMZ) and pentamidine are both licensed for the treatment of Pneumocystis carinii pneumonia (PCP). However, their use is associated with various adverse side effects. In this prospective study, 26 AIDS patients with 32 episodes of PCP were treated with pentamidine (4 mg/kg/d). Each patient was treated for 12 to 21 days, depending on the rapidity of onset of the clinical response. During the 32 PCP episodes, hypoglycemia occurred in 16 instances, azotemia in 12, liver toxicity in 10, and leukopenia in 8. The occurrence of thrombopenia, leukopenia, and liver toxicity was not related to age, pentamidine levels, or other complications. However, patients who had hypoglycemia during pentamidine treatment had higher serum pentamidine levels than patients who did not have hypoglycemia (107 +/- 40 versus 70 +/- 26 ng/ml, p less than 0.004). In addition, we observed that patients with azotemia showed higher pentamidine levels during treatment (120 +/- 35 versus 64 +/- 22 ng/ml, p less than 0.001). In fact, 100% (11/11) of patients with serum pentamidine concentration greater than 100 ng/ml had fasting hypoglycemia and/or azotemia, while 33% (7/21) of those with pentamidine levels less than 100 ng/ml had these side effects (p less than 0.001). The relative risk of these complications with pentamidine levels greater than 100 ng/ml was 3 (95% confidence interval, 1.6 to 5.5). Fine-tuning the dose of pentamidine may eventually prove useful to avoid toxicity and optimize therapy.

Acquired Immunodeficiency Syndrome↗