Quality control programme in mammography: second level quality controls.

Mammography is the most reliable method by which to detect lesions in the breast. Since contrast between normal and pathological areas in the breast is extremely low, mammographic image quality should reach high standards without exceeding acceptable exposure levels for the breast. A quality control programme in mammography has been implemented. This programme is subdivided into two levels. The first consists of simple daily checks of image quality and film processing, while the second deals with more complex checks of mammographic unit, screen-film system, darkroom, illuminators, viewing conditions and reference dose determination. The values of all the parameters undergoing measurement are compared with the limiting values given by National and International Protocols. This paper describes the second level controls carried out every 6 months by the medical physicist. The parameters described are only those which have been studied and analysed in detail since the quality control programme in mammography was implemented. Such parameters (kilovoltage, focal spot dimension, half value layer, tube output, automatic exposure control system, screen-film characteristic curve and mean glandular dose) were measured during the period 1991-1995 and the results summarised. The values obtained prove the constant correct functioning of the equipment.

Daily quality control programme in mammography.

The Medical Physics Department of S. Chiara Hospital (Trento, Italy) has developed, promoted and organized a quality control programme in mammography in the Department of Diagnostic Radiology. The aim of this paper is to describe the procedure for daily quality control carried out by the radiological technologist and analysed by the medical physicist, and also to discuss some interesting results obtained in the various departments during 1994. A sensitometric strip provides the film characteristic parameters to meet the requirements of DIN 6868 Part II (base plus fog level, average gradient, relative speed, maximum density, speed index and contrast index). A test phantom radiograph provides information on the detection of microcalcifications and simulated tumours (high and low contrast resolution) as well as on the central background density and the contrast. The exposure time-current product, mAs, needed to expose the phantom is always noted. Characteristic parameters of the two systems are compared with limiting values given by International Protocols or with the permissible ranges calculated in advance. It has been possible to discover variations in the performance of mammographic and automatic processing units due to the quality control programme. In one department, for example, the malfunctioning of the automatic exposure control device was observed. In another, replacement of mammography films and the automatic processing unit resulted in a better image quality.

[Quality assurance of mammography in the province of Trent]. / Garanzia della qualità nella mammografia nella provincia di Trento.

In 1991, a second program for quality control in mammography was carried out in the Physics Department of the Trento Hospital. All the six mammographic centers around Trento entered the study and 9 mammographic units were thus considered. Two main types of measurements were obtained: a) determination of the physical variables affecting radiologic system optimization; b) evaluation of image quality and average breast dose, according to DQM program criteria. The film variables, mean gradients and base plus fog level, the half-value layer (HVL) and the entrance exposure free in air were scored as acceptable in all cases. The average breast dose was calculated on the basis of literature data, given the entrance exposure free in air, the HVL and the focus-skin distance values. All the mammographic units but one were scored as "D" (acceptable) on the average breast dose curve, which is defined by the national average value obtained during phase II of the DQM program. This Quality Control program allowed all mammographic units to be optimized and also emphasized the need for periodical quality controls.

[Sotalol in the Wolff-Parkinson-White syndrome: an electrophysiological and clinical study]. / Il sotalolo nella sindrome di Wolff-Parkinson-White: studio elettrofisiologico e clinico.

Distinctly different from the other beta-blocking agents, sotalol prolongs action potential duration in myocardial and Purkinje fibers, and increases atrial as well as ventricular effective refractory periods. Similarly, antegrade and retrograde accessory pathway refractory periods are increased by sotalol. The electrophysiologic and clinical effects of sotalol were studied in 40 patients (31 male and 9 female, mean age 32 +/- 14 years) with Wolff-Parkinson-White Syndrome (WPW). All patients had disabling episodes of supraventricular tachyarrhythmias (ST). Of the 40 patients, 15 (37%) had spontaneous recurrence of paroxysmal supraventricular reciprocating tachycardia (PSRT), 14 (35%) of atrial fibrillation (AF) and 11 (28%) of both PSRT and AF. All of the patients were non responders to serial transesophageal electropharmacological tests using I C class drugs. Sotalol 252 +/- 73 mg daily was administered, and, in steady-state, a new transesophageal study (TS) was performed to observe the re-induction of PSRT and/or AF. 34 patients (85%) were responders to TS (noninducibility of ST, or nonsustained ST or AF inducibility with an increase of 30% in the minimum R-R interval between pre-excitated beats during AF) and the results were confirmed during a follow-up of 17 +/- 9 months. In the non-responder group (5 patients), a I C class drug was associated with sotalol. One patient, who was a "non responder" to sotalol, sotalol + I C class drug, and to amiodarone, underwent surgical therapy. In the 26 patients (65%) who had episodes of PSRT (37%) or episodes of PSRT and AF (28%), it was impossible to reinduce PSRT in 85% of the cases. AF was induced at baseline in all of the studied patients, but after sotalol administration in 15 patients, it was impossible to reinduce AF. The rate of induced AF decreased from 208 +/- 39 beats/min to 156 +/- 36 beats/min (p < 0.001). The mean shortest R-R interval between pre-excitated beats increased from 214 +/- 35 (baseline) to 293 +/- 97 msec (sotalol steady state) (p < 0.001). No side effects were observed. A significant prolongation (p < 0.001) of the QTc interval was observed in all the patients after sotalol administration (from 0.39 +/- 0.2 to 0.42 +/- 0.02 sec.). On the basis of our results, we may conclude that sotalol has a potent effect on the antegrade refractoriness of the anomalous pathway and, in WPW syndrome at risk, is also effective in patients who don't respond to I C class drugs.

[Radiotherapy of T1N0 neoplasms of the glottis. Analysis of the parameters that influence local control]. / La radioterapia nelle neoplasie T1N0 della glottide. Analisi di alcuni parametri che influenzano il controllo locale.

Treatment and tumor-related parameters were reviewed in 176 patients with T1N0 carcinoma of the glottic larynx submitted to primary radiation therapy from 1980 to 1992. Our aim was to analyze local control and treatment-related toxicity. Over-all local control rates at 10 years were 88.3% with irradiation alone and 94.5% after salvage surgery (larynx preservation: 91%). Verrucous histology was a negative factor affecting local control and anterior commissure involvement exhibited only a negative trend but had no statistical significance. Among treatment-related factors, local control was 76.5% after split-course and 91.1% after continuous-course irradiation (p < 0.05). With continuous-course irradiation, the total dose influenced local control only for single of 2 Gy (local control rates were 69% with 60 Gy and 93% at > or = 64 Gy; p < 0.05), but not for single doses of 2.25 Gy and total doses ranging 56.25-65.25 Gy (local control failed in 55 patients). Early and late complications did not increase with single doses > or = 2.25 Gy. Our current policy in T1N0 nonverrucous glottic carcinoma is to use a single fraction of 2.25 Gy and a total dose ranging 56.25-63 Gy according to tumor size, with a continuous course.

[Radical radiation therapy of carcinoma of the rhinopharynx: analysis of 80 cases]. / Il trattamento radiante radicale del carcinoma della rinofaringe: analisi su 80 casi.

From 1976 to 1987, 98 patients affected with nasopharyngeal carcinoma were observed at the Oncology Center, Trento, Italy. Eighty of them were treated with radical radiation therapy (average total dose: 6432 Gy, range: 5500-7400 Gy) on primary tumor and positive neck nodes. The clinically negative neck received 5000 Gy. Each dose ranged from 180 to 250 Gy. Fifty-nine patients were treated with the split-course technique with an interval of about 15 days after receiving 4000 cGy. The patients were 60 males and 20 females, their age ranging 17-81 years (mean: 57 years). Histology diagnosed squamous cell carcinoma in 15 cases and undifferentiated carcinoma in 65 cases. All patients were staged according to TNM (UICC, 1978) criteria. Ten patients were stage I/II. Complete local control was obtained in 81.3% of cases. Actuarial global survival at 10 years was 52%, actuarial relapse-free survival was 49%. Mean follow-up is 33 months (range: 4-122 months). Squamous cell carcinoma at histology and advanced nodal involvement (N2-N3) were negative prognostic factors. Six patients had a relapse in the nasopharynx and 5 in the neck; the incidence of distant failures was 20%. The most frequent mid-/long-term side-effect was xerostomia.

[Radiotherapy, radiotherapy combined with surgery, radiotherapy combined with chemotherapy in the treatment of carcinoma of the pyriform sinus. A retrospective study]. / La radioterapia, la radioterapia associata a chirurgia, la radioterapia associata alla chemioterapia nel trattamento del carcinoma del seno piriforme. Analisi retrospettiva.

A rectrospective analysis was performed of the results of 104 consecutive patients with carcinoma of the pyriform sinus, who underwent radiation therapy. Thirty-four patients underwent radical surgery and postoperative radiation therapy (group 1); 36 patients received radical radiation therapy alone (group 2); neoadjuvant chemotherapy was administered prior to full-dose radiation to 20 patients (group 3); 14 patients received palliative radiation therapy (group 4). Loco-regional control and survival rates at 5 years were 60.4% and 34.3% in group 1, 23.8% and 23.8% in group 2, 17.5% and 23.8% in group 3; no patients in group 4 survived at 5 years. Patients in group 1 experienced significantly better survival and local control than those in groups 2 and 3. No differences were observed between groups 2 and 3. Loco-regional recurrence was the main cause of failure in group 2 (69.4%) and 3 (70.0%). In group 1, 20.3% of cases developed distant metastases. Overall 5-year survival rate was 23.7%, confirming the poor prognosis of this disease. These results provide further support to the need of improving prevention and early diagnosis to improve both results and outcome in patients with carcinoma of the pyriform sinus.