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K A Johansson

Publications and source records attributed to K A Johansson.

15 recordsLinked to original sources
PubMed1991

Quality audit of radiotherapy with EORTC mailed in water TL-dosimetry.

A mailable TL-dosimetry (LiF) system has been designed and tested for the EORTC Radiotherapy Group for periodic monitoring of radiation therapy machines between and prior to on-site visits. Three TL-dosimeters were enclosed in a capsule which was placed in a holder and irradiated in photon beams in a water phantom. The institutes were instructed to irradiate the capsule to an absorbed dose of 2 Gy. After the irradiation, all capsules with dosimeter, the holder and completed data sheets were returned to Gothenburg for evaluation. The heating procedure used for reading the dosimeters was optimised regarding fading and reproducibility (less than 0.5%, 1. S.D.). The fading of the TL-signal was eliminated by adding an external annealing to the heating procedure. Both supralinearity and energy dependence were tested and routinely corrected for. The dosimeters were individually calibrated. During 1987, 1988 and the first part of 1989, dosimeters were mailed to 22 institutes, participating in clinical trials organised by the Radiotherapy Group. Of the 178 beams measured, 89% were within acceptable levels of variation for the absorbed dose states (less than or equal to 4%). The photon results gave a mean of 1.012 and a standard deviation of 0.025.

Absorption↗
PubMed1991

Entrance and exit TL-dosimetry in the conservative treatment of breast cancer: a pilot study for the EORTC-Radiotherapy Cooperative Group.

Mailed dosimetry, using thermoluminescent dosimeters, can play an important role in quality assurance procedures in radiotherapy. In 1989, a pilot study was started with the main aim to show the feasibility of this method for the multicentre EORTC trial 22881 on the conservative management of breast carcinoma. Two anthropomorphic breast phantoms and six patients with breast carcinoma were irradiated according the prescriptions of the protocol. TLD measurements of the entrance and exit dose were performed in 6 MV tangential X-ray beams. It proved to be possible to correlate the dose measured in the entrance and exit points of the beams to the calculated dose closely under the surface. A thickness of at least 5 mm bolus material must be applied over the dosimeters and a distance of at least 3 cm from the lateral and medial field borders must be maintained in order to reach a clinically acceptable accuracy in the measurements.

Breast Neoplasms↗
PubMed1991

Quality assurance in conservative treatment of early breast cancer. Report on a consensus meeting of the EORTC Radiotherapy and Breast Cancer Cooperative Groups and the EUSOMA (European Society of Mastology).

A consensus on a quality assurance programme of the treatment of early breast cancer was reached in a multidisciplinary meeting of surgeons, pathologists, radiotherapists, physicists and radiographers. Guidelines for treatment preparation and execution have been set up, including careful location and excision with marking of the primary tumour. The target volumes for irradiation of the whole breast and boost area have been defined. Radiation dose prescription rules, specification and checking procedures are given, together with measures to achieve a homogeneous dose within the target volume. The rules for a quality assurance programme in each clinic are designed for checking equipment and treatment method.

Axilla↗
PubMed1991

Primary radiotherapy for glottic laryngeal carcinoma stage I and II. A retrospective study with special regard to failure patterns.

A retrospective study has been made of 302 patients with vocal cord carcinoma stage I and II treated between 1963 and 1983, emphasizing treatment failure patterns. The primary treatment modalities were radiotherapy for 266 patients and surgery for 36 patients. The minimum follow-up was 4 years. After primary radiotherapy there were 63 local recurrences and 7 neck lymph node recurrences, all appearing outside the target volume. The actuarial loco-regional recurrence-free rates at 5 years were 78% for T1, 76% for T2a (normal cord mobility) and 60% for T2b (impaired cord mobility) tumors. The actuarial regional lymph node recurrence-free rates at 5 years were 99, 100 and 93% for T1, T2a and T2b tumors respectively. The actuarial corrected survivals at 5 years were 95, 96 and 79% for T1, T2a and T2b tumors with primary radiotherapy and salvage surgery for recurrence. Salvage surgery was less successful in T2b compared to T1 and T2a tumors. In conclusion, after primary radiotherapy with salvage surgery the loco-regional control rate was high and very similar for glottic cancer T1 and T2a but less satisfactory for T2b tumors. Regional lymph node metastases were not a large problem in any of the subgroups. More effective radiotherapy with higher dose levels or an altered fractionation might increase the local control rate for T2 tumors with impaired cord mobility.

Adult↗
PubMed1987

Quality assurance control in the EORTC cooperative group of radiotherapy. 3. Intercomparison in an anatomical phantom.

Two papers concerning the quality control study organised by the EORTC (European Organisation for Research on Treatment of Cancer) Cooperative Group on Radiotherapy have been published. The medical profile (part 1) and the dosimetric intercomparison (part 2) of the participating institutions were presented. This part (paper 3) presents an integrated clinical and dosimetric investigation in an anatomical phantom. A tonsillar tumour and a homolateral subdigastric node were marked in an anatomical phantom. The institutions were asked to treat the phantom once like an ordinary patient. The phantom was loaded with dosimeters and irradiated. From the results obtained, it can be concluded that we did not find any major dosimetric problem related to absorbed dose calibration or calculation in the phantom. However, several major problems were related to non-optimal planning, treatment technique and dose distribution. The investigation shows the importance of a quality assurance programme for cooperative groups.

Models, Anatomic↗
PubMed1986

Quality assurance control in the EORTC cooperative group of radiotherapy. 2. Dosimetric intercomparison.

The European Organization for Research on Treatment of Cancer (EORTC) has performed site reviews at 17 institutions participating in clinical trials organized by the Cooperative Group of Radiotherapy. In this paper the dosimetric part of the quality assurance control programme is presented. In a previous paper (part 1) the medical profile of the participating centres was presented. In part 3 an integrated clinical and dosimetric investigation in an anatomical phantom will be presented. The deviations between the absorbed dose values, for specific points along the beam axis in a water phantom, determined by us and reported by the hospitals were within an acceptable level of variation (about +/- 3%) for 85, 70 and 71% of the 60Co gamma, X-ray and electron beams, respectively. In some scanning electron beams, too large deviations were found. The flatness and symmetry of the beams were measured. 73% of the X-ray and 60% of the electron beams were within the acceptable levels of variations. Dosimetric recommendations for institutions participating in EORTC clinical trials are presented.

Cobalt Radioisotopes↗
PubMed1986

Quality assurance control in the EORTC cooperative group of radiotherapy. 1. Assessment of radiotherapy staff and equipment. European Organization for Research and Treatment of Cancer.

A quality control study was carried out by the EORTC Cooperative Group of Radiotherapy. From January 1982 to December 1984, 17 institutions were visited by a group of "experts" in radiotherapy and radiation physics. The evaluation included three steps: a comparison of megavoltage units, technical and staff environment, and data present in clinical and radiotherapy charts for each center; radiation physics calibration of photon and electron beams; and radiation physics measurements on a stimulated clinical case using an Alderson Rando anatomical phantom. This paper presents the results of Part 1. The results of Parts 2 and 3 will be analyzed in separate papers. Large variations were observed in the number of patients treated per year, per radiotherapist, per radiation physicist and per technician. On average, 400 patients were treated per year per megavoltage unit, but 8/17 centers treated more than 500 patients per unit per year. The number of simulators was suboptimal in 12/17 centers. These observations were summarized by a workload and staff index, and this index shows that in 5/17 centers major problems are present which make it difficult to comply with all the requirements of EORTC protocols. The quality of work-up regarding tumor extension was considered to be satisfactory in all centers. Dental care in patients irradiated to the head and neck was not well organized in 5/17 centers. Interaction between CT scan and dosimetry treatment planning could be improved in most centers and this should be one of the primary objectives of future quality control.

Brain Neoplasms↗