Patients receiving tangential breast irradiation represent a significant proportion of the workload in a radiotherapy department. This paper describes the optimisation of an existing technique for tangential breast irradiation. Simulator sessions have been made more efficient by adopting a systematic approach to the simulation process, and set up times on treatment have been reduced and accuracy increased by improving the reliability of the patient set-up. There has been an overall reduction in both the problems and the time taken to both simulate and treat patients.

Patient position variation has been minimised by the use of vac-fix bags and the choice of reference tattoo placement on the patient's skin. The single simulation session for planning treatment has been organised into three parts: definition of target volume, calculation of treatment and field parameters and simulation of treatment fields. The improvement in patient set-up on treatment has been confirmed by a reduction in the variability of FSDs measured during treatment.

Aims: To investigate the impact on localisation of utilising contrast enhanced computed tomography (CT) scans and the formal input of a radiologist in the radiotherapy planning process.

Method: Ten head and neck / brain patients had pre- and post-contrast CT scans in the treatment position. Over several months, their unenhanced and enhanced scans were re-contoured by the original oncologist, and a radiologist. These new contours were compared to the original unenhanced contours and differences in contour volume, geographical position and tolerance doses on the associated PTVs were evaluated.

Results: The use of contrast lead to significant differences in the size of GTVs. Mean differences in GTVs of 32.8 % were significant at p=0.01. No significant impact on the position of the contour centre was noted. The impact of the radiologist lead to large differences in GTV (mean 20.5 %), but large SDs meant this result was not statistically significant. The contouring precision of the oncologist showed no significant difference for GTVs and PTVs.

Conclusions: The use of contrast when planning the radiotherapy treatment for head and neck / brain patients was found to lead to significant differences in GTV size, a lesser effect on PTV definition and little impact on the position of the contour centre. It may have important implications for multi-phase treatments where the GTV (rather than the PTV) is targeted for boost doses. Differences due to the input of a radiologist appear to be considerable and require further investigation when additional patient numbers have been acquired to improve precision.

Background: Radiotherapy is well established in the treatment of non-Hodgkin's lymphoma (NHL) but there is considerable variation in the radiotherapy regimens prescribed, even within one cancer centre. This paper compares the varying radiation schedules prescribed in the Beatson Oncology Centre, Glasgow, in a sample of patients treated in 1996 with a second sample treated in 1999 following the creation of a lymphoma team with defined treatment protocols.

Method: In 1997 a retrospective study within the Beatson Oncology Centre recorded the treatment details of 35 patients treated with radiotherapy for NHL in 1996. The various radiotherapy dose and fractionation regimens prescribed were analysed to identify the rationale behind the variations by correlating them to the grade of disease, the age of the patient, the prescribing consultant and use of cytotoxic chemotherapy. A further audit of 36 patients treated over a three-month period in 1999 re-examined the radiotherapy prescribed and was able to include intent of treatment and stage of disease in the analysis.

Results: The demographics of the 1996 and 1999 patients were similar. In the latter group all patients had grade of disease recorded and 83% had stage recorded compared to 91% had grade and only 31% had stage recorded in 1996. The range of doses prescribed was 20–45 Gy (Gray) (median 36) for LGNHL (low grade non-Hodgkin's lymphoma) in 1996 with a range of 5–50 Gy (median 30) for HGNHL (high grade NHL). In 1999 the LGNHL range was 20–45 Gy (median 30) with HGNHL 20–50 (median 40). The 1999 audit showed better recording of data and this allowed further analysis of radiotherapy regimens. The patients could be grouped into three categories of treatment intent: primary radical treatment with radiotherapy alone (36%), consolidation following chemotherapy (25%) and palliation (39%). The radical and consolidation groups received similarly high doses (median 40 Gy) which were significantly greater than the palliation group (median 20 Gy).

Conclusions: The creation of a lymphoma team has improved the recording of treatment data and reduced the variations in clinical practice. We would advocate that patients with NHL should be irradiated according to evidence based protocols and suitable patients should be considered for the current BNLI trial of radiation dose in NHL.

Nasopharyngeal carcinoma (NPC) patients with parapharyngeal space (PPS) involvement are routinely given boost irradiation in Hong Kong. The current technique that employs a single field has many limitations in terms of dose distribution. This study is aimed to compare the dose distribution between the newly designed 3-dimensional conformal radiotherapy (3DCRT) and conventional techniques for the boost treatment of PPS so as to determine the more optimal treatment.

Fifteen NPC patients with unilateral PPS involvement were recruited. Their CT images were loaded into the FOCUS planning system for treatment planning. The planning target volume (PTV) and seven organs at risk (OARs) including the spinal cord, brain stem, optic chiasm, mandible, temporal lobe, temporo-mandibular (TM) joint and lens were outlined for dose assessment. The conventional and 3DCRT plans were then generated for each patient and the dose distributions were compared using dose parameters derived from the dose volume histograms (DVHs).

The 3DCRT technique provides better target coverage and significantly better dose to the planning target volume than the conventional technique. The 3DCRT treatment plans gives better sparing of the ipsilateral TM joints, mandible and lens, but it is less effective to spare spinal cord, brain stem, optic chiasm and temporal lobe. Nevertheless, the total doses to these OARs remain within the clinically defined thresholds and are clinically acceptable.

Background and Purpose: The aim of this study was to determine set-up accuracy when comparing an Orfit® thermoplastic shell to a traditional acetate shell for the treatment of patients with age related macular degeneration.

Method and Materials: 20 patients with age related macular degeneration were sequentially allocated to be positioned in either an Orfit® shell or a traditional acetate shell (ten patients in each group). On each day of treatment, radiographic portal imaging was used to ascertain accuracy by comparison with the CT image and verification radiograph.

Results: 140 portal images were assessed by three independent readers. Pearson Correlation and ANOVA statistics were performed on the data to assess differences between the two types of shell. Inter- and intraobserver variations were also analysed. Results, for both Orfit® and Acetate, revealed that over 95% of error movements were 2 mm or less.

Conclusions: The study indicates that both devices are of comparable accuracy and that the Orfit® shell is an acceptable method of immobilisation for the treatment of age related macular degeneration.

Technological improvements in imaging and increased sophistication in radiotherapy techniques are causing the necessity for the reassessment of treatments. In particular tumours of the brain and head and neck region are benefiting from improved localisation, planning and treatment. This paper presents an overview of these developments.

From April 1997 until September 1998 an observational study was performed with respect to the quality of the “informed consent procedure concerning patients who were candidates to participate in the EORTC-trial 10925/22922. This phase-III trial deals with the question of whether irradiation of the internal mammary chain together with the ipsilateral supraclavicular chain leads to a better survival in patients with operable breast cancer. Patients with either medially located primary tumours or with (ipsilateral) axillary lymph node metastases were eligible for participation. Patients were, in our study, considered eligible if they were candidates for participation in the above mentioned EORTC-trial. After they had agreed to participate in the informed consent study, 2 radiological technologists interviewed 51 patients. It appeared that patients were well aware of it) the important characteristics of their disease; ii) the purpose of the treatment; iii) the fact that they were candidates for participation in a phase-III trial; iv) the fact that randomisation had taken place (for the participants). According to the answers of the patients it appeared that the quality of the information, as given by their physician, was good. Further attention needs to be given to the time allocated to the patients to consider their participation in the trial. The quality of the informed consent procedure could be measured adequately. Preferably this type of analysis should be performed at the start of a (large) trial. By doing so, the quality of the informed consent procedure can be evaluated and eventually the quality of the procedure can be improved.