| 1. |
- Kjellén, Elisabeth, et al.
(författare)
-
A Phase I/II Evaluation of Metoclopramide as a Radiosensitiser in Patients with Inoperable Squamous Cell Carcinoma of the Lung
- 1995
-
Ingår i: European Journal of Cancer. - : Elsevier BV. - 1879-0852 .- 0959-8049. ; 31:13-14, s. 2196-2202
-
Tidskriftsartikel (refereegranskat)abstract
- The feasibility of administering metoclopramide (MCA) as a radiosensitizer has been evaluated in 23 patients with a pathological or cytological diagnosis of a squamous cell carcinoma of the lung, clinically evaluated as inoperable. All patients received 40-60 Gy radiotherapy fractionated into 1.8 Gy fractions 5 times per week (Monday-Friday). Two MCA treatment regimens were used: (i) MCA at 2 mg/kg administered by intravenous infusion 1-2 h prior to radiotherapy 3 times per week (Monday, Wednesday, Friday); and (ii) MCA at 1 mg/kg administered by intravenous infusion 1-2 h prior to radiotherapy 5 times per week (Monday-Friday). 11 of the 23 patients treated with radiotherapy and MCA had none to mild pneumonitis or fibrosis and another 8 of the 23 had moderate levels. No patient had their therapy interrupted due to radiation-related side-effects. The MCA-related side-effects were as expected, i.e. 78% of the patients experienced sedation/tiredness and 48% expressed restlessness/anxiety symptoms. Both the total dose and serum levels of MCA were significantly associated to the MCA side-effect profile. Tumour response, duration of tumour response and survival were significantly positively correlated to the total and weekly doses of MCA administered to the patients during their radiotherapy treatment. These favourable phase II data have justified the initiation of a phase II/III randomised multicentred trial being carried out in Europe to evaluate MCA as a radiosensitiser.
|
|
| 2. |
- Hurkmans, Coen, et al.
(författare)
-
Limitations of a pencil beam approach to photon dose calculations in the head and neck region
- 1995
-
Ingår i: Radiotherapy and Oncology. - 1879-0887. ; 37:1, s. 74-80
-
Tidskriftsartikel (refereegranskat)abstract
- The inherent limitations of a specific pencil beam model have been studied when applied to a cylindrical geometry simulating the neck region. A comparison is made between measured and calculated absorbed dose in a cylindrical phantom. The goal is to quantify the deviations in the absorbed dose level, i.e., the dose per monitor unit, when photons are used for the treatment of head and neck tumours. Square fields ranging from 5 x 5 up to 30 x 30 cm2 are studied for photon beam energies of 60Co, 4, 6 and 18 MV. Ionisation chamber measurements have been performed in the cylinder as well as in two other configurations in order to trace the origin of possible deviations. For 18 MV no significant deviations are found between measurement and calculation in the cylindrical configuration. For the lower energies, an overestimation of the calculated dose in the cylindrical configuration up to about 6% for a 20 x 20-cm2 60Co field has been found. These deviations have been traced to the basic approximation for the integration volume for phantom scatter calculations inherent in this pencil beam implementation.
|
|
| 3. |
- Knöös, Tommy, et al.
(författare)
-
Limitations of a pencil beam approach to photon dose calculations in lung tissue
- 1995
-
Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 40:9, s. 1411-1420
-
Tidskriftsartikel (refereegranskat)abstract
- A common limitation in treatment planning systems for photon dose calculation is to ignore the impact on electron transport and photon scatter from patient heterogeneities. The heterogeneity correlation is often based on scaling operations along beam rays as for the method according to Batho or the more novel approach of 1D convolutions along beam paths applied in pencil-beam-based systems. The effects of the limitation have been studied in a mediastinum geometry for a wide range of beam qualities by comparing the results from a pencil-beam-based treatment planning system with the results from Monte Carlo calculations. As expected, the deviations within unit-density volumes are small while deviations in low-density volumes increase with increasing beam energy from approximately 3% for 4 MV to 14% for 18 MV x-rays as a result of increased electron disequilibrium.
|
|
| 4. |
- Weber, Lars, et al.
(författare)
-
Verification of a dynamic wedge implementation in a pencil beam based dose planning system
- 1995
-
Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 1879-0887 .- 0167-8140. ; 37:Suppl. 1, s. 26-26
-
Tidskriftsartikel (refereegranskat)abstract
- The use of dynamic movements on linear accelerators during irradiation have found a revised interest lately due to the integration of computers to control the linear accelerator. An example of this is the generation of fields that resemble ordinary wedge fields. These fields are produced by moving one of the collimator blocks during irradiation, i. e. dynamic wedges.A pencil beam based system with the possibility of modelling dynamically modulated dose distributions from collimator movement specifications has extensively been investigated. Special interest has been focused on depth doses, profiles and output factors which have been generated by dynamic wedge fields. The data from the treatment planning system has been verified with measurements in water on a Varian 4 MV linear accelerator.The results indicate that calculations accurately predicts the outcome from dynamic wedges without any additional measurements than those used for characterisation of static open beams.
|
|
