Three-dimensional photon radiotherapy planning for laryngeal and hypopharyngeal cancers. 2. Conformation treatment planning using a multileaf collimator.

Three-dimension dose distributions have been computed for 15 MV X-ray radiation therapy (MEVATRON 77, Siemens) of laryngeal and hypopharyngeal cancers using isocentric rotational technique with multileaf collimator. Using a new concave contour tracing algorithm, satisfactory dose delivery to the target volume and efficient protection of the normal tissues can be achieved.

Methods of image reconstruction from projections applied to conformation radiotherapy.

The problem of optimizing the dose distribution for conformation radiotherapy with intensity modulated external beams is similar to the problem of reconstructing a 3D image from its 2D projections. In this paper we analyse the relationship between these problems. We show that the main image reconstruction methods, namely filtered backprojection and iterative reconstruction, can be directly applied to conformation therapy. We examine the features of each of these methods with regard to this new application and we present first theoretical results.

[Three-dimensional radiation planning. Studies on clinical integration]. / Dreidimensionale Bestrahlungsplanung. Untersuchungen zur klinischen Integration.

The routine use of three-dimensional treatment planning was evaluated in a clinical project funded by the German Krebshilfe at the Radiological Department of the University of Heidelberg. 166 patients entered the prospective study within 14 months, 155 of them were treated according to the 3D-plans. More than 50% of the patients had thoracic tumors, followed by pelvic tumors. One medicine physicist and one specially trained technician performed the treatment planning. The target volumes were contoured in the CT slices at the planning computer by the responsible radiotherapists. A mean of 6.5 hours per patient was necessary for all planning procedures, however, this time consumption shows a trend toward less time of only four hours including about ten optimization steps. Meanwhile approximately 20 to 30% of all computer assisted planning are performed in 3D, corresponding to about one plan per day. The achieved time consumption is a clinically accepted quantity, that allows the introduction of 3D-planning into clinical routine.

Clinical experiences with direct magnification mammography with the DIMA Plus M11. / Klinische Erfahrungen mit der direkten Vergrösserungsmammographie mit dem Gerät DIMA Plus M11.

OBJECTIVE: The evaluation of mammographies carried out by conventional technique (standard imaging and focal imaging with 1.9x magnification) should be compared with a direct magnification image (standard imaging with 1.7x magnification, focal imaging with 4x magnification and preparation imaging with 7x magnification) provided by the mammographic device DIMA Plus M11 of the company feinfocus Medizintechnik. MATERIAL AND METHODS: Out of over 1,000 mammographies (DIMA technique) 50 histologically proved cases were selected for evaluation. Within a three months period these cases underwent conventional standard mammography as well as 1.9x magnification and DIMA-mammographies. The second X-ray was carried out when it was necessary for a pre-operative marking. RESULTS: When mammographies of mammaries, which were radiologically transparent and easily compressible, where taken by DIMA-technique, they showed a distinct advantage, especially in unclear micro-calcification cases, in comparison to the mammographies carried out by the conventional standard imaging. CONCLUSIONS: Direct magnification images carried out by DIMA Plus M11 provide a better breast cancer diagnostic. This refers in particular to focal images with 4x magnification and to digital mammography, which is yet being developed.