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Kouris P, Moutsatsos A, Pappas EP, Beli I, Pantelakos P, Karaiskos P, Pantelis E. Assessing the dose rate delivery of helical TomoTherapy prostate and head & neck treatments. Biomed Phys Eng Express 2021; 8. [PMID: 34755680 DOI: 10.1088/2057-1976/ac37cb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 11/09/2021] [Indexed: 11/11/2022]
Abstract
The dose rate distributions delivered to 55 prostate and head & neck (H&N) cancer patients treated with a helical TomoTherapy (HT) system were resolved and assessed with regard to pitch and field width defined during treatment planning. Statistical analysis of the studied cases showed that the median treatment delivery time was 4.4 min and 6.3 min for the prostate and H&N cases, respectively. Dose rate volume histogram data for the studied cases showed that the 25% and 12% of the volume of the planning target volumes of the prostate and H&N cases are irradiated with a dose rate of greater or equal to 1 Gy min-1. Quartile dose rate (QDR) data confirmed that in HT, where the target is irradiated in slices, most of the dose is delivered to each voxel of the target when it travels within the beam. Analysis of the planning data from all cases showed that this lasts for 68 s (median value). QDRs results showed that using the 2.5 cm field width, 75% of the prescribed dose is delivered to target voxels with a median dose rate of at least 3.2 Gy min-1and 4.5 Gy min-1, for the prostate and H&N cases, respectively. Systematically higher dose rates were observed for the H&N cases due to the shallower depths of the lesions in this anatomical site. Delivered dose rates were also found to increase with field width and pitch setting, due to the higher output of the system which, in general, results in accordingly decreased total treatment time. The biological effect of the dose rate findings of this work needs to be further investigated using in-vitro studies and clinical treatment data.
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Affiliation(s)
- P Kouris
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 11527 Athens, Greece
| | - A Moutsatsos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 11527 Athens, Greece.,Radiotherapy and Radiosurgery Department, Latropolis Clinic, 54-56 Ethnikis Antistaseos, 15231 Athens, Greece
| | - E P Pappas
- Radiotherapy and Radiosurgery Department, Latropolis Clinic, 54-56 Ethnikis Antistaseos, 15231 Athens, Greece
| | - I Beli
- Radiotherapy and Radiosurgery Department, Latropolis Clinic, 54-56 Ethnikis Antistaseos, 15231 Athens, Greece
| | - P Pantelakos
- Radiotherapy and Radiosurgery Department, Latropolis Clinic, 54-56 Ethnikis Antistaseos, 15231 Athens, Greece
| | - P Karaiskos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 11527 Athens, Greece
| | - E Pantelis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, 75 Mikras Asias, 11527 Athens, Greece.,Radiotherapy and Radiosurgery Department, Latropolis Clinic, 54-56 Ethnikis Antistaseos, 15231 Athens, Greece
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Abstract
The histopathology of two patients with radiation-induced neoplasms of the brain following therapeutic irradiation for intracranial malignancies is described. The second neoplasms were an atypical meningioma and a polymorphous cell sarcoma, respectively. They occurred 12 and 23 years after irradiation (4000 rad), within the original field of irradiation. In both cases, the radiation-induced tumors were histologically distinct from the initial medulloblastomas. Both patients were retreated with local irradiation using permanent implantation of radioactive iodine-125 seeds.
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Becciolini A, Cremonini D, Fabbrica D, Balzi M. Qualitative and quantitative effects on the morphology of the small intestine after multiple daily fractionation. ACTA RADIOLOGICA. ONCOLOGY 1984; 23:353-9. [PMID: 6095607 DOI: 10.3109/02841868409136033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The behaviour of qualitative and quantitative morphologic parameters in rats exposed on the abdomen only to multiple daily fractionation (MDF) of 3 Gy X 2 and 3 Gy X 2 X 2 with 12 h splits was analyzed. Both doses were sublethal. The number of epithelial cells in the crypts and in the whole formation, the mitotic index, and the labelling index appeared to be markedly reduced at early intervals after irradiation. Repair and recovery quickly led to normal morphology. The effects of an 8 Gy single dose were compared with those from multiple fractionations.
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Turesson I, Notter G. The response of pig skin to single and fractionated high dose-rate and continuous low dose-rate 137Cs-irradiation-III. Re-evaluation of the CRE system and the TDF system according to the present findings. Int J Radiat Oncol Biol Phys 1979; 5:1773-9. [PMID: 528240 DOI: 10.1016/0360-3016(79)90560-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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