Regional Tumor Oximetry: 19F NMR Spectroscopy of Hexafluorobenzene

• Published in: International journal of radiation oncology, biology, physics Vol. 41; no. 1; pp. 161 - 171
• Main Authors: Hunjan, Sandeep, Mason, Ralph P, Constantinescu, Anca, Peschke, Peter, Hahn, Eric W, Antich, Peter P
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.04.1998; Elsevier
• Subjects: Animals; Biological and medical sciences; Carbogen; Carbon Dioxide; Fluorine; Fluorine NMR; Fluorocarbons - metabolism; General aspects; Magnetic resonance imaging; Magnetic Resonance Spectroscopy - methods; Male; Medical sciences; Oxygen - metabolism; Oxygen tension; Partial Pressure; Prostatic Neoplasms - metabolism; Rats; Tumor; Tumors; Tumor; Fluorine NMR; Carbogen; Magnetic resonance imaging; Oxygen tension; Oxymetry; Methodology; Rat; Fluorine; Rodentia; NMR spectrometry; Dynamic conditions; Vertebrata; Improvement; Accuracy; Mammalia; Animal; Experimental tumor; Monitoring
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/S0360-3016(98)00020-0

Purpose: An accurate method for monitoring oxygen tension (pO 2) of individual tumors could be valuable for optimizing treatment plans. We have recently shown that 19F nuclear magnetic resonance (NMR) spin-lattice relaxometry of hexafluorobenzene (HFB) provides a highly sensitive indicator of tumor oxygenation. We have now refined the methodology to provide enhanced precision, and applied the method to investigate dynamic changes in tumor oxygenation. Methods and Materials: Dunning prostate adenocarcinoma R3327-AT1 was grown in the form of pedicles on the foreback of male Copenhagen rats. When the tumors reached ≃1 cm diameter, HFB (20 μl) was administered, either centrally or peripherally, by direct intratumoral (IT) injection. Local pO 2 was determined using pulse-burst saturation recovery (PBSR) 19F NMR spectroscopy on the basis of the spin-lattice relaxation rate, R1. Results: Interrogation of the central region of tumors provided typical values in the range pO 2 = 1.4–6.4 mmHg, with a typical stability of ±2 mmHg over a period of 20 min, when rats breathed 33% O 2. Altering the inhaled gas to oxygen or carbogen (95% O 2/5% CO 2) produced no significant change. In contrast, interrogation of tumor periphery indicated baseline pO 2 in the range 7.9–78.9 mmHg. Altering inspired gas produced significant changes ( p < 0.0001) with O 2 or carbogen, although the change was generally greater with carbogen. In each case, pO 2 returned to baseline within 16 min of returning the inhaled gas to baseline. Conclusion: We believe this method provides a valuable new approach with the requisite precision and accuracy to investigate tumor pO 2.